[Scout1]

I was standing next to my son's 99 DOHC when he started it and noticed a pretty strong carbon/exhaust smell. I know what antifreeze/head gasket type leaks smell like and this was not it. The car runs fine, no codes or pending codes. Live data read outs look normal as far as I can tell. No smoke from exhaust but the inside of the end of the tailpipe is pretty sooty. It does not get very good gas mileage as a lot of you guys claim on the forum, but most of the driving is quick in town traffic trips, no real open road driving. It gets maybe 15mpg. I did a lot of work to this car when I bought it for my son and it seems to be pretty tight. Good compression, new plugs, new intake gaskets, new air filter and so on. I have not changed plug wires, they look almost new and appear to be of high quality. It runs good other than the gas mileage. Any ideas, or just live with it? Thanks.

Ed

 

[901-Memphis]

The in town stuff is going to be the worst mileage. Your best mileage will result from speeds on the interstate steady in 4th gear with cruise control.

I get 15 mpg all year long no matter what conditions driving in the city

When i hit 99% interstate travel with cruise control @ 65 mph i top 30 mpg.


Have you checked for leaks in the exhaust before the cat?

 

[Scout1]

901, Exhaust is tight and in good condition. The smell is pretty strong and I think an indication of it running rich. This may be normal on first start up but I don't know. Maybe it is supposed to run a little rich when cold. Like I said it runs good and no codes, so I guess I will leave it alone unless it gets worse. Thanks.

Ed

 

[901-Memphis]

Maybe there is an OBD 2 code reader that can tell you air fuel ratios in real team on a laptop that you can borrow from someone and figure out exactly if thats happening?

I wouldn't be the least surprised to find out they run rich cold.

Cleaning that idle air control valve with brake cleaner could possible give some assistance to the A/F ratio because i know the Vulcans clog up there just like myne has.

I have also had EGR problems in the past as many others have had with using bad gas and getting that area clogged with carbon too.

If the car is running right with no pending codes i think you will be fine until it throws one out to say otherwise.