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I can see your videos, but I can't see the pictures. When I click on the link to one of the pictures, google says the album is empty.
From the videos, the rpm increase by turning on the a/c is normal. I'm sure the PCM is increasing the rpm to compensate for the extra load from the a/c. The idle moving around is not normal.
Your idle is behaving like you have air in the coolant system, or maybe a stuck open thermostat? Turning on the a/c forces both cooling fans to turn on and stay on. You may be reducing the coolant to go into open loop, or the thermostat isn't closing to raise the engine coolant temp. Watch the coolant/engine temperature on your app and see how it behaves.
If the engine is cold, remove the radiator cap and make sure the radiator is filled to the top.
You can also take a paint pen or whiteout and draw a line on the face of the crank pulley from the crank bolt to the edge. Drive the car if you can or let the engine idle for a bit. When you shut off the car, check that you have the same line. The crank pulley is really two metal pulleys with rubber between them to dampen the crank harmonics. The rubber can tear/delaminate where the outside metal doesn't spin with the inside metal connected to the crankshaft. It is an easy test and worth a shot to try.
Huh. Not sure why the pictures aren't coming up since I put them as shareable.
I agree that the initial RPM movement when the AC compressor starts is abnormal. It's the continued fluctuation after that. My wife has even had instances where the car will stall when coming to a stop/idle.
As for the thermostat, I replaced it about 2 years ago (15K miles ago). This problem exists before then and continued after the new part was installed.
Coolant levels are normal, both in the radiator and the reservoir tank. I can double-check for any air bubbles, though. I'll also try the crankshaft pulley test.
I actually brought the car to a Honda dealership to see if they could identify the issue (with all the same notes I provided here). The technician did the absolute bare minimum - put a scan tool on and literally read back the CEL codes I already knew of:
Misfires - they wanted to replace the ignition coils and spark plugs (despite me already doing that)
O2 sensor code (which sometimes pops with the misfire codes) - they wanted to replace the O2 sensor for $400+.
To prove they did a ****ty "comprehensive diagnosis," they totally missed the oil leak I have, which is readily apparent when below the car (I'm 95% certain it's a rear main leak, and I've left it to go since I do want to spend my time/money on dropping the transmission). I'm bringing the car back today so someone else who is hopefully more confident can read my notes and do a better diagnostic. I replaced the O2 sensor since I had one in my garage, essentially just to prove that the sensor isn't the issue.
The second Honda technician looked at it today. He removed the O2 Sensor and spark plug/ignition coil repair (I swapped them out from my other Honda to prove that the same damn issue is still present).
He came back with these two notes (below, as screenshots).
Thoughts? It feels like $1000 for a "maybe this is the issue?". Granted, if the timing belt is off by one tooth, my first reaction is that the place which put it on for me (it was actually done by my parents when I was abroad) would be responsible for the mistake.
Just remembered the 01 accord had a map sensor and not a maf.
It is strange the bank 2 behaves differently than bank 1 when doing a power balance test on the coils. Any chance you started having issues just after the timing belt change?
Just remembered the 01 accord had a map sensor and not a maf.
It is strange the bank 2 behaves differently than bank 1 when doing a power balance test on the coils. Any chance you started having issues just after the timing belt change?
Memory/Timeline is a little foggy here.
By my best recollection, my parents replaced the belt for me at a Honda dealership when I was working/living out of the country. When I got the car back (about a year later), is when I started noticing symptoms, which were not quite as pronounced as they are now, 3 years later.
I was posting when you posted your results from the dealership. Call the original shop to see if they would correct their mistake? It can't hurt to ask.
To verify you'd have to remove the upper timing belt covers, turn the crankshaft by hand until you get #1 to top dead center, then look at the cam timing marks. It isn't technically difficult, but you may have to remove components like the serpentine belt tensioner, etc. to access the timing belt cover bolts. I'm not sure if you want to diy verify the issue, or let a shop handle it.
I was posting when you posted your results from the dealership. Call the original shop to see if they would correct their mistake? It can't hurt to ask.
Ha. You read my mind. That was one of the first things I did after I got the work order. They basically told me: Tough ****.
Not surprising, TBH, but irritating nonetheless. It's also a good reminder of why I try to do this myself whenever possible, and I'm capable.
I'm debating if I'll take the car back and DIY it, or let the shop handle it. I'm going to owe them $200 regardless for the diagnostic. So it's essentially another ~$250 to have them resolve the timing belt issue.
I'm also thinking of starting with the timing belt before even considering the valves. I'm not sure if that's the right decision, but I feel there's more evidence that the timing belt is the culprit.
06-09-2023, 12:52 AM
