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View Full Version : Fuel pump primes car starts then 15 seconds later idles like crap

mostdopes13
07-08-2013, 09:22 PM
It's an s13 redtop sr20det t25 with stock injectors. the problem i'm having is i went to turn the car on and it started then died immediately. i didn't hear the pump prime so i popped the cover off held on by 4 10mm bolts. literally that's all i did then the car turned over and ran fine. got home and turned it on a few hours later same thing happend so i just went back and wiggled the harness for the pump and sure enough starts right up. then it happened again but finally just wouldn't prime. i popped the pump out and the ground looked horrible all fried so i made a new ground and positive and it still wouldn't work.

I have a spare walbro pump so i put it in and the car starts and stays at idle fine and revs great really smooth but after about 15-30 seconds the idle gets really rough and shakes violently. doesn't die all the way but just really horrible idle.

I've replaced the pump and filter but the pump i replaced it with was my old used one so not sure if it's good.

just looking for some suggestions on what to try next any advice will help
Drink&Drift
07-08-2013, 09:34 PM
Could be a number of things,

A good place to start would be to make sure the gas in the Tank is good, has it been sitting for awhile? is there debris in the bottom of the tank?

The spare pump you had could also be kind of sketchy, rule of thumb is to never replace used parts with other used parts, go get a brand new pump, they aren't much, and go from there. im almost certain that's your problem.
mostdopes13
07-08-2013, 09:38 PM
Could be a number of things,

A good place to start would be to make sure the gas in the Tank is good, has it been sitting for awhile? is there debris in the bottom of the tank?

The spare pump you had could also be kind of sketchy, rule of thumb is to never replace used parts with other used parts, go get a brand new pump, they aren't much, and go from there. im almost certain that's your problem.

i've been driving it every day for the last few months and there's nothing at all in the tank it's clean. I can't think of what else if would be besides the pump either because i can hear it prime good and pump fuel but after like a second of priming it sounds like it gets really weak and isn't pumping much at all