Hello everyone,

I see that there are some similar posts and questions but none seem to address the issue very well.

Over the last three days my 1990 Civic Hatch DX with a 1.5 l (SOHC, Duel point injected ) engine and 333K has developed increasing vibration, loss of power and poor gas milage.

This car has been remarkably reliable and efficient. I still get 40 mpg when running the highway. It's peppy, agile and I love it.

I have owned this vehicle for three years and work on it regularly. All the usual suspects seem innocent.

My first impression was the Idle Air Control Valve. I had an extra one so I cleaned it and swapped it out today. The car was a little hard to start but it did start. I idled it for about 10 minutes to check for leaks and left work. It seemed to be running fine but 3 blocks later it sputtered a couple times then died. After many attempts to restart it I gave up and swapped back in the original IAC valve and cleared the codes. It still wouldn't start. It turns over like it is starting but when you release the starter the engine dies.

I hear the fuel pump working, It tries to start so I am fairly sure that it's getting fuel (I can smell it) and spark.

In the last 6 months I have replaced:
Alternator
Ignition coil
Roter
Spark plugs
Spark plug wires
Dash pot (the one that slows the drop of the accelerator when you let off the gas)

Battery is a year old.

The only changes I have made in the last 10 days was to replace the coolant and filled up with regular gas from Phillips 66. Normally I run midgrade.

If the contacts in IAC valve are bad would this result? I see in the Haynes manual that the resistance should be between 7.0-13.0 Ohms (I need to double check that) when I tested it, the original seemed low while the replacement seemed within range. I'll check again tomorrow.

Until then, any ideas? Any help would be appreciated.

Thanks


Essay0ns

 

Usually with a bad IACV the symptoms will be that the rpms will bounce from like 500 to 2000 at most and just go up and down, it may make it die but when I had a bad one it didn't make my car die just what I described to you.

 

Yeah, mine has been doing that but irregularly. I have been able to disconnect the IACV and the engine would still run. Of course, it would throw a CEL on the instrument cluster. Talking with a mechanic last night, he suggested maybe a fuel pump not providing enough pressure.

It seems to be unable to maintain enough fuel or spark to keep the engine running. I wonder if it is one of those diaphragm units connected to the fuel system.

Stumped...

 

An engine with that many miles is bound to have lower than normal compression. Do you drive enough to qualify the poor fuel mileage? I've had a few EF's come in with touchy TPS connectors. You wiggle the harness enough and it will stall out.

What prompted you that there was a problem?

 

Did I not post on this thread?

 

I'm having the same problem, search turns up no info.

1991 D16A6 in an RT4WD 6spd wagon 110k miles - starts fine and dies when it should idle. If the gas pedal is feathered and held down slightly an idle can be maintained.

Once it's warmed up it runs perfectly.

This car sat all summer, just replaced the alternator and it ran perfectly for a few days. Now it will not idle when cold.

No bouncing idle, no warning lights. Starts fine with a bit of gas from the pedal.

We have a few other 1990/91 D16A6's in the drive and can swap parts to chase the problem if necessary, but could use some help homing in on a specific cause of this 'dies when cold' problem.

Thanks,
Dave