Misfire...
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Lead Driver
Joined: Aug 2009
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From: Laquey, MO
I've got the OBDI calibration...
Thread Starter
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Lead Driver
Joined: Aug 2009
Posts: 7,581
Likes: 250
From: Laquey, MO
Well guys - I've been all over that engine and haven't found a single thing that helps. Here's what I found...
- PCV hose under the throttle body had been replaced and was in good condition. The PCV valve, however had failed. Replacing the valve made no noticeable improvement.
- Traced the vacuum lines in and around the engine compartment but did not find anything amiss.
- Discovered something had been chewing on the bank 1 02 sensor wires. Nothing severed but certainly mangled. Replaced sensor but no major improvements.
- On a long shot, I swapped different coils onto #2 & #4 to see what that did. Still runs like crap.
I don't know what else to try. The freeze frame data on my misfire codes all show major differences between the bank1 and bank2 fuel trims with bank1 being much higher than bank2. This supports that something is letting air in and causing a lean condition for bank1. Problem is, I cannot read live data so I can't see what's happening until it throws a code and has freeze frame data.
I was planning on taking the new camper out next weekend, but that plan seems dead in the water unless I can figure this out.
- PCV hose under the throttle body had been replaced and was in good condition. The PCV valve, however had failed. Replacing the valve made no noticeable improvement.
- Traced the vacuum lines in and around the engine compartment but did not find anything amiss.
- Discovered something had been chewing on the bank 1 02 sensor wires. Nothing severed but certainly mangled. Replaced sensor but no major improvements.
- On a long shot, I swapped different coils onto #2 & #4 to see what that did. Still runs like crap.
I don't know what else to try. The freeze frame data on my misfire codes all show major differences between the bank1 and bank2 fuel trims with bank1 being much higher than bank2. This supports that something is letting air in and causing a lean condition for bank1. Problem is, I cannot read live data so I can't see what's happening until it throws a code and has freeze frame data.
I was planning on taking the new camper out next weekend, but that plan seems dead in the water unless I can figure this out.
Thread Starter
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Lead Driver
Joined: Aug 2009
Posts: 7,581
Likes: 250
From: Laquey, MO
Back again. I crossed my fingers and got the van out for a test run. It still feels rough, but I have made some improvements code wise. The only code I have this time is a P1131. The freeze frame data for the code shows Fuel sys 1 - CL-Fault. I've been able to track down that this indicates that the fuel system did not achieve closed loop status, possibly because of the 1131 code. Why I find this interesting is because the data on my other codes all showed Fuel Sys 1 - CL. This is the first time I've seen the fault in the data.
Here's another a couple of questions that I'm afraid I know the answer to already.
1. While working on the van, I noticed that I have the dreaded broken exhaust manifold bolt issue in a couple of places. Could this be the source of the lean condition suggested by the PO1131 code?
2. Could the vibrations I've been feeling around 2,000 RPM be a transmission problem rather than an engine issue? They are the worst in overdrive but still show up at that rpm when the overdrive is off.
Thanks again for sticking with me on this...
Here's another a couple of questions that I'm afraid I know the answer to already.
1. While working on the van, I noticed that I have the dreaded broken exhaust manifold bolt issue in a couple of places. Could this be the source of the lean condition suggested by the PO1131 code?
2. Could the vibrations I've been feeling around 2,000 RPM be a transmission problem rather than an engine issue? They are the worst in overdrive but still show up at that rpm when the overdrive is off.
Thanks again for sticking with me on this...
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Lead Driver
Joined: Aug 2009
Posts: 7,581
Likes: 250
From: Laquey, MO
I wish it was as simple as a single cylinder not hitting, but it isn't. I had a coil come unplugged before and its pretty obvious. It has a defined miss at idle but revs pretty smooth. The problem becomes most pronounced when under load at 2K RPM. I dealt with something similar when I changed the plugs last time and it took new coils to smooth things out again.
I've got a better scan tool on its way so I can check the misfire counters. I've got a hunch that I've got lots of misfires across the board giving me grief. It'll be here tomorrow so maybe Thursday after work I can plug it in and take a peek at them.
I've got a better scan tool on its way so I can check the misfire counters. I've got a hunch that I've got lots of misfires across the board giving me grief. It'll be here tomorrow so maybe Thursday after work I can plug it in and take a peek at them.
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