fuel delivery

[e-dirtym52]

the car drives fine up until i'm driving for about 25-30 minutes and has a little bit of a slow throttle response to begin with. then it seems that it's not getting much fuel and the throttle response gets even worse. i can barely get up hills from a stop and i can be buried on the gas at times and the car will go nowhere. pretty much like it just stops getting gas. then out of the blue it will start to drive perfectly fine again. i've checked fuel pressure and it's fine but i haven't checked it yet after driving on it for a while.

the question is, is there anything i can do to increase the throttle response and keep it from doing whatever it's doing after driving for a while?

it doesn't toss any codes except the purge valve code from not having a charcoal canister. vacuum is good and the car runs rich. i was thinking of finding someone with an air to fuel meter and hook it up to see if it just starts leaning out.

this wouldn't be vapor lock would it?
m52 obd1 by the way

[e-dirtym52]

I have replaced the fuel filter and fpr as well

[Roysneon]

I think I have something very very similar going on. No further suggestions for you, but I am interested in any further developments. If you take the oil fill cap off does it smell like gas in your oil?

[meanEG]

Do you have a catalytic converter? And what is the condition if you do? Make sure it is not rattling.

[e-dirtym52]

No cat. 2.5 in straight pipe. Oil doesn't smell gassy really. But the plugs are wet

[meanEG]

Need to run with a fuel pressure gauge and monitor when it starts to have drivability issues.

[e-dirtym52]

Well that's what I'm planning on doing with the air to fuel meter to see what's happening. But it already has a slow throttle response to begin with when it does drive fine and was wondering what could help with that.

[meanEG]

you didnt do anything to the timing chain right? just checking. how old is your fuel filter? and lines?

[e-dirtym52]

i had to re time the engine and rebuild the vanos but it's all been done correctly and with the proper tools. fuel filter was replaced about a year ago and all my vacuum lines are tight.

[meanEG]

Have you driven the car after you did the timing chain work/vanos?

[e-dirtym52]

yea i did that during like december or january. it drives just fine up until about 25-30 minutes of driving. it gets a little temperamental and is hard to get going from a stop. and then is pretty weak if i try to get on it. i got stuck on a hill the other day because i couldn't get enough gas going before i was rolling backwards down the hill. i thought it was the clutch for at first thinking i toasted it but after i got out of the hill it drove just fine. then i rolled up to a stop light and could barely get it going from a stop when it was on a flat plane. i was wide open throttle barely getting through the left turn and then BOOM out of nowhere the motor kicks in and i burn rubber through the intersection. no slip in the clutch when that happened.

[meanEG]

I would try to get a can of duster and spray the ecm with it when its acting up. Also try do and electrical sensors. You could also do the opposite and try to heat up sensors and the DME while it is in the shop. It souls like you have a very weird issue.

[meanEG]

Well that's what I'm planning on doing with the air to fuel meter to see what's happening. But it already has a slow throttle response to begin with when it does drive fine and was wondering what could help with that.

That really is not going to be a good test. I would use a fuel pressure gauge first. Unless you are going to use a wideband, and even then I would want to know what my fuel pressure was.

[e-dirtym52]

I was planning on using a wideband. I have access to a fuel pressure gauge but how would I monitor that while driving? Have a passenger hold it and connect it right off e pump?

[meanEG]

T it from the feed line under the intake. Run the hose into the cabin from the window. If the house isn't long enough, don't close your hood all the way and sit it on the windshield.