I have been getting help with a no start 6.0 in another thread, but I guess it's time to go down the rabbit hole. It's at 65k miles, was sitting around for half a year with a previous owner. Started with hpo issue that I seem to have resolved with new ipr, with the help of the forum members here. I'm also doing injector seals, nipple cups and dummy plugs in the meantime to seal off the system.

I had ran a compression test with a 300psi gauge on a couple cylinders as I was changing glow plugs and harness, and they showed above 350 psi. A couple others showed barely 150, so I figured I blew up the gauge. That's when I went and bought a harbor freight diesel gauge and while I was waiting for the otc adapter whip to come in I took apart the oil rail and was getting ready to do injector seals and nipple cups.

I have now tested all the cylinders with the proper gauge but only to get the same dreadful result low compression ranging from 150-200 and rising 50 only with a bit of oil added to the cylinder.

If I don't have compression I'm obviously not going to get it to start although everything else showed up good on the torque gauges before it was apart. I need some help here. Any ideas of why I don't have compression on any cylinders? I'm getting a new compression gauge today just in case, but seems unlikely it's the gauge.

 

If the compression is the same between all cylinders you should be fine

IIRC you had Hpo problems

What's cranking ICP &IPR%

 

Have to ask, is the injectors installed and tightened down? Are you SURE the cheap HF gage is good? Was it running before you started working on it? Is the intake or exhaust resticted in any way? ALL of them being low and the same makes me think something is wrong with the testing method.

 

I may have gotten paranoid after reading about a failed egr cooler leaking coolant into cylinders and rusting the walls and rings. Hope that is not my issue will post numbers tonight, blade.

 

Bob, I got it as a no start. Intake is down to just the turbo and exhaust system seems to be ok. Injectors are tight, but I have vapor escaping from the head area with cranking. After removing the valve cover I have not been able to locate the exact area it's escaping from, but it looks like the valve train.

 

Got an interesting suggestion talking to a fellow mechanic, pour cylinders full of motor flush and check back the next day to see how much remained. Also will check my timing to see whether that might have gotten messed up by previous owner. Does this engine have valve clearance in case of messed up timing?

 

The cam and crank are gear driven. I don't think it's going to be a timing issue here. I would pull the valve covers though. At 65K miles compression shouldn't be an issue but things happen........ That's not even broken in good for a diesel motor.

 

Have you had this truck running yet ,or are you just going through the motions of fixing all known issues first ?

 

I haven't gotten it started yet

 

I would test that gauge on a known source, something seems abnormal to me, Hard to believe that all the cylinders would have a ring failure let alone that they would produce numbers that close across the board. You also say your old 300 psi gauge was not high enough and got damaged this indicates that you have Higher pressure well at least one those cylinders. You could perform a leak down test on the cylinders, this will give you a clear idea of where your compression loss is That is of course that there is a leak and not just a bad gauge

 

I'm a little late to the party but you can count me in as another, who has a hard time believing you have low compression as your issue if all eight cylinders are giving you readings that close together. At 65K miles, it seems very unlikely that you have base engine issues. Like already suggested by catapeed above, do a leakdown test since you're already that far. THAT, will tell you for sure if you do in fact have any compression loss. Have you run an injector buzz test like I suggested to you in your other thread? Better yet, do you have access to another running 6.0L diesel truck you can "borrow" a FICM from to swap in temporarily? Will the engine start and run on Brake Parts cleaner? If it does, compression is most definitely not your issue. And in answer to your question regarding fuel and high pressure oil system, NO it does not need to be primed up in order to run a manual compression test like you're doing.

 

I believe he already stated that he's getting ICP psi up to 2K psi almost instantly without IPR duty cycle going up to 84.77% since replacing the IPR valve. He HAS TO have injector(s) that are not firing or functioning properly in order not to start at this point, because all his other numbers seem good if I recall correctly.

 

M-chan, always appreciate your advice. By a buzz test are you meaning whether or not the injectors buzz on koeo? They definitely buzz. I'm thinking about going pin to pin on the harness though, but would I have the .8-6 FPW if my injectors or ficm was malfunctioning? I found a ficm from a 6.0 that I'll be testing. Guy drives it daily though so I need him to free up.

I've used ether in the past, just as I saw fpw appear, just a few sprays. It seems that the engine bogs down though with longer sprays. Still no start, and this is when I started digging deeper. I may be overlooking something and that's why I appreciate all of the input on this forum.

Will be visiting hf to exchange the tester today and possibly grabbing the leakdown tester but I'm in dire need of an assistant to get me at bdc of the piston. Anyone in the Tacoma Washington area who can lend a hand?

 

Catapeed, npccpartsman,

Is it possible to mess up timing with the change of the HPOP? I may be mistaken but I believe the previous owner had it replaced along with a couple injectors. I wish he was more specific but he claimed to have no mechanical knowledge.

 

No it is not possible, The HPOP is Driven by the camshaft and that is driven by the crank, It is all gears.