Sadly the SES light came back on today.

Had a pending P0300 when I got to work about 30 miles.
Cylinder 1 had 401 misfire history counts started with zero
Cylinder 4 had 391 misfire history counts started with zero
Cylinder 6 had 60 misfire history counts started with zero.

It was 41 degrees going to work and 46 coming back.

I left work before I get out of the gate the SES turned on.

When I reached home the counts were

979 cylinder 1 increase of 678
725 cylinder 4 increase of 331
142 cylinder 6 increase of 82
I replaced the timing chain and had a relearn done.

I replace the distributor to address -9.7 degree CMP retard.
Now +/- 1

This is with the cap and rotor and the crank position senor that came with distributor.

Should I get another CASE relearn done or change back to the AC Delco stuff from the old unit?

I will get a pic of the plugs later tonight or this weekend

 

If you still have a crankshaft position sensor that has a broken bolt and is not mounted securely, you need to fix that situation and do a crank sensor relearn.


George

 

I realize now I forgot to come back and say that the JB Weld worked. The crank sensor bolt is tight now but not much change.

Also had an oil sender spraying oil.out too. Fixed with AC Delco parts

 

Ok, got back to this and thought I was making progress, Replaced coil wire after I found a orange spot on the coil after the water spray.

Would set and unset the code depending on how the truck was driven. It tends to have more misfires when cold, when idling and going up hills.

since I could see it sparking at the back after I misted the engine bay with water I decided to put on the cap and rotor from my old distributor.

Then I reached too far I decide since I was in the that deep to go ahead and put in the camshaft potion sensor from that unit as well. It was re;earned so I figured the engine would be happy.

So I pulled everything apart without removing the distributor couldn't see it moving as I was working by myself. I swear it wasn't moving but when I put the ratchet on the crank bolt it moved fine.

So long story short the CMP retard now is -59 degree from +/- 1 degree. Have the fun P1345 code.

I even put back in the cam potion sensor that I took out.Still -59 degree and runs ok but way under powered.

The misfires aren't too bad now but the truck is almost can't be driven

Got another CASE relearn with a Cam retard set?

Pull the distributor and move it a tooth or two?

Need to think about this one.

 

I think that you may be mixing up a few terms and procedures. A case relearn is a procedure where the pcm learns the waveform of a new or reinstalled crankshaft position sensor which is located near the crank pulley. The camshaft position sensor is on the side of the distributor and has no relearn procedure. As a matter of fact it technically has no adjustment. Being the OCD types that we are around here we sometimes modify our distributor hold down so that we can rotate the distr as necessary to offset engine wear and get cam retard back towards 0 because if it gets far enough out it can cause problems.

Did you unbolt the hold down and raise the distr and disengage the gear from the drive causing the gear teeth to lose their index?

I am also not completely sure what problem you are trying to solve. Before todays problems, are you trying to solve a performance issue or are you trying to get your misfire counters to all read zero even though the truck runs fine and has no codes?

George

 

My goal was to get it so it wouldn't set a P0300 in the parking lot at work almost every day when I would leave. I could clear and it would be fine until the next day,

I did have a CMP retard of 0 +/- 1 until I decided to change the cap, rotor and cam sensor back the ones from my original unit.

Didn't loosen the distributor hold down at all. And I turned the crank with a ratchet the rotor points to the #1 and #4 post when the timing mark it lined up with the notch on the timing cover.

So either i have killed to cam sensors, broken the wire or the new distributor was always off tooth.

The truck now runs bad but no real misfire issues/counts. No power and struggles to get up to speed.

So if I decide to move the distributor would I advance it i.e. move the rotor forward clockwise or back. New Cam Sensor?

My mechanic is backed up for 3 weeks so getting help is not likely there.

 

There are a lot of moving parts here and I am starting to lose sych with the story so a couple of things. First, the truck thinks you have misfires but you also have sensor problems so the PCM may have been getting bad data. Does the truck run good or lousy during these P0300 episodes?

You talked about a loose sensor screw needing JB Weld. Is that your crankshaft position sensor by the flywheel pulley or the camshaft sensor next to the distributor?

What was the reason for needing a case relearn in the first place, what was changed?

If you did not disturb the distr gear engagement and you had a 0 degree cam retard then why do you think that the distr is off by one or more teeth?

What was the reason for the arching that you saw and was that corrected?

Do you see any carbon traces inside the distr cap indicating a crossfire issue?


George

 

BTW, If you want to verify the gear position of the dist then get to TDC on cylinder #1 (verify with the spark plug removed) and see if the rotor is pointed to the #6 mark. Each gear tooth is worth around 14 degrees of cam retard.


George

 

Had a noticeable but not significant misfire at idle before this started.

Had an oil at the crank snout and base of the timing cover.

Tore into it from bottom which meant I pulled the front diff and oil pan to pull the timing chain cover. While I was there replaced the timing chain. Also found a broken motor mount on the passenger side. Replaced both motor mounts, differntial bushings, tie rods, diff seals and the broken driver side cv shaft. Because of the timing chain replacement it was taken in for a CASE relearn along with a front end alignment. On the way to the shop it set a P0300 code. This was fought with the ignition coil, cap and rotor changed so it could be done.

Given back with a misfire on 1 and 6 and recommended change of plug and wire on cylinder 1. Changed the wire on and plug on 1. Truck ran well enough to drive between Kansas City and Butte Montana. Had misfires and set P0300 codes a few times cleared and got the truck home.

Trans was running hot so finished the wire and plug changes until I could get it in for service. Had the low fuel pressure confirmed at 52-54 psig. Also sorted out that 1 was misfiring not cyl 2 as it was being shown. Truck given back with misfires not at idle and going uphill which confirmed what I was seeing. And confirmed the ear on distributor was cracked

So began digging found the CMP retard was -9.7 so replace distributor with aluminum billet unit which corrected the cmp issue but the misfire was on the same cylinders.

Found And corrected the nut in timing cover that holds the crankshaft sensor was pulled out. No change to the way truck runs.

Yesterday I tried installing the cap and rotor installed on my old distributor. These are AC Delco parts.

Now the CMP retard is almost 60 degrees and the truck seems to struggle for power. cranked the a couple times and it seemed the dist was moving

 

Lets go back to the beginning and retrace these problems as they came up:

1) What was done to address the marginal fuel pressure problem, this could have been your sole issue with the original misfire at idle? What are the fuel pressure readings now?

2) Did you verify the timing when the chain was replaced? #4 at TDC, sprocket marks aligned.

3) When you installed the crankshaft position sensor did you check the clearance and shim as necessary (0.030" I believe)? Did your bolt repair place the CPS in the exact correct position? Was your CASE relearn performed with the CKPS loose or firmly mounted?

4) Am I correct in assuming that the timing chain and CKPS sensor were the only things done that lead to the P0300 codes? I don't understand - "This was fought with the ignition coil, cap and rotor changed so it could be done." What was actually done here?

5) Have you verified the position of the distr? #1 at TDC and rotor at #6 mark.

I'll stop here until we get this stuff cleared up.

George