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cumminsdr, Mechanic
Category: Medium and Heavy Trucks
Satisfied Customers: 3653
Experience:  All types of Cummins applications
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I have an isx cm871 in my 2009 peterbilt. i have

Customer Question

i have an isx cm871 in my 2009 peterbilt. i have intermittent turbo " cough" and an occasional white smoke smelling like fuel. it seems to be overfueling occasionally. i have replaced 3 turbos, all timing and metering selenoids, injectors, complete genuine cummins overhaul, head rebuilt, imap sensor, exhaust back pressure sensor, and delta p sensor. dpf has been cleaned and baked. had it dyno'd at kenworth nad they said all is good, had a mechanic data log it on a trip and send results to cummins and they said its ok. buy i know that this engine shouldnt smoke and i know what over fueling smells like. HELP!!!
JA: What's the make/model/year of your truck? Engine type?
Customer: 2009 peterbilt 388 with an isx cm871 cummins
JA: Anything else you want the truck mechanic to know before I connect you?
Customer: thats it i think....
Submitted: 10 months ago.
Category: Medium and Heavy Trucks
Customer: replied 10 months ago.
engine serial #79340866. the ecm did need 7 updates as weel. they done earlier this week.
Expert:  cumminsdr replied 10 months ago.

Are you going to try checking yourself? can you smell fuel while idling?

Customer: replied 10 months ago.
I have a mechanic coming to look at it again today. The last omexhanic who did all the repairs seems to just be a parts changer and can't diagnose much.
Customer: replied 10 months ago.
Sometimes I can smell fuel at an idle but no smoke at idle.
Expert:  cumminsdr replied 10 months ago.

OK you can use a infered temp gun to check for overfueling injectors. Check the temp of each exhaust port on the manifold, the all temps should be close if you have a higher or lower reading on any cylinder the injector is bad. Sometimes you will have to pull back the exhaust manifold and check for a wet or smoking exhaust port But that's for hard to find cases. Injectors can fail at any time even when new. IF you did change the injectors they have a 1 year warranty so it shouldn't cost to replace it.

Customer: replied 10 months ago.
The problem is that it only does it sometimes. I had this happen once before and before anyone could find a bad injector it had wiped out the turbo. I need to find this problem before it causes more issues. Also when the turbo "coughs" there is no smoke or loss of power. It will be boosting fine and then just unload.
Expert:  cumminsdr replied 10 months ago.

The turbo chuff is normalish and still being looked into.

During transient vehicle operation, customers may experience abnormal turbocharger noise. Some of the more common descriptions of this turbocharger noise are chuff , cough, bark, sneeze, and surge. Some customers may notice multiple turbocharger noises in succession, while others may notice only one slight noise before the engine immediately sounds normal again.

There is not a standard test to verify this complaint. Do not replace any components on the engine for this complaint.

Then pulling back your exhaust manifold may be the best option to check for a wet port. You can always tell when a port is wet or has been contaminated with fuel.

Customer: replied 10 months ago.
I will check it today.
Expert:  cumminsdr replied 10 months ago.


Expert:  cumminsdr replied 10 months ago.

Hi, Just following up. Please don't forget to rate my service

Expert:  cumminsdr replied 10 months ago.

Please don't forget to rate my service

Customer: replied 10 months ago.
the mechanic took another look at it and said it was one of the reman injectors. replaced all with genuine cummins and the truck is still smoking intermittently and smells of unburny fuel.
Expert:  cumminsdr replied 10 months ago.

Just following up. Please don't forget to rate my service.

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