Ok so my 1990 3.0 is running really rich, you can smell it in the exhaust, and my idle is really high in the mornings and doesn't want to come down much more than 1800 before its had a good long while to warm up. I have no clue whats going on so anyone have any suggestions?

I think I'd hook up a meter to the diagnostic port to see if it identifies any codes. A good place to start checking would be the o2 sensor and cleaning the ISC. Add a can of BG-44K for injector cleaning. Check the air filter. Check the ignition timing. Look for vacuum line leaks. Check the oil for gas - 20-30% of air at idle comes through the PCV valve - replace it. Fuel pressure regulator - maybe, but not likely. Many other possibilities - even bad battery connections. Check these and maybe others will have additional ideas if you don't find it on this list.

Good luck,
Frank

I used a can of Berryman's Chem Tool which usually cleans her right out, but it didn't seem to really improve/worsen it at all. If I recall correctly this started occurring shortly after I "cleaned" the ISC, I dont know if that would mean anything to anyone. I'm going to pull as many plugs as I can reach tomorrow and check to see if any are fouled, but its still runnings smoothly so I kind of doubt it.

Berryman's Chem Tool? How did you use that?

Frank

Its just stuff you dump in the gas tank... I think its basically a concentrated carb cleaner that you can add to your gas.

I've used it as a carb cleaner to clean intake manifolds and such, but it's pretty strong stuff and I wonder if it does any damage to injectors and seals..... maybe not if it's prescribed for that use. I use BG-44K as an occasional fuel system additive.

Frank

I think I am going to go ahead and replace all the plugs with NGK's, and do the PCV valve + maybe a fuel filter for now. I believe the plugs were done about 35k mi ago, but I think they used Bosch, which I despise and do not trust so I will just eliminate those from the equation. How long should plugs be good?

Service interval for our plugs is 30,000mi. I do mine once/yr whether I reach the interval or not, I mean heck - six spark plugs cost just as much as one quart of Mobil 1. <img src="/forums/images/graemlins/lol.gif" alt="" />

Remember that lean misfires can cause rich-smelling exhaust. The fuel vapor comes through and the smell even though it's lean. It would be easier the know what's going on if you had access to a four gas analyzer and a scope. I'm betting you don't have either of those laying around so for now I would replace any worn secondary ignition parts (plugs, wires, cap, rotor) and then clean your fuel injectors. You probably don't have the tool for that either, but if you ask around, someone in your area might. Or you could pay a shop to do it. Independant shops are usually less expensive for that kind of thing, but shop around. It really does help (I used to think it was a big rip-off until I started performing the services and testing the results before and after (required for GM warranty)).

Also, if you have an exhaust leak BEFORE the O2 sensor it can really screw up the way it runs. The sensor sees the extra oxygen and fattens up the system even though it isn't needed.

Hope that helps,

Clay

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My turbo seems to be running rich. Sooty exhaust pipe and rotten MPG. The turbo motor has a secondary air system that lets air into the exhaust at the downpipe, right where the O2 sensor is. Something to do with more air for catalysis when the engine is cold. Mine definitely has a leak right where the the feed pipe goes into the downpipe, which is again where the O2 is. Could this likely be causing similar to happen to me? TIA

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