2003 Crv idle problems
#1
Honda-Tech Member
Thread Starter
2003 Crv idle problems
TL;DR:
If you're having idle issues where your engine stalls out when the gas isn't applied, or your rpms are bouncing around or hanging too high, and an engine code is not popping up, check the IAC(idle air control). You may be tempted to clean the throttle body since you have it off. DO NOT clean directly around the throttle plate and bore, it may look like carbon build up but it's a seal and if you clean that away your problems will get much worse. If you already made that mistake, buy some Molykote dri lubricant, and paint on a new seal.
Looking for a little insight before I start throwing more money at this issue.
So recently, my 2003 crv m/t randomly decided that it wouldn't stay running unless I was giving it gas. Without fail, if I wasn't revving it, the rpms would drop to zero and the car would shudder off. After a little digging online, I came to the conclusion that it was the IAC. Took off the throttle body, removed the IAC and cleaned it out(didn't look all that dirty tbh. No clogs anyway) also decided to clean the throttle body as well, didn't look all that dirty either though. Put it all back together, reinstalled it on the car, reset the ECU and did the idle relearn, as well as bled the coolant system. Idle would not drop below 2800, but at least it was staying on. Could not get it to come down, so I bought a new IAC from AutoZone(desperation) same procedure, idle now hovered around 1500-2000. Would sometimes drop down to 1000, but the rpms would bob slightly every few seconds. Also, p0505(IAC malfunction) was popping up on the engine codes. Thinking it was now a junk duralast part, I bought another IAC from RockAuto, and returned the AutoZone one. Similar symptoms after tossing on the new part, but not as bad as the duralast part, and the idle would settle around 950-1075. If I revved the engine, the idle would hang a bit, bob a few times, then settle. When I cover IAC hole on the Tb, the idle settles down to a nice 800. There is a **** ton of suction coming from that hole. I don't believe there is a vacuum leak beyond the tb, as when I cover the Tb, the engine dies right away. I'm kind of at a loss for where to go from here, is it possible I damaged the tps while cleaning the butterfly? I have to go pick up a multimeter and test if it's still calibrated, but thought I'd ask first at least.
Also, if anyone knows where I can pick up an air bypass control thermal valve without buying the whole coolant assembly, I'd appreciate it oh so much. I accidentally snapped off the top nipple, and have the hose running into the manifold plugged for the time being.
If you're having idle issues where your engine stalls out when the gas isn't applied, or your rpms are bouncing around or hanging too high, and an engine code is not popping up, check the IAC(idle air control). You may be tempted to clean the throttle body since you have it off. DO NOT clean directly around the throttle plate and bore, it may look like carbon build up but it's a seal and if you clean that away your problems will get much worse. If you already made that mistake, buy some Molykote dri lubricant, and paint on a new seal.
Looking for a little insight before I start throwing more money at this issue.
So recently, my 2003 crv m/t randomly decided that it wouldn't stay running unless I was giving it gas. Without fail, if I wasn't revving it, the rpms would drop to zero and the car would shudder off. After a little digging online, I came to the conclusion that it was the IAC. Took off the throttle body, removed the IAC and cleaned it out(didn't look all that dirty tbh. No clogs anyway) also decided to clean the throttle body as well, didn't look all that dirty either though. Put it all back together, reinstalled it on the car, reset the ECU and did the idle relearn, as well as bled the coolant system. Idle would not drop below 2800, but at least it was staying on. Could not get it to come down, so I bought a new IAC from AutoZone(desperation) same procedure, idle now hovered around 1500-2000. Would sometimes drop down to 1000, but the rpms would bob slightly every few seconds. Also, p0505(IAC malfunction) was popping up on the engine codes. Thinking it was now a junk duralast part, I bought another IAC from RockAuto, and returned the AutoZone one. Similar symptoms after tossing on the new part, but not as bad as the duralast part, and the idle would settle around 950-1075. If I revved the engine, the idle would hang a bit, bob a few times, then settle. When I cover IAC hole on the Tb, the idle settles down to a nice 800. There is a **** ton of suction coming from that hole. I don't believe there is a vacuum leak beyond the tb, as when I cover the Tb, the engine dies right away. I'm kind of at a loss for where to go from here, is it possible I damaged the tps while cleaning the butterfly? I have to go pick up a multimeter and test if it's still calibrated, but thought I'd ask first at least.
Also, if anyone knows where I can pick up an air bypass control thermal valve without buying the whole coolant assembly, I'd appreciate it oh so much. I accidentally snapped off the top nipple, and have the hose running into the manifold plugged for the time being.
Last edited by PolkaSauce; 08-09-2019 at 06:07 PM.
#2
Honda-Tech Member
Thread Starter
Re: 2003 Crv idle problems
Okay so I tested my tps today, I know it's supposed to be between .50 closed and 4.50 wot. I've got it sitting at .48 closed and 4.53-4.54 wot(kind of bounces between the two, doesn't stay steady)
I know theyre allowed to be a hair off of those numbers, but is that too far of a jump?
I know theyre allowed to be a hair off of those numbers, but is that too far of a jump?
#3
Honda-Tech Member
Thread Starter
Re: 2003 Crv idle problems
Figured I'd keep this updated for anyone that stumbles across this possibly having the same problem. So, I put on a new iacv, couldn't get the tps to spec, put on a new one. Got it calibrated at .49 closed and 4.50 wot. But before I slapped the Tb back on, I decided to inspect it, thinking maybe I messed up something else in the process of cleaning the Tb. Held it up to the light, and saw that there's light poking through between the throttle plate and the bore in some areas. I noticed there's sort of a permanent black ring on the bore, around the throttle plate, and a bit on the plate itself, some of which that had been wiped away during the cleaning. The gap is most likely causing the IAC to surge and overcompensate. Service manual says something about not using carb cleaner as it can damage a molycoating in the Tb(hindsight). Other forums have cited similar issues after tb cleaning. I've ordered some Molykote, going to cross my fingers and apply it. Will keep this updated. Pretty sure what started out as cleaning a dirty IAC didn't need to end up being this pricey, but, that's how we learn right?
#4
Honda-Tech Member
Thread Starter
Re: 2003 Crv idle problems
Final update;
Put a molykote seal around the throttle plate. Was a pain in the *** because it comes as a spray, ended up spraying into a cap and used a paint brush to apply to the edges of the throttle plate over and over and over again. Not the best application, made a mess of it, pretty sure it's not a complete seal. Bled the coolant of air again, did the idle relearn, again. Drove around and made sure the drive cycle was completed. It made a HUGE difference. The idle is, for the most part back to normal. Settles between 675-700. Engine codes are gone. Passed a smog. Life is good. The engine is way more sensitive to input now, and when the rpms are coming back down, it hangs for just a second or two around 1100, then drops down to normal. But if those are the biggest of my issues, I'll take it.
I hope this thread is able to help anyone out there having similar issues and save you some unnecessary spending.
Put a molykote seal around the throttle plate. Was a pain in the *** because it comes as a spray, ended up spraying into a cap and used a paint brush to apply to the edges of the throttle plate over and over and over again. Not the best application, made a mess of it, pretty sure it's not a complete seal. Bled the coolant of air again, did the idle relearn, again. Drove around and made sure the drive cycle was completed. It made a HUGE difference. The idle is, for the most part back to normal. Settles between 675-700. Engine codes are gone. Passed a smog. Life is good. The engine is way more sensitive to input now, and when the rpms are coming back down, it hangs for just a second or two around 1100, then drops down to normal. But if those are the biggest of my issues, I'll take it.
I hope this thread is able to help anyone out there having similar issues and save you some unnecessary spending.
#5
Honda-Tech Member
Re: 2003 Crv idle problems
Was it the throttle plate that was the problem or the idle relearn that did the trick? (Done on the engine at operating temp both times I assume?)
I cleaned my throttle body before and had similar high idle for abit but eventually it cleared itself.
I cleaned my throttle body before and had similar high idle for abit but eventually it cleared itself.
#6
Honda-Tech Member
Thread Starter
Re: 2003 Crv idle problems
Once I put the thin seal on between the edge of the throttle plate and the bore of the throttle body, the high idle went away immediately. I basically coated it till I could no longer see a ring of light shining past the throttle plate. Idle re learn was done on cold start, holding 3k rpm until operating temp, and then sat to idle for 5 minutes. She's running strong! Only issue I have left now is high idle on start up, but that's cause I snapped the thermal air bypass valve off on the intake manifold by accident. I have the hose plugged, idle settles once car reaches operating temp.
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