Sounds like everything is working properly. It's designed to idle at 1500 when first started. It will gradually slow down to 700 as the engine temperature comes up to normal running temperature.

 

Really? But it takes so long to get there. And it didn't do this until after I cleaned the IACV.

 

I just had this high idle problem on my 89 civic with the 1.5. turned out to be the coolant temp sensor was bad ( computer thought motor was still cold even though it was warmed up so it kept the idle high ).

 

Sounds like a possibility. Any idea where this sensor is located? I´m going to go to a ¨you pull it¨ to get some parts.

Thanks!

 

When this happened was your computer throwing a code? Mine doesn't have a CEL so I´m just guessing with everything.

 

on my 89 civic the coolant sensor is located at the thermostat housing. not sure what year or model you have. if you don't already have one p/u a good shop manual. you can test the sensor with a volt meter. my car did not set a code for this part. new part for mine was about 25.00. don't know if I would put a used one in. definently try and test is before throwing parts at it if you can. keep us updated.

 

Sensor is screwed into the end of the head below the distributor. It has two wires. The one next to it with one wire is for the temperature gauge on the dash.

It should also be mentioned to check your coolant level (in the radiator, not just the plastic tank, with the engine cold). Air in the cooling system will cause inconsistent idling due to it splashing on the sensor.

 

I'd like to check it with a volt meter first. Is there a voltage I'm looking for, or am I just checking to see if it has volts? Also, I've never used a voltmeter, so what do I connect it to?

Thanks.

 

You check it for resistance. Unplug sensor and set meter on ohms, probe the two pins of the sensor. I think it is supposed to be about 2000 ohms with the engine cold (75 F) but you would need to look in service manual for the exact number.

 

Okay,

I picked up another IACV and guess what. This one idles high too. Only it idles high for a longer period of time, and almost never goes below 1050-1100ish RPMS if my lights are on. If I brake hard and come to a complete stop, the RPMs will drop to 600-700ish and then come up to 1100, and then settle in at 1000. This is with the lights off. (with lights on this doesn't happen. RPMS just stay at 1100ish.

I also noticed a difference with my shift light. The light won't turn on until my RPMs are much higher than what I'm used to. This is especially true in lower gears.

"New" IACV is clean and registers at 11 ohms with my amp meter.
Old IACV also comes in at 11 ohms.
Old IACV had lower RPMS sooner, while the "New" one seems to take longer.

When I turned on my lights with the old IACV the car didn't like it much. RPMS wouldn't change much and the car seemed to struggle. The heater fan was a little better.

"New" IACV responds to lights being turned up and RPMS go up to about 950-1050 when at idle. This is also true with the Heater fan. However, RPMS won't change in the 1, 2, and 3, settings for the fan. The will only go up 10 950-1050 with the fan on speed 4.

I can tell that this "new" IACV is different, however it's not dropping the RPMS the way I wanted. It's almost worse. What should I do from here?

I haven't checked the coolant sensor yet, but I haven't ruled it out either. 2000 ohms sounds really high considering the IACV was at 11 ohms.

I'm getting my timing checked tomorrow. I'll keep everyone updated.

Thanks