Did I get a bad pump? I'm confused here.

Short story on the background of this problem:

Car began to have intermittent no start problems. Car would crank, but not start. Used a gauge and found there to be 0 psi of pressure whenever the problem occurred. OK, problem narrowed down to fuel. Problem became less intermittent and it would do it almost everytime. The car got to the point that it would not start for days. Before changing the pump I tested to make sure I was getting power at the connector for the fuel pump at the back of the car. I was.

Replaced the fuel pump with the racetronix complete kit w/ harness. Car started up, seemed to be running great. Thought the problem was fixed (aside from my fuel gauge not working, was going to have to pull the assembly out again).

Yesterday the car died while running. Then would not start. Symptoms seem identical, although I was too pissed to troubleshoot last night. I have to imagine I'm getting 0 psi of pressure again.

Now, I've heard about a failing opti with a low res signal send a PCM signal to shut off the fuel pump (or not activate it), but when does this come into play? I imagine this happens during cranking, and NOT with the key on "on" and just going through the two second prime. So it should at least prime right?

Also, when is there 12V going to the pump. I know for 2 seconds after you turn the key to on it primes and gives 12 V. While the car is cranking does the fuel pump get 12V? Obviously while its running, but what about cranking.

What else could be wrong here. Could I have just gotten a bad pump? Got about 20 miles on it before it died.

 

Checked fuel pressure regulator?

 

Ah, that brings me to another question. Would my fuel pressure regulator give me 0 psi at the gauge if it was the problem? I've always been under the impression that it would not.

 

damn.. dropped to page 3 quick.. anyone?

 

replace the fuel filter just to be sure, might be clogged.

 

fuel filter is brand new.

 

Make sure the relay that is under your left foot rest is good. You should hear it click when you turn the key in the on position. If it doesn't, then bingo Maybe it is that easy? Hopefully. Good luck!

 

i dont hear any clicks when i turn mine on... is that special for racetronix or something?

javier, just gotta take it out and see if the pump is working.... u changed it from the top right?

 

Well the relay is right underneith the foot rest and when you turn the key to the on position, you should hear the relay click, which is priming the fuel pump..

 

Real quick way to tell if you have a fuel problem since you don't want to use a fuel pressure gage. Squirt fuel directly into the TB while someone cranks the engine over. If it starts and shuts right back off. You got fuel problems.

First thing to check is the fuel pump FUSE which is #3 in the I/P fuse panel, 15 amps labeled PCM BAT. If that's ok go to the connector under the body in front of the axle near the tank vent. Left rear tire off, on a jack stand makes it easy. Take note of which pins have the grey wire and the black wire located on the top row, white connector. Measure across the grey and black wires with a volt meter while you have someone turn KOEO for 2 seconds. If you measure 12 volts there for 2 seconds AND your engine previously started by priming it with fuel, you have something wrong at the pump.

If you don't have 12 volts there, unplug the connector and measure the pins at the mating connector coming out of the body panel. Do KOEO again for 2 seconds and see if voltage is now there. If it is now there, the pump is bad. If it is not there. Proceed to the relay.

It aint fun to probe the back of the relay with it plugged in. When KOEO, there should be 12 volts at pin 30 for 2 seconds. If not, check pin 86 for a good ground. Then see if 85 gets voltage for 2 seconds when KOEO.

Good luck
Dave

 

Who said I didn't want to use a fuel pressure gauge? I tested it last night but didn't get a chance to post about it. Slapped the fuel pressure gauge on it again, and sure enough 0 psi.

The problem is still somewhat intermittent so I know for a fact it's not a fuse. I can sometimes get the car to start up, but it just dies right away.

I tested the electronics already before I swapped the pump at the rear connector. I know what I'm looking for but was curiuos about the questions I had in regards to when the circuit gets 12 V (aside from when you first turn it on for 2 seconds).. does it get 12V while cranking as well?

What about the opti aspect of it, will it even affect the car when it primes? I can't imagine it would.

Unfortunately I believe the pump is dead again (I can't believe I got a bad pump from Racetronix on my first shot, what luck...).

Emir, no, I dropped the rear and the tank.

To do the further diagnosis in tank I'm cutting a whole this time.

 

Have you tried the prime lead?

AFAIK, the f/p relay will be operational as soon as the computer sees signals from the opti (including cranking).

 

Isn't that the little square connector up by the computer? You put a lead from the positive battery to that connector and that supplies power to the fuel pump directly.

 

Thought I'd finally post a follow up on this.

With all my home projects I never got around to getting back to the car in a timely manner, but I went ahead and started some real troubleshooting today.

I checked for power at the new racetronix harness, 0 volts. Hrm. Checked the stock harness, 12+.. hmmm!

Check the racetronix fuse, blown.

I followed the harness to see wtf was going on, and found that I must not have forgotten one of the zipties.. whooops! Wire fell on the header and burnt it to a crisp, it was melted onto the header itself :/.... Got a 10 gauge butt connector spliced in and heatshrink wrapped it, good as new.

The car RUNS I ziptied it all back up properly now.

I still have to cut a hole in the back to access the fuel pump b/c my gauge is dead. The float must be stuck or something, but at least I know I don't have any more pump issues!

 

ttt for the day folks.