CPS drama - SOLVED
Thread Starter
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Tuned
Joined: Nov 2016
Posts: 385
Likes: 116
From: Full time RVer
I have done and checked everything I can think of and still no start. If nothing else comes to light. I guess I have no recourse but to have a tow truck haul it to the dealer 16 miles away. This will be the first time I could not fix the issues since I have owned it.
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
I would definitely message Diesel Tech of Chattanooga first, I posted their link up in post #13. From what I've read here they are extremely helpful, first class people. I've heard more than one report of them troubleshooting over the phone to help guys out. If you figure out the PCM or IDM need repair they can fix ya up. Worth a try before hand your keys to a hungover "tech" who's motto is "Eh not my truck".
Thread Starter
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Tuned
Joined: Nov 2016
Posts: 385
Likes: 116
From: Full time RVer
I would definitely message Diesel Tech of Chattanooga first, I posted their link up in post #13. From what I've read here they are extremely helpful, first class people. I've heard more than one report of them troubleshooting over the phone to help guys out. If you figure out the PCM or IDM need repair they can fix ya up. Worth a try before hand your keys to a hungover "tech" who's motto is "Eh not my truck".
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
Sure thing, hope they get you lined out on the quick. I see in your sig you have Auber Instruments listed, mind if I ask what of theirs you're running. I've been eyeballing their dual channel multimeter and am curious of your opinion.
Thread Starter
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Tuned
Joined: Nov 2016
Posts: 385
Likes: 116
From: Full time RVer
Thread Starter
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Tuned
Joined: Nov 2016
Posts: 385
Likes: 116
From: Full time RVer
I tried moving a wrench in front of the CPS sensor and the tach needle moves slightly. It does not move when installed in the engine.
I had the engine rebuilt by Baril in Green Bay 3 years ago. They do the engine warranty work for the Fabic (Cat) dealer. It only has about 38,000 miles on it. I find this unbelievable. Baril machined the LPOP surface and gasket surface a few thousandths in the front cover to clean up minor wear by the LPOP gears. As a result, the tolerance by the CPS sensor should be more tight than typical 7.3s. I guess the depth gauge will tell the story tomorrow.
I had the engine rebuilt by Baril in Green Bay 3 years ago. They do the engine warranty work for the Fabic (Cat) dealer. It only has about 38,000 miles on it. I find this unbelievable. Baril machined the LPOP surface and gasket surface a few thousandths in the front cover to clean up minor wear by the LPOP gears. As a result, the tolerance by the CPS sensor should be more tight than typical 7.3s. I guess the depth gauge will tell the story tomorrow.
Thread Starter
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Tuned
Joined: Nov 2016
Posts: 385
Likes: 116
From: Full time RVer
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Lead Driver
Joined: Oct 2005
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From: Ponca City, OK
I would be surprised if it was any more than +-.005, and that seem high to me. I suppose you could pull the hpop reservoir and gear to have a look. Without all the fuel bowl nonsense in the way it's a simple enough job, and that would drive me insane until I opened her up to verify all was well.
Thread Starter
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Tuned
Joined: Nov 2016
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Likes: 116
From: Full time RVer
I would be surprised if it was any more than +-.005, and that seem high to me. I suppose you could pull the hpop reservoir and gear to have a look. Without all the fuel bowl nonsense in the way it's a simple enough job, and that would drive me insane until I opened her up to verify all was well.
I don't believe it's a mechanical issue though. I had the engine rebuilt three years ago. It only has about 38,000 miles on it. I think the PCM's ability to sense the CPS sensor has declined?
My truck has always had an issue with romping. At idle, the rpm fluctuates about 30 rpm. Every time I let off the throttle, it will romp about 125 rpm 4 or 5 times. It does it very time I shift the ZF5. Over the years I have tried a few different tunes. Only Bill's and Jonathan's work in my truck. The three other tuner's tunes always make the engine romp about 200 rpm continually after returning to idle. Dusty told me their is something unique about my truck. I believe it's how the PCM is sensing the CPS sensor. I.e. weak. That being said. I have not driven a different 7.3. So I'm not much of a judge on what's normal for a 7.3.
I'm going to message Jonathan and ask him what his thoughts are on this matter?
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
I suppose there could have been an error when the PCM was assembled and whatever capacitor or resistor or some such isn't getting as solid of a connection as it should. One of the few things I know without doubt in this world is anything is possible.
Thread Starter
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Tuned
Joined: Nov 2016
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From: Full time RVer
I already received a reply. I was asked if the cam wheel was removed when I had the engine rebuilt? No Are their any scratches on the face of the CPS? No And to send a quality close up picture of the CPS. He also stated that it would be easy to test and that he owns a 1997 and would stick my PCM in his truck and check if it starts? Great!
Thread Starter
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Tuned
Joined: Nov 2016
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From: Full time RVer
I was asked to make 3 aluminum can shims and try them on the CPS. No start and no tach needle movement with either. I think it's time to send the PCM in? He did state it's very, very, rare for the CPS circuitry to fail in the PCM.