fuel pressure question. 95 gt 5.0

wildman87 · May 11, 2010

Ive been having a preignition problem, seafoamed it and all that fun stuff. my fuel pressure runs at like 30psi and kicks up to 32 when you give it some throttle. should i change the pump out? already changed the filter. had to cycle the key like six times to get it up to 30psi koeo

Itkix · May 11, 2010

Might can just pull vacuum hose off regulator and turn up to 39, and try that,while running.

toyman · May 11, 2010

I'm going to assume you have the stock fuel pressure regulator. If that is correct it is not adjustable as hinted in another post. The issue may not be in the pump but rather the FPR. The pressure should be 39-41 psi KOEO and KOER in the 35+ psi range when measured at the fuel rail.

revhead347 · May 12, 2010

If you pull the vacuum line off the FPR, the fuel pressure at the schraeder valve should be 39psi. Could be the fuel pump or the regulator itself.

Kurt

NinJa_FLiP · May 13, 2010

my guess would be the fpr itself.. the fuel pump should either work or not.. meaning fuel pressure or no fuel pressure..

revhead347 · May 13, 2010

NinJa_FLiP said:
my guess would be the fpr itself.. the fuel pump should either work or not.. meaning fuel pressure or no fuel pressure..

More importantly, if it's not pumping enough fuel at idle, then it wouldn't pump enough fuel for the car to run at throttle at all.

Kurt

Sn95 bryqn · Oct 1, 2016

I changed my fuel pump to 190 lph with stock fpr and now my car will not start at all.. Any help ?

Moosee1955 · Oct 1, 2016

If your engine is stock this is too much fuel. Your flooding your engine. Why didn't you put in a stock pump. Pumps can get weak and still pump but not enough, screens clog, lines get plugged. Put in a stock pump unless you have a lot of high performance add ons, heads, cams, injectors. If you have access to a compressor remove fuel filter, line at rail and blow out lines make sure theirs no crud in there. Adjustable regulators only are needed with high output pumps and all the high out put items mentioned. Put in the right pump, preferably a Ford part, they work the best, my 2 cents from an old timer of 45 years doing this crap.

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Moosee1955 · Oct 1, 2016

Just read your getting pre ignition problem. Run dtc codes make sure a sensor isn't causing some of it. Low fuel output is another.

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jozsefsz · Oct 2, 2016

Moosee1955 said:
If your engine is stock this is too much fuel. Your flooding your engine.

This is terribly wrong advice. The volume a pump is capable of producing has nothing to do with how much pressure appears at the rail. You will NOT flood your engine or cause any issues with a larger fuel-pump even with stock injectors and rail. The only time this could possibly happen is if you out-flow the return line or overwhelm the fuel pressure regulator - which would absolutely not happen with a 190lph pump. Or a 255.

Op - go back and retrace your steps. Check that the fuel pump is running, and check your fuel pressure. If you did it right, and it was running before you changed the pump, you did something wrong.

Chythar · Oct 2, 2016

Moosee1955 said:
If your engine is stock this is too much fuel. Your flooding your engine.

As jozsefez said, this is not correct for the 94-95 engines. We have a return-style fuel system, meaning that any unused fuel gets sent right back to the fuel tank. If OP has a stock engine and no plans to upgrade, the extra fuel pressure isn't needed but it won't hurt anything either.

Moosee1955 · Oct 3, 2016

You guys are right, I apologize. If he installed his pump right, and lines are clear it should run. Again run a fuel pump pressure test. But putting on a larger pump will not fix a detonation problem, unless the injectors are under fueled due to high performance parts. Fuel pumps usually work or don't . The pickup screen in tank can get clogged with debris , but as a rule unless car has sat for a long time no. I don't know where in this thread that he changed pump. Wild man 87 said he had low fuel pressure that was it. Preignition was what he was trying to fix. Sn95 bryqn was the one that changed to 190lph pump. We were diagnosing 2 different vehicles I think. Anyway again my apologies , I was diagnosing from past experience on vehicles that flooded with too big a pump, even with a fuel pump regulator installed and working. My flooding stopped when I installed correct pump. Keep us posted on the fix.

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Sn95 bryqn · Oct 3, 2016

Hey thanks for all the replies i found my problem was not anything to due with fuel pump, my msd ignition coil went bad, its the 2nd one i went thru in a year.

Sn95 bryqn · Oct 3, 2016

For some reason though ever since i bought the car it seems to be slow at acceleration, i have a stock throttle body, and i believe a bad iac when I unplug it and plug it back in i get no response at all in idle. Im not sure if my tps is off or what since my friend fooled around with the idle stop screw... How can i properly set my tps since i was told the idle stop screw tweeks it to silly mode. ; /

Sn95 bryqn · Oct 3, 2016

Any proper way to set idle stop screw and where should i look for acceleration tweeks in the sensors/engine?

Sn95 bryqn · Oct 3, 2016

Moosee1955 said:
You guys are right, I apologize. If he installed his pump right, and lines are clear it should run. Again run a fuel pump pressure test. But putting on a larger pump will not fix a detonation problem, unless the injectors are under fueled due to high performance parts. Fuel pumps usually work or don't . The pickup screen in tank can get clogged with debris , but as a rule unless car has sat for a long time no. I don't know where in this thread that he changed pump. Wild man 87 said he had low fuel pressure that was it. Preignition was what he was trying to fix. Sn95 bryqn was the one that changed to 190lph pump. We were diagnosing 2 different vehicles I think. Anyway again my apologies , I was diagnosing from past experience on vehicles that flooded with too big a pump, even with a fuel pump regulator installed and working. My flooding stopped when I installed correct pump. Keep us posted on the fix.

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Know anything about my last post u can help with ?

Moosee1955 · Oct 3, 2016

From what I read, you might be putting on wrong coil. Do you have cdi ignition? They put out large bursts of voltage, up to 500 volts. You've got to put on proper coil, spark plugs, spark plug wires or you'll keep frying coils. With stock ignitions, coils usually last life of vehicle. Get proper coil, or switch back to original ignition. Power gains are minimal with most wire/ coil swaps. You really want to pump spark, switch to a magneto like drag cars!

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jozsefsz · Oct 3, 2016

I've had nothing but bad luck with MSD anything - coils last a year tops, wires misfire and cross-fire out of the box, and caps that arc between the posts. There was a time when it was an American company making quality parts in El Paso. Now it's just an importer of re-labeled Chinese crap just like any eBay low-buck seller. But it's such a racy red color isn't it! /sarcasm Sorry MSD fans, but that's my truth.

The base idle reset procedure you'll find searching this site will show you how to properly adjust the stop-screw and the air bleed to get a proper idle that doesn't hunt, surge, or hang. You have to really try hard to exceed the voltage the SN95 computer allows as the minimum on the TPS by adjusting the screw. If it's set properly, the IAC shouldn't have much of an impact at idle unless an accessory (A/C for example) comes on.

If you're not hunting, surging, or hanging, there's nothing wrong with your IAC or how that's set. Messing with it will guarantee that you'll now be hunting, surging, or hanging. It will in no way improve your acceleration to tinker with it. If you have a '95 5.0 with stock gears and an automatic, it's not going to feel very fast without some real work. With that said, routine tune-up items and ensuring you have the timing set properly can always make a difference.

Sn95 bryqn · Oct 4, 2016

jozsefsz said:
I've had nothing but bad luck with MSD anything - coils last a year tops, wires misfire and cross-fire out of the box, and caps that arc between the posts. There was a time when it was an American company making quality parts in El Paso. Now it's just an importer of re-labeled Chinese crap just like any eBay low-buck seller. But it's such a racy red color isn't it! /sarcasm Sorry MSD fans, but that's my truth.

The base idle reset procedure you'll find searching this site will show you how to properly adjust the stop-screw and the air bleed to get a proper idle that doesn't hunt, surge, or hang. You have to really try hard to exceed the voltage the SN95 computer allows as the minimum on the TPS by adjusting the screw. If it's set properly, the IAC shouldn't have much of an impact at idle unless an accessory (A/C for example) comes on.

If you're not hunting, surging, or hanging, there's nothing wrong with your IAC or how that's set. Messing with it will guarantee that you'll now be hunting, surging, or hanging. It will in no way improve your acceleration to tinker with it. If you have a '95 5.0 with stock gears and an automatic, it's not going to feel very fast without some real work. With that said, routine tune-up items and ensuring you have the timing set properly can always make a difference.

Must be true about msd crap im getting everything you said. I actually bought a oem coil and have a better faster spark with the msd cap/rotor im going to change them out also with a oem

Moosee1955 · Oct 4, 2016

Make sure if you have a cdi ignition, also have matching coil. Again your not going to feel large gains with the msd. Your biggest gains are with engine mods, Exaust, power chip and re programming computer for extra fuel requirements of parts. I've said it on the ford expedition forum, and I'll say it here, in most cases these cars run best and have least problems with Ford parts. Whether stock parts or their high performance stuff. I've worked on cars and trucks for going on 45 years now. I have 0 comebacks or breakdowns when I do. Just my 2 cents from the old Moose!

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fuel pressure question. 95 gt 5.0

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