Isx wont start

[Toddmsc]

I have an isx cm2350.
It had coolant in the fuel. Bypassed tank heaters and confirmed injector cups or cracked head. Being around many of these, the machine shop, and from my personal experience...I have never seen a sohc head crack yet. The dual cams I've seen plenty of.

Anyways, truck has a b.s warranty on it so and I have enough on my plate to deal with so I figured with, I'll have them deal with it. Drove it to shop no codes, not running rough, nothing out of the normal operation of the truck. They bring it in call me say its head or cups warranty doesnt cover either. So I told him ok fine put it back together I'll do the work myself. Only reason I brought it there was the hope of warranty footing the bill. He calls me later and says well its together but doesnt run send a tow truck. At this point I'm confused to why I gave them a running truck with no codes and I get one back that doesnt run. They say bc they used the old injector o rings and most likely they are leaking causing a low pressure no start problem. So i got it towed home.

I had finally got some time and took back apart. Pressure tested it and 1 4 5 6 all leaked. Cummins has a tsb on leaking sleeves and they make a retaining ring kit to solve the problem. Bought it, did it, and fixed the problem. This pressure test none of them leaked anymore. Sweet! So I think.....

Put new o rings on the delivery tubes and new orings on injectors. Put all together. Primed it made sure there were no air bubbles. Made sure at the primer pump, the in side of the high pressure pump and at the filter housing. Still no fire. I do have the notorious fuel lower than commander and the injector metering rail one low pressure codes. The primer pump is doing its job.

What would have made the high pressure go all of a sudden? Can I get away with a new head on the pump?

I do not have insite still waiting for it to come in cant take not having it anymore. Would have been nice to see rail pressure before spending the 1500 on a fuel pump head.

Thoughts guys?

[Rawze]

how many miles on it? -- some more history?

How much dod you try to crank it? -- it can take 2 or 3 cycles of 30-sec plus to get one to fire off once the fuel system has been all apart. -- ALSO, did you try to pressurize the fuel tanks to 10 psi to ensure nothing is leaky, and help prime it?

- Also there is no telling what that shop did.

[Toddmsc]

I have def primed and cranked enough lol. I just finished up a head job on a friends triaxle and i did the same process as mine and it fired ran rough for 10 15 secs and smoothed right out.

I've pressurized the tanks and found nothing.

History on truck? Bought at 750k did clutch, rear main, and front structure gasket at 860k. Not a lick of other problems. Truck has always been super reliable.

[Rawze]

(01-04-2020 )Toddmsc Wrote:  I have def primed and cranked enough lol. I just finished up a head job on a friends triaxle and i did the same process as mine and it fired ran rough for 10 15 secs and smoothed right out.

I've pressurized the tanks and found nothing.

History on truck? Bought at 750k did clutch, rear main, and front structure gasket at 860k. Not a lick of other problems. Truck has always been super reliable.

have u cracked the return line open a bit on the front of the rail to see if the high pressure relief is leaking? / blowing fuel past it? - they are notorious for getting leaky or trash in them and cause starting and other issues if they are bad enough.

Also, those feed tubes going into the head for injectors, .. they are a one-time use (crush-fit), and cannot be swapped around once mated to an injector. -- If injectors have been out, and re-installed, or if someone has swapped them around, then they easily could be blowing fuel past them and into the return causing the rail pressure not to build fast enough during cranking. - they (and injectors too) can be tested with an old school diesel fuel pressure test set and an adapter... it is a life saver for the ISX, i don;t know why cummins does not have info on using one for the isx, or an adapter for one.. maybe want to sell injectors?...
ref: http://rawze.com/forums/showthread.php?t...56#pid2556





just some guesses. There are others on here who actually own those model engines that may have more ideas.

[Unilevers]

until you can see actual fuel pressure when cranking you are wasting your time guessing.

If you have those codes its most likely a bad leak or blown pump.

1 - Get insite
2 - small sniff of ether verify engine will fire (rules out total failure/timing)
3 - Verify low pressure and that lift pump is running constant
4 - Check rail relief
5 - Pop pump head and check check valves/plungers
6 - Isolate injectors and check for leaks
7 - verify rail pressure with manual gauge for sensor plausibility
8- try test ecm

[Toddmsc]

I'm going to go mess with it more now.

Unilever's
1 insite I've already ordered still waiting for it. I've gone too damn long without it and now its frustrating.

2 she runs fine off the sniff. Dies once you stop.
It ran fine when I brought to that shop making me believe put together with a leak or pump failure from the coolant running through it....then them trying to start it air bound was probably its last straw.

3 lift pump is actually really strong and very constant certainly doesnt have lack of flow in that department.

4 going to check rail relief today.

5 also today gonna pull head bc I have new one on the way in am. Truck has almost 900k on it and no records that I see it was ever changed.

6 I wanted to do this. Unfortunately dont have any old lines to weld and make plugs to do this. Any other suggestions on how to do it?

7 have to find someone with a gauge..

Rawze
Going to check that relief today.
I was unaware and havent heard about the feed tubes being a one time use deal. Not saying I'm right or maybe just lucky but I've never replaced them. Usually take them out, mark it and the injector and always put back in respective holes with new o rings and never had an issue. Unless of course shop paid no mind of attention to this and mixed them up.

I've even jumped the metering rail pressure sensor to make ECM think it had the pressure and not even the slightest chance of it starting.

If you crack high pressure line at pump and crank you can def see pressure build a slight bit but no where near what itd need to start.

I've done many of these 2350s and never had a problem yet. I've done heads, rebuilds, cam jobs, injectors. Always trouble free and ran great via quickserve specs for exact serial.

Problem is when you look up fuel pressure trouble shooting they run you over the hill before you can actually do it their way. 200 bucks for the orfaced test line, then they want you to get beakers and measure for cranking. Quite a few tests they want you to perform in insite. They make it virtually impossible to do yourself. But at the same time you know as well as I do these jokes of mechanics at dealer will waste your time bc they are inexperienced and wont do it properly ether...so theres always that.

To me I think the pump head is absolutely throwing parts at it. But my theory is truck has 900k. No record of it ever being done or updated. So I dont think itll hurt anything to replace it. Its security at this point.

Cannot wait for insite tho, good god not having it is a total pain in the arse.

[snailexpress]

Sorry if it sounds damn, check fuel actuator connection.

[tree98]

You say you've done a lot of work to cummins engines before? You've done all this without insite?
What do you normally set your liner height at when you do an inframe?
Are you aware that these pumps fail if not rebuilt around 400K miles, and turn your engine into a boat anchor? I'm saying completely un rebuildable.

[Toddmsc]

Yes I've done it all without insite so far. 2350s are min of 7 thou max of 14. No two can be a thou and a half off each other.

I'm fully aware of this. Didnt buy this particular truck until it was already in its 750s. Now its 900. Never had a problem with it. First time ever its just not started.

Checked pressure relief. Was not leaking. Went through it all again to make sure nothing was missed. Pulled pump head and via quickserve passed all tests.

Going to have to find a way to individually check injectors. Something isnt adding up here.