I just did the compression test, here are the results:

1-321.5

2-333.5

3-294

4-312.5

5-78.5

6-315.5

7-312

8-335

Number 5 seems to be the biggest problem
What would you guys recommend as my next step?

 

Next step is a leak down to see if it is a valve or the rings ..

 

Well, the owner of the truck and I decided that whether it was a valve or ring problem, it would not make sense to sink a bunch of money into a motor that has at best fair compression. So, he is finding another motor to put in it.

I will be changing it for him, and probably will have more questions later.

Thank you everyone for answering my questions, it is very helpful!!

 

Yep good choice on swapping the whole works or if that doesn't pan out rebuild it but rebuild will probably cost more.

 

Can my truck still be started with low compression

 

Yes... how low? it will be worse in the cold. Do not use ether.

 

Took my sons 94 F250 (7.3 turbo diesel) in to the shop because she has a super rough idle and some white smoke coming out of the tail pipe. Shop said they replaced the bad fuel injector but it did not resolve the problem. They did a compression check and said that particular cylinder is bad (150psi) and proceeded to tell me that the engine is toast. He did not do the compression check on the rest. He also told me that it would be a very expensive repair especially if it needed to be rebuilt or a new/reman dropped in.

I talked to my ex-husband (who is a diesel mechanic) and he said that it could be bad piston rings or bad valve. I did not ask for his help on this issue other than asking for his opinion (he just takes too darn long to fix things). My son is still making payments on this truck (he bought it on his own without any help in getting financing) and would prefer to get this baby fixed rather than making payments on something he can no longer drive.

Question is......what would the ballpark cost be if its just a broken ring? (My son really blows up when he does not like the answers I get from the mechanics at the shop.)

In the meantime, I will look for a reman for his rig. Hopefully I'll find something affordable and someone reasonably affordable to drop it in.

Knowing my son, he'll drive her until she blows up.

 

Best to find a used good engine and swap it out. Then he can tear down the current one and see what happened.

 

My advice would be to do a compression test your self or get a second opinion before doing anything. Did they give you the results of the compression test ?

 

Not for all of the cylinders, just the bad one (came back with 150 instead of 350). When I call them in the morning to find out how much we already owe on that one fuel injector the installed, I'll find out what the compression is on the other 7 cylinders.

Thinking I'll call the Diesel Instructor (since I know him) up at our local college to see if he can help. Maybe the students this year needs a project to do. Can't afford to take it to another shop for a second opinion.

I'd do the test myself but I'd probably screw something up.

 

compression test isn't that hard to do, just a bunch of crawling around under the hood

 

Is this a PSD? What are the 8th and 10th positions of the VIN?

Generally, I would be very doubtful of the word of a "mechanic" who compression tests only one chamber, let alone one who makes any diagnosis based on testing just one.

 

^^ditto....need to see how that one cylinder compares to the other to see if it is an overall wear issue or something isolated to that one cylinder...




Makes you wonder if "the mechanic" properly torqued down the injector before doing said test....I know my two cylinders that were lower on compression had bolts that were a lot easier to get out...aka not torqued down properly...

 

Brand new engine.
430psi all around...it starts going downhill with age.

 

7 years ago ......

OP was here 14 years ago