Bogging on acceleration.

steveo

Member
Dec 15, 2008
195
0
16
Alberta
No I haven't done anything with the old pump. Just bought a new one and will be putting it in. It is a holley 255lph pump and was only 150 picked up in Edmonton. Once it is in I am just hoping that it will fix the problem that was occurring. If it doesn't I move down the check list. Not the easiest way around it but I am impatient and have only one car, so this one needs to work.
 

metaphysico

Mad Scientist
Jan 2, 2008
428
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45
Gainesville, Georgia
A word of warning, get an after market fuel pressure regulator if you are going with the 255, then bypass or drill out the j-tube. Also when you were saying about the pump priming itself, the mk3 does NOT prime itself like a normal car. The cranking signal turns on the fuel pump then the maf/afm signal takes over to keep the fuel pump running, its strange but true. So turning the key on and listening for the pump will do you no good. Also you should check to see if the pump was bad, or if it was the wiring or fuel pump relay or fuel pump resistor, and if you are going to be doing the pump anyways look up the fuel pump rewire and resistor bypass.
I has serious problems with my car after putting the 255 in it, at 75% throttle it would blow thick black smoke and I checked and saw I was around 70psi on the lines, I dont know if it was from the j tube or the fpr or both but put the after market fpr and bypassed the jtube and no problem. Also with the walbro unit I got it does not seem to have a backflow preventer or it was not working properly so fuel pressure drops back into tank so it takes a little bit of extra time to start the car now.
 

Nick M

Black Rifles Matter
Sep 9, 2005
8,898
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U.S.
www.ebay.com
If you are so impatient, why didn't you just do the jump test in the diagnostic connector? Then you would be several days back and already have an answer. Just a thought for you.
 

supraguy@aol

Well-Known Member
Dec 30, 2005
4,239
43
48
Atlanta
metaphysico;1586206 said:
... Also with the walbro unit I got it does not seem to have a backflow preventer or it was not working properly so fuel pressure drops back into tank so it takes a little bit of extra time to start the car now.

I have this same problem with my Walbro. within 10 seconds of shutting down, my FPR gauge drops to zero psi in the line. I have to kick the starter for a split second to get the pump to run, then I can start it. I was thinking I was the only one.
 

steveo

Member
Dec 15, 2008
195
0
16
Alberta
Nick is that when you jump the FP and B+ connectors together? I tried that and it didn't work. But then the next day when the car wasn't touched and just sat all day it started up first try. But still bogged hard on acceleration and no codes when I got home. When I had pulled the filter and shook it out a bit there was a lot of brown liquid coming out of it, so I am assuming it was pretty old. I just reordered a Walbro fuel pump kit from Driftmotion because Mopac here fucked up hard and brought in the wrong pump.
 

steveo

Member
Dec 15, 2008
195
0
16
Alberta
After getting a ride home I though about what Meta had said. With the bigger pump the pressures will still be higher. Since I am running a 1g-gte supra with the stock AFM it will run pig rich with that pump. But if I were to add a 7MGE AFM would that work in extra air to compensate for the extra gas that will be getting thrown through my injectors? Almost like the larger injectors and lexus MAF on a 7M-GTE? Would that make sense to any of you or am I just being retarded again.