87 Warm Weather Start/Run Problem

[kompara]

My '87 has trouble running when first started on a warm (50 degrees or higher is warm here in Ohio) day. Tons of white smoke out the rear, backfiring thru the intake, stumbling and bogging when trying to accelerate and, seems like, a slight miss. Once it "clears its hairball" and warms up it runs fine, no trouble for the rest of the day. . . next morning, same routine. On a "cold" day the problems are minimal. My local Corvette "specialist" dealer is stumped. The car has 56000 miles and was tuned (plugs, ignition wires, new MAS) and ran fine 4000 miles ago. Any suggestions folks? Thanx!!!!!!

 

[XJ6GUY]

mine did the same thing but not as bad, it went away after i ran the old gas out of it and refuelled.most likely just old gas and water in the tank from the weather changes here.....cheers


tom in cleveland

 

[Bmann08]

Could be as strange as the starter not turning the engine over properly.?

 

[spyysee]

the white smoke sounds like water...how it's getting in is your challenge.
hopefully it's just water in the fuel, as previously stated.
Check your oil and make sure it doesn't look like "mousse".

 

[kompara]

mine did the same thing but not as bad, it went away after i ran the old gas out of it and refuelled.most likely just old gas and water in the tank from the weather changes here.....cheers


tom in cleveland

Tom, Thanks for the reply but it runs this way all summer long, even with new gas.

 

[tnovot]

I can't vote for the starter theory but will agree with spyysee that you should check your oil for water content.
Do you have to add coolant often? Maybe at certain engine temps, expansion and contraction open up or close a cracked water jacket or other internal water leak. That really wouldn't explain the engine misses though unless water was also getting into the intake somehow.

 

[kompara]

Thanks for the replies folks but there's no water in the oil.......the white smoke (if I remember the fabulous 50's and dual quads that hardly ever ran right) could be from the engine "loading up" with fuel but, if that's the case, I don't know how/why this is happening. It's only a guess anyway. Keep the thoughts coming!!! Thanx

 

[RedRagTop]

By new MAS, do you mean MAF? Getting any codes? Almost sounds like something that is cracked or open when cool but closes due to expansion when warm...

 

[kompara]

Sorry about that, I meant Mass Air Flow Sensor. I understand your thought on the temperature related crack/leak but after initial start in the morning I can let it sit for four hours or more before restart and not have any problems. Seems as though it has to sit quite a while, like overnight, for the problem to arise. I do get a check engine light at initial start if I let the engine stall.

 

[RedRagTop]

If you did the MAF you may as well change the relays mounted behind your battery. They are cheap at about $25 the pair and are suggested periodic maintenance.
C4vettes.com will show you how...

 

[kompara]

Randy......My Haynes manual shows the burn-off relay to be located under the right hush panel near the ECM rather than behind the battery. I did locate the relays behind the the battery that have, apparently, the same part number as the burn-off module. Any thoughts?????? Anybody else out there feel free to jump in!! Thanx

 

[Vettefan87]

The relays were bad on my 87 but it didnt run that bad. Mine would stall from time to time and mine always had the check engine light on. it never smoked like what you stated. You might have to take it to a diagnostic shop, just my opinion.

 

[RedRagTop]

I am assuming your 87 has the same set up as my 88. This may not be so. I'm not sure about the burn-off MODULE, but the two relays, which are the same, located behind the battery, are the main source of MAF codes. This job is an easy 3 beer after lunch project and well worth the time/effort. I screwed mine by having too much oil on the K&N.
Good luck.
RJS

 

[taegdh]

You didn't mention if it had sat idle for an length of time, but being you mentioned Ohio, I'll take it that it did. That could present a problem for the gas going "bad" as has been mentioned before. I had a similar problem last year, ended up dumping in a bunch of "dry gas" and going on 93 octane for a half dozen tanks. Also put in a new fuel filter.
Being you're up in Ohio I'll just take it for granted you know what "dry gas" is and where to get it.
If this persists, you have to find where the water is coming from because it doesn't compress, and can really mess up your engine.