Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
I’ve got a 2011 Honda Pilot 3.5 that has a high/erratic idle. I replaced the timing belt, valve cover gaskets, upper intake gaskets, throttle body gasket. Valve cover gaskets and intake gaskets were replaced for oil leak from valve cover. One of the intake studs was corroded to the intake itself and in ended up breaking the bolt off in the lower intake but I was able to get it out with an easy out. I also replaced the front valve cover because I cracked it trying to get the intake manifold off. After these repairs the idle is high. Sometimes it’s around 1000-1100. Sometimes I can cycle the key and it may idle around 1400 and set P0507. I have tried the idle relearn multiple times without any luck. I did perform the crankshaft relearn after the repair. I’ve also reset the ECM multiple times before attempting the idle relearn. I’ve cleaned the throttle body as well. If I do a throttle snap it will raise up then come back down and then raise back up on its own like i hit the gas pedal again. My fuel trims are normal hanging right around 1.0 so I don’t think I’ve got a vacuum leak anywhere. I removed the intake manifold again just to recheck everything and the intake was full of oil. I’ve rechecked my timing and my timing is still lined up. I cannot find anything wrong with any data. I’ve also had someone tell me they have a Honda 3.5 at their shop that idles high and it is normal. But with this so erratic and the computer saying its wanting idle around 700, I don’t think this is normal. I hate to tell my customer to take it to Honda but I’m about at that point. Thanks in advance for any help, tips, well wishes lol
My "go to" is maybe a vacuum leak , Purge valve stuck open.
Proper temp sensor readings.
I happen to have a 2015 in front of me , not quite the same throttle body.
Possibly run and drive it , see how the fuel trims go.
Does that year pilot have a MAF or only MAP?
On a speed density engine (MAP only) like you would find on most older Honda engines, engine vacuum is measured to determine load. As vacuum decreases, it is inferred that load increases. So anything that created a low vacuum situation, like the timing belt being a tooth off on the rear camshaft or valves out of adjustment, will be interpreted as load. This will in turn increase the injector on time, and you get high idle.
The 3.5 engine does not just idle high and set codes for high idle as your colleague stated, but you all ready know that, lol.
Was the work on this one done for maintenance sake, or was there an issue with the car?
I've had struggles with this generation of Honda 3.5L before, especially after disconnecting the battery or cleaning the throttle. I've found that the reset/relearn process is very specific. There's a Honda TSB that spells it out:
First, do the TP Position Check in the ETCS menu. *Turn the key off and leave it off for a few seconds*. Then, do the ECM/PCM Reset and let it idle for awhile. Recheck for idle speed and P0507.
It's the key off part that makes all the difference, in my experience. Otherwise, the procedure never seems to work.
I've had struggles with this generation of Honda 3.5L before, especially after disconnecting the battery or cleaning the throttle. I've found that the reset/relearn process is very specific. There's a Honda TSB that spells it out:
First, do the TP Position Check in the ETCS menu. *Turn the key off and leave it off for a few seconds*. Then, do the ECM/PCM Reset and let it idle for awhile. Recheck for idle speed and P0507.
It's the key off part that makes all the difference, in my experience. Otherwise, the procedure never seems to work.
Good info, I haven't run into one that gave me a a problem yet, but I'll be better armed when I do!
Do you know what the throttle % should be at idle? This one is at 14% at idle. Seems a little high to me. I think I may have a throttle issue because I attempted a crank relearn again just for the heck of it and after raising rpm’s to the fuel cutoff my scanner just says let off accelerator completely and won’t move to finish the relearn. Like it’s not seeing the throttle completely closed
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