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2002 Acura TL type s won't idle when at operating temperature
I had a spark plug blow out on me on my way home from work
Drove it the rest of the way home
Pulled the plug out. and all that was left of the coil that melted inside the spark plug tube.
I installed a timesert and a new plug. after starting it up it runs very smoothly. Idles and drives better than before. It's smooth as silk.
But I noticed when she gets up to operating temperature her idle slowly starts pinging around from 800 down to 450-500 then back to 800. Then slowly it gets worse and worse until she dies. You can keep it running by holding throttle but it gets progressively worse until she downright sounds like a diesel. and dies the second you take your foot off the gas
I tested this a few more times. Cranks right up when she's cold and runs perfectly. not so much as a twitch in fluctuation in the rpm. But soon as she warms up again she starts acting up.
I thought perhaps trash got down into the exhaust and maybe damaged the up or downstream O2 sensors. I replaced them but the issue persists.
Did you remove the head to install the insert? Did you use thread locker?
I did not remove the head. And yes I used thread locker.
I caught 99% of the shavings with grease on the end of the tap and then air blasted the hole to blow any remaining chips out.
just now took the throttle body off and checked it and it's clean as a whistle and the solenoid for the iacv is moving freely with no hesitation.
An update on it not idling. It will idle. .. sometimes? It sat in the driveway for 20 minutes idling just fine but soon as I gave it gas to go forward it started dieseling really bad but clears up once you up the rpm. when she's driving highway speeds she's driving just fine no hesitation. Nothing. Only when at idle does she run badly
After you drive it on the highway and the temp is up does it idle fine if you let it sit in the driveway? Wondering about a vacuum leak.
It's completely random. Sometimes it does sometimes it doesn't. when I say random. I mean true random. it's not really manually reproducible. I think it idles fine sometimes because the right set of circumstances happen and it can do so. But something Is clearly causing it to upset. putting it in neutral at red lights helps the situation (foot still needs to be slightly on the pedal) but when I put it back in drive to then go. It sometimes completely stalls out and I have to restart the car.
It's so weird to me that it struggles at idle but on highway or driving 30-40 mph it drives perfectly. Good acceleration. No hiccups to speak of
I am not thinking it's a vacuum leak as I always thought a vacuum leak would increase the idle speed not decrease it.
I feel like I've checked every sensor. Other than the temp sensors. I feel like are working though the fan comes on like they are supposed to. No check engine lights either.
I am not suggesting the temp sensor is bad, what I leading to was air stuck around the temp sensor when you shut down causing a bad (high) temp sensor reading. These Acura need to have the air removed from the coolant, otherwise strange idling can occur. Basically you need something like the picture below and you "burp" the air out of the coolant, squeeze the hoses, don't let it suck in air, etc. You can search the forum and should find this mentioned multiple times.
A vacuum leak can cause idling problem both in raising or lowering RPM. It just depends on where, how and what, If you haven't recently checked, look at the vacuum going to the motor mounts. If I remember correctly they are active when the car is at idle but not when driving (over 1500rpm). You can check the manual.
I am not suggesting the temp sensor is bad, what I leading to was air stuck around the temp sensor when you shut down causing a bad (high) temp sensor reading. These Acura need to have the air removed from the coolant, otherwise strange idling can occur. Basically you need something like the picture below and you "burp" the air out of the coolant, squeeze the hoses, don't let it suck in air, etc. You can search the forum and should find this mentioned multiple times.
A vacuum leak can cause idling problem both in raising or lowering RPM. It just depends on where, how and what, If you haven't recently checked, look at the vacuum going to the motor mounts. If I remember correctly they are active when the car is at idle but not when driving (over 1500rpm). You can check the manual.
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I just checked the vacuum lines going to the mounts. it appears to be fine. I tested it by unplugging the hose that feeds it and blocking that off so no air could be pulled. Eliminating any sort of leak from that source and the issue persists.
As far as coolant being an issue. I don't want to rule it out but I just can't imagine it being the case. I've never had an issue with coolant. In fact I've never had to fill it with coolant since I've owned it. As it's always maintained the correct level. Nor has it ever gone down.
Just to rule anything out I'll give it a try tomorrow tho. I'll try and see if any air is trapped.
OK update. when I did the plug install. I noticed the same vacuum line was disconnected from the engine. I thought it was weird and plugged it in. not thinking much of it.
The same one I pulled off to test is now causing it to run smoothly at idle.
When I cover the port the engine starts acting like it wants to die.
Maybe that vacuum line was disconnected for a reason lol because it appears all is fixed
It's weird that having a vacuum leak is the solution......
Which vacuum line is it? As you said very weird! Could someone have routed the vacuum lines incorrectly? IF you can post some pictures.
From what I can tell. It's the vacuum line going directly to the engine mounts. and I know it's being plugged into the correct port because I saw the vacuum diagram photo. for some reason connecting this hose causes it to run badly. when I remove it it clears up immediately. if I cover the tiny port with my finger. It instantly dies
Still doesn't explain why my car makes a diesel sound when accelerating at idle. However now that I removed that vacuum hose, it no longer makes the sound unless other accessories are turned on such as the headlights and the AC combined. This will create that diesel sound on acceleration from a stop. However it quickly goes away. Can't be good either way.
From the description above, it seems like the vacuum hose in question is #30 with its port connection to the rear IM?
You are correct. that line was always unplugged since I owned the car. I plugged it up when I was working on the timesert. That's when all of this bad idling started.
best case scenario: Sounds like Idle relearn with the hose connected properly is needed.
worst: you have a leaking engine mount or faulty mount control solenoid.
best case scenario: Sounds like Idle relearn with the hose connected properly is needed.
worst: you have a leaking engine mount or faulty mount control solenoid.
The idle relearn calls for it to get up to normal operating temperature than to idle for 5 minutes. The engine will not even idle with that hose connected... So how would it be able to relearn in that case?
The from the valve cover to the vacuum solenoid relay for the motor mounts, when it was disconnected was it plugged or crimped closed? I agree with Whitetiger that either one or both of your motor mounts or the solenoid is bad. However, disconnecting the vacuum line without blocking would still be a vacuum leak. So I am a bit confused.
Did you try disconnecting the battery for a min to clear the previous idle relearn?
Yes I did. But when the vacuum hose is connected it will not idle at all. Thus it cannot perform the idle relearn if it's unable to idle in the first place ^^ haha
Disconnecting that vacuum line is the only way I can see to make it idle normally. Which means there's definitely something else blocking air flow elsewhere and it's getting air from that port to help it run
05-14-2023, 10:27 AM
