HELP !! Rough idling after comp test

Ivan G · 07-09-2002, 05:14 AM

I had to have some minor work done to my 82 SC suspension to get rid of an annoying squeak (which is fixed now !)

I also asked the dealer to do a compression test on the engine (the results were fantastic)

Nothing else was done to the car, as far as I know

However, on the way home after I picked the car up (the engine was warm when I collected it), I noticed that the idling was very rough. Instead of sitting nicely at 800rpm, the idling was down to around 400 and very rough.

From a cold start a few hours after I got home, whilst the engine started first go (as usual), the idling was so low that the engine kept on stalling......

Question is whether it is possible that there was something the mechanic could have done (or didnt do) before, during or after the compression test which would have caused this !!

I am not mechanically minded at all so I was hoping I could get some ammo from you guys to throw at the dealer when I call him tomorrow...or else he will tell me its "co-incidence"

Thanks !

Targa77 · Targa77's Garage

I would call the dealer and tell them that. Let them worry about about it. Also, they would have to remove sparkplugs on each cylinder to perform the check. Make sure all sparkplug connectors are firmly seated.

Jdub · 07-09-2002, 06:37 AM

A comp test is often a good time to replace the spark plugs. Was this done? If not, do you know that the tech. torqued the 'plugs into the block correctly? I would ask that they check this work. Also, it is best to put plugs back into the block when cold as I understand it, so if they did this work when the engine was hot perhaps the plugs were not well seated?

Plug wires an obvious check. Pull and snap each back on firmly.

John

LFogelson · LFogelson's Garage

I had a similar problem last week... the oil cap was on loose. Worth a quick check. Good luck.

jhh967 · 07-09-2002, 04:41 PM

I would like to second the idea of the previous respondents that its probably a spark plug problem. If its not that there is a possibility that something fell down in the combustion chamber and got caught under the exhaust valve. Its pretty unlikely, but I've seen it happen.

john walker's workshop · 07-09-2002, 05:00 PM

you could check if the frequency valve is still working by pulling the plug off the relay under the passenger seat, between the computer and tunnel. if nothing changes (lower idle, rougher run), the relay may be bad, or it's fuse blown. the domelights use the same fuse, so if they work, the fuse is ok.
maybe the tech adjusted the mixture and idle speed out of the goodness of his heart.

Ivan G · 07-10-2002, 05:37 PM

OK, its fixed and for those that wanna know, it landed up being a loose "vacuum hose"