FrozenMerc
Full Access Member
I need some help from the brain trust on here.
The short story. Over the last week I replaced the head gaskets and studded the heads on my '85 6.9 IDI in preparation of a future turbo kit and to hopefully address a magically disappearing coolant problem. The motor has 122,000 miles on it, and other than a few dents (digested glow plug tip???) in the top of #3 piston, everything looked really good inside. Nice clean bores, etc.
I got it back together and fired it up. After a few seconds of cranking, it hit on all 8 right away, and I shut it off after only running for a few seconds last night. This morning, I put the hood back on, buttoned everything up and went to back it out of the garage. Again it fired instantly, ran on all 8 and idled smoothly at 800 rpms. I backed it up to a pile of branches that came down in a storm last Friday and loaded those. Figuring a quick trip out to the dump site would be a good way to warm it up and break it in. I left it idle while I loaded the rear. After taking off, it started puffing white and I soon lost a cylinder or two, within the first mile. Limped back to the house to start diagnoses.
Now, it will start right away, but idles roughly, down to maybe 600 rpms, which to me indicates a misfiring cylinder. I can rev it up, but it is definitely rough and there is a large amount of white smoke out the tailpipe.
I cracked each fuel line at the injector, thinking maybe there was air trapped in the system. There seemed to be good fuel at each injector. I have checked each exhaust port with an el-cheapo IR gun, #7 is definitely cooler, but it is also the hardest to get to, so I am not 100% confident in the measurement. The rest are fairly equal within 5 or 10 degrees.
My thoughts are for the following problems:
1. Injector is hung up. Could have gotten contaminated during teardown or reassembly. The injectors are about 4 years and 20,000 miles old.
2. Timing is off - I did pull the injector pump, gear and cover as one unit. The motor was at TDC and I dropped it back down with the "Y" straight down, but I can't verify that it isn't 1 tooth off. Again, the way it initially fired rules this out in my mind, but I am running out of ideas.
Any other thoughts or items I should look at? Any help is greatly appreciated.
Thanks
The short story. Over the last week I replaced the head gaskets and studded the heads on my '85 6.9 IDI in preparation of a future turbo kit and to hopefully address a magically disappearing coolant problem. The motor has 122,000 miles on it, and other than a few dents (digested glow plug tip???) in the top of #3 piston, everything looked really good inside. Nice clean bores, etc.
I got it back together and fired it up. After a few seconds of cranking, it hit on all 8 right away, and I shut it off after only running for a few seconds last night. This morning, I put the hood back on, buttoned everything up and went to back it out of the garage. Again it fired instantly, ran on all 8 and idled smoothly at 800 rpms. I backed it up to a pile of branches that came down in a storm last Friday and loaded those. Figuring a quick trip out to the dump site would be a good way to warm it up and break it in. I left it idle while I loaded the rear. After taking off, it started puffing white and I soon lost a cylinder or two, within the first mile. Limped back to the house to start diagnoses.
Now, it will start right away, but idles roughly, down to maybe 600 rpms, which to me indicates a misfiring cylinder. I can rev it up, but it is definitely rough and there is a large amount of white smoke out the tailpipe.
I cracked each fuel line at the injector, thinking maybe there was air trapped in the system. There seemed to be good fuel at each injector. I have checked each exhaust port with an el-cheapo IR gun, #7 is definitely cooler, but it is also the hardest to get to, so I am not 100% confident in the measurement. The rest are fairly equal within 5 or 10 degrees.
My thoughts are for the following problems:
1. Injector is hung up. Could have gotten contaminated during teardown or reassembly. The injectors are about 4 years and 20,000 miles old.
2. Timing is off - I did pull the injector pump, gear and cover as one unit. The motor was at TDC and I dropped it back down with the "Y" straight down, but I can't verify that it isn't 1 tooth off. Again, the way it initially fired rules this out in my mind, but I am running out of ideas.
Any other thoughts or items I should look at? Any help is greatly appreciated.
Thanks