TBI Throttle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.

Car wont start with out ether runs rough

Old 09-25-2017, 03:49 PM
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Car wont start with out ether runs rough

1991 305 TPI Z28 coupe. Started running rough after warmed up, then died while going down hyway after warmed up. will start again with ether after cooled down. Replaced : throttle position sensor , temp sensor, ignition control modual , fuel filter, ECU, maf sensor. Im going to sell it for parts ifg Ican't get it running.All these things I replaced are from tips on here. does any one know what causes this or is it oen of those things that might be 1 to 1000 different things?
Old 09-25-2017, 04:16 PM
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Re: Car wont start with out ether runs rough

You've already sunk some dough and time into this. A little more might do the trick.

The ignition coil is cheap and easy to change. May want to give that a go. They can respond to heat soak when they start to fail.

It can't be that many things.

So just to be clear:

Cold it starts fine and runs fine. Then when it warms up it dies until cooled down again?

Before it did this was it running fine?
Old 09-25-2017, 04:16 PM
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Re: Car wont start with out ether runs rough

If your engine has TPI (Tunes Port Injection), you'll want to post this in a different section, or ask a Mod to move it for you. This section is for TBI (Throttle Body Injection) posts.
Old 09-25-2017, 04:31 PM
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Re: Car wont start with out ether runs rough

Have you omed the injectors ? Stock multecs fail when warm the coils short out.

Old 09-25-2017, 05:34 PM
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Re: Car wont start with out ether runs rough

Originally Posted by Colemaro
Replaced : throttle position sensor , temp sensor, ignition control modual , fuel filter, ECU, maf sensor... ...or is it oen of those things that might be 1 to 1000 different things?
If you INSIST on taking wild guesses, you could be at it until the end of time. You'll learn more from the data stream than you'll learn in a dozen internet postings.

Put a scan tool, a compression tester, and a fuel pressure gauge on that thing, and find out what's actually wrong. Fix only the true problem.
Old 09-25-2017, 05:42 PM
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Re: Car wont start with out ether runs rough

^^ agreed but he didn't mention the coil. $35, 20 minutes, and a likely suspect in heat soak issues. Even though I would be smarting from those parts too, the coil is mighty tempting...
Old 09-25-2017, 07:14 PM
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Re: Car wont start with out ether runs rough

Originally Posted by Tootie Pang
^^ agreed but he didn't mention the coil. $35, 20 minutes, and a likely suspect in heat soak issues. Even though I would be smarting from those parts too, the coil is mighty tempting...
A $15 spark tester and five minutes could verify the ignition coil.

Point being, diagnosis before parts replacement.
Old 09-25-2017, 07:17 PM
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Re: Car wont start with out ether runs rough

Might be to late looks like the owner has given up
https://www.thirdgen.org/forums/cama...ale-cheap.html
Old 09-25-2017, 08:02 PM
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Re: Car wont start with out ether runs rough

Nice of him to follow up.
Old 09-26-2017, 12:52 PM
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Re: Car wont start with out ether runs rough

I'd check fuel pressure at the fuel filter under the car first, then ohm out the injectors if pressure is good. If pressure is not good at the fuel filter, then I'd suspect the fuel pump.
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