Changed Fuel pump

I'm kind of new to this so please forgive me. I just had my fuel pump changed in my 97 blazer LT. It was driving fine for about 2 hours then it started acting like it was starving for gas. A code did come up about the O2 sensor but i didn't change it yet. Now since I parked it won't start just sounds like it wants to. Oh! before I turned it off I put it in park and gave it some gas and it hesitated quite a bit. Need help guys.. puzzled . Could a bad o2 sensor do be the problem?

Turn the key to the on position and listen for the pump. You should hear a buzzing sound in the left rear of the vehicle.

Also change your fuel filter. I dont know how an 02 sensor could stop it from starting or running.

Thanks I have been doing some reading on various threads and I think it may be the ignition switch as well. What do you think? Everyone feel free to chime in for input.

Thanks I have been doing some reading on various threads and I think it may be the ignition switch as well. What do you think? Everyone feel free to chime in for input.

A well known prob for '97s. Turn your key to on. Are the guages workings/idiot lights on? (If no, it's the switch). If you have gauges/lights,Is the pump priming as stated above? If no whining from the pump, could be either the relay (in the glove box, switch them around), or the pump itself (connector came off), or the dreaded ECM unit took a crap (on the right fender well, check the connections at the ECM, and also on the fire wall by the 3 relays close to the wiper motor.

I will re-check the connections. All the gauges/lights are working and the pump priming. I can hear it. Stays on for about 2 seconds. As stated I just put the pump in on Sunday. Could it still be the switch because of all the phantom problems it causes because i did get a sensor code but no Check engine light? So I'm lost?????

I will re-check the connections. All the gauges/lights are working and the pump priming. I can hear it. Stays on for about 2 seconds. As stated I just put the pump in on Sunday. Could it still be the switch because of all the phantom problems it causes because i did get a sensor code but no Check engine light? So I'm lost?????


How much gas did you put in after changing the pump? I know I used a full 5 gallon gas can and the thing was bucking by the time I got it to the gas station down the street. It needs a fair amount of gas to run. Check the fuel pressure with a tester from the local parts store. Only $40 bucks or so, and you can use it on plenty of other types of cars.

As far as the O2 sensor goes, it needs to be at a proper operating temperature to work, so it isn't used at all at startup. I mean, it won't cause a no-start if it fails.

If it's a '97, replace the ignition switch. I'm not a fan of throwing parts at a possible problem, but they all seem to go bad, with differing symptoms. My dying ignition switch gave several transmission codes/problems.

Ok. I got very low fuel pressure about 35-45 psi but the pump is running. Could it be the fuel regulator and is so can someone tell me where it is and how do I get to it? The ignition switch is new by the way and fuel filter is new. Help!

Ok. I got very low fuel pressure about 35-45 psi but the pump is running. Could it be the fuel regulator and is so can someone tell me where it is and how do I get to it?
What brand of fuel pump was the replacement? The consensus on this board is to use a Bosch, AC Delco or Delphi replacement pumps. The rest are junk.

Remember when turning the key on the fuel pump will only run for 2-seconds and then the key must be off for 10-seconds before the pump will run for another 2-sec. During the 2-seconds the pump runs you need at least 60-61 psi at the schrader valve. When the pump turns off the pressure will leak down some, but it needs to hold around 50 psi. A quick leak down to 35-45 usually indicates a leaky regulator or the pump failing to hold pressure. If you have a quick leak down, clamp off the return line to the fuel tank and if you still have a quick leak down then the problem is probably in the upper intake, i.e., regulator, nut kit or injector lines.

Check this thread for info on fuel regulator (http://www.automotiveforums.com/vbulletin/showthread.php?t=489033&highlight=fuel+regulator) And, this one (http://www.automotiveforums.com/vbulletin/showthread.php?t=503238)

Wow! Great thread! Thank you! I used a GM dealer pump. I will check the intake for that leaky regulator and report back. I hope that is it.

Okay. I got to the FPR and man was it shot! I wonder was the replacement of the new fuel pump just enough push to force the old FPR to the point of going or was it already on it's way out. Just curious:confused:

I imagine it was already on the way out. It seems as though GM engineered everything to die of old age on these things.

I have now replaced the Fuel Pressure regulator, ignition switch, fuel pump and fuel filter and last night I did the fuel pump test by putting a 12v supply to the red fuel pump test wire and making the fuel pump run. I heard it primming but the psi only reached to about 45. So now I am lost,confused and :banghead: I don't get it! It was running fine when the fuel pump was first put on then after about 70 miles started to stall and then when I cut it off it developed the no start problem. What is up???

I have now replaced the Fuel Pressure regulator, ignition switch, fuel pump and fuel filter and last night I did the fuel pump test by putting a 12v supply to the red fuel pump test wire and making the fuel pump run. I heard it primming but the psi only reached to about 45. So now I am lost,confused and :banghead: I don't get it! It was running fine when the fuel pump was first put on then after about 70 miles started to stall and then when I cut it off it developed the no start problem. What is up???

I bet you your battery is pretty dead after constant starting attempts.

First, test the battery voltage, it should be over 13.4volts.

Unconnect it and charge it with an automatic battery charger.

Also, what kind of pump did you install? Carter or Delphi?

How much fuel do you have in the tank? In case the gauge is different than before the fuel pump replacement, make sure you have 1/2 tank of gas reading on the fuel gauge.

At this point, the only thing that would make for low PSI at the schrader valve would be a plugged fuel filter, a bad pump or low voltage going to the pump. Is your battery fully charged? Try putting a jumper start on the battery and see it the fuel pressure comes up.

Check the battery with a load type tester. AutoZone will do it for you. I had a similar problem when my battery was going bad. Cranked over great, but the starter was taking all the juice and nothing was left for the fuel pump.

Did you put the pump in yourself or have the dealer do it. It's possible the fuel filter could be on backwards which might clog it up. (The filter has little arrows on it to indicate the direction of fuel flow) The pump should be under warranty, but that doesn’t cover labor cost.

If jumping the battery doesn’t help, I would replace the fuel filter, as they are not a high dollar item and not that hard to replace. If that doesn’t help then no doubt it’s the fuel pump.

However, before replacing the pump, disconnect the fuel pump wire connector at the gas tank, apply a 12v supply to the red fuel pump test wire and leave it there while checking for current on the 12v feed wire in the wire connector at the gas tank. (On my 95 the 12v feed wire going to the tank is gray) Test the current with a voltmeter, while using the ground wire in the connector for a ground. It should read 12.5v or something a little more than 12v.

If you don’t have at least 12v on the Gray wire try using a different ground. If you have 12v, make sure the wire connector at the gas tank is making a good connection to the fuel pump wire connector.

If you have 12v+ and the pump still doesn't put out 60+ PSI, the pump is toast and needs replaced. (Make sure the battery has 12V+ when doing this test)

If you need to replace the pump, get a Bosch, Delco or Delphi – in that order. The rest are junk, which is probably what you got from the dealer, as they often use after market replacement parts. Here’s a link for a good price on a Delphi fuel pump, but also check out the on-line prices at AutoZone and O’Reilly’s.

http://store.getgmparts.com/index.html

Good luck and let us know what you find, as it will help others.

Oh yeah, Welcome to the world of used S-10’s and S-15’s. Once they get 10 years old they become very high maintenance pieces of crap.

Oh yeah, Welcome to the world of used S-10’s and S-15’s. Once they get 10 years old they become very high maintenance pieces of crap.

Amen brother....amen.

Thanks guys! I will let you all know the out come. Helping others and sharing info in the S-10’s and S-15’s family is the only we will beat the" Stealer" dealer absurb cost. You guys are the best.

The fuel pump was a AC Delco GM pump. It was put in by my mechanic who is pretty good. He did however tell me that that there was quite a bit of white corrosion on the connecter!! That could be it!! We will be checking everything out on Sunday.

The fuel pump was a AC Delco GM pump. It was put in by my mechanic who is pretty good. He did however tell me that that there was quite a bit of white corrosion on the connecter!! That could be it!! We will be checking everything out on Sunday.

Hopefully, he just didn't just tell you and do nothing about it. It might be the problem, but I doubt it.

The fuel pump was a AC Delco GM pump. It was put in by my mechanic who is pretty good. He did however tell me that that there was quite a bit of white corrosion on the connecter!! That could be it!! We will be checking everything out on Sunday.

I'll agree with BlazerLT, and say you might ave a deeper problem.

I'll start by saying I've had my pump out of the tank 4 times in the last year and a half. (it's searchable in this forum, and sometimes rather funny)

The corrosion is unusual for the Blazer pumps, but quite common on the S10 pumps and the older style open pumps on '95s and '96s. I know this because I got an S10 pump by mistake for my truck, and it had a packet of electrical grease to put inside the connector housing, as well as a recommendation from the General to replace the wire harness. The '97 Blazer doesn't have a replaceable harness, and the connectors have a billows style insulator/cap on them that prevent moisture from entering the housing. Are those billows on your connectors still in one oval shaped piece?

That being said, it still wouldn't hurt to put the conductive grease inside the housing, and a bad connection (white corrosion) wouldn't cause low pressure, it would cause no pressure. Also on the '97s, it's impossible to mount the fuel filter the wrong way(one end is a squeeze fitting, the other end is a threaded insert), so I'd have to say your problem most likely is the new pump itself. Or perhaps when the pump was installed, the sock got bent in half restricting your fuel intake (The sock is on the bottom of the housing and gets wedged between the pump and the bottom of the tank), but both of these are just guesses on my part.

Update: My mechanic came over and dropped and cleaned the contacts and tried to start it but the battery was dead so I said that I would get a battery in the morning at advance auto. I figured since it had that old delco battery in there it was time for a new one. I also picked up a can of starter fluid just to see if the truck would even start after all this time and parts we put into in it what the hell and it did! It ran for about 10seconds not rough or anything then cut off. So am I back to square one "The fuel pump"?

Update: My mechanic came over and dropped and cleaned the contacts and tried to start it but the battery was dead so I said that I would get a battery in the morning at advance auto. I figured since it had that old delco battery in there it was time for a new one. I also picked up a can of starter fluid just to see if the truck would even start after all this time and parts we put into in it what the hell and it did! It ran for about 10seconds not rough or anything then cut off. So am I back to square one "The fuel pump"?

Was the new battery charged up? Was it even installed?

Yes. The new battery is in but check this out. After It ran I then looked underneath and there was gas coming out from the tank area just
dripping and now there is no pressure showing on the gage. You think maybe the fuel line came loose?

I think you need to get a new mechanic. This guy doesn't seem to know what he is doing.

Did he even test fuel pressure?

Not sure in the beginning but truck was up and running for about 70 miles then started to stall and then finally it's to the point of where it's at now. Could it be that the fuel or gas line came loose?

Not sure in the beginning but truck was up and running for about 70 miles then started to stall and then finally it's to the point of where it's at now. Could it be that the fuel or gas line came loose?

Could be a lot of things.

Again, DID YOU MECANIC TEST FOR FUEL PRESSURE.

Did he even test fuel pressure?

Yes. When it stopped running it was only reading 35-45psi. I was there and saw that.

Now: After It ran I then looked underneath and there was gas coming out from the tank area just dripping and now there is no pressure showing on the gage. I checked that myself after I put the battery in this morning and started it with the starter fluid.

Something could have come unattached.

You need to get that looked at ASAP seeing bad connection + raw fuel = burnt truck.

Take it to a different mechanic or force the one that did this to fix the problem, it is his job done improperly and he is reponsible to fix it.

There's 3 hoses on the top of the tank. 3/8" feed line, 5/16" return line, and 1/4 or 5/16" vent line. The vent line is a snap fit connection. The feed and return lines are pinch connections (a plastic pinch connector that should've been replaced. a $0.50 piece that caused my pump to leak).

If one of these hoses were originally leaking, your SES light should've come on with an evap code.
None the less, you'll have to lower the tank to see if it's the connectors, or if a line is split (they're all plastic, and dealer items only) I'm guessing now it's the feed line.

It could also be that the feed or return lines aren't seated properly into the pump housing. Those pinch connectors only snap in one way into the lines. (the pich conns fit on the pump housing inlets/outlets, and you push the hoses onto the inlets/outlets until you hear an audible snap)

That explains quite a bit. The stalling and then the no start something is loose or came off for sure because if the pump was bad it would not be pumping that gas that I saw coming out when it started with the starter fluid.


He stated that he would come over and drop the tank and check everything. I will keep you guys updated and post results. Again thank you guys.

The fuel pump was a AC Delco GM pump. It was put in by my mechanic . . .
That explains a lot in and of itself, as we are dealing with information in 3rd person here. It's hard to tell what your mechanic has done or not done. Not to diss the mechanic, but it just leaves a lot of unknowns.

As Mike pointed out, the connecting line at the tank/pump appears to be leaking which would account for the low and/or no fuel pump pressure.

Do you even know if you're getting 12+ volts to the pump and if the pump is being supplied with a good ground??

You need to get that looked at ASAP seeing bad connection + raw fuel = burnt truck.
At one time I considered this as a solution for my no start truck. :evillol:

At one time I considered this as a solution for my no start truck. :evillol:

You know, you got a point there.

Yes. The new battery is in but check this out. After It ran I then looked underneath and there was gas coming out from the tank area just
dripping and now there is no pressure showing on the gage. You think maybe the fuel line came loose?

If you take the spare tire down and out you can poke your head up in there and see the fuel lines. If you have a big head like me, take a digital camera, shove it up there and take a couple of pictures. You'll be able to see where the leak's coming from.

Update: There are apparently two places where
the fuel pump sucks in fuel (in the gas tank). One of the lines came off
on the new fuel pump, here is a picture of the new pump and the two green
arrows indicate the line and the nipple it should be attached to:

http://www.nofadz.com/~sonic/pump1.jpg (http://www.nofadz.com/~sonic/pump1.jpg)


Here is how it is supposed to look (old fuel pump):

http://www.nofadz.com/~sonic/pump2.jpg (http://www.nofadz.com/~sonic/pump2.jpg)


We have no idea how the hell this happened, but now I am searching for a
way to permanently attach the line so it won't come loose again. I know
that there are certain epoxies that are resistant to gasoline, so we might
try that. This is what caused the low fuel pressure. I
cannot believe that a brand new pump fell apart like this.

Update: There are apparently two places where
the fuel pump sucks in fuel (in the gas tank). One of the lines came off
on the new fuel pump, here is a picture of the new pump and the two green
arrows indicate the line and the nipple it should be attached to:

http://www.nofadz.com/~sonic/pump1.jpg (http://www.nofadz.com/~sonic/pump1.jpg)


Here is how it is supposed to look (old fuel pump):

http://www.nofadz.com/~sonic/pump2.jpg (http://www.nofadz.com/~sonic/pump2.jpg)


We have no idea how the hell this happened, but now I am searching for a
way to permanently attach the line so it won't come loose again. I know
that there are certain epoxies that are resistant to gasoline, so we might
try that. This is what caused the low fuel pressure. I
cannot believe that a brand new pump fell apart like this.

Return the part, it is defective.

Don't fix something that isn't your fault, it was defective from the start.

Dude, you would not believe what i hae seen come out of new never been open boxes.I think the best 1 I ever seen was an ACDelco plug with no threads on it.You got a crappy pump.