Bad fuel pump???

87-WE2

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May 17, 2011
Finally mounted my boost and FP gauge today. I think i need a new fuel pump, but i guess it could be something else. Opinions?? Injectors and chip are new. New accufab fpr about 6 mos old. Fp verified line off approx 3 weeks ago at 43. I can do it again if needed. Fuel filter has about 2k miles on it. I have been running a mix of 30% E85 to 70% 93 for fuel. I have been getting O2 readings down to about 720 at top of 3rd. Here's what happens during driving:

Rolling into throttle fp will climb until it reaches about 48-49, then abruptly drops back at WOT. Video to follow. Before buying a new pump setup, i'd like to verify that this one is toast. I do have a hotwire kit that was on the car. I know the pump is old, but not sure HOW old. I can dig thru receipts to possibly find out if needed.

Is there anything else it could be or that i need to check prior to buying a new pump and hotwire?
 
I guess that's a "yes"?:confused:
Sorry, but I can be a little thick-headed. My wife said something earlier today about me not being able to take a hint - i have no idea what the heck she meant.
 
X2..........had same problem...further I drove the car out of town the worse it got..... After new pump, Now at WOT I get around 60-65psi.
 
I wonder if the sock is getting sucked in as the fuel flow increases until it plugs the intake of the pump.
If you just change the pump and use the same sock, it may keep happening.
 
I wonder if the sock is getting sucked in as the fuel flow increases until it plugs the intake of the pump.
If you just change the pump and use the same sock, it may keep happening.

I hadn't thought of that, but it makes sense. It sure seems like it wants to climb, then immediately DROPS 3-4 PSI when it gets to a certain point. I won't be reusing the sock though - I ordered a double pumper yesterday. I will see when I get the old one out and post back up. It may be awhile though.
 
If anyone is interested here's what a bad fuel pump looks like.
 

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you can drop the tank and see if there is a split in the line going to the sender as well. Also see if the sock it dirty or clean.

then again if i drop the tank i would just replace the pump with a DW unit
 
Nothing wrong with anything on the old unit except that it was an old unit. I can tell you it was one of the Walbro 20000169 pumps or whatever. The sending unit looked pretty bad. I'm glad it's gone. The tank looked pretty good inside. Regardless, the old setup is gone - replaced with a Racetronix complete double-pumper setup with new Walbros. I will say that the Racetronix DP setup is a nice piece. I was worried about the wiring, but it's pretty dummy-proof if you read around in their support forum before installing. I can promise you I am an idiot when it comes to these cars, so if I can figure it out anyone can.

The new pumps work well with E85. Now running 22PSI, no knock, and 800 O2's at top of 3rd. Hadn't even played with fuel or timing in chip.

Thanks to all for help in positively identifying the problem.
 
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