I have a question about a 1990 chevy 1500 (I know its not a ranger)

[johndeeregarner]

I have a friend that has a 1990 Chevy 1500 with a 350 in it and it has a couple problems with it. I know its a Chevy but try to bear with me. The speedometer isn't working at the moment but when they took the instrument cluster off and made sure all the connections were good it started working, then stopped when they started the truck again. Anyone have experience with these that could help me out?

Also, the engine idles ruff. They have replaced all the spark plugs, distributor cap, plug wires, and the O2 sensor. Is there anything else that I could check?

By the way. Just so all of you know, the only reason that I am posting this on here is cause we have tried the Chevy forum and they don't really know what they are talking about. I just figured you guys might know something about it. And I have NOT switched sides (Ford vs. Chevy and all that). This is just a friends truck that I am helping fix. Just thought I'd throw that last paragraph in there.

 

[snake]

On the rough idle, check the compression, try injector cleaner, replace the fuel filter, and check for vacuum leaks. Could also have a faulty EGR if so equipped. If it has an IAC clean that as well.

 

[johndeeregarner]

Ok, we haven't checked the compression yet so I'll do that. And they did replace the fuel filter, so don't think its that.

One more thing. It smokes white smoke. Don't think its the heads or the head gasket though. It may be the rings or the valve seals. I need to check the compression on it to make sure.

Thanks for the suggestions,
JDG

 

[RustedRanger]

I had an 88 and it acted kinda like that. It could be head gaskets. Mine got oil into the coolant and the head bolts were not tight at all. It was full of carbon and it was cheaper to get a new crate motor than to rebuild it. I think it had been badly overheated. I hope for your friend that it doesn't turn out that bad.

 

[wrecking-crew]

if it sat for a while the white smoke might be condensation iin the exhaust. try running seafoam thru it

 

[mentalbreakdown00]

The TBI gasket is bad about cracking and disapearing, will cause a vacuum leak and make it idle high, run rough, and rich..... last but not least make sure you set the timing with the brown/ black wire disconnected... 0 deg timing

 

[johndeeregarner]

Ok, they got it to idle fine now. But it still smokes. We're thinkin' the head gasket is blown, but we're not sure. She drives it now and its doin' fine, besides the big puffs of smoke every time she accelerates. Its pretty funny!

 

[mentalbreakdown00]

ok you can go to carquest and get a block check kit and check for co2 in the cooling system, doesnt cost a whole lot and just follow the directions on it..

 

[Jspafford]

GM's are known for bad intake manifold gaskets... I just did one on a 4.3L over the weekend. It will dump coolant into the crankcase if bad.

 

[johndeeregarner]

Yeah, it burns oil and water. So..that should say something. Their thinking about just replacing the engine with a new one and then rebuilding the old one.

 

[D.J.]

What did the compression test show?

 

[D.J.]

I have always been told, blue smoke = oil burning, black smoke = unburned fuel, white smoke = coolant or water burning! Anyone ever heard this on a gasoline engine.