Exhaust smells like van is running rich


Old 02-03-05, 07:36 PM
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Exhaust smells like van is running rich

Hi all. I've tot a '95 Chevy G20 conversion van, 120K miles on 5.7L engine. The exhaust smells like the van is running rich, but since it's got fuel injection I don't know what - if anything - I can do about it. Any suggestions?

Overall, the van rides very well. I don't see a noticable power loss. Some days it seems to have less pep than others, where I've got to really press down on the accelerator to get going. Other days, it jumps when I hit the gas. Perhaps since I'm in South Florida, the humidity has something to do with it, as the cooler/drier days yield the best perception of performance.

I'd like to clear the exhaust smell up and (hopefully) improve gas milage. It smells like I'm wasting more than I'm converting into forward momentum

Thanks in advance,

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Old 02-03-05, 08:44 PM
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The first thing I would look for is a plugged air filter. If the filter is ok, it

probably needs a trip to a good service dept.
Old 02-04-05, 04:37 AM
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Also, the usual pm stuff: plugs, wires, cap & rotor, and a fresh O2 sensor wouldn't hurt if yours hasn't been replaced lately. Might save you the cost of going to a garage besides which those are likely to be the first things they check anyway.
Old 02-04-05, 03:38 PM
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Thanks for the suggestions. As for the air filter, it is a new K&N. I haven't checked/replaced the other components, as access to the engine compartment will require a good hour or two's worth of time taking everything apart to get to it.

The passenger side seat needs to be removed, since it does not slide far enough back to allow for removal of the engine shield. Also, there is a wooden console, TV, DVD, CD changer, etc., not to mention I can't figure out how to disconnect the power mirror control wires.

I've been dreading this for about two months now. I know it's going to turn into a weekend project just to do a basic tune up.
Old 02-04-05, 03:39 PM
Join Date: Apr 2002
Location: Pittsburgh,Pa
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Does it smell like rotten eggs/sulfur?If it does it may be running rich or the gasoline you are using is higher than normal for sulfur content.A misfire will also cause a rotten egg smell.Everything that has been suggested so far would be good places to look as would changing brands of gas if you only use 1 brand.
Old 02-04-05, 03:59 PM
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The smell is more sickening-sweet, if that makes sense, and is most noticable when first started after sitting a while.

I don't detect a rotten egg odor, or at least it's not strong enough to really notice. You mentioned one brand of gass, and yes, I have been using only one brand since buying the van about 5 months ago.

As far as the other suggestions, should I just go ahead and replace the items suggested (cap/rotor, wires, plugs, O2 sensor)? Other than the PM work I've done, I have no idea about the PM history on the van - and it is at 120K miles - so I'm guessing it couldn't hurt.

Old 02-04-05, 04:23 PM
Join Date: Apr 2002
Location: Pittsburgh,Pa
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A rich mixture will never smell sweet but burning coolant can so check the coolant level.Keep us posted.
Old 02-09-05, 01:09 PM
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I once had a cougar that was loosing power similar to what you're describing and it turned out the catalytic converter was plugged up. A good test for this is to just drop the cat and run the vehicle. I tried it and it ran great. I put a straight pipe in and the car lasted another couple of years.
Old 02-11-05, 12:03 PM
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The coolant comment is worth checking out. See if the coolant level is going down, or if there are exhaust bubbles or tan creamy oily deposits either in the radiator or on the dipstick. If the level is going down, there may be a head gasket leak that allows some coolant into a cylinder. I just replaced a head gasket on a 1995 Chevy S-10, and remember the type of smell you are talking about. Also - a lot of coolant burning out through the exhaust can ruin the catalytic converter.

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