Well, I finally got my first diesel. 1996 f350, CCLB, 4x4. Auto. It has 226k on the clock. A few dings and dents, but great nontheless. I bought it as a "project" truck, as the owner sold it "needing work". He had a shop look it for him (ford mastertech worked on it), and they said the #7 cyl had low compression. The oil was 5ish quarts low too. He did oil changes every 3k miles, so it didn't have more than that many miles on it. I got it for an absolute steal as he had already bought a truck and I think was done playing diesel. He didn't want to put an engine in it/pay more for maintenance and whatnot. First thing first, I did the napa BHAF air filter setup on it, and WOW it is night and day different than before. It had a pos K&N on it.
Then I fixed the pigtail that plugs into the #6 and 8 cyl hookup on the valve cover gasket. It was slightly crapped up, so the glowplugs weren't working as they should have been. I wired in a new one and it starts much better(the hard starting was another one of his concerns).
About the low compression on #7....
Is it possible they mis-diagnosed it or can it still run fairly well with low compression on one cyl? Is it really easy to mess up a compression test? It seems like if he threaded the tester in properly, there is no way to mess it up. The truck seems to run well for me, but maybe it is lacking some power that I am unaware of. I plan on driving it till it really needs work. So my real question is can it run ok and be somewhat un-noticeable even though it has low compression? Thanks!

 

Did he happen to give you the compression numbers? You might not notice it if its low on compression, especially not being used to the truck. That's not that many miles to be low on compression. Could have sucked in a bunch of crap with that k&n on there. What's the turbo wheel look like?

Oh, yeah, congrats on the purchase! PICS!

 

If its low on one cylinder it will have a slight miss. Put your ear near the exhaust pipe and listen for just a little miss. If its smooth then the shop was after some bucks. Did you solve the oil mistery?

 

Thanks! I got the diesel bug 2.5 years ago and I am still giggling everytime I drive it... addicted to the turbo sound already. The blades on the turbo look good still. The napa 6637 was a great move. I'll get some pics monday, it's parked at work.

So i'm open for ideas on what mods I need next. I am thinkin 3" downpipe and 4" all the way back, no cat, and high flow muffler.
Any ideas what else should I do? Turbo? injectors?
thanks!

 

muffler? we dont need no stinking muffler! I was nervous when I did my diy exhaust with no muffler thinking I could add it later IF I needed it...That was almost a year ago...NO MUFFLER NEEDED for me.Its my daily driver /family cruiser and there are no noise complaints. Welcome to your newest addiction! Go ahead and empty your wallet and tell your friends you are moving out of state. NOW your life is all psd! haha

 

I wouldn't do any mods until I verified the compression is up on all cylinders. A cheapo harbor freight tester (if you don't have one) and some time and you can find out for sure.

 

My personal opinion is that people point towards bad cylinder compression far to quickly.

Could be something as a bad seat on the copper ring on the injector.

Unless you bend a connecting rod, I don't see these trucks "suddenly loosing compression"

 

If the turbo blades are undamaged I would be very surprised for it to be low comp. From what I have seen dusting has been the biggest cause of failure .....there are lots of potential causes and even more incorrect diagnoses.darin is smart also,may get it running for a good baseline before mods.otherwise troubleshooting could be a nightmare.

 

What he said.

 

Thank you guys for your quick input. If I posted a sound clip of the exhaust you think ya'll could verify a small miss? I will get pics posted soon. Talking to some of the techs where I work (I work in a service shop, doing light maintenance and detailing while still in college), they agree it sounds like all eight are working. I had another ford service guy look at the blades, and he said they look absolutley normal for 226k miles. I'll get a pic of that as well.

 

The blade could have been replaced, do you know if it has? That is why I mentioned the blade, if its good and original, that kind of eliminates one way of bad compression. Other things still could have happened. If it were mine, I'd still pop the valve covers off and do a check before I started putting much money in other things. Take a saturday afternoon and verify.

Do you notice any blowby? Take the oil fill cap off the valve cover and put it upside down over the hole while its running. If it vibrates off, that's normal. If it blows off, you've got something wrong.

 

Low compression and low on oil could both have the same problem. BAD RINGS

 

Alright got some pics coming as soon as I find out how to do this properly!
Hopefully you guys are still following this thread and can give me some good input.