HI

My 1990 Integra had a high reving, hunting idle. (The engine temp seemed to be unstable as well). When I removed the intake hose and covered the FITV hole with my finger the idle would slow down and stabilize.

So I removed the FITV. The white plastic piece was not fully screwed in, so I gave it a few turns to seat it. After this the car started fine the first time and idled fine. However now the engine won't start and it makes a strange backfiring noise while turning over.

I removed the FITV again and noticed that no air would pass through (since I'd screwed the plastic piece down), so I backed it out until some air could pass through. I also checked it in hot water and it seems to be working fine (blocking the air as it is warmed).

The engine is still making it's strange backfiring noises when I try to start it and not firing.

Before that I also:
-removed the IACV and cleaned it out, didn't change anything
-checked the coolant temp sending unit and it was fine

Any suggestions as to what may be the problem or what I should try next?

Thanks!

Garnet

 

Did you remove the distributor to check the coolant temp sensors? It sounds like you may have reinstalled the plug wires in the wrong order.

 

Hi, thanks for the suggestion:

I didn't remove the distributor or check those coolant temp sensors but maybe I should? It does sounds like the timing of something is out, it's not catching, it sounds just the opposite, like it's firing at the wrong time and stopping the engine from turning over for a moment.

I didn't know about the sensors in the distributor, I'll do some searching.

Thanks.

 

One other thing, this problem started when we had a cold snap (freezing, but not a lot below that). I drove the car one night and it warmed up idling, but then got cooler as I drove it. The gauge temp and temp of the air being blown by the heater seemed to correlate, i.e. gauge temp would read cooler and heater air got cooler.

At this time it started and hunted. Just recently won't start since I checked the FITV.

Thanks.

 

Sounds like your coolant level is low.

 

Ditto that, air in system, bleed the system to make sure there is no air in system.

I would also check valve timing, make sure timing belt has not skipped a tooth. 94

 

Thanks, coolant level seems fine, although air in the system seems reasonable for the hunting problem. Would be easier to tell if it was starting.

I just checked the compression, as I figured that was an easy way to test if the timing belt had skipped, and it seems to be fine. I also noticed that the engine turned over normally with the spark plug wires disconnected, and that as soon as I connected them the engine did it's strange 'turn over-stop-turn over' thing it's been doing.

It's like the timing is too far advanced and firing as the piston is coming up, causing it to stop the rotation.

So would it make sense to advance the timing by rotating the distributor, or is there something that retards the timing on start up that is possibly being bypassed?

Or do you think I'm totally off the mark here?

Thank again for any advice.

 

I thought I would update this for future reference.

The vacuum leak was the FITV, the valve was fine but the seal wasn't. I used some silicone around the o-rings and it idles normally now.

The 'going cold' problem was caused by the thermostat being stuck open. There's a little brass dongle on the thermo that jammed itself into the opening.

There's still one more problem as the engine stumbles at low revs, either sitting or driving, so I'm working on that. Let me know if you have any insights. Thanks.