Aftermarket pump install trouble

WRBSTi06

New member
Hey ladies and gentlemen, my factory fuel pump started to get weak, not holding pressure and had trouble starting. So I went to a local shop and bought the DW200 fuel pump. Prior to the purchase I researched continuously on installation, which is pretty straight forward. But anyway I knew that aftermarket, high volume pumps are a direct drop and go. No tuning required, nothing. I installed the DW200 pump with the pre sock filter, wiring harness that was included along with the rubber grommet at the base of the pump assembly. Everything back together, I fired the car up and idled fine. AFRs looked stable. (Yes I did prime the pump before cranking). Went for a test drive and that's where everything went down hill. WOT 2-4 gear would stumble horribly but only for a second or two, after the stumble it would clear up and pull hard like it should clear to 7K rpm. After the test drive, my car had a poor idle, it idled like it would if the car was equipped with 280 cams. Also my AFRs are leaning out then rich, would fluctuate between 12.5 up to 15/16:1. Thinking the possibility of a lemon pump, I installed a Walbro 255 this previous week. Which in turn caused the car to run MUCH worse. The pump would surge horribly, the test drive was worse as well. Instead of a stumble it sounded like anti-lag between 5500-6500rpms. CEL lit up and came back with P0301, P0302, PFFFF, PFFFE and a P0172. The 301/302 codes are misfires, from what I researched, the "PFFFF and PFFFE" codes are also misfires but the AP cannot read them properly. I've also read that most scanners can't pull those DTCs either. Thinking that the issue could be the fuel pump control module, I tore out the trunk liner and inspected the control module only to fine that it was scolding hot. I swap out the module with another scoob and the same thing happens, the module is smoking hot. After much diagnostics I felt it necessary to reinstall the factory pump. After the install of said factory pump, the car runs like a top. Pulls hard from start to finish, no CELs, and the pump control module is only slightly warm. Is it by any possible chance that anyone has had a similar issue? Or for some oddball reason I need a tune with the new high volume pump? Car is an 06 STi. Mods are as followed: Cobb intake, Cobb lightweight crank pulley, TBE w/ O2 dump, AP with the stage 2 OTS map and a Front Mount IC.
 

Grinder34

Track Monkey
Thats odd. I have a DW200 and it was a plug-n-play application. Its weird that TWO pumps did screwy things to you...and now your OEM one is working fine. Could it be a loose electrical connection somewhere else? I have no other ideas, sorry.
 

HolyCrapItsFast

Drinks beer!
I can't say that I have ever had any problem with after market pumps except a power hungry bosch. Most of them were plug and play as suggested.
 

WRBSTi06

New member
I have exhausted myself trying to think of ANYTHING that could cause this issue. It's relatively difficult to find a fuel pressure tester that is able to adapt to the fuel in line, but everywhere I've looked( advance auto, autozone, ect ect) have only the testers for shrader valves. I've researched everything and everywhere to find a solution to the problem but no one seems to know why these pumps caused my car to run so horrible. I hope someone here has had the same issue or something close to it that'll chime in. I appreciate the kind words guys! Hopefully I can come to a conclusion on this problem. Who knows maybe my STi is one of those cars that just needs a tune for the higher volume pumps! Haha. Can E85 cause any harm to stock fuel systems on these cars?
 

HolyCrapItsFast

Drinks beer!
You should not have to tune for a fuel pump if it is just drop in... The only time you need to tune for a pump specifically is when you bypass or eliminate the controller. E85 should have no bearing on the fuel system. I personally have used it in my STi for six years straight with no ill effects.

This is a weird one and I have no answers for you. I find it strange that the controller heats up with the after market pumps. I have never run into that before and I can only think, through some cruel joke the universe is playing on you, that the pumps themselves are bad. I have had good success with the Aeromotive 340. :tup:
 
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