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Too little fuel?

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Old 08-24-2011, 06:50 PM
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Car: 86 IROC-Z, 98 Z28
Engine: 370 LSx, LS1
Transmission: T56's
Axle/Gears: 3.73, 3.42
Too little fuel?

The car's a 92 RS 305 TBI. Went to the store, came out and the car wouldnt start. Took the filter off to watch the injectors, and it seemed like it came out in drips, no spray. Hows the pattern suppose to look on start up?

The car cranks fine, but wont fire. The car has a msd box, and blaster coil so next will be that I guess.
Old 08-24-2011, 06:59 PM
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Re: Too little fuel?

no gas? did you check spark? it seems like im always recomending it but I think you got a bad ignition control module. it depends if the injectors are spraying a little or not at all. if they are spraying some then more than likely your having a gas problem. ie. bad fuel pump, relay, etc..
Old 08-24-2011, 08:13 PM
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Car: 86 IROC-Z, 98 Z28
Engine: 370 LSx, LS1
Transmission: T56's
Axle/Gears: 3.73, 3.42
Re: Too little fuel?

Originally Posted by UnderCover89TBI
no gas? did you check spark? it seems like im always recomending it but I think you got a bad ignition control module. it depends if the injectors are spraying a little or not at all. if they are spraying some then more than likely your having a gas problem. ie. bad fuel pump, relay, etc..
I looked at the injectors again, to see if it'd start and I saw no fuel coming out. Didn't even hear the fuel pump prime. So I guess its time to check the relay out.
Old 08-25-2011, 06:21 AM
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Re: Too little fuel?

If you have someone to start the car you can try banging on the tank, the fuel pump might start working.
Old 08-25-2011, 09:15 AM
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Car: 86 IROC-Z, 98 Z28
Engine: 370 LSx, LS1
Transmission: T56's
Axle/Gears: 3.73, 3.42
Re: Too little fuel?

It runs... but it doesn't want to idle.

I replaced the fuel pump relay, well the relay on the firewall, furthest towards the drivers side. Fuel pump primed, and it started up after a couple cranks.

Any ideas on why it wont idle now? It idled fine for the first min or so. Then the rpms started falling, then back to idle, then falling, then back to idle, and so on till it wanted to cutout. I had the air filter off, and the iat sensor (or whatever its called) disconnect so I reset the battery, and plugged it back in, but that didn't help.

UPDATE: Went back to check some things, now the car wont start again. Fuel pump isnt priming again. WTF

Last edited by Rich92 RS; 08-25-2011 at 10:30 AM.
Old 08-25-2011, 10:30 AM
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Re: Too little fuel?

Fuel pumps not priming agian wtf.
Old 08-25-2011, 10:45 AM
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Re: Too little fuel?

Maybe a bad connection on the fuel pump relay connector? or maybe just coincidence and your fuel pump is actually bad
Old 08-25-2011, 11:19 AM
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Car: 86 IROC-Z, 98 Z28
Engine: 370 LSx, LS1
Transmission: T56's
Axle/Gears: 3.73, 3.42
Re: Too little fuel?

Connection seems fine. One of the prongs on the old relay was burnt, so the connector has some discoloring from it. I doubt thats affecting it though. I was about to check the fuel pressure to see if the fuel pump was going out, but I guess thats not going to happen.

If I jump terminal A to E on the fuel pump relay the fuel pump should prime correct? If it doesn't time to replace the fuel pump? Could the ignition module, be bad?
Old 08-25-2011, 11:29 AM
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Re: Too little fuel?

A dying pump's excessive electrical load may have caused the relay damage.

The module controls both spark & injector firing, on separate circuits.

Last edited by xch3no2; 08-25-2011 at 11:32 AM. Reason: ,
Old 08-25-2011, 04:24 PM
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Car: 86 IROC-Z, 98 Z28
Engine: 370 LSx, LS1
Transmission: T56's
Axle/Gears: 3.73, 3.42
Re: Too little fuel?

It looks like I replaced the fan relay instead of the fuel pump relay. Either way both have new relays now. After letting the car sit for a few hours the fuel pump primed . So Ive got the fuel pressure tester hooked up and will try to start it in a couple hours, on the off chance it'll prime.

Any recommendations on a fuel pump or where to buy one? The owner will never be modifying the car.
Old 08-25-2011, 05:36 PM
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Re: Too little fuel?

there should be a red wire with a connector coming off the fuel pump relay that doesnt go to anything. this is the fuel pump test connector. put power to it and the pump will run until you disconnect it. also you could soak a rag in gasoline and put it above the tbi and see if it will idle.
Old 08-25-2011, 06:52 PM
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Re: Too little fuel?

Most people run Walbro pumps and even though you say he is never going to modify it. I'd still put at least the WALBRO 190 LPH fuel pump in there. The stock pump is barely adequote for a stock engine.
Old 08-27-2011, 02:12 PM
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Car: 86 IROC-Z, 98 Z28
Engine: 370 LSx, LS1
Transmission: T56's
Axle/Gears: 3.73, 3.42
Re: Too little fuel?

We pulled the pump to find this:

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Looks like we'll need a new fuel pump harness connector, but what about the harness/connector from the top of the tank to the body? Where can we get one? Or will that one be fine?

Last edited by Rich92 RS; 08-27-2011 at 02:20 PM.
Old 08-28-2011, 07:23 PM
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Car: 86 IROC-Z, 98 Z28
Engine: 370 LSx, LS1
Transmission: T56's
Axle/Gears: 3.73, 3.42
Re: Too little fuel?

A big thanks to everyone who replied; UnderCover89TBI, ex-x-fire, xch3no2, one92rs. Thank you for the help, and replies. Also a thanks goes out to Pocket.

The car is up and running.
Old 08-28-2011, 11:25 PM
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Re: Too little fuel?

Im glad you got her going well.
Old 08-29-2011, 12:36 AM
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Re: Too little fuel?

cool now go drive the hell out of it.
Old 08-29-2011, 12:39 AM
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Re: Too little fuel?

Based on the fact that you don't hear your Electric fuel pump, Check fuses, relays,But I'll bet its your fuel pump.. If so, Rockauto has great prices on Pump&strainer...
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