20 Degrees Retarded..........

[alpinecrick]

1996 K1500, 5.7

The intake manifold cracked at the temp sensor hole just in front of the thermostat housing.

Found an intake, the install went smooth--I thought.

When I started it I knew something was amiss, it started hard like it was out of time. Put my scanner on it and cam retard says 20 degrees retarded. Thought I was a tooth off. Reset the distributor one tooth back, no dice, won't start. One tooth forward, won't start. Find TDC, set the distributor and rotor right where it should be, starts hard and 20 degrees retarded.

Have a brand new Delphi distributor, installed it, drove the truck to my mechanic and we went through the same routine, no dice, it runs, but it's 20 degrees retarded.

If I turn the distributor within the limited arc, it makes no difference, still 20 degrees retarded.

I'm thinking my pcm is toast?

 

[Oldblue98]

1996 K1500, 5.7

The intake manifold cracked at the temp sensor hole just in front of the thermostat housing.

Found an intake, the install went smooth--I thought.

When I started it I knew something was amiss, it started hard like it was out of time. Put my scanner on it and cam retard says 20 degrees retarded. Thought I was a tooth off. Reset the distributor one tooth back, no dice, won't start. One tooth forward, won't start. Find TDC, set the distributor and rotor right where it should be, starts hard and 20 degrees retarded.

Have a brand new Delphi distributor, installed it, drove the truck to my mechanic and we went through the same routine, no dice, it runs, but it's 20 degrees retarded.

If I turn the distributor within the limited arc, it makes no difference, still 20 degrees retarded.

I'm thinking my pcm is toast?

 

[Oldblue98]

Crank position sensor's are known for failing on them, has it been replaced ? They get old brittle and oil soaked... Usually will cause engine to kick back with timing issues, not a healthy thing for starter heads, ring gears, broken bolt boss's on block. Just an idea and something to give thought to.

 

[alpinecrick]

Crank position sensor's are known for failing on them, has it been replaced ? They get old brittle and oil soaked... Usually will cause engine to kick back with timing issues, not a healthy thing for starter heads, ring gears, broken bolt boss's on block. Just an idea and something to give thought to.

Crank sensor was replaced with a AC Delco less than 10k ago. Nothing was wrong with it, but I replaced a leaking timing cover and decided to replace the sensor too.

 

[laidbackbigun]

Do a camshaft position relearn. We do it with a snap on solus at work. Ckp relearn.

 

[Oldblue98]

Crank sensor was replaced with a AC Delco less than 10k ago. Nothing was wrong with it, but I replaced a leaking timing cover and decided to replace the sensor too.

I did not realize the repeated trouble that was common with new crank position sensors until I had a issue with mine and started diving into the subject and doing lots of reading on the kick back issues and guys that had replaced the sensor for the new one to fail a short time later. Not saying that is the issue by any stretch, but just saying being new not long ago don't mean much from what I have read.

 

[alpinecrick]

Do a camshaft position relearn. We do it with a snap on solus at work. Ckp relearn.

Thanks for the info. My mechanic has a Solus, he's kind've old school, not sure if he knows how to do it. I'll talk to him on Monday.

 

[Supercharged111]

Not unusual you can't get the right cmpret, but very unusual that it doesn't change when you rotate the distributor. A worn timing chain contributes to cmpret setup challenges, though not in the manner you describe.

 

[alpinecrick]

Not unusual you can't get the right cmpret, but very unusual that it doesn't change when you rotate the distributor. A worn timing chain contributes to cmpret setup challenges, though not in the manner you describe.

New Sealed Power roller timing set last summer. But I've been thinking if the timing set may have something to do with it.

The problem is, it was running fine until I pulled the manifold. No indication of a timing issue.......

 

[Supercharged111]

I'm interested in the outcome, just remember to set cmpret between 1000-1200 RPMS.