Once at operating temp car won't stay lit at idle--walbro fuel pump?

**madchemistnj** · 08-29-2008 08:55 AM

Okay so im driving into the Bronx hoping the Yankees actually win against Boston (go Giambi).

On the way in the car is working just fine as usual until we hit some rare George Washington Bridge traffic.

Then the car starts stalling out when idling. I need to keep blipping the throttle to stay lit. 45 min of avoiding stalling on the Cross Bronx exp is just a little stressful. But e brake, clutch and heal toe practice is always worthwhile. Const 2000 RPM didnt even help only stayed lit if it was driving at 20+ mph or varying throttle/rpm.

car had 1/3 tank of gas and there were no CELs It was hot out (82ish).

Higway driving car works fine. Started to happen again later on town roads and at lghts. Filled the tank to the top and haven't been able to replicate the problem.

Question:
Is the pump overheating?
Is the pump dying?
Could it be that one of the hoses is cracked an air is getting into the lines?

My set up is the following:
2001 S4 with K03's MTM ECU tuned for dps and 5 bar fpr, walbro 255 lph pump in a Audi 100 basket, labree dp (sans heat sheilds).

Any insight would be greatly appreciated.

thanks
Jason

**Rated S** · 08-30-2008 07:48 PM

Wish I could help you, bump for an answer.

**S4 John** · 08-30-2008 09:30 PM

altenator? battery?

**JackalS4** · 08-30-2008 09:34 PM

Alternator/battery loose connection - or dying/dead?

Check your volt gauge, should be in and around 14V during normal driving/running. Check/listen underhood for anything out of the norm.

Fuel pump may have a bad connection somewhere...hard to say.

Good luck!

**madchemistnj** · 08-31-2008 10:13 PM

pretty much isolated the issue to fuel delivery. Everything else checks out okay right now.

It was really acting like it was starving for fuel. I've pulled the Walbro pump and tested it and its pulling the standard amp at 12v, but it does start to warm up pretty quickly. The stock pump barely changes temperatue when running. It does however suck up a lot more current (it was going bad).

Fuel filter was okay, not great but no where near as bad as I have seen in other cases.

Has anyone used the Bosch 040 pump? Or is the 044 the only one worth using? I like the 040 as it has an open bottom.

**S4 in_lowplaces** · 09-02-2008 04:44 AM

i'd check your injectors as well. Run vagcom and see what codes you get. when you pulled the pump did you make sure there wasent anything blocking the filter

**AudiSportB5S4** · 09-02-2008 07:52 AM

Originally Posted by madchemistnj

rare George Washington Bridge traffic.

.

**madchemistnj** · 09-02-2008 08:09 PM

UPDATE:
044 pump is enroute!! with the help of a few key folks I was able to pull together what I needed to install an 044. Installed a new fuel filter. The old one was tough to blow through, but nowhere has hard has I seen them in the past.

I ran an output test on the injector and they all seemed to click the same. No codes so we'll see.

thanks
J