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Fuel Pump Replacement


DelCoch
10-17-2006, 09:08 AM
Fuel Pump Replacement

First of all, I would hook up a jumper wire to the fuel pump test wire and double check the fuel pump pressure. (see below for location of test wire) Also, make sure your battery is fully charged. A weak battery will not power the fuel pump 100% and will cause a no start. If you have over 61 psi when using a jumper on the test wire then you pump may be ok?? If so check your wiring as described in this thread (http://www.automotiveforums.com/vbulletin/showthread.php?t=588381&highlight=Fuel+Pump).

Also check this Thread about low voltage (http://www.automotiveforums.com/vbulletin/showthread.php?t=568768&highlight=Fuel+Pump)

Second, the consensus on this board is to use a Bosch or AC Delco replacement pump.

Iíve included a couple photos from when I replaced my pump, but mine is a í95 4x4, which has a different type pump, but the gas tank, etc. should be the same. Probably take about 4-hours to replace the pump the first time you do it.

On a 4x4 - Remove the spare tire Ė Remove the skid plate under the gas tank if so equipped. Remove the left rear wheel and make sure you have good support, (jack stands on a solid surface) under the vehicle so it wonít fall on ya. Remove the neg battery cable.

The fuel line nuts that connect to the sending unit and fuel pump at the gas tank freeze up with rust. The line nuts get rusted to the fuel line and when you try to turn the line nut the fuel line will twist. Thus, I suggest getting a good penetrating oil from your auto parts store,- WD-40 wonít do it. Spray the line nuts up real good before trying to disconnect them. If the line starts to twist spray it up real good and let soak for a couple hours, maybe overnight.

Also, spray the 15mm nuts on the front and rear gas tank support straps with penetrating oil. These also get rusted and the ends of the straps have been known to twist off.

There is no drain plug on the gas tank, and the tank will weight well over 100 pounds when full, not fun when lying on your back under your vehicle, even with only a couple of gallons of gas in it. No problem I thought, just stick a small rubber gas hose down the filler neck and pump the gas out, right? Wrong!! Where the filler tube connects to the fuel tank, there is a little plastic ball inside the filler neck, which is only a couple millimeters smaller than the inside of the filler neck. It lets gas go into the tank, but not a small hose. (see photo) The purpose of the little ball is to prevent gas from running out of the tank if the vehicle turns upside down, as the gas will press the ball against a seat and seal off the filler neck. Next I thought I would disconnect the filler tubes and remove them from the vehicle. Wrong again. The filler tubes have a bracket made onto them that is bolted to the frame where they cross over the rear axle, and there is not enough room between the body and the bolt to get a wrench on the bolt.

So, before you drop the tank, try to get all the gas out of it. This can be done two ways:

1) If your fuel pump still works half way; Thereís a fuel pump test wire under the hood on the driverís side next to the fender, under the hood hinge. Itís a red wire that has a gray or black plastic cover on the end of it and it just hangs there next to the electrical junction box, not hooked to anything. Put a live 12 volt jumper wire to it and the fuel pump will run if it's not toast. If the pump runs then disconnect the fuel line at the fuel filter, (which is located on the inside of the frame under the driverís door) put a hose onto the gas line coming from the tank and into a container. Then connect the battery cable, run the fuel pump to empty the tank and then disconnect the battery cable again. Or, you can connect an auxiliary gas pump to the gas line and pump the gas out of the tank.

2) Or, loosen the nut on the rear gas tank strap to lower the rear of the tank just enough to disengage the rubber hose on the filler neck at the rear of the gas tank, then put a small hose into the tank and either use an auxiliary gas pump to pump the gas out of the tank or you can use a siphon. (Whatever you use, it must be designed to pump gas Ė otherwise you might have a big, big fire) Fire is a great danger when removing a gas tank. Iíve seen repair shops burn down when gas is spilled and a shop light falls into it.

After the gas is out of the tank, if not already lowered, lower the rear of the tank 2-3 inches. On the top rear of the tank towards the left rear wheel, disconnect the rubber hose from the plastic fuel vapor relief valve Ė see photo for location. Also disconnect the wire connector that goes to the fuel pump. Use a set of flare nut wrenches and a secondary wrench on the fuel lines to loosen them at the fuel pump.

Loosen, but do not completely remove the front gas tank strap, just drop the front of the tank down 2-3 inches and reach around the front of the tank under or through the plastic shield on the front of the tank and remove the hose from another plastic vapor purge valve located on the front left of the tank.- (see photo for location) Usually this plastic connection on the front valve, from people not knowing its there, gets broken off when the tank is lowered. A new one at the dealer is 20 bucks.

The plastic shield on the front of the tank won't come off until the tank is out of the vehicle.

When you are ready to drop the tank, use a floor jack to support it and remove the straps.

Once you get it removed be sure to clean all the dirt and gravel from around the sending unit and locking ring, as you donít want this dirt to fall in the tank when you remove the pump.

Unless the pump has been replaced before, you will probably find the flange and locking ring on top of the sending unit having a thick coating of some kind of epoxy on it. I had to take a hammer and screw driver to chip all this crap away and then still had a hard time getting the lock ring to turn. After you knock down the 3 tabs, it turns clock wise Ė See photos. Use a brass punch to prevent sparks when hammering on these rings. After replacing the pump I sealed mine back up again with epoxy glue to keep water out of the tank.

Remove the retaining ring/locking ring from around the sending unit pipes and wire harness. Once free, the sending unit/fuel pump simply comes up and out of the tank. As you withdraw it from the tank it may require a 180 degree twist to get the pump out of the tank. Make note of how the pump sets in the tank and which way the float is pointing before you remove the pump. The new one needs to go back in the same way, with the float facing the same direction.

Make sure the new o-ring gasket that comes with the new pump is the right size, same size as the old one Ė if not, pick up one at the dealer. They are about 10 bucks. Lubricate the new gasket with oil when installing it.

Follow the directions that come with your new pump and install in reverse order of above. Use the floor jack to hold the tank up while connecting everything. Donít forget to connect the front hose on the purge valve. While under there replace the fuel filter also.

Once everything is connected and the tank re-installed, put at least 8-10 gallon of gas in it and reconnect the battery cable. You will have a lot of air in the fuel line, so I would again put a jumper on the fuel pump test wire and check the fuel pump pressure again. Once you get over 61 psi remove the jumper wire and it should start up.

Someone else please jump in here with what I missed,

Good Luck

http://img.villagephotos.com/p/2006-5/1178639/Image1m.jpg
http://img.villagephotos.com/p/2006-5/1178639/Image2m.jpg
http://img.villagephotos.com/p/2006-5/1178639/Image3m.jpg
http://img.villagephotos.com/p/2006-5/1178639/Image4m.jpg

rockethobbit
12-02-2006, 09:48 PM
Will these procedures work on a 96' S-10 V6 2WD ExtCab?

Does anyone have any other links to how to remove the tank? This seams to be the hardest part for me. Trying to disconnect the cables and hoses at the top of the tank while it's still mounted appears to be impossible when I look at it.

I heard of a guy who just cut a hole in the bed to get to it and that seemed temping rather than hassle with the tank removal, but if I can find clear instructions on how to get it out I would prefer to remove it.

Thanks.

randy78
12-04-2006, 07:46 PM
61 psi ?

who told you that ?

lol

randy78
12-04-2006, 07:51 PM
Will these procedures work on a 96' S-10 V6 2WD ExtCab?

Does anyone have any other links to how to remove the tank? This seams to be the hardest part for me. Trying to disconnect the cables and hoses at the top of the tank while it's still mounted appears to be impossible when I look at it.

I heard of a guy who just cut a hole in the bed to get to it and that seemed temping rather than hassle with the tank removal, but if I can find clear instructions on how to get it out I would prefer to remove it.

Thanks.


to drop the tank on a pickup you just remove the front tank hanger blt in the frame and then the rear strap bolt and lower it down enough to get all the hoses off, its a kind of tight clearance but you can do it

jackstand the tank side of the truck up soe to get extra tank to ground clearance, it will help out a bit

good luck

blazee
12-04-2006, 09:46 PM
61 psi ?

who told you that ?

lol

That is GM spec, and fairly accurate. Any less than 61psi causes hard starting. Less than 55psi and it won't start without starting fluid. Less than 43psi and the engine won't run at all.

oirole
07-03-2007, 07:12 PM
im trying to drop the tank on a 99 jimmy. the fuel pump is sitting here and ready to go in.

has anyone out there ran into stripped bolts on the fuel tank straps? i have, and im wondering if i should get the SAW-ZAW out to cut them off. then i would have to grind off the heads of the STRIPPED bolts, and get the cores out. then finally replace the straps and bolts when im done.

this turns this 1/2 day project into a full day project.

any suggestions would be appriciated?

Blutarski
10-23-2007, 06:42 PM
im trying to drop the tank on a 99 jimmy. the fuel pump is sitting here and ready to go in.

has anyone out there ran into stripped bolts on the fuel tank straps? i have, and im wondering if i should get the SAW-ZAW out to cut them off. then i would have to grind off the heads of the STRIPPED bolts, and get the cores out. then finally replace the straps and bolts when im done.

this turns this 1/2 day project into a full day project.

any suggestions would be appriciated?

Any help on this? The rear strap bolt that attaches to the frame rail, with the threads hidden inside the frame, simply spins - I'd cut it, but the whole spark shower in the presence of gas vapor.... hmmmm

Blutarski
10-27-2007, 11:00 AM
Figured it out, just cut the bolt - use a regular hacksaw if needed, shouldn't be an issue. When you buy your pump, just buy the short end of the front strap, plus the replacement bolt and clip to go with it(if salt and rust are an issue in your area), it will all make sense. Also get a new lock ring for the pump, as that will probably be a rust pile as well.
Good luck.

peterjon1
11-09-2007, 10:49 PM
Just a FYI--dealer wants $300 for that filler neck. I got my replacement (when mine rusted out) from a jy for $20. Parts guy sez "No wonder we don't stock those!"

JasonSpaeth
12-19-2007, 12:14 PM
I do not understand. I thought the grey test lead wire was on the driver's side near the brake master cylinder. You are stating that it is behind the fuel pump relay which is in the glove box. I do not see access to get behind the relay to get to any wire. And, on the engine bay side access is blocked by the heater fan motor.

What I did do - and I am not sure if this tells us anything - is I hooked my voltage tester to the positive terminal of the battery and onto the grey wire at the fuel pump/tank. With the key on, it registered 11.68 volts.

Does this tell you anything? What do you suggest I try next? Sorry if I am not following you on the grey wire thing - I am just confused. Thanks.

dtb2253
02-11-2008, 02:10 PM
It appears the fuel pump is out on my sons 2000 S-10. Great information here, but i have 2 more questions:

1. His is a 4WD 6 cyl. Where would the fuel pump test wire be located on my vehicle?

2. Looks like it might be easier to raise the cargo box rather than drop the tank. Did this on a 1988 S-10 and it worked very well. Any input regarding this approach?

Currently charging the battery (was low ~10V) and waiting for it to warm up here - its 8 degree F. Any other input would also be welcome.

Thanks all.

old_master
02-11-2008, 08:52 PM
The fuel pump prime connection on a 2000 is right next to the fuel pump relay in the underhood fuse panel. There is a single, recessed, unused, terminal in the fuse panel. When you apply battery voltage to it, the fuel pump should run continously.

Two ways to service the pump: pull the box or drop the tank, either way works well.

Key ON, Engine off, pump running, pressure must be 60 to 66psi. After the pump shuts off, pressure must remain above 55psi. Post your results.

djjm3
02-21-2008, 03:48 PM
Also.... Black & Decker Has a JackRabbit Pump Part #134000-03, cost is $37.00...(call 800.544.6986 and they can find a service dealer close to ship to you) Clamp the tube to the front end of the fuel Filter and you can pump the gas Safely .....

01-Cavy-01
02-27-2008, 07:01 PM
how would i go about testing and figuring out how much psi the pump is running at, i have to change the pump since the old one gave out on me but i was thinking this would be a simple drop and go replacement..is it needed to test the pressure of the pump after installing the new one or is the pump only tested when trying to diagnose causes for hard starting?

Knight stick
03-03-2008, 11:15 PM
I have a 2000 S10 4.3 Vortec 4WD 57,000 miles. My fiancee informed me one day that the last time she started the truck, the check engine light came on. When I checked the truck, the engine would turn over but it would only run a few seconds with starting fluid. The truck was not being driven since I needed to replace U joints & replace the tires. I could not locate the fuel relay switch. I priced fuel pumps in my area. They are a special order & will cost $343.00 to $369.00 depending on the parts store. I could hardly believe the price!!!! I have thought about cutting a hole in the bed to allow access to the fuel tank & sealing it back after I had installed the fuel pump. Has anyone attempted this....successfully??? I welcome any information.

Sdedeker
08-01-2008, 05:05 PM
Just replaced the fuel pump on my 2000 Old Bravada and wanted to just give a brief rundown on my experience. First of all THANKS Delcoch for the write up. It helped me out a lot. I did find a few differences in my application. First of all I did not have flare nuts on the fuel lines that were attached to the fuel pump. I had some quick disconnect plastic connectors. All I had to do was take a pair of pliers and press the two tabs on each side and then pull the hose off. It took me about 30 minutes to figure this out because of the tight space and very little visabilty, but once I did they came off in about 30 seconds. I also did not find any epoxy or other type of material sealing the pump. Other than that, my total time was about 3 hours from start to finish. I took the beast out and now it runs like it use to with no hesitation or stumbling.

Schrade
05-25-2009, 01:00 PM
Little help here...?

I got the 2 strap bolts almost all the way off - just enough left to hold the weight if it drops. It will NOT drop tho', enough for me to disconnect the filler neck and vent neck hoses, and finish draining half a tank.

What else is holding the tank, besides the 2 straps?

On the rear strap, I already got loose the OUTBOARD bolts, and the plastic shield removed.

What holds the rear strap in the frame rail???

Anybody?

Schrade
05-25-2009, 01:02 PM
And do you HAVE TO remove the rear wheel to do this?

Schrade
05-25-2009, 06:42 PM
What was holding me up IS the filler tube and the vent tube. The rubber lines are stout pieces, and they are the actually the only thing holding up the tank right now (on the back end - front is on the crossmember).

In fact the 2 hoses are so stiff, they are holding up half a tank of gas. AND, they are NOT frozen onto the necks. I've gotten a screwdriver under the hose tip, hit it with some armor all, work the screwdriver a little, and the hoses are both loose on the necks; just VERY STIFF, and there's almost no wiggle room. Not enough anyway to worry about spillin' the half tank it I could break it free.

So I carefully cut 2 slits in the hose from the top to the bottom clamp (still tight), peeled it back, and cut. It gave me enough of an opening to get in a small siphon hose, and draw about 7-8 gallons.

Now I should be able to cut the vent hose section likewise, and just lower the tank, in the am. The fuel feed and return lines came off ok, but the third hose at the pump head got 'kinked'. Might need replacement too...

Sdedeker
05-26-2009, 12:56 AM
And do you HAVE TO remove the rear wheel to do this?

It makes things a little easier to get to when you have that rear tire off. I even dropped the spare tire and got it out of the way.

Since it has been almost a year now, I don't remember a lot of the fine details. I do know I had to fight the filler hose and it took a lot of muscle to get it off. But with a little work it did come off and I didn't make any cuts into anything. I do believe that I had to replace the hose clamp as it was in pretty bad shape. Also, make sure that you detach the front vent hose and not just yank it out. What I did was place a motorcycle jack under the gas tank, that way I had full control over how fast it came down. I had very little gas left in mine but it was still fairly heavy and I would have hated to try and manhandle it by myself. My biggest issues were getting the hose clips off of the pump. I was expecting flare nuts but mine had some quick disconnects that if I did not have the rear tire off, it would have been almost next to impossible to get off due to space issues getting my arms up in there. It probably took me 2 hours to get it out and 1 hour to get it back in.

Schrade
05-26-2009, 08:49 AM
It makes things a little easier to get to when you have that rear tire off. I even dropped the spare tire and got it out of the way.

Since it has been almost a year now, I don't remember a lot of the fine details. I do know I had to fight the filler hose and it took a lot of muscle to get it off. But with a little work it did come off and I didn't make any cuts into anything. I do believe that I had to replace the hose clamp as it was in pretty bad shape. Also, make sure that you detach the front vent hose and not just yank it out. What I did was place a motorcycle jack under the gas tank, that way I had full control over how fast it came down. I had very little gas left in mine but it was still fairly heavy and I would have hated to try and manhandle it by myself. My biggest issues were getting the hose clips off of the pump. I was expecting flare nuts but mine had some quick disconnects that if I did not have the rear tire off, it would have been almost next to impossible to get off due to space issues getting my arms up in there. It probably took me 2 hours to get it out and 1 hour to get it back in.

I already had the rear on ramps when I saw 'Pull the wheel'. AND, I disconnected the 3 pump lines not at the pumphead, but at the joint by the framerail.

I work slowly, and take pics as I go (WISH YOU COULD POST PICS HERE!!!)(I GOT MY WATER PUMP PICS TOO) I photo doc all Jimmy and vette work for if I re-sell.

I had no choice but to cut the filler hose. Did NOT want to, but I couldn't force it off, with a half tank ready to pour out.

Front vent hose? Do you see it here (http://www.gm-trucks.com/forums/index.php?autocom=ibwiki&cmd=article&id=403)

FantasticChadwick
05-26-2009, 11:16 PM
Just replaced the fuel pump on my 2000 Old Bravada and wanted to just give a brief rundown on my experience. First of all THANKS Delcoch for the write up. It helped me out a lot. I did find a few differences in my application. First of all I did not have flare nuts on the fuel lines that were attached to the fuel pump. I had some quick disconnect plastic connectors. All I had to do was take a pair of pliers and press the two tabs on each side and then pull the hose off. It took me about 30 minutes to figure this out because of the tight space and very little visabilty, but once I did they came off in about 30 seconds. I also did not find any epoxy or other type of material sealing the pump. Other than that, my total time was about 3 hours from start to finish. I took the beast out and now it runs like it use to with no hesitation or stumbling.


My story almost exactly on my 2000 Bravada.

Difference is I read this post first so I skipped the half hour or trying to figure out how the fuel lines disconnect.

All in all a very easy project. I jacked up the left side of the vehicle and placed it on jack stands. I removed the left rear tire and the spare tire. The few minutes to do these things is well worth the gains in accessibility to everything.

The most difficult part of the project for me was separating the large fill hose from the tank. You just can't seem to get a good angle for pulling on it. I let the weight of the partially full tank, mixed with twisting the large hose, do the work to separate them. I drained the last 5 gallons from my tank after I removed it.

I'm pretty convinced the vehicle is running much better than it has run in a long time. It COULD be my imagination, but I think the engine was a lot smoother and more responsive after the procedure. Sadly, I have passed my beloved Bravada on to my wife, as her daily commuter now, so I don't have as much wheel time on it, but I have been a little un-impressed with its performance of late. Driving it with the new pump restored my delight and satisfaction with this vehicle.

While I already had one of the wheels off I took the opportunity to replace the rear brake pads at the same time (I replaced pads on both sides). Total time, fuel pump and pads, was about 3.5 - 4 hours and that was with a ton of distractions.

FantasticChadwick
05-27-2009, 03:24 PM
Oh yeah, one thing I did that I think is worth mentioning is I used compressed air to blow all the dirt and debris out from around the old pump before unsealing its lockring. There was lots of dirt caked around it and I didn't want it all falling into the tank when I removed the old pump, so I blasted it away with compressed air.

I completely removed the tank and stuffed rags in the filler holes before blowing the dirt away. Then I un-twisted the lock ring and blew more dirt away before unseating the old pump.

hans109h
01-30-2011, 05:50 PM
After 4 hours today I got my tank out and am ready to reinstall, but when removing the front tank strap nut I tore the bolt off with it as it was seized up on myy 1998 chevy blazer. I'm thinking that the bolt part that attaches with 2 rivets directly to the frame is a dealer only part?

Can anyone verify this and provide the part number if you got one?

Thanks,

Hans

Blutarski
01-31-2011, 06:44 AM
After 4 hours today I got my tank out and am ready to reinstall, but when removing the front tank strap nut I tore the bolt off with it as it was seized up on myy 1998 chevy blazer. I'm thinking that the bolt part that attaches with 2 rivets directly to the frame is a dealer only part?

Can anyone verify this and provide the part number if you got one?

Thanks,

Hans

As I recall that part comes with the strap. I had to cut the bolt off of mine and was dreading the final result until I saw it was easily replaced. (again, as I recall) I bought mine at a dealer out of convenience, but it wasn't a major expense.

XWrench3
12-26-2011, 06:38 PM
i have a question, has anyone ever tried using an external pump on one of these? if the fuel will flow through the existing pump, i would think it would be a LOT less trouble to mount an external pump than try to go through all this trouble.
I have already spent most of a day, and i have gotten just about nowhere trying to do this. i know that being old with arthritis does not help. but in many places, only a 1:500th scale man could ever even get into to some of these places to remove bolts, nuts, or clamps. /// :sarcasmsign:i do however know of a very easy way to do this job. it involves an abandoned gravel pit, and 300 pounds of TNT! oh, and you will need $30,00.00 to purchase a new vehicle afterwards. but the results would be very gratifying!:naughty::biggrin::lol2:

old_master
12-26-2011, 06:52 PM
Some of the older fuel injected Ford vehicles use an external pump :) ....along with a low pressure, high volume pump inside the tank :( The problem with installing an external pump, without an internal "lift" pump, is that it can't "lift" the fuel from the tank and still build sufficient pressure at the injectors. The cost and effort involved to "cobble it" far exceeds the cost and effort to fix it right ;)

XWrench3
12-29-2011, 01:56 PM
i have 2 questions about this. looking for a replacement pump module assembly, i found one at advance auto parts, an ac delco pump (p/n MU1755), for $371.99. it says it fits 2 door models (which mine is) EXCEPT those with a Robust fuel sender (k53). how do i know if i have this? my suv is a stick shift model, so with my luck, it is probably something weird. /// 2nd question is, while checking to see if there was actually poer getting back to the pump, one of the terminals lit the power tester, but it was quite dim, like it was maybe 6 volts. but when i checked it, it registered 12v. this doesn't seem right to me. any idea's? the manual i have is a Haynes. it leaves a LOT to be desired. but it is better than nothing.

old_master
12-29-2011, 03:37 PM
....i found a [pump] at advance auto parts, an ac delco pump (p/n MU1755), for $371.99. it says it fits 2 door models (which mine is) EXCEPT those with a Robust fuel sender (k53). how do i know if i have this?

Check the RPO codes in the glove box for K53, (very rare option).


....getting back to the pump, one of the terminals lit the power tester, but it was quite dim, like it was maybe 6 volts. but when i checked it, it registered 12v. this doesn't seem right to me. any idea's?....


Year, make & model is necessary to answer this.


....the manual i have is a Haynes. it leaves a LOT to be desired...

You ain't kiddin' there, that's the problem with them. Half of the information is missing, the other half is flat out wrong, and you can't trust ANY of the specs they publish. Total waste of paper.

.....but it is better than nothing.

Nope. In this case, "nothing" would be better.

XWrench3
12-29-2011, 05:22 PM
Year, make & model is necessary to answer this.
2000 GMC Jimmy sls conveinience pkg, 4 wd, 5 speed manual, 2 door

XWrench3
12-29-2011, 05:24 PM
Check the RPO codes in the glove box for K53, (very rare option).

where in the glove box? i do not see anything?! its a 2000 jimmy 2 door 4wd

old_master
12-29-2011, 08:40 PM
Might be in a door jamb, maybe even the rear hatch. White sticker about 2.5" by 4.5" with the VIN and a bunch of 3 character codes. Look for "K53", if it's not there, you don't have the "robust fuel" option.

XWrench3
01-01-2012, 06:52 AM
thanks old master! i found it. i have 2 "k" codes, k34 and k65 or k66, somehow it got scratched and i am not sure which it is. but at least it is not the one for the robust fuel system. not, to get a pump. would you recommend anything else to replace while i am at it?

MT-2500
01-01-2012, 01:09 PM
where in the glove box? i do not see anything?! its a 2000 jimmy 2 door 4wd

Replace with a 2 door pump.
Always replace with a AC Delco/Delphi fuel pump.
Replace filter and fuel fump fuse and some pumps require a wiring plugin replacement.
And check bottom of tank for dirt/rust/water.
If any clean tank out.
Check with parts place when you get your fuel pump on/for wiring change over..
Good luck and let use know how it goes.

old_master
01-01-2012, 01:17 PM
Here's an AC Delco module on Amazon for half the price and free shipping:

http://www.amazon.com/ACDelco-MU1755-Fuel-Tank-Module/dp/B001S30IGY/ref=sr_1_1?ie=UTF8&qid=1325445074&sr=8-1

It will come with the new style electrical connector and it must be soldered on using rosin core solder, then insulate it with heat shrink tubing. DO NOT use the crimp style connectors that come in the package.

XWrench3
01-01-2012, 03:45 PM
is there a difference between an ac delco and delphi? ac delco used to be the oem supplier for GM, but i know of Delphi because an uncle used to work for GM, and they changed the name to Delphi. i don't know much about what the differences were. is Delphi the oem supplier now? is there an appreciable difference between the two?
also, this is a two door model, and i noticed there is a different p/n, so i have to assume there is a difference in the assembly someplace. and i have no intentions of trying to find out what. i am figuring that the price difference is because they sell a lot more 4 door versions than 2 door. this has been a lot of trouble getting the tank out, and i do not want to have to do it again. one other question that popped up is if just the pump is available separately, as opposed to the entire unit. i would think if just the pump is available, it would be substantially less expensive. $500.00 used to buy a half way decent driver car, now it will hardly buy a pump. i am pretty sure someone is making a lot of money from parts that are no where near this expensive to build.

old_master
01-01-2012, 05:41 PM
I'm pretty sure AC Delco and Delphi modules are made by the same manufacturer. If I'm wrong, someone will correct me ;)

Due to the shorter wheel base, 2 door fuel tanks are mounted in the center of the vehicle, behind the rear axle. The 4 door tanks are mounted to the inside of the frame rail, just in front of the rear axle. Different tank configuration requires different pump module. The MU1755 is the correct module for your 2000 2 door. Gotta be careful with online parts, some places are very clever & deceiving in their ads and make you THINK you're getting an AC Delco at a cheap price. When in fact you're getting some inferior piece of junk module from overseas ;)

The pump can be serviced separately from the module however, the fuel level sender and the fuel tank pressure switch, are both common failure parts as well, and they're included with the module. As long as you've got the tank down and the module out, do it once and forget about it. $175 for all that "piece of mind" is cheap.

XWrench3
01-06-2012, 08:23 AM
well, to save money i bought a fuel pump kit, instead of an entire module. i had to do it, or not be able to do the repair for a couple of months. so everything is going along alright, until i try to put the pressure hose onto the top of the module. no mater what i do, i can not get it fully seated. i tried immersing the hose in boiling water, after of course putting petroleum jelly on the inside of the pipe and on the barb. i have tried repeatedly streaching the pipe out with a tapered punch with heat. i can get it just over the second barb, but not all the way to the top like the factory one was. my only thought is to try to epoxy the hose on, and prey it doesn't come off after it dries. the only thing i have not tried is immersing the tube in boiling oil, or direct flame to the pipe. i am 99.9% certain that a direct flame wil ruin the pipe. so i am not going to do that. my fear about using hot oil is getting to much heat into the pipe making it brittle. there has to be 20 ways to connect the pump to the module, why do they always have to choose the most difficult?:banghead::banghead::banghead: before i smear a bunch of jb weld all over the inside of this thing, does anyone have any ideas?

XWrench3
01-10-2012, 05:46 PM
WELL, i finished the replacement yesterday, the truck started right up and ran great. no visable leaks, with the 9 gallons i had at home, so i figured i had better go fill it up and make sure there were no leaks. after sitting all night with a full tank, no leaks. so i figured i was all set. WRONG! i got a whopping 26.7 miles, and the truck died. i can hear the pump run, but there is not enough pressure to let the engine run. i am going to have to go spend $50-60.00 tomorrow on a pressure tester, to find out if there is ANY pressure, and if so how much. so now i am going to have to repeat the job, which excites me almost as much as having my head placed in a guillotine! at this point i dont know if it was something i did wrong, or if the pump is defective. but i know i am going to have a pressure reading before i can even try to get a warranty replacement pump, if that is the problem.

old_master
01-10-2012, 08:13 PM
Advance auto parts has a nice one: http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Fuel-Pressure-Tester-Kit-Actron_9030328-P_N3065_A%7CGRP2020A_____

Closest stores to you are Fremont & Rockford.

Harbor Freight has one for around $20, but not near the quality.

XWrench3
01-10-2012, 08:29 PM
i was talking with a neighbor who had several s-10 type vehicles. the last one he had was a 1996 blazer. he said that he put 5 fuel pumps in it, all of them ac delco, after the second replacement, he cut the floor out of the cargo area so it would be a lot easier to replace. i actually thought about doing that this time, on my first replacement pump. if the sheet metal was flat, i WOULD have. but the only way i can think of making a decent patch would be to get a chunk cut out of another vehicle that was larger. i have to admit, unbolting the box on a pickup is easier than dropping a tank. if this is going to be a recurring problem, i am wondering if maybe i should get a piece cut out of another vehicle, and keep a spare pump in the truck!

XWrench3
01-10-2012, 08:36 PM
i was also wondering if someone makes an electric fuel pressure gauge that could be mounted below the dash permanently. maybe connect to the test port? i would not want to try to cut lines to install one. if it was not gasoline, i would just use a mechanical oil pressure gauge. but i have had lines break before, and 60+ psi of gasoline spraying inside of the truck is straight up suicide!

old_master
01-10-2012, 10:06 PM
Five pumps, wow, probably a poor ground or poor connection at the module connector. Both are fairly common, along with a restricted fuel filter. Those are about the only things that will toast a pump prematurely. Provided the pump has a good ground and good connections, the AC Delco pumps are good for 100K miles. As for the fuel pressure monitor in the cab: I've often thought about that. The only safe way to do it is like you mentioned, electronic sender to a gauge in the dash. Some vehicle manufacturers have been using that technology for several years. It allows the PCM to monitor fuel pressure and some scan tools can view it directly. As far as cutting an access hole... there are several members here on AF that have done it... it's your vehicle ;)

XWrench3
01-10-2012, 10:10 PM
what regulates the fuel pressure on one of these? and where is the regulator located. i thought about that. wondering if maybe something happened and it is letting the pressure return to the tank. the pump runs, but the truck just died and will not restart.

old_master
01-10-2012, 10:22 PM
The fuel pump output pressure is between 75psi and 108psi. Pressurized fuel goes through the filter, across the injectors and to the fuel pressure regulator. The regulator and injectors are inside the plenum. The regulator is a very simple design and rarely fails on 96 and newer CSFI systems, (like yours). The regulator has a spring loaded rubber diaphragm, and a valve to allow unused fuel back to the tank when regulating pressure between 60psi & 66psi.

http://i561.photobucket.com/albums/ss58/cwhook/Fuelpressureregulator.jpg

XWrench3
01-11-2012, 12:32 PM
well,i found the trouble. the fuel pipe came off from the top of the housing. i thought i might have trouble with that. because i could not get the pipe on very far. after immersing the pipe in boiling water for a few minutes, i finally got it on over the first barb. but that was as far as it would go. i was hoping that after the pipe hardened up from cooling, it would stay put. but i guess the pressure was just to much. now, i am not sure what to do. i cut the old line off from the top to make sure i did not break the fitting, which would render the housing useless. so i can not put that back on. and i can not force the new hose on all the way, even with heat. i know regular rubber fuel line would blow apart under that much pressure. any ideas???

XWrench3
01-11-2012, 12:35 PM
oh, i forgot to mention, the hose fitting on the fuel pump itself, and on the top of the housing are 2 different sizes. the one on the top of the housing is larger. the fuel pipe that was included in the fuel pump kit has both ends the same size. which is why i heated the pipe up in boiling water, so it would hopefully stretch enought to fit.

old_master
01-11-2012, 01:40 PM
Should be 3 lines on the top of the module all with quick connect fittings. Lube the O ring with engine oil and push them on until they click.

1/4" is fuel vapor going to vapor canister.
5/16" is fuel return from the regulator.
3/8" is pressurized fuel going to the injectors.

Post some pictures that show what line you're having trouble with. The pump kit that you bought... did it come in a box labeled "AC Delco"?

XWrench3
01-11-2012, 08:06 PM
yes, it is a genuine ac delco pump kit. the problem line is the clear hard plastic line that connects the fuel pump to the top of the module INSIDE of the tank. the hose barbs on the top of the module are huge by normal standards, and i can not find a way to get the hard plastic to go over them. out of desperation, knowing that bad nasty weather is coming tonight, i purchased rubber fuel injection hose, and fitted it with clamps where the clear line goes. then put it back together and checked for leaks. it does now start and run, and holds 62psi on the gauge that i bought this morning at advance auto parts (THANKS for telling me about that!) the worry that i have is if the rubber hose will hold up in that environment. if nothing else, i hope it will make it to spring. i really hate laying in wet half melted snow, or 30 mph winds especially working in gasoline!

old_master
01-12-2012, 04:16 PM
Gotta be sure it says "Fuel Injection Rated" on the line. No worries about being exposed to gasoline, it will not deteriorate BUT, what might be a concern is the "accordian" style clear plastic line is designed to bend without kinking when you push the spring loaded module down into the tank. If it's restricted, fuel flow will decrease and the pump will have to work harder which will shorten it's life expectancy.

Holding 62psi is great! What is the key on, engine off, fuel pressure while the pump is running?

XWrench3
01-12-2012, 07:53 PM
yes, the line says right on it "fuel injection", i know regular line will burst around 25 pounds (don't ask me how i know). i did think about the line kinking, and tried it. it looked to me like it may restrict the flow. so, i measured the length between the pump and module hose barb when fully open. then i measured how far the module collapsed as i installed it into the tank, and shortened the hose that much. the result was i could just feel the bottom of the module hit the bottom of the tank with about the thickness of the circlip left. so the hose will have to compress whatever that thickness is. the 62 psi is with the pump hotwired with the engine off, and the battery fully charged and connected to the battery charger(10 amp). when i first start the pump, i can watch the pressure raise rapidly, and i can see the needle hit almost 70 pounds for just a half second or so until the pressure release valve opens. i let the pump run for about an hour like that as i finished up installing the fuel tank crash gaurd, and lowering the vehicle and taking care of tools. i wanted to make sure if there was going to be a problem, it would hopefully show up in the driveway before it left me stranded somewhere. i did not check the pressure while it was running. i know the pump has way more flow than the engine could ever use at max rpm wide open throttle. and since it takes wide open just fine, i can not imagine there is a problem there. now, i did not replace the filter, it was replaced this spring, and it probably has less than 3000 miles on it. the inside of the tank was cleaner than our kitchen floor usually is. so i really do not see a need to. i did notice one thing that i am not so sure about. i noticed that the pressure bleeds off from the rail. it is pretty slow, and it took probably an hour to get down to around 35 psi. since the pump runs for a few seconds prior to starting the engine, (i always wait till the pump is done running before starting the engine) i would think this is ok. please tell me if it is not!

old_master
01-12-2012, 09:21 PM
Sounds like you did your homework on the line in the tank, should be good. GM does not publish any "engine running" fuel pressure specs for this engine, there are far too many variables involved.

Testing fuel pressure and leakdown: Ignition in the RUN position, engine OFF, (or hot wire the fuel pump). While the fuel pump is running, the fuel pressure must be 60psi to 66psi. After the pump shuts off, fuel pressure must remain above 55psi for at least 10 minutes. This checks a ton of stuff and if it meets those requirements, regulated fuel pressure to the injectors is good. There is also a volume test for the pump; it's rare that you'd ever perform the test though, usually the pump just takes a crap.

Allowing the pump to shut off before cranking is actually a good idea, (cuts down on starter wear). Tough to get into the habit, but if you're there, cool.

XWrench3
01-19-2012, 03:02 PM
just something i picked up on with our first fuel injected vehicle. i figured if they wanted the pump to run before you started the engine, they had a good reason for doing so. and it only takes a few seconds, so why not start the engine after the system is primed and ready to go. in severe weather, it may mean the difference between the engine starting or not. especially if the battery has had a drain on it, or is weak. and who knows when that is going to happen, until you hit the key. my battery is less than 2 years old, so there should not be an issue with it.

old_master
01-19-2012, 03:28 PM
It's a good habit to get in to.... turn the ignition switch to the RUN position, wait for the fuel pump to stop running, then turn the ignition switch to the START position. This allows the fuel pump to receive full battery voltage to prime the system.

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