No Start and Uneven Cranking

blown99 · July 20, 2006

Had a school bus (international bus) towed in today for a no start condition. Batteries were low so I charged them, checked for codes, no active codes. Performed hard start no start diag. with MDII. Have 1200 psi for the icp, 45 pis fuel pressure, 13.5v showing for ECM volatge. While cranking it sounds very uneven, low compression, so I do a relative compression test. Cylinder 2, 4 read 0 rpm and 3 and 5 are around 6-8 rpm, the rest about 10 or 11 rpm. Cranking rpm was 175 rpm. No sounds of it even attempting to start skip smoke etc. Sounds kind of like a car with a slipped timing belt. Tech line wants me test the high pressure oil manifold/system and check for a broken branch tube. Doesn't sound like the right rode to go down. I'm leaning towards a valve train issue. Wondering what others have run into. I can't see a bad rocker arm on one cylinder keeping an engine from running. (tsb's on rocker arm failures). Thanks for any info.

Diesel Jay · July 21, 2006

The manifold between the high pressure oil pump and each individual cylinder head [branch tube] can break and cause hard starting. When that happens, too much high pressure oil gets dumped back into the crankcase and the engine won't start because the injectors aren't getting enough oil pressure.

As an aside, the Nav hotline guys are generally very good. Most are ex Ford/Nav dealer techs who have been in trenches, and the engineers that are involved are well seasoned. They're a good bunch of "no-BS" guys, the kind you'd go have a beer with after your shift. More of the time, they'll lead you down the correct road with their advice.

- Jay

HGM · July 21, 2006

I would definitly look at your oil syst, at 1200psi, what is your IPR? If its upwards near 85%, its a safe bet you have an oil leak.

I would also be interested in if you have syncronization. Not sure what the PIDs look like on MD but w/o Sync and FICM Sync, the injectors wont fire(FPW will give you a clue).

blown99 · July 22, 2006

Ok, tested the high pressure oil system today, pressurized the system and found no leaks/air leaking. Dissabled the glow plug system and gave it a little starting fluid - nothing. removed valve covers and checked rockers and puch rods- ok. Performed a compression test. Cylinder 1, 3 have 375psi,5, 7, 8, 6, have 140- 150 psi, 2 has 275 psi, and 4 has 175psi. I remove the high pressrue oil manfolds and bar the engine over to verify that the valves are opening and closing. Did not appear to have any bent valves as the vavle heights visually looked the same. Tech line wants me to drop the pan and look. All looks good, no scores, no metal on the drain plug magnet. I still think that the cam timing has changed as the cam gear is only sweated and keyed to the shaft. Engine group said that it wasn't possible because I would get a cam and crank sensor codes saying that the signals are not matching/synching. There is no popping back through the intake or exhaust while cranking and I did notice white smoke (smelled like fuel) coming up past the push rods while cranking for extended periods. The injectors are buzzing while it is cranking, IPR is about 21%. Also removed the fuel lines at the back of the fitler housing and put balloons on them and cranked to check for compression blowing back through an injector, nothing found. So basically the rear 4 cylinders have low compression with the exception of #2. Spec is 375 - 400 psi.

ktmlew · July 22, 2006

Was the vehicle parked for a long time, like several months? They have had problmes with exhaust valves sticking in the guides and they get intimate with the pistons. Call it "lot rot"...

There has also been some problems with roller lifters coming apart. I would pull the oil pan and see what is found lurking in it... /forums/images/%%GRAEMLIN_URL%%/poke.gif

HGM · July 23, 2006

I havent tried it before, but can you rig a cyl leakdown tester? I'd be interested in where its leaking to.. Do you get blowby out of the crankcase filler when cranking? The pan shouldnt take too long to remove, that might tell you something

blown99 · July 23, 2006

I removed the pan. Not a spec of anything. I had white smoke vapor coming up past the hpo manifold/rockers while cranking for extended periods.

ktmlew · July 23, 2006

I removed the pan. Not a spec of anything. I had white smoke vapor coming up past the hpo manifold/rockers while cranking for extended periods.

Sounds like piston or ring damage? The leak-down test would give more info...might just be time to bite the bullet and pull the heads?

It's "broke" somewhere! /forums/images/%%GRAEMLIN_URL%%/crybaby2.gif /forums/images/%%GRAEMLIN_URL%%/poke.gif

Kyle E. Grathwol · July 25, 2006

White smoke=Low compression. This engine is either out of time or has bent valves or rods. If it cranks erratically I am betting on pistons contacting the valves. If it wasn't iron related, it would have run on ether.

I know you said that the rear 4 were low on compression but I would think that all cylinders are affected or else it would try to start on the other 4 and belch white smoke out the pipe from the 4 low ones.

Did they give you any history when they dropped it off? Was the bus just pressure washed? Serviced?

blown99 · July 25, 2006

The rods don't apear to bent ( from looking up past the crank) Also didn't notice any scoring on the camshaft indicating broken cam followers. Supposedly they were driving it, started running very bad, nursed it back to the yard, shut it off, then there techs went out to look at it, and killed the batteries trying to start it. I didn't get a chance to tear the heads of today as us international guys are 3-4 deep in the 6.0 work too.

Keith Browning · July 25, 2006

Interesting thread, looks like a tear down is necessary here. A sad note - one of my techs did a head gasket job a week ago and I believe both heads were replaced due to flatness concerns. Came back on a hook at the end of the week and he just got it torn down again. Cylinder #2 has an exhaust valve snapped off and embedded into the piston.

My point is that the resulting debris actually traveled to the next two cylinders causing more damage. What looked like a problem with the entire bank actually can be pinpointed to one cylinder. Start diggin!

blown99 · July 28, 2006

I performed a cylinder leakage test and found the air going right into the crankcase, past the rings. I removed the heads and pushed out the pistons and found my answer. All of the ring gaps were lined up! except on two pistons (the two being the ones with 375psi compression). The carbon tracks blew right past the rings and trough the oil control ring. Also decided to check the heads for warpage as I have no info on the previous running condition. Found both heads to be warped pretty good. Cylinder walls look good. So as part of Navistar up-time program this engine will be getting a new EGR cooler, oil cooler, turbo (pulled apart no good)water filter bracket and hoses, coolant expansion tank, new rocker arms, two cyl. heads, 8 psitons, rod bearings, just about every gasket and a branch tube update. Everything but the injectors (which I am sure I will find are bad once this is running) block and crank will be new.

Torqued_Up · July 28, 2006

Why doesn't somebody just sell him an FQR long block?

International Tech · July 28, 2006

Im suprised that they dont send a long block. Especially since its a school bus. We had a tech this week had an 04 box truck w/ a 365 running rough. It had low compression on 2 cylinders on the right bank. Tech line just had him remove the cylinder head and inspect. We didnt see anything. They didnt even want us to pull the pistons. They sent us a long block. hmmm....

blown99 · August 24, 2006

Well after a month of waiting for parts I finally was able to reassemble this engine. I put a set of heads on it as the old ones were warped. The replacement heads came as a kit with neww rocker boxs, stepped locating dowls for the different head gaskets and different injector hold down clamps. It was/is a late 2006 head update kit. Anybody else install one yet?? Installed new pistons, rings and rod bearings. EGR cooler, oil cooler, coolant filter and degas bottle, reflash, as part of the uptime deal. Engine fired right up and ran excellent.

Keith Browning · August 24, 2006

I see you repaired this one and you just posted another thread with the same concern. What was the root problem with this one anyway? Looks like pistons and rings. Was there a concern with the rings and did this vehicle sit as well?

I'm starting to think that this engine does not like sitting for periods of time. So far, all I have seen from long term "un-use" is frozen turbos and sticking exhaust valves. Amazing what a little surface rust can do!

blown99 · August 24, 2006

I found all the ring gaps lined up on this engine with the exception of two cylinders which were somewhat spaced. There was heavy carbon/soot tracks past the rings. I could not get a straight answer as to how long it sat. I was told it was running rough, driven back to the station shut off and would not restart when the fleet mechanics went out to check it out. I don't know how long it was between the two. There was also a heavy ridge of soot at the top of the cylinder that needed to reemed away in order to remove the piston/rings assembly, which isn't characteristic of an electronic diesel with only 31K.