Vehicle setting P1345 Scan tool showing +28.

HECHT29

MEMBER
1999 CHEVROLET TAHOE
125,000 MILES

Vehicle setting p1345 Scan tool showing +28 degrees of cmp retard at 1000 rpm. Its starts to misfire when adjusting dist. Toward 0 degrees at 1200. Also when the cmp is unplugged it still reads 28 degrees. Could this be wiring or bad VCM?

Monday, March 4th, 2013 AT 6:55 PM

5 Replies

RANDICO

MECHANIC
174 POSTS

The code is correct, The CMP is inside the distributor, its controlled by a reluctor and it does spin out of position, another distributor will be the solution

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Monday, March 4th, 2013 AT 7:16 PM

HECHT29

MEMBER
3 POSTS

New distributor was installed with the same problem. 28 degrees of CMP retard at 1200 rpms.

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Monday, March 4th, 2013 AT 9:12 PM

RANDICO

MECHANIC
174 POSTS

The data for CMP 0-2(degrees) Perform a CMP offset, below 1000RPM the reading should be -2 to 2 (degrees) If you raise the engine speed to 2000 it should be 2*. Run the engine and turn the distributor in a counterclock wise until you read 0*. Then lock it down. Before all this you have to clear the codes, P1345 is CKP and CMP correlation. Look in the distributor and inspect for poor connection

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Tuesday, March 5th, 2013 AT 12:23 AM

HECHT29

MEMBER
3 POSTS

I ran all new wiring from CMP to VCM. After starting the vehicle with code cleared, I tried to set the CMP Retard to 0 degrees. With the scan tool I turned the dist trying to get to 0. At +15 degrees the engine started to pop and misfire. Adjusting it from -15 degrees toward 0 degrees the engine kicks back when trying to start. Another words I can't get any closer to 0 degrees, It will run ok at +15 degrees and start ok at -15 degrees. Just wonder if the cam gear is wore out? The dist. Gear was very wore and sharp edges. It still set the code.

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Wednesday, March 6th, 2013 AT 1:23 PM

RANDICO

MECHANIC
174 POSTS

The way to find out is rotate the distributor rotor in different position, if it moves around then yes the camshaft is worn, but that's unlikely, I have the same year make and model, (well its a 98) when you turn the distributor you know you throw the timing off. Can you pop the distributor out and bring it one tooth back and better yet with the distributor out and hook e up you can turn it, and see if you get 0.