Immediately after installing a Walbro fuel pump, my evo started idling weird. After letting off the gas when backing up or coming to a stopsign, the idle drops to 400 or so and if the car isn't warmed up yet, it stalls periodically.
Has anybody else experienced this?

 

reinstall it

 

reset the ecu?

List what mod do you have and it will be easily to troubleshoot.

 

did you install the plastic collar of the old one to the new?

 

I was thinking of resetting the ecu, you think it might be that?

mods:
AVO turbo-back
Perring cat-delete
HKS 264/272
AEM intake
Greddy Profec B Spec2
Greddy Type-S BOV (recirc, minus small spring)

 

Do you mean the "factory o-ring" or rubber grommet that fits onto the pump?
If so, then yes, I reused the factory one as per the instructions here:
http://www.evomoto.com/tech_info.php?techID=21
since they recommended doing so.
The rest of the parts I used from the install kit, including the new filter.

 

Bad fuel pump!!! Well it might be, a freind of mine had the same issues with this. Some of these pump come faulty. First try to reinstall it, if not try to put the stock pump back in. If you dont have an issue after the stock pump is back in, then you probably have a faulty unit.

 

Pull the neg battery off for at least 1hr or so to reset the ECU... hold the brake pedal down for a couple minutes to make sure all the power is gone from the car.

If this doesn't fix it, at least you know that your ECU has been fully reset and isn't the reason why you are having stalling issues.

I had a similar problem, but mine was due to a dirty maf sensor from putting too much recharge oil on my filter. I reset the ECU, but didn't allow enough time for the ECU to fully reset when I connected the battery back up the first time.

Keep us posted.

Joe

 

As far as reseting the ecu it only take a couple minutes. Just pump your brakes like Kiss said . I have reset mine in about 1 min a couple times. The way you can tell your ecu is reset, is it will start to idle at about 1600 rpm for a bit while the ecu adjusts fuel and timing. But from the symtoms you said it almost sounds identical to my freinds problem.

 

I mean the white plastic retainer that holds the factory O-ring from falling off from the outlet of the pump. If you forgot to put this back, the O-ring will fall off and loose fuel presssure causing idle and drivability problems as you describe.

 

i think he needs a s-afc to lean out the mixture since the walbro pumps more fuel at the same voltage level(more efficient than stock)

 

If you installed it right then I believe you have a bad pump

 

Thanks for all the suggestions,
I'm going to go reset the ECU, then rip it all apart to make sure I installed everything properly.

 

The walbro doesnt have anything to do with adding more fuel to the engine. The injectors take care of that. All the walbro does is keep fuel pumping into your injectors to prevent a lean condition at higher rpms while the injectors are running a higher duty cycle.

 

I don't know, mine idled bad when I installed it just prior to my Dynoflash tune, but never stalled. It didn't feel or drive right, then as soon as my ECU was flashed and street tuned, it idled perfect and ran smoooooth.

You do run richer with the pump under boost without fuel tuning.