Hi, my TPI bretherans.

TOday I tested my FP and BAM, the needle jumped to about 43-45psi and lowered to about 25 in matter of a second or two. It stayed at around 20 or even lower.
My buddy and I are thinking its a leaky injector. This is due to me failing emissions (running rich CO and HC). SO, I just want to confirm with you guys that run the same set up and know a thing or two about the TPI, if this "preassure loss" is an injector. Taken in to concideration that my car fails somg running rich.

 

Hey man, I got to thinking after you left here - it could also be a torn diaphragm in the FPR as well... That would allow the fuel to return back to the tank immediately. Short of pulling the plenum (again!) & pulling the FPR apart, I'm not sure how to check for that...

(BTW, pulling the FPR apart has caused many a third-genner to learn/invent new profanity...)

For anyone else reading this - the gauge really did drop from around 42# or so to 20-25 within about a second... It was pretty quick. The more I think about it, the more I'm suspecting the FPR diaphragm - because if it were an injector doing this, you'd likely see issues w/ starting the car...

One other thing to note is that the line leading to the charcoal canister would "vent" or make noise for several seconds after shutting the car off - and the old canister was saturated. I'll admit that I don't know the emissions system as well as perhaps I should...

Thanks all.

 

well, does anybody know why this is. My car starts up immidiatelly(Like a new car) and it runs fine with pretty good gas mileage. I never had a problem with it starting, or running. Its just runing rich??

Could a leaky injector or two or three do this to the preassure??

I usually get black stuff on the ground on warm up (a little)

Three injectors were replaced by a shop by the previous owner, and there might be a chance that they might be bigger injectors.

There is no fuel in the vacum line from the regulator. Fuel pump has been replaced.

Need some suggestions.

 

A torn FPR diaphram will dump fuel through the vacuum line. Pull the line off and cycle the FP, look for fuel exiting from the FPR vacuum port.

The dropping fuel pressure could be the injectors, the fuel pump (check valve), or the FPR.

The injector changing isn't unusual. The stock Multecs are known for being, well, a lousy excuse for an injector. If some have been replaced the others can't be far behind. And, if they are not the exact same injector then other issues occur.

RBob.

 

Would the fuel pump valve make me run rich?

 

Not run rich. If it is bad it will cause the fuel pressure to drop off once the fuel pump (FP) stops running (the drop from 43 psi to 20 psi once the FP stops).

Re-evaluating the original posts: does the fuel pressure drop off to 20 psi while the FP is still running? Or after it stops?

If it is while the FP is still running, then there is another issue. Good possibility the in-tank hose or turtle is leaking.

RBob.

 

Havent tried to measure the preassure with the car on. This was with the key on, test!

SO, if my car was to run with low fuel preassure, wouldnt it run lean??? There is no possiblitiy for it to run rich with low FP. Is there???

What are the things to make it run rich.
Fuel preassure (high)
Injectors malfunctioning
Canister
....