Diesel engine stumbles....

[bamaboy473]

Well, that solves the, "do we drive it farther away from home?", question, doesn't it?

The next challenge is having to leave this CG today, and whether we can try to make it home going 60, because....well, several reasons.

I didn't notice any fuel on the ground, but didn't really find the pump, either, so no dripping might mean that there's no large leaks?'

HOWEVER, I did notice that the exhaust manifold has a nice crack all the way across and wonder now whether an exhaust leak there might cause the CEL or other symptoms?

[Ljwt330]

Originally Posted by bamaboy473

Well, that solves the, "do we drive it farther away from home?", question, doesn't it?

The next challenge is having to leave this CG today, and whether we can try to make it home going 60, because....well, several reasons.

I didn't notice any fuel on the ground, but didn't really find the pump, either, so no dripping might mean that there's no large leaks?'

HOWEVER, I did notice that the exhaust manifold has a nice crack all the way across and wonder now whether an exhaust leak there might cause the CEL or other symptoms?

Always nice to get new information, thanks for the update.

The cracked exhaust manifold is notorious in those year ISL engines. Yes, it could trip the CEL as well as interfere with the function of the turbo, possibly causing stumbling. This is definitely something to repair asap. Much less expensive than replacement of the CAPS pump.

Still, I recommend getting the codes pulled and interpreted before driving any significant distance. Mobile truck techs can do it and you will likely know whether or not a drive is high risk.

[bamaboy473]

Good plan. I'm now on the hunt for a mobile tech guy.....

Well, scratch that plan. Nobody works on Sundays in the Montgomery area, so wing and a prayer are the plan to get us home, I guess. Wish us luck.

[Ljwt330]

Originally Posted by bamaboy473

Good plan. I'm now on the hunt for a mobile tech guy.....

Well, scratch that plan. Nobody works on Sundays in the Montgomery area, so wing and a prayer are the plan to get us home, I guess. Wish us luck.

My virtual fingers are crossed for you. Good luck and report back when you reach home.

[bamaboy473]

I'm hoping that the Dollar General has JBWeld. Besides them, we're out in the country for about 80 miles...so why is it that situations usually happen nights and weekends?

[153stars]

Could stay at walmart, gander mountain, Camping world, Rv park ,state park or truck stop ect.
How much carbon or soot are you seeing as how long has it been cracked , how big of gaps. Possible you have cracked manifold and fuel issue, as in change filters, look for the hidden strainer if its there hard its to find, find lift pump google and search here for pics, don't think fuel leaking much it's vacuum sucking in air. If you're not alone have someone cycle key and listen for pump.
Don't remember the owners that found cracks necessarily having a stumble issues they just heard or found them, I remember at one that has a crack and just keeping an eye on it.I'm not saying don't worry about it , just might not be root cause. One pic 2 manifold pipes cracked completely off after removal , they said the noticed better power climbing after repair, as they had been driving like that for a while.

[krivanj]

Change both fuel filters first.

[Ray,IN]

Originally Posted by CC38EL

Don't know what engine you have in your coach, but if it's a 2002 series Cummins ISC, check under your coach for diesel fuel spotting.

You could have a failing lift pump....notorious for these engines. One of the symptoms is what you're describing.

This applies to all ISC engines, and ISL with a lift pump.
The lift pump only leaks fuel when the engine is not running, then only what fuel is in the filter and lines above the lift pump; thus the stumbling = sucking air when running.


The best method of determining this issue is to install a pressure gauge in an unused fuel/water separator housing port. This gauge should read ~15 psi when the lift pump is running, and ~ -5 psi when lift pump is not running. Less than -5 may indicate a possible air leak.

[Ray,IN]

Originally Posted by bamaboy473

I should have said that we have an ISL400 with 63K miles (2003 model), if an ISL is susceptible as well, would failure be immediate or gradual?

We can either go another 500 miles to finish our trip, or can divert and head home for a 200 mile route. What does the brain trust say about how severe a lift pump can be?

Create an account with Cummins Quick Serve, input your engine serial number and it tells you everything about your specific engine.

[bamaboy473]

UPDATE: We made it home with a 180-mile trip, so that's good. What I did was use the clear Gorilla Glue along with some screen (that kept the epoxy from just falling into the crack). The Weld that I got at Advance might have worked, but set time and cure time went almost a full day, and I didn't want to spend the night where we were....so clear was a blind attempt to MacGiver us back home.

Here is more mystery......I kept the RPMs under 1750 in hopes of not using the turbo because the crack (complete all the way around the manifold) was very close to the turbo T. The CEL did not come on once, and the difference between 1550RPM and our normal 1750RPM was 7MPH, but the fuel used changed from 8.2 to 10.2. That sounds bizarrely good, so would a crack that caused exhaust leak to the turbe rob that much MPG?

Originally Posted by 153stars

Could stay at walmart, gander mountain, Camping world, Rv park ,state park or truck stop ect.
How much carbon or soot are you seeing as how long has it been cracked , how big of gaps. Possible you have cracked manifold and fuel issue, as in change filters, look for the hidden strainer if its there hard its to find, find lift pump google and search here for pics, don't think fuel leaking much it's vacuum sucking in air. If you're not alone have someone cycle key and listen for pump.
Don't remember the owners that found cracks necessarily having a stumble issues they just heard or found them, I remember at one that has a crack and just keeping an eye on it.I'm not saying don't worry about it , just might not be root cause. One pic 2 manifold pipes cracked completely off after removal , they said the noticed better power climbing after repair, as they had been driving like that for a while.

[bamaboy473]

Originally Posted by Ray,IN

Create an account with Cummins Quick Serve, input your engine serial number and it tells you everything about your specific engine.

Thanks for this link. Tomorrow I'm going to check the condition of the crack and go from there.

As to fuel filters, I'm changing the main, there isn't a secondary on my engine, but when I drained the filter at the CG, there was no water, and during the drive home, there was not on stumble, EXCEPT for the one time that accelerating away from a stoplight caused the RPMs to get over 1800 and maybe the turbe kicked in, but backing off the throttle stopped the stumble immediately.

Could engine stumble that sounds like fuel related have actually been all caused by a large crack in the manifold? As I said before, the stumble happened mostly on up-hills, and that would be when the turbo kicked in. Just wondering....

[rvbiker45]

Glad you made it back to the barn without any disastrous happenings. Rest easy now, you can get her fixed in your own back yard.

[bamaboy473]

Agreed, there's not much that can equal being held captive on the side of a road when the coach is down and nobody is able to get to help for hours or days.

Glad that the bride and dog are sleeping in their own beds instead of laying awake all night growling at me

[Ray,IN]

Been there done that. Yes the crack will render the turbocharger almost useless under a load.
I had my exhaust manifold replaced with a new Cummins improved manifold. It is heavier made and heavier in weight.
This was mine, you can see the broken parts, leaking exh. port flanges, turbo mount, etc. I also experienced higher mileage with new manifold.