1992 'monster' vette running on 7?

[djxib]

I have put about 50 miles on the 92 monster 'vette since I got it, and noticed on my way back home tonight that it has started to run a bit lumpy. Not entirely unexpected that a couple of things would go wrong (it has hardly been used in the last few years).

Symptoms:

- Rough Idle
- slight hesitation/jerkiness on light throttle
- full throttle sounds/feels ok, although not quite as responsive as usual and engine sounds a bit rough.

I plan to get it tuned up and dyno'ed over the next couple of weeks, but I wonder if anyone could post a quick checklist that I could run thru at home. First on my list is to check all plug leads, as it feels like it is running on 7 cylinders only.

Thanks!

**Saw other threads about rough idle at high temperatures, so just took her out for a spin from cold. Still running rough.. too dark to check the plug leads yet. **

Incidentally, after a run the temp guages all seem normal (water temp on half, oil on about a third). However, after a 10 minute run the under-bonnet temperature is ROASTING - way too hot for example to go anywhere near the oil dipstick. Nothing (perhaps) to do with the bad running, but definitely seems that something is running too hot. Or is this just a vette thing?

 

[MoeJr]

The distributors on these cars are known for high failure rates eso. early LT1's. I would look here first.

 

[redc4corvette]

How many miles on the car? you might try the o2 sensors and chevy has a recall on some of the 1992 opti-spark dist.I forget where the list is but the list is on one of the forms.It goes by vin number,check the water pump.
More info will give better results.Just my 02.

 

[WhalePirot]

Electrics and fuel, AFTER finding the errant cylinder. If you have a tach you can read (while pulling one plug wire at a time) the 'no-RPM-drop' cylinder.

Then, spark side being easiest, check for a good, healthy blue spark, using a fancy tool or an insulated screwdriver inside the plug boot, jumping the spark to ground or the plug. Hopefully you can do this before things get too hot!

You can visually check for leakage from a wire in a darkened garage by observing bluish arcing along a plug wire.

I'd pull and inspect the plugs, reading the condition and color of deposits before getting into the distributor.

Just a small start.

 

[djxib]

Thanks all for your advice. It ran much better the next day, and the only thing that was different was that it was raining the day before. Damp into part of the electrics perhaps?

The previous owner told me that the guy who rebuilt the engine said that the modified cam would give rise (forgive the pun) to a lumpy idle.

I'll live with it for a while.

Cheers,
Andy.

 

[Vettelt193]

check the vac. tubes connecting to the intake too... there are a few of them, some small, some big. With the blower, you could have a loose one, which would screw idle up, and also could cause a bit of power loss at higher revs.

I am not sure on the details on your car though, how much boost, what kind of supercharger, etc.