Replaced battery, now will not run

[Dynomite]

Originally Posted by FormulaReed

About 2 weeks ago, I replaced the TPS, plugged in my scanner and set the TPS voltage. Car was running good. Went for a drive, turned her off and on and everything was fine.

The forecast was calling for some snow and I knew that I would not be driving the corvette for awhile so I took the battery out and plugged it into a float charger.....

Well, today the weather was great and I wanted to take the vette for a spin, nut when I put the battery back in it cranked fine, started up but than died. I tried a few more times and got the same thing. I can smell fuel, so I think it's getting fuel.

Any ideas? It wants to run, but it turns off like the ignition is being cut.

My car is a 1991.

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If you smell gas then could be Fuel Pressure Regulator........especially if the LT5 starts after sitting for a while then floods out and quits.

Starts up then begins to run rough and dies

[FormulaReed]

I'm hoping to get sometime this week to work on my car.

Will a bad fuel pressure regulator show with just a fuel pressure gauge on the fuel rail? Can I inspect it with out pulling the plentium?

I

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[Dynomite]

Originally Posted by FormulaReed

I'm hoping to get sometime this week to work on my car.

Will a bad fuel pressure regulator show with just a fuel pressure gauge on the fuel rail? Possibly depending on how big a leak....but if you have raw gas (or smell gas) within the Plenum that is a sign of leakage.

Can I inspect it with out pulling the plenum? No....Unless you have Phil's Modified FPR

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The "Valves" within the FPR can corrode or collect rust particles.


Phil's Modified FPR (Before and After Installation.

[FormulaReed]

After some down time due to an attempted theft and having to get the steering column rebuilt, I'm back to trying to fix my car....

I put the column back in, took the battery off the charger, hooked it up and tried to start her... I was pretty shocked when she fired right up and settled into a nice idle. So I let her warm up, and all was good.

I went for a drive today, and it was running great, just mobbing on the freeway, doing 70 in 5th. I went to give it some gas and she just fell on her face.

I pulled off the freeway and the idle was hung at like 1.5k. It never died, but it was not happy. Felt like it was misfiring, but cleared up once the revs were up. Never got a cel.

So. I got home and hooked up my scanner. No codes. The only thing I saw was that the TPS voltage was a little high (.61v) so I set it to .55v. Restarted the car and it ran like ****. Turned it off, turned it back on and it ran fine. It tossed a code 42.

I decided to pull the plugs. They looked fine, but I replaced the, anyway. The only thing was that one was really loose, like finger tight at best. After I did that, I started the car and it ran pretty good. I went for a drive and did some data logging. It ran good, but the idle was still hanging. Didn't drive in on the freeway.

I've replaced the TPS sensor, crank position sensor, map hose, both fuel pumps.

It seems ok when it's cold, but once it's warmed up the issues start. Could a loose spark plug cause this? Would a bad o2 sensor cause this, I'd think it would throw a code? IAC? What should it read at idle and how much should it change when I'm driving?

Thanks in advance.



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[BigJohn]

Did someone foul your gas?

[lfalzarano]

I’ve lost several plugs that came loose and popped out. A loose plug gives you a rough idle only in my experience. A blown plug makes a horrible sound!

The high idle might be the IAC. After fixing that, it still ran high. Finally, sent the throttle body to Marc. He found a piece of gunk on the engine side of the throttle plate, causing the high idle. Plus , installed Marc’s chip which also helps.




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[Ccmano]

I’m confused, you covered a lot of territory here. You mention several issues but not if they were fixed. Is the high idle the only issue that remains or are there others?
H

[FormulaReed]

Originally Posted by Ccmano

I’m confused, you covered a lot of territory here. You mention several issues but not if they were fixed. Is the high idle the only issue that remains or are there others?
H

Haha. Yeah, that post was not super clear.

The idle is still hanging when it's warmed up. It's worse if it's been driving at a constant speed. If im shifting through the gears it's ok.

I didn't drive it very far after I replaced the plugs, so I'm not sure if that cured the throttle issue.

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[FormulaReed]

Update: I replaced the IAC today. The old one looked pretty bad and there was a bunch of carbon crud on it and in the housing. I cleaned up the passage way and installed the new one.

I let it warm up and went for a little drive. It seems like the throttle hanging and high idle are fixed. Might just be psychological, but the throttle response felt really good.

It still doesn?t come down to idle right away, it takes a few seconds for it to come down. But I?ve heard that?s somewhat normal.

It feels like the idle is low, it?s 675 rpm when warm. Is that ok? What are others seeing?

Thanks!

[Paul Workman]

If you said what year yours is, I missed it. But, mine is a 90 and after highway speed/rpm and comming to a stop, the idle is high initially before dropping gradually to normal over 2-3 seconds.
Also, if for any reason the engine should stall while the car is rolling (happens occasionally on hot humid days with the clutch depressed), the car has to be brought to a complete stop for 2-3 seconds before the idle will return to normal. And, the same thing after shutting the hot motor off to fill the tank; high idle for 2-3 seconds. I've come to accept the behavior as "normal" for a 90, far as I can tell
However, my wife's 91 Z does not behave the same way. It never has done the high idle thing - @ least not yet when I've been behind the wheel.