Got a 91 crx stock D15B2 dpm-fi 5 speed
runs fine when its cold but as soon as it gets hot it starts acting messed up.
when you take off the gas to shift the rpms stay up, the longer it runs it gets worse. and when it gets at it worse the idle actually goes up to 3000 even when stopped at a light in neutral. and when its doing this if im driving and let off the gas, keep off the clutch, and keep it in gear the car wont die, just keeps driving by itself.
also after driving for awhile, like 15ish minutes the CEL turns on, checked the led code multiple times and its always code 1 which is the o2 sensor. but goes away after turning it off.

remember it ONLY acts like this when its HOT

dunno if its relevant but only one radiator fan turns on... and its the drivers side, which I'm pretty sure is for the a/c only, which I already took out.

I already cleaned the iacv and bled the cooling system. replaced the pcv hose. checked for vac leak with both methods of carb cleaner and butane, found NOTHING

somebody mentioned maybe the temp sensor could be bad? but then why would the gauge be working in the dash?

also heard stuff about the fitv, but I'm reasonably sure that dpmfi dont have fitv.

I'm planning on doing a mini me swap in soon as i get the parts, maybe the problem will fix itself when I do that?
but in the meantime its getting warmer outside n so of course the idle is becoming a very big issue, can't be good to drive like that, so haven't been able to go much of anywhere when its nice out.

please help...

 

******* bump

 

dashpot maybe?? BUMP

 

there is the coolant temp sensor and the coolant temp switch. the switch controls the dash and the ect (engine coolant temp sensor) is what sends codes to the ecu. i would try replacing the ect sensor. it might work or it might not. worth a shot tho. i also had somewhat of the same issue but mine did it when it was hot and cold. i tried everything you have tried with yours and i couldnt find my problem. i replaced the ecu and it fixed it. dont really understand it but it worked haha

 

would the temp gauge in the dash work if that was the case then tho?

 

please bump for ***** sake

 

Yes the temp gauge in the dash would still work. That is the coolant temp switch and as long as your dash gauge works then your collant temp switch is fine. But your collant temp (sensor) could be bad. The sensor does not have anything to do with the dash gauge. The dash gauge will still work fine if the sensor is bad. I really don't know if changing the sensor would help you are not but I just wanted to let you know that they are two different things. The switch controls the dash gauge and the sensor is what sends codes to the ecu.

 

yeah but Idk if it would be that eihter because if it was bad wouldn't I be getting a cel code for that as well?
a friend suggested thermostat might be stuck open. what you guys think about that?
think i might give it a try once I get some time.

 

When your idle starts going high, have you tried putting your foot under the gas pedal and pulling it up? I've done this for a long time now as a temporary workaround; it seems to stop the erratic idle.

I was just wondering if I have a similar issue. I'll be trying to diagnose mine in the coming weeks as well.

 

For you it sounds like your throttle cable is sticking. I would try replacing that. And yes that could be a possibility that the thermostat is sticking open. Like I said I don't really know for sure what it could be. I swapped the ecu on mine and it fixed the idle problem but my car always ran like **** once it got warm. Turned out to be a cracked head. When the car was cold it ran fine but when it warned up that crack expanded and let air into the cylinder causing the car to bogg alot. But my idle problem was fixed by getting a lmother used ecu off eBay.

 

dood! I bet maybe it could be a problem with the head!
cuz the number 3 cylinder is always full of oil when you take out the spark plug even after I put in a new gasket kit.
n a little backround, I got the car dirt cheap at 400 cuz the timing belt came loose. turns out the tensioner got cross threaded so It happened again after I fixed it. so I had to pull the whole engine so I could helicoil the hole.

I should hurry my *** up n finish getting the mini me parts I need. I bet it will solve itself.

 

yeah exactly. i couldnt figure out why mine was running so bad and eventually i started loosing antifreeze. i was burning it in the exhaust and my exhaust was pretty white coming out the tailpipe. it eventually got worse and worse and blew my head gasket. i had all kinds of oil all over my spark plugs like you were saying and i couldn't figure out why. and mine was the same as yours if the car was cold it was fine and then as soon as she started getting warm on me she ran like **** because the crack would open up more. my car is in the process right now of getting a new motor cause that motor had 305,000 miles on it. but yes hopefully you can figure out what your problem is. sounds like it could be the same problem that i had.

 

let me know what you find out about it though.

 

throttle plate sticking? causing high idle, spray brake clean to clean and stop sticking.
passenger side fan is cooling and drivers side is ac cooling

jump the 2 wires and see if it the fan comes on to determine if can or sensor

 

damn, sounds like the same **** yo.
I'll post anything I find out so it helps other people!

I can't decide now weather to stick with doing the mini me swap n all I've collected or get a full ls set up from my bud for like 500
ahhh decisions!