hard miss at startup

[4 wheelssmoking]

I am looking for some thoughts on this.

In short, I started the truck a few mornings ago [temp around 80F] and it had a very rough idle\miss.
I shut it down , waited a few moments and restarted with the same result. So I let it idle for maybe 30 sec. and blipped the pedal a few times. I looked to see if there was any noticeable smoke, but there was not any. Also no unusual smell of un-burned fuel. No change . I shut it down and grabbed the autocal to check for codes, nothing . No CEL either.


Having all ready loaded the family and gear I figured I would drive to the end of my road [2.5 mi.] and back to see if any thing changed. The first mile or so was very rough , like it was running on 3. I thought to change the settings on the csp switch and also the BD throttle sensitivity booster to see if they made any difference, but no change in the miss.

The next mile every thing cleared up and smoothed out, no more issue. So I decided to continue on with the days journey. No problems over a 35 mile trip.

The days prior to the problem I had no symptoms, and have never had any issue with the engine or fuel.
I added the Caterpillar 2 micron auxiliary filter to the system at 14,000 miles, and change all filters on the heavy service schedule.

Current mileage is 98,000ish.
I have driven it twice since the problem accruing around 200mi. and have no problems.

Kinda weird huh?

 

[TCDiesel]

95% of these types of problems can be avoided by Using Dia-Electric grease on every connections from Head lamps to tail lights. Its best to do it when new, Blue tech motors have 1000s of bits of data being transferred, 1 millsec of interruption all heck break lose.

 

[Wiredawg]

95% of these types of problems can be avoided by Using Dia-Electric grease on every connections from Head lamps to tail lights. Its best to do it when new, Blue tech motors have 1000s of bits of data being transferred, 1 millsec of interruption all heck break lose.

I agree with the relevance of the health of the data network infrastructure on these trucks. I failed on a couple other threads on the TDR forum to convince the gallery the sensitivity of the network can create strange problems.

This is the part of maintaining our trucks that will be tougher as they age is the network gremlins. Dielectric grease is our friend... I have a large tube in my toolbox and smaller tubes in each of our vehicles.

Cheers, Ron

 

[mhswitch]

Question on application of the dielectric grease on connectors. Does the grease only get onto the sealing surface gasket or onto the conductor pins?
I'm think my 2017 possibly may have Gremlins

 

[Wiredawg]

it's good on both. dielectric grease doesn't actually fix the problem, you may have to shiney up the conductors (burnish) then apply the dielectric grease. indications of oxidation are white powder for white metal or green for copper. You want to disconnect positive and negative terminals on batteries before doing this. Be careful separating and reattaching connectors. I also have contact cleaner that works pretty good in the contacts.

Inspect the wiring too.... sometimes oxidation/corrosion penetrates wiring. Grounding points are important too. loosen ground lugs, wire brush lug, body attachment points, spades, and the bolt. Apply dielectric grease into bolt hole, spade connectors,and the bolt. Tighten it up.

I haven't started on my 2017 5500 yet, just got the OEM wiring service manual on it, so I'll do a little at a time until completely done.

Edit: I have actually started, when I installed my performance module between ECM and the fuel pump, I applied dielectric grease to those connectors.

Hope this helps.

Cheers, Ron