Bad fuel pump? 95 3.8L 158k miles

[wiswind]

For the work and bother involved......and the cost of a new fuel filter that you KNOW is good......If I am taking the filter off....I am putting a new filter on.
Certainly.....I would replace the fuel filter FIRST if there is a glimmer of thought that it "could" be an issue BEFORE I give thought to messing with the fuel pump.

I have the same thought on the fuel pump and 'sock' filter.....If I am going to remove it to look at it.....I am going to have a replacement unit sitting there to go back in....particularly in our older vehicles.

In both cases....LABOR is more bother/cost than the parts.

Of course it pays to eliminate the cheap and easy solutions before going into costly and difficult ones.

[tripletdaddy]

The only way to test the fuel pump for its absolute pressure is to disconnect the filter and test it there using whatever adapters necessary, thereby, eliminating any issues at the engine and the filter. I suggested this a LONGGGGG time ago.

However, you need to know what the fuel pressure is at the rail with a brand new filter in so you know what the pressure is at the injectors, which is the spec you need to meet. Testing the pressure at the pump, will give you an idea of how much pressure it can deliver and help you ascertain what you have at the rail is reasonable. Really, a new filter and low readings at the rail should be enough to reject your pump.

Have you been finding any crud in your filters? Back flush your old filters you've changed or will change into a clear jar to see what crud is in it. You need to be sure you don't have a crud problem that could be killing your pump and clogging your filter.

[searcherrr]

The Nightmare story of the VAN from the 9th circle of Hell continues.

FIRST OF ALL THE CAMSHAFT SYNCHRO AND CPS WERE REPLACED AND I GOT THE VAN BACK YESTERDAY. READ ON FOR STATUS.

I took it for a spin with my Dad (who is ready to light it on fire) and we were both extremely pleased with what seems to be a very considerable (if I'd put a number on it I'd say its a 30-35% difference in feel/drive/pickup) performance gain and MUCH smoother running. Keep in mind it is much colder outside right now too though.

After 1 wrong part ordered (not my fault) I bought a new Synchronizer and CPS from Ford and had them install it.I was told that the old synchronizer was installed BACKWARDS (180 degrees opposite of what it should be) on what they called "the exhaust stroke". 3 SPECIAL proprietary tools were necessary for this job to get done and it involved removing the alternator etc.. to get clearance for removal.

Jumping for joy and having a lot more hope than I normally do because the van just drives insanely better and "stronger" than it did before, my analytical skills kick in and my mind says, "Ya gotta REALLY drive it first to know for sure."

Today I took it on a long roundabout shopping spree with mom. We went 108 miles. I refueled at exactly the same pump I'd filled up on before. I refilled with 6.347 gallons which comes out to roughly 17mpg yet again (NO CHANGE IN MPG WITH NEW PROPERLY SET SYNCHRO AND CPS) and this is after driving primarily at 65 - 80mph interstate travel. Maybe 10 of those miles were "in-town miles".

All day it did not do the "try to stall" thing, but again it was colder outside and my temp gauge was down a lil more than usual thus we were not using the A/C and thus the radiator fans were not kicking on at any time UNTIL LATER when I made it do that. Then the same old problem rears its ugly Demon head where it "tries to stall as soon as the radiator fans TURN OFF". The "near stall" or "rolling idle" which I think the tech called it is not nearly as bad as it used to be and I am very much convinced that the synchro and cps were not set right so this was 1 of X number of contributing problems resolved.

The only thing I'm wondering now is if the computer (driven for 2k miles with the wrong Synchro and CPS setup) is trying to reproduce old engine behavior from learned data. Though driving 108 miles I would've thought that data would've been purged and relearned.

Whether I use the A/C or not, the "near stall" (not nearly as bad now) still only occurs after the radiator fans turn OFF.

I have not checked fuel PSI again, but I don't really think I need to as I don't believe the Synchro and CPS replacement would've changed that. Ya'll think I should?

tomj76 and LeSabre97mint (Dan) - "I think Dan's got the right diagnosis. The pressure should be at least 30 psi after the first time the key is turned on. Since it isn't, then the pump is faulty, there is a blockage in the supply line or there is air in the fuel line/supply."

I really concur at this point and I don't understand why neither shop I've been to thinks my fuel PSI not being in spec is not an issue. Since the FPR is now new as of a few weeks ago the only thing left is the pump, injectors and filter (which is 9k miles old). There has been report of bad gas in my neighborhood where we all fill up and I do have a new filter so I'll have him replace this first cause I'm not doing it myself. I wash my hands of more DIY service at this point.

tripletdaddy - I guess what has stopped me from checking PSI right at the pump in the past has been not knowing how to hook up a gauge directly to a plain (no fitting or connector) plastic/rubber line and have it be sealed well enough to get a reading. I guess now that I think about it more i could've used one of those couplers that fit into rubber/silicone lines and push against the sides of it for a vacuum tight seal, but I was afraid to ruin (by expansion) the fuel line that fits to the back side of the fuel filter because its so old and "to me" fits very loosely already to the fuel filter orifice.

I've never changed any fuel filters on my Windstar myself so I can't answer to the "crud" backwash question.

Action:
Its going back to the shop. The guy I had do the synchro and cps is very analytical and made it personal to fix (coincidental him and my Dad used to work together) and from what I felt driving it I know he was right that it was setup wrong (they are skeptical on whether the old sychro is even bad). I'm going to have them pursue the fuel system elements now starting with putting in the new filter and pressure testing.

[tomj76]

>I don't understand why neither shop I've been to thinks my fuel PSI not being in spec is not an issue.

Probably because the tell-tale sign of fuel line blockage is loss of power at acceleration... also just in case you're not aware, the fuel pressure regulator's job is to keep a constant pressure across the injectors. The fuel pressure will go up and down with the intake vacuum level. Since vacuum level fluctuates with throttle settings, the pressure will follow.

The fuel pump runs for a few seconds then stops when the key is turned to on (without the starter motor cranking). This should be enough flow to get pressure on the fuel rail if the lines are already filled with fuel. The slow build up implies empty fuel lines or low flow. However, if flow is really low, then fuel consumption in high acceleration conditions would exceed the flow rate and fuel pressure would drop.

High speed (i.e. 80 mph) is seriously degrade fuel economy, especially on a boxy design such as a minivan. According to federal government resources, fuel economy is degraded by some 5-10% for each 5 mph over 50-55 mph. This is nothing new, as I remember similar results published in a newspaper during the late 70's oil crisis. At higher speeds wind resistance, frictional loss, and engine combustion issues limits the fuel economy. At 75 mph, you could easily reduce fuel economy by 20%. A 22 mpg would be reduced to 17-18 mpg.

[searcherrr]

Originally Posted by tomj76

>I don't understand why neither shop I've been to thinks my fuel PSI not being in spec is not an issue.

Probably because the tell-tale sign of fuel line blockage is loss of power at acceleration... also just in case you're not aware, the fuel pressure regulator's job is to keep a constant pressure across the injectors. The fuel pressure will go up and down with the intake vacuum level. Since vacuum level fluctuates with throttle settings, the pressure will follow.

The fuel pump runs for a few seconds then stops when the key is turned to on (without the starter motor cranking). This should be enough flow to get pressure on the fuel rail if the lines are already filled with fuel. The slow build up implies empty fuel lines or low flow. However, if flow is really low, then fuel consumption in high acceleration conditions would exceed the flow rate and fuel pressure would drop.

High speed (i.e. 80 mph) is seriously degrade fuel economy, especially on a boxy design such as a minivan. According to federal government resources, fuel economy is degraded by some 5-10% for each 5 mph over 50-55 mph. This is nothing new, as I remember similar results published in a newspaper during the late 70's oil crisis. At higher speeds wind resistance, frictional loss, and engine combustion issues limits the fuel economy. At 75 mph, you could easily reduce fuel economy by 20%. A 22 mpg would be reduced to 17-18 mpg.

Fuel Pressure doesn't change at all when I run the various tests at idle and 2500 rpms.

Low flow - Start with fuel filter. I know. I'm taking it back Monday.

Empty fuel lines - If I was leaking somewhere you'd think I'd notice huh? I mean could I be leaking so slightly that its just evaporating out rather than dripping? FUEL CAP BAD? Some other location? Any of you replaced your fuel filter and noticed the rear line to it comes on and off very very easily; almost too easily? Think this is a possible source of evap leak?

FPR - could I run with the vac line disconnected from the FPR and then figure MPG and be ok to run like this just for a test? I ask because when I remove the vac line from the FPR this is the only time FUEL psi is within spec.

80 mph - This was mostly the speed I was at in cruise mode (just to keep up with other traffic even). I guess I need to get out there and test it only at 65mph, though this still doesn't explain only 9-10 mpg in town use.

[tomj76]

>Empty fuel lines - If I was leaking somewhere you'd think I'd notice huh?

You'd think so... a little gasoline makes a lot of odor, especially indoors.

Fuel economy in city conditions depends heavily on how the vehicle is driven. In general, the more the driver is forced (or chooses) to use their brake, the lower the fuel economy. Of course, this can depend a lot on the city where the vehicle is driven, since agressive driving habits vary with the city, or even across parts of a large city. Also, the weight of the vehicle is a big factor. Make sure you're fuel economy comparisons are done under equal conditions.

[searcherrr]

Well, I do tend to drive um.... aggressively, but honestly I really don't believe that I can be shaving off 7mpg from 17 down to 10 just by doing that. The changes I'd make to my driving to drive paw-paw style would not be very much and when I'm on the interstate i try to use cruise whenever possible.

[tomj76]

>honestly I really don't believe that I can be shaving off 7mpg from 17 down to 10 just by doing that.

You'd be surprised. Read the information found on this link... http://www.fueleconomy.gov/feg/driveHabits.shtml

[12Ounce]

tomj76 is right! Driving practices make all the difference. When I see some of these folks gunning their big SUV's away at the green light and braking at the next red light ... I wonder if they are paying as much per gallon for fuel as I am.

[searcherrr]

I know for sure after 1st key flick (no engine start) that after pressure has been relieved or sitting overnight it only gets up to like 12psi. That alone is a confirmed problem and as surprising to me as it is that I'm told by the shop(s) and others on here that probably doesn't affect mpg..... well I just don't know what to say about that.

It just makes common sense to me that if there is a problem with fuel flow that mpg will suffer. The engine does "from time to time" rarely give me a bogg down on acceleration, but I always chalked it up to transmission shifting because its so rare, but I guess in my quest to notice each and every minute detail about this problem I should've brought it up to the tech before, as I finally did today.

Van is back at the shop. New fuel filter is going in due to thought about "bad gas" since my neighbor definitely got some in his Ford Explorer and it caused him some problems (fuel filter, plugs) and we fill up at the same gas station. Fuel pressure tests (key flick and other) will happen following the filter replacement.

The tech is also entertaining that perhaps the new IAC/ISC (from NAPA) may not be delivering OEM results and/or possibly that the PCM wasn't programmed for my specific engine. All I know is that the PCM was installed and came from FORD and was ordered by my other trusted shop.

I definitely made it clear that the engine "attempts stall" after the fans turn OFF. Finally someone is going to pay attention to this and look into it. Maybe for idle issues the NEW IAC is the culprit here all along.

tomj76 - I read that article and I've seen the "mpg" episode of mythbusters too (lol), but I can tell you all wholeheartedly that in my original engine despite city/hwy miles I got very close to the same mpg per tank all the time and I wasn't always driving the same speeds (not always 80 on hwy; more like 60 - 70). If I can get rid of the problem where it tries to stall after the rad fans turn OFF and I still am getting the same crappy mileage then I may just chalk this up to my driving behavior.

When I get the van back (if not much was done besides the fuel filter) I'll make some test runs driving top speed 60mph and fill up and again top speed 80mph and fill up.

The tech also suggested since I have had the sychro adjusted properly that I log 2-3 tanks of gas and see what the average is before proceeding further after what they are doing today. He seemed to think that my 108 mile trip wasn't necessarily enough to get a good mpg reading.

I'm not trying to rebut ya'll about the driving behavior. I'm willing to accept I'm driving to make a sports car out of my winnie, but I need to do my own tests in my own Demon van before I believe it 100%. Maybe I'll find out I just have a heavy foot.

[tripletdaddy]

Searcherr, the gas could be "leaking" internally past the fuel pump check valve, the fpr, and the injectors. If you get just a mild wiff of gas, it's probably from the EVAP gas canister or the fill cap, vent or hoses to the tank. For the longest time, I would smell a strong odor of gas for awhile after I would refill the gas on our old Escort. I like to fill the tank real full because the gas gauge and the trip odometer aren't very reliable and it will barely go 300 miles on a tank. Anyway, just discovered the fill and vent ruber hoses at the tank are leaking. I must not have tightened them enough over ten years ago.

I haven't looked for myself at what kind of connection is required at the tank line to the fuel filter, but I would expect one would have to use a variety of rubber hoses and male barbed and threaded adapters, etc, to connect to a guage. However, I also said that if you have a new, clean filter in place at the time of testing, taking your measurements at the rail port is the best and most meaningful, since that is where the specified pressure is needed, ie. at the injectors. If the pressure is low there, then you need to figure out why. If no lines are pinched, that leaves either the pump, the sock is clogged, or possibly the tank is getting air locked, ie. there isn't air replacing the fuel that is removed creating a vacuum.

On your stalling problem when the fan cuts off, I asked one of the Taurus moderators what he thought. I started this before realizing you have already looked at what he suggested. But, it still is an informative read that you might get something from it.
" Back EMF should not be a problem since they use relays to control all of these. Often diodes are used with the relays to shunt back EMF from the relay coils, but they would not be needed on the switched high current side. I know there will be a diode for the A/C clutch coil, but don't believe there is a similar one is used with the radiator fans."

"I believe the CCRM just contains 2 relays, one for high speed and one for low. I think the back EMF consideration still applies though as the relay should disconnect the fan from the circuit once the relays open. Maybe if one of the relays were not working properly, there would be a potential for back EMF. I don't really think that's likely to be the problem though."

"My initial suspect would be the Idle Air Control motor. The symptoms are kind of backward from typical in this case, but the IAC should close slightly when the cooling fans shut off due to the decreased load on the electrical system and ultimately the engine. Maybe the IAC is closing too far and killing the engine. Does the engine idle speed up when the fans are unplugged and you run through the sequence that would normally cause a stall? If not, I think that points more towards the IAC issue since there's no tachometer or current sense for the PCM to know whether or not the fans are actually running. The PCM will still command the IAC to increase engine speed for fan operation. "

"I'd suggest you pull the throttle body and thoroughly clean the throttle plate, IAC passages, and IAC servo. If this makes any improvement, then the next step should be to check the function of the TPS sensor and/or replace the IAC servo."

"Stalling when the engine is at low rpm also makes me suspect the EGR system could be coming in to play somehow, but I'm not thinking of a correlation between the EGR system and the cooling fans. Plus I'd expect more of an issue on a cold engine. "

Hope what he said is helpful.

Oh, BTW, "The Nightmare story of the VAN from the 9th circle of Hell continues." and

"my Dad (who is ready to light it on fire)"
made me split my sides!!!
That's funny and understandable.
You have seemingly endless patience seeing this through.

Good luck.

[searcherrr]

Thanks man. Glad there is a lil entertainment in all this hoopla too. lol

Just to be clear the van "never does actually stall" - it just tries to really hard enough to make ya paranoid that you are gonna be stuck somewhere one day and only "tries to stall" when those fans turn off. Still, IAC/ISC is now in play as a consideration again even though it is NEW from NAPA.

Throttle body was supposedly cleaned twice very thoroughly by my 1st trusted shop.

When the fans are unplugged the van does NOT "attempt stall" at all, nor do RPMs seem to change at the time fans would be "expected" to come on. I told this to the tech too, but I have no idea what it means because initially it would lead you to think the fans might be bad, but they are brand new due to this thought and its still doing it.

My money is on minute fuel flow/pressure adjustments just after the fans turn off and that less fuel is required to run the engine at a lower idle RPMs and thus possibly the fuel is cutting off too much and then it catches itself before stalling every time.

Fill and vent rubber hoses leaking - something to check/consider..... though again the only whiffs of gas I really get do come from the evap area.

Pressure has been measured at the rail and it is low. Key flick only brings it to 12 psi after sitting overnight or full pressure relief prior to key flick. Hopefully tomorrow I will have some answer about the pressure being low and go from there.

Thanks for running this by your buddy.

[12Ounce]

Instead of unplugging the fan motors, have you tried unplugging the ac compressor?

[searcherrr]

Originally Posted by 12Ounce

Instead of unplugging the fan motors, have you tried unplugging the ac compressor?

That would be the same as leaving the a/c off right?

I have left the a/c off several times and let it build heat till the fans kick on by themselves. Still happens. In any case its me who's connecting the "almost stall at idle" issue with the bad mpg on a hunch. Its the only thing besides the low fuel pressure that I have to grab at.

If leaving the a/c off is not the same as pulling its connector then the answer is NO, I have not tried that.

[garync1]

Did not get a chance to read all of this but if you ever do decide to change the fuel pump. It not that bad of a job.. I changed them with a half full tank but don't recommend it.. But if you a have a 1/4 tank or lower its not that bad. Unhook the straps and with a floor jack slowly bring it down until you can get your hand on the plug to unplug the fuel pump.It is a bit of a balancing act. But you can back the van up on ramps like I do and drop it. Also not that high so if it does fall there is no real harm. Just takes a little longer than if you had a lift with a modified transmission lift to help lower the gas tank.. Then you just tap the center ring so it will unlock and then pull the unit out.. Well sometimes there is five or six bolts but most have a center lock ring.. Don't forget to take cap off can tank and take out the filler neck bolt so it will drop. Don't want to break the filler neck of course.