Truck Running Rich

[RevT]

If I havent touched anything on my truck, what causes it to run rich? I've got a 90 model 351 W EFI, with 165K on it. I'm gonna pull the plugs shortly, probably after I move this week.

And how do I fix it? Through the timing?

Thanks,
RevT

[Warrlord]

Could be the fuel pressure regulator...........the diaphram in it could be leaking. it's operated by manifold vacuum so if the diaphram is bad, it'll suck fuel through the vacuum hose right into the intake.

Leaky injector(s) or a faulty ECU could also cause it to run rich but the most common is the fuel pressure regulator.

Start the engine, let it run for a couple minutes. Shut it off, then pull the vacuum line directly off of the regulator, if there's any gasoline in anywhere in that vacuum line, you found it.

[cory]

i allways threaten mine with a sawzaw, as you can see it's not working

[JuBean]

Another stupid question is have you tried pulling trouble codes or is the check engine light on? When this happens on my truck it is either the engine coolant temp sensor (for the PCM, not the gauge in the dash) out of range or the MAF out of range. On my truck it is always just a loose wire but if either one were not functioning properly the PCM would say screw the sensors and run pig rich.

[RevT]

Another stupid question is have you tried pulling trouble codes or is the check engine light on? When this happens on my truck it is either the engine coolant temp sensor (for the PCM, not the gauge in the dash) out of range or the MAF out of range. On my truck it is always just a loose wire but if either one were not functioning properly the PCM would say screw the sensors and run pig rich.

Nah havent pulled codes. I just started thinking about it yesterday. Probaly take me another two weeks to act on it....LOL

Anybody in the springs got a code reader? I hate counting the blinkx, I'm no good past 10....

Thanks for your help. I think they havae a code reader at the base hobby shop.

RevT

[NorthernStar08]

Take away its charge card

[JuBean]

Take away its charge card
Actually you would need to give it several cards so that when the bills start to come in the budget is very lean:p

[bassdude]

Could be the fuel pressure regulator...........the diaphram in it could be leaking. it's operated by manifold vacuum so if the diaphram is bad, it'll suck fuel through the vacuum hose right into the intake.

Leaky injector(s) or a faulty ECU could also cause it to run rich but the most common is the fuel pressure regulator.

Start the engine, let it run for a couple minutes. Shut it off, then pull the vacuum line directly off of the regulator, if there's any gasoline in anywhere in that vacuum line, you found it.

Dang yur smart!
i just had the same thing on mine. $40 and five minutes later good as new.

[Digger]

Could be the fuel pressure regulator...........the diaphram in it could be leaking. it's operated by manifold vacuum so if the diaphram is bad, it'll suck fuel through the vacuum hose right into the intake.

Leaky injector(s) or a faulty ECU could also cause it to run rich but the most common is the fuel pressure regulator.

Start the engine, let it run for a couple minutes. Shut it off, then pull the vacuum line directly off of the regulator, if there's any gasoline in anywhere in that vacuum line, you found it.

2x Both my old bronco and my brothers had the regulator's go bad. It usually resulted in the computer throwing an O2 sensor code.

[RevT]

So the last few days my Bko has been just dying on me. It wont stay running at idle. SOOO I'm out today trying to pull some codes because its also running rich. I'm pretty happy cause I think I'm getting somewhere....

Then I remember a few days ago I was in there tighting some stuff, so thought I better just double check.

YEP I left one of the electric connectors unplugged, and that fixed my stall problems.....

However I think all the stored codes was from that. SO I'm back to square one.

So I cleared the codes. Now I need to drive it around some to get some more codes.....

I did check the fuel pressure regulator, or at least what I thought it was ( a small cylinder thing on my fuel rail with a vacuum hose running out of the top) No fuel if thats it.

RevT

[Tilt168]

suscribing so i can stay on the look out for this in queenie!