Good afternoon. I ohm #2 plug wire, well within its limits (2.75). Switched #2 and #6 plugs, did find a 1/4 inch vacuum line split at the connector,replaced the line. Misfire did not move to #6, still on #2 with a high count. Was able to read the CMP @-8.18 degree, do you think that is enough out of limit to cause the #2 issue? A new gear is 75 bucks so may do a gear change, if blazer cools down enough to work it I will time everything up and pull the distributor and really look at the teeth wear.

I help my cousin’s husband on his farm couple days a week, he is 87 and works his 125 acre cattle and hey alone, I do all his equipment upkeep, this moron blew up the biggest tractor engine that I did an inframe overhaul on about 3 months ago, so he sourced a used engine to swap out from a corn picker, all the accessories had to be moved from old engine to the new used one including the injector pump, I kept the same drive gear with that pump. After installing the engine I could not get it to fire up at all, I knew the timing of the pump was by the book, but I doubted my self and decided to remove the pump enough to rotate the shaft 180, all that and still no crank. So I had no choice but to remove the front timing cover and triple check. I ended up with both pumps gear driver side by side when I noticed the timing marks were different in relation to the key ways, huh that’s funny plus the new used engine pump gear had 2 marks for the 4 cylinder, 4 and 4M. So installed that gear to the 4 mark and slapped the cover on and it cranked, running rough but running. So off with the cover again an moved 2 teeth over to 4M and slap the cover again and bam! She’s running like a sewing machine! There was no way to know that tiny bit of secret JD info.
Guess what I’m saying is if I can build and swap out tractor engines I should be able to fix my Blazer!

 

Yes CMP retard that far off might cause misfires or the wrong cylinder to be labeled as the misfire. You need to change the hold down and rotate the distr until you are as close to 0 as possible but no more than +/-2:



If you don't want to wait for that hold down you can ream the existing hold down out into an oblong shape. If you want it as fixed as possible then its some combination of distr gear, timing chain slack and cam gear.

Oh we can fix your blazer, just depends on if you want to stay with it until the end. I will hang with you as long as you want. I work on 1,000 hp marine diesels so I understand.

George

 

I’m torn between changing the gear or just getting a new distributor, this one is not original to the engine, it’s a billet type. Might just be worth it to reinstall as is and try to get it close to zero. I need to get the wife to watch the rotor while I move the crank to check for any slack, I think the original owner replace the timing chain and distributor together. I can see the firing marks inside the cap are not firing directly on the post but more towards the backside which I assume is caused by the gear ware.
I fully appreciate all of your help and advice, believe me I want it to run like it did 4 years back when I bought it. There is no rust anywhere, Inside is in great condition, it’s well worth saving.

 

Worked the CMP down to 1.8 today. #2 was showing a low number misfire in the driveway, will drive to the farm Monday so I’ll see how that goes.

 

Sounds like progress.


George

 

Quick test drive this morning and it was running great, no misses. Stopped at the Deere place for parts pick up, driving back get the SES and feel it missing. Assuming it’s #2 still, will check fuel pump pressure ( it’s only about 4 months old) and will look really close at the spyder electrical connector. What else?

 

First thank you for your input! I had the T body completely off about 5 months ago to clean an removed the lip on the inside as some here suggest.. I cleaned it pretty good and checked for play in the throttle shaft which was good.

 

I’m rechecking fuel pump pressure. When the key is on I get the 2 seconds prime ( 58 psi ). I ran a test light from positive post of the battery to the prime terminal at the fuse block but this does not turn the pump on, what does this mean?

 

Trying to hot wire the fuel pump with a test light is like using a corroded wire with unacceptable resistance. You need to use a fused wire of the proper gauge. Why are you hot wiring the fuel pump if it turns on at key on?

George

 

I was trying to see if pump pressure would climb any higher than 58 psi. It drops to about 56 psi during a 10 minute time frame. I replace the poppet spyder system with an updated one about 6 months ago. Still searching for the #2 misfire cause.