C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Starting Issues

Old Jan 26, 2007 | 06:51 PM
  #1  
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Default Starting Issues

I posted this in the general section without much luck so I thought I would try here.

I have a '93 automatic with 56,00 miles on it. When you start the car normally, it will start but idles very low and then sounds as if it "chokes" off. If you start the car with the accelerator depressed just enough to idle the car around 1100 RPM's for a minute or so it runs fine.

The throttle body & AIC valve have been cleaned in the last 1,000 miles as well as new plugs & wires. All was done at the Chevy dealership so at least I know I didn't screw something up.

It ran fine when I got it back, it just started this in the last couple of days. The weather here has been quite mild (our low day last week was in the 50's) so there hasn't been any brutally cold days and the car is kept in the garage. I also checked and have no codes.

Any help would be appreciated!
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Old Jan 26, 2007 | 07:21 PM
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Have you checked for any vacuum leaks?
Have you checked to see if any plugs are loose?

I would suspect that something was moved to access the things the dealer worked on.

I'm totally off the cuff here but I think they cracked a vacuum line that was age hardened or left a connector loose.

In cleaning out the intake was the MAF touched? IIRC those clean themselves off and manually cleaning them can be problematic.

As a diagnostic step, what would happen if you unpluged the leads from the MAF housing? Would the car stay in open loop or would it die suddenly? I don't know.

I think it's either vacuum related or a sensor is giving bad data to the comp.
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Old Jan 26, 2007 | 07:25 PM
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Could be fuel delivery. fuel pump, clogged filter, etc. Have fuel pressure checked.
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Old Jan 29, 2007 | 10:47 AM
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Default

Originally Posted by 94z07fx3
Have you checked for any vacuum leaks?
Have you checked to see if any plugs are loose?

I would suspect that something was moved to access the things the dealer worked on.

I'm totally off the cuff here but I think they cracked a vacuum line that was age hardened or left a connector loose.

In cleaning out the intake was the MAF touched? IIRC those clean themselves off and manually cleaning them can be problematic.

As a diagnostic step, what would happen if you unpluged the leads from the MAF housing? Would the car stay in open loop or would it die suddenly? I don't know.

I think it's either vacuum related or a sensor is giving bad data to the comp.
I have already checked all of the plugs and they were fine. I didn't think the 93 used a MAF, I thought they used Manifold Absolute Pressure but I may be wrong.

My initial thoughts were leaning toward a vacuum leak as it only does this intermittanly but I hadn't thought about the fuel filter. I'll check that this weekend.

This past weekend I went out after the car had been parked about 2 weeks and it fired right up. I drove it around most of the day Saturday and no starting problems until the trip home. This one last time same issues.
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Old Jan 29, 2007 | 02:29 PM
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From: Lawrenceville GA
Default Starting issues

Had most of your systems plus some recently. I replaced the map and got immediate improvement. But not for good...after extensive reading and then following threads, I replaced the ecm..2 weeks later the car runs better than ever. I think "zip" will rebuild yours for $100.00.
Keep posting!
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