Heres an interesting one, hoping someone can point me in the right direction. I have filled my car up with gas twice in the past month at the same location, and both times after I filled the tank, the car had a serious problem starting... to the point where I had to feather the gas pedal to get it to start and stay running. Once it finally turns over, it needs about 20 seconds of feathering the pedal around 1.5k rpm to stay running. This has ONLY happened as I am trying to leave the gas station. Its obviously fuel delivery, One thing I want to try is opening and closing the tank, releasing the pressure.

Anyone have any thoughts?

EDIT: added that I have a JWT ECU to the title (car only exibits the problem while running the JWT ecu)

 

sounds like the fuel filter is bad.

 

try changing the fuel filter, should help

 

thanks for the tips... interesting, the filter has about 10k miles on it, i changed it at my 60k service. I guess I will give it another shot... if the fix is as easy as a 7 dollar filter ill be extatic. can anyone chime in on why this would only happen when I fill up? very curious...

 

update- can someone do me a favor and take off your gascap, and look down. is there a little flap there that swings open and closed to let the filler nozzle in? I could have sworn i had one but theres nothing there, i can see straight down. you dont suppose... thats in there reaking havoc? ugh...

 

yeah my dose have one. Do you think it might of fallen in

 

hmm thanks. well, i dont have one there, so its safe to assume im dropping the tank on my first day off in a while. greeeaaat.

 

It could be that the fuel at that particular gas station was contaminated with water. In which case the filter would be kaput, anyway.

 

I remember my auto teacher telling me a story about this. They had a car come in with a similar problem only it would run for a few seconds and die. They couldn't figure out what the problem was until they dropped the tank. It ended up somehow being a piece of tin that covers something like a techron bottle. When the car was started, it sucked that piece of tin up and clogged the line. I also have that metal flap so if yours isn't there, I'd say it's a good possibility that's the problem.

 

thanks, i decided since ive got less than 1/4 tank full right now, its a good weekend to drop the tank and see what surprises i find

 

I agree ..... fuel filter seems to be the problem

 

update: well I changed the filter, and opened up the tank to take a peek inside and didn't find anything suspicious. I did all this with pretty much an empty tank. When i was all done, car started up just fine after a few cranks. Proceeded to goto a gas station and fill up. Get back in the car... wont properly start (WTF?!). Once I did get it running, I attempted to shut it off, move the key to off and take it out, car is still running and continues to run sputtering. Any thoughts guys?

 

check your fuel pressure man

 

ya ill nab a gauge and a t fitting to test i guess... still perplexed on why it only acts like this immediately after i fill the tank, no other time, grr

 

The car continued to run with the ignition off?
Well I can only see two reasons for that:
1) The ignition was actually still on, in other words the ignition switch is defective and probably falling to bits. OR...
2) Pre-ignition is so bad on your motor that it continued to run like a 'glowplug' motor. (Carbon hotspots / wrong sparkplug heat range)
- I have seen this on carburettor cars with mechanical fuel pumps. However I doubt this could happen on the Max because the ignition switch not only controls the sparks but also the fuel pump; no fuel = not running.
So, my guess is (1) - unless your car has had its wiring bodged up by some amateur!

 

I should mention that i've been running the JWT na 99 ecu (modded 96 5 spd ecu). I'm gonna go back to stock and see if the ecu is the culpret (but still why only when i fill the tank up?)

 

JWT ecu seems to be the culpret... put the stock in and can't replicate the problem... anyone have thoughts on why this is happening? I e-mailed jwt no responses yet.

 

I have changed a fuel filter so many times and it has never solved the problem. Changing the computer chip may become common - 2006 now.

 

UPDATE:

Well, I was doing some thinking to myself, I put together a theory. What was different between the 95/96 and the 99? Well, from what ive read from doing many a search here, I see the EVAP system seems to be really different (going from mechanically controller to electrically). Now, given that my knowledge of the EVAP system is limited to knowing WHAT it does, this might not make sense. Could the EVAP system be flooding/leaning me when I start? I tried calling JWT however they have not responded (typical).

I don't really want to bore anyone with this, so anyone who knows about the EVAP system/differences between 95/96/99 please chime in, thanks!

 

anyone, anyone, beuler?

 

When you fill your tank are you "topping it off". This could be a problem in relation to a different ECU and how it controls the EVAP

 

mmmk......

 

Could be your fuel pump. Filling it up to the brim repeatedly puts alot of pressure on it and could be detremental. But it's more than likely that little flap thingy.

 

hmm ive narrowed it down to the ECU but thanks.

 

Try not filling it up all the way next time, maybe to only 3/4 or so and see if that helps any

 

My father in law is having a similiar problem. Whenever he fills up at the same pump of that gas station the car will not start it will take like 4-5 turns before starting then he has to rev it as well. It's only that one pump makes no sense everything in his car is stock though. Maybe we should lower his tank and see if there is anything in there.

 

From what I've read, topping it off is a no-no on any car . You may overfilled it and ruined the charcoal canister that is supposed to absorb all the excess fumes off the gas tank. I'm thinking that should have triggered a code and screwed things up, but your ECU has been changed, so it may or may not read that problem. You may want to see if that canister is soaked in gas. If so, change it out. If not, just fill it to the first "click" next time and don't top it off and see if that helps the problem. I'm thinking you flooded the canister with an overfill and it's never going to dry out on its own. By having that system "stopped up" with gas, you don't let any air into the gas tank which means you can't let much gas out....thus the hard starting and engine problems. Cracking the cap should get it going again, but driving around with no cap is really dangerous....especially if you ever get hit! See if the canister is the problem.

 

I appreciate all the insight and help, however this seems to be an ECU problem rather than a "topping it off" problem. Still have not found anyone who can verify if a 96 ecu will not control an EVAP system from a 99 properly, since like I said, it ONLY does this with my JWT in there. grrrrr

 

zazon:

ECU doesn't know you fill up your tank (in 4g max I think). if so, the problem is not in your ECU.

 

um, right, but read my posts above.