Cummins misfire when turbo boost above 10 psi

Yes I had a 5.9 that bucked so badly I thought the transmission was going out.

Changed the filters and all gone. Glad to hear it fixed your problem.

Pogoil.

All - Thanks again for allowing me to benefit from your wisdom and experience. I replaced both fuel filters and the problem appears to be gone. Took it for a test drive, mashed the throttle and the turbo boost went well beyond 30psi without any bucking/misfiring.

Regards,
Frank

FrankK wrote:
Sorry, one other update on this. I had no "lit" idiot lights (e.g. water in fuel, check engine, etc.). I also checked for stored engine diagnostic codes and there were none. So I'm going to replace the fuel filters first (they are a little less than a year old) and if that does not resolve the issue, I'll check the electrical connectors for the ECM. I too, like to start with the easy and cheap, then work towards the difficult and expensive. :)

When ours would hiccup or actually quit because of the bad ground of the ECM, it never gave any codes or lights it would just skip a beat and continue to run, or just quit.

when we shook the harness it would actually make and brake the ground to the ECM, and when it did the engine would stutter.

Filters first, then check the ECM by shaking the harness to it. It's an easy fix if that is the problem.

Sorry, one other update on this. I had no "lit" idiot lights (e.g. water in fuel, check engine, etc.). I also checked for stored engine diagnostic codes and there were none. So I'm going to replace the fuel filters first (they are a little less than a year old) and if that does not resolve the issue, I'll check the electrical connectors for the ECM. I too, like to start with the easy and cheap, then work towards the difficult and expensive. :)

Thanks to all for the replies. We managed to make it home. Unfortunately, there's no shops open in No. VA today that have both filters in stock, so I'll have to buy them tomorrow and install tomorrow evening. I'll post an update after I've changed the filters.

Tom/Barb wrote:

dougmac wrote:

Tom/Barb wrote:

Pogoil wrote:
Clogged fuel filters will cause what fills like a miss at higher demand of fuel.

Happened to me with a 5.9 Cummins. Fuel filter change fixed it.

Pogoil.

The 8.3 350 ISC is a computer driven engine / tranny system, it will give you a engine service light when it senses a low fuel pressure. the OP has no light.

that he has told us about.

You will only see a check engine light for a fuel delivery problem on a common rail fuel system. I suspect he has a CAPS fuel system. If this is the case, you would not see a check engine light for low fuel pressure.

When we got his symptoms we always got a light and the computer read out of fuel pressure not with in parameters.

Sorry, I should say... may not see a check engine light on a CAPS system... dependent on the severity of the problem.

Frank
Our coach is a 2000 Windsor with the 350hp. ISC engine also. I like others tend to point to fuel filters. You probably have 2, one with a transparent bowl on the bottom and the other has a sending unit to show possible water in fuel. Ours does the same thing when the filter starts to clog, it'll stumble on a grade and the stop engine light comes on then when the load is off of the engine the light goes out. A grade for us here in So. Louisiana is a bridge or overpass. Changing the fuel filter works every time.
What puzzles me on your post is that it happens every time the turbo boost gauge gets to 10. Heck ours runs at +- 10 all the time at hwy. speed, 60/62mph and will go up as grade increases or going into a headwind to a max of about 25. Those readings haven't changed since the coach was brand new. The Cummins people say that this is the normal reading on the gauge.

Dave

dougmac wrote:

Tom/Barb wrote:

Pogoil wrote:
Clogged fuel filters will cause what fills like a miss at higher demand of fuel.

Happened to me with a 5.9 Cummins. Fuel filter change fixed it.

Pogoil.

The 8.3 350 ISC is a computer driven engine / tranny system, it will give you a engine service light when it senses a low fuel pressure. the OP has no light.

that he has told us about.

You will only see a check engine light for a fuel delivery problem on a common rail fuel system. I suspect he has a CAPS fuel system. If this is the case, you would not see a check engine light for low fuel pressure.

When we got his symptoms we always got a light and the computer read out of fuel pressure not with in parameters.

Tom/Barb wrote:

Pogoil wrote:
Clogged fuel filters will cause what fills like a miss at higher demand of fuel.

Happened to me with a 5.9 Cummins. Fuel filter change fixed it.

Pogoil.

The 8.3 350 ISC is a computer driven engine / tranny system, it will give you a engine service light when it senses a low fuel pressure. the OP has no light.

that he has told us about.

You will only see a check engine light for a fuel delivery problem on a common rail fuel system. I suspect he has a CAPS fuel system. If this is the case, you would not see a check engine light for low fuel pressure.

I'm with the others... fuel delivery problem. Start with the fuel filters and go from there if you still have a problem.