Hi All,
I bought a '91 Civic Hatchback last year to keep fuel costs down and have been very pleased with it until recently. A few months ago it began occasionally running rough on startup (like its running on 2 or 3 cylinders) for a few seconds then it evens out and runs fine. Now it always does this and sometimes I have trouble starting it.

Has anyone else dealt with this? What did you do to solve it?

Thanks,
Chris

 

Does the Check Engine Light (CEL) stay ON when the engine is running?

Sounds like a problem with the Electronic Air Control Valve (EACV) (also known as the IACV). Search the forum for a DIY method of cleaning the valve with carburetor cleaner. If cleaning doesn't solve problem, the EACV may need to be replaced.

 

Nope, no CEL. It comes on as I start it as part of normal operation, but it never stays on as I drive around.

I think this is a separate issue, but it has also been overheating. I'm replacing the thermostat tomorrow.

Thanks,
Chris

 

have you checked the EACV??? do you have oil in your water?

 

1) Not all EACV problems will throw a CEL code.

2) As you mention, a bad thermostat is one possible cause for overheating. Another is a failure of the radiator fan to turn ON when the engine is hot. Have you ruled out this possibility? Also, does the engine lose coolant, indicating a leak?

 

Hi All,
I've now cleaned the EACV. It was filthy, but cleaning it didn't fix my problem. After more troubleshooting, I believe I have a faulty injector. Its difficult hot or cold, it always runs rough now (previously it only ran rough until it warmed up), and the exhaust has puffy white smoke that has the faint smell of fuel.

I've isolated the problematic cylinder. I pulled the plug wires one by one. 2, 3 and 4 caused a drop in RPMs, 1 had no effect.

So now a few more questions.
1) Should I do any more t/s to fully isolate the injectors?
2) How can I tell which injectors I need? I know the car has been modified, but I don't know how much. The previous owner told me that he swapped out the engine, and then swapped the head later. The block is D15B6.
3) Would it be safe to get injectors from a junk yard? I doubt I'm going to have the car another year so I'd rather not pay full retail.

Thanks,
Chris

 

White smoke together with overheating is worrisome and may indicate that your head gasket is blown. Are you losing coolant?

Does the plug in cylinder 1 spark? Why do you think the fuel injector is bad in cylinder 1? Might the problem with cylinder 1 actually be low compression, possibly due to a blown head gasket?

 

I'll check the compression on it tomorrow. It does lose a little coolant, so you may be on to something. Is it possible that the gasket could slowly go out over a period of months? The car ran perfectly until last Aug/Sep, ane has been getting progressively worse since then. If it is the gasket I'll likely look for a JDM rather than try to fix it.

Thanks,
Chris

 

Yes, a head gasket problem can become progressively worse over time. Avoid driving the car as the burnt coolant in the exhaust will cause additional problems, such as a clogged catalytic converter.