Mechanics

90 ROUGH IDLING SOMETIMES

1990 Honda Civic

Car runs great 168k miles. Sometimes it will lose rpm at idle then accellerate and lose rpm, strong fuel smell from exhaust. Turn the car off or drive it and it goes away. Doesn't happen all the time only about 5% of the time.
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Bellmp
September 1, 2006.




Check for vacuum lines for leaks, check coolant level, bleed the coolant to remove any air.

Bruce Hunt
Sep 4, 2006.
Bleeding the air froim the cooling system must have done it, thanks
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Tiny
Bellmp
Sep 16, 2006.
I have the same car 91 Civic Hatch, but with 114k on it. It has the same problem but it seems to do it all the time. I think its burning oil. I pulled the plugs and they had oil on them. The car also smokes white from the exhaust and there is dirt coming from the exhaust openings. When I pull the third plug it seems to idle fine, It could be a number of things. Where do I start?

Tiny
EFOptmst
Oct 30, 2006.
Dirt coming from the exhause openings - what exhaust openings?

You are obviously loosing coolant from the cooling system. Any water or coolant in the oil?

I suggest a compression check. Determine if the cylinder compression is weak and check to see if the compression is consistant in all cylinders.

After that it is time to get down and dirty. I would pull off the head, have it looked at and checked for cracks and warpage. I would look at the head gasket to see if it is bad and note what the top of the pistons look like. Are they oilly, does it appear that the oil is coming from the rings or dripping down through the head. The engine is not good. Head gasket and head check could fix it or improve it. But if the rings are bad it is engine rebuild or replacement time.

Bruce Hunt
Oct 30, 2006.
I believe it was carbon /water coming from the exaust and the little pinhole in the muffler. It has new hoses and it is not using coolant, and there is no coolant/water in the oil. I drained some oil, and put some new oil in and a bottle of that thick molasas shit in it. I think it worked. Im goin for a tune up first then the head gasket was my next move. I pulled the spark plugs(which also were covered in oil, not good) and cleaned them up, put them back in and drove it for a while and kept it runnin. It seemed to help, I think the spark plugs are staying dry. The idle problem is now bearable, but not perfect, but now my revs are drained a little when I put on electroes like lights and defroster.

Tiny
EFOptmst
Oct 30, 2006.
The idle is still going up and down? If it occurs all the time, look at the hoses for a vac leak. The intake manifold and manifold gasket could be leaking. Don't discount this. Had any work done around this area? The air could be getting into the intake manifold unregulated and confuse the computer thus causing the surging of the engine.

Bruce Hunt
Oct 30, 2006.

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