6.5 shutting off while driving

[Jochen Woern]

Need help:

My Burb has started to shut itself off this morning while driving. Fires right back up though after I pull over.

OK, I noticed lately that the Voltmeter is going down and once I did not get anything in the morning while trying to start it. Acted kind of "dead" with no movement or starter cranking sound. After trying to start a couple more times it finally fired. About a year ago, I had a similar problem with the Voltmeter going down and I barely made it home once. After taking the battery terminals off , they were very much full of the usual "goop". After cleaning the terminals, all was good again up until now.

You guys think this could be the same problem? Should I start with trying to clean the battery terminals first? The batteries are not too old, I think they are holding the proper charge.

Is this a possible PMD/FSD problem?

Any help is appreciated. Thanks in advance.

[JTodd]

Start with the battery terminals, the alternator connections and all of the grounds - there are a number of them to check, clean, cover in dielectric grease and fasten tightly.

[DmaxMaverick]

Start with your battery cables. If they haven't been replaced, you could be chasing a wild goose. Once replaced, verify all the grounds are in good shape, then look at the ignition switch for the problem (if the cable/ground workover doesn't do it).

The PMD/FSD can cause the symptoms you describe, but it will have no effect on the way the starter cranks or voltages act. Voltage fluctuations can cause a lot of problems that mimic other failures. A bad ground and/or poor battery cables/connectors can cause the PCM to limp or fail.

[Jochen Woern]

Thank you all.

Checked the battery terminals and cleaned everything thoroughly. The Voltmeter shows a lot more charge now, so I am hoping this was the problem.

Anyone have a chart or a good describtion as to WHERE all the grounds are located?

Battery cables look good to me.

Thanks.

[Jochen Woern]

More help please, .................... she is still shutting off on me.

Checked all battery connections and grounds (that I could find), can not find anything loose or not properly cleaned. Voltmeter still reads more than before, pretty much dead center on 14.
The truck still shuts itself off while driving, fires right back up after stopping with no problem at all.

Had it run in the driveway this afternoon for a while, suddenly shut off as well. Again, fired right back up and kept on running with no problems.

While driving, I can not tell any issues until it shuts off. Once it fires back up, I drives as it should.

I just changed the fuel filter no more than 400 miles ago, the alternator is about 1 1/2 years old.

What else could it be? Should I take it to the dealer for a proper diagnoses? It scares me because what will I do if it shuts off while I am trying to pass someone or while pulling out on a busy intersection?

Any help would be greatly appreciated.

[Robyn]

Sounds like the infamous PMD creeping into your life.
The optical sensor in the IP can do this but a PMD is very likely the culprit.
The fuel lift pump and or the Oil pressure switch can do it.
Make sure fuel will flow from the drain line on the filter even with the engine running. If not you have an issue.

Check the fuel supply first and if thats ok move on to the PMD.

Good luck


Robyn

[Jochen Woern]

Thanks Robyn.

Ok, there is one thing I do not quite understand in regards to the fuel:

- Why would it fire right back up with no issue at all if there was a problem with the fuel flow?

If it is the PMD which on my truck I am sure is still stock, with what shall I replace it?
Anyone has a picture of a "before" and "after" PMD installation, can I do this myself? Where exactly is it located?

Thanks in advance.

[Jochen Woern]

While driving to work yesterday, the truck quit on me 4 times within 10 miles while driving to work. One time it would NOT start back up right away as it usually did, so I decided to have it checked at the local GM Dealership.

They had the truck since yesterday morning at 8:00 AM, they drove it so far for about 40 miles and the darn thing does NOT quit on them nor does it throw any codes at all. :(

I just absolutely love cars and trucks that act up during nomral day to day operation but do act as if nothing happened while in the shop.

The BURB stayed overnight and the Dealership will go at it again today. I guess we shall see. The dealer just does not want to exchange the PMD/FSD without the proper code.

[Robyn]

If the dealer tells you they need a code showing to change the PMD, just cough twice and take your rig home.
A failed PMD rarely sets a code.

I have replaced many of the little creatures due to issues and never have I seen a code on a PMD show up.

That is a copout and tells me they dont know what they are doing.

The symptoms you describe are classic PMD failure.

Although there can be other issues that will do this but "UsuallY" there will be codes.

Sort of a rule of thumb is, if the rig is dieing and other issues such as fuel filter, lift pump and such have been checked and are ok and there are no codes the issue is almost always the PMD.
I would be getting me a remote PMD mount and an extension cable. The RH nostril in the bumper is a sweet place to mount the PMD (PMD facing in away from the elements)

You dont want the PMD mounted back on the IP anyway.

The new DTECH PMD's are priced right and seem to be ok so far.

Good luck

Robyn

[Jochen Woern]

Just like most of you thought, it was the PMD/FSD that was failing which made my Burb shut off while driving. This was finally verified by the dealer today.

In order to make this a remote installed PMD/FSD, I purchased the following FSD Cooler Kit from KENNEDY DIESEL (see attached pics):

Item Name: Deluxe FSD Cooler Package
Category: 6.2/6.5L Parts
Sub-Category: FSD Cooler
Price: $535.00
Kit includes everything you need: FSD Cooler, New FSD(PMD module), Calibration resistor #5 (#9 optional), and remote extension harness.

Hopefully this will be the proper cooling kit in order to mount this PMD/FSD out of the heat. The KENNEDY installation kit is the one which mounts to the intake manifold.

Has anyone out there used this kit from KENNEDY? Can anyone give me a good comfortable feeling letting me know that I purchased a good kit?

Thanks in advance.

[Jochen Woern]

Anyone??????????????

[tommac95]

Hello Jochen-
The kit you bought includes the most advanced/engineered heat sink available , and the harness is also top-notch. Take care to install the heat-transferring gasket between the cooler and (under) the FSD. Also remove and install the plug-in electrical (multi-pin) connector with care , to avoid distorting the connector sleaves ; consider some silicone on the contacts.

If you drive just in colder Canada the IntakeManifold mounting would be fine , but for California i'd suggest beneath the AC output (in cab) , ahead of the radiator in airstream , or , as Robyn suggested , in the airflow of a bumper 'hole'. These locations are less susceptible to the sort of "heat soak" situation that is present underhood following shutdown when the cooling airflow stops , and engine heat radiates through the compartment.

A good installation on the intake manifold is still a bit of an upgrade ....

[Jochen Woern]

Thank you very much!

[Robyn]

Mounting your cooler in the "Nostril" is an easy little job and the cable should also be easy to route into the area.
The inside the cab locations can be tedious as you have to cut and splice the cable to get it inside without cutting a huge hole in the firewall.

Out of the heat and into the cool air is the ticket.
I would also recommend carrying a spare PMD even if its only a known good used one.
If your setup is done right you can even mount two on the same cooler and in the event of a failure you just swap the wires and off you go. I have also seen folks keep one on a manifold mount cooler tucked away and its a snap even at night in nasty weather to unplug the cable and plug in the extra and just lay the cooler on the manifold. (This would get you home)

Glad you are on top of it.

Best
Robyn