governed at 65

[psaracino]

i picked up a 95 3500 6.5 diesel, at around 65 and above its almost like it is governed the truck bogs down and the check engine like comes on, if you turn off the truck and start it back up its perfectly fine, how could i get rid of this and get that truck going faster

[bobt]

One possibility is that the fuel filter is getting plugged and reducing fuel flow. Maybe time for a new filter.
Bob

[DennisG01]

Just a random guess, but maybe it was a government (for example) truck? Is it running right - gets good throttle response at various RPMs? Meaning, does the bogging only happen in relation to speed? I'd think that if there were mechanical problems (or dirty filter), the problem would manifest at more than just a speed - wouldn't the problem be noticeable in relation to throttle, not speed? Just thinking out loud.

What is the code? That would be great place to start. Most local parts stores will check it for free.

If it's a "governed" thing, then having your ECM re-flashed will take care of it - along with all the benefits of a better program.

[JohnC]

A governor wouldn't set the check engine light. A blocked fuel filter won't set a code. You can read the codes with a paper clip. Let us know what you find.

[DennisG01]

John - out of curiosity... if one wanted to, could a governor program be written into the ECM to defuel?

And, could a failing boost solenoid/leaking vac line/bad pump cause a de-fuel? I've gotten a p0236 code before for a bad solenoid, but don't recall if it de-fueled. Or, does this not even pertain to OBDI?

[JohnC]

if one wanted to, could a governor program be written into the ECM to defuel?

It's already there. The "red line" and PTO speeds are software.


And, could a failing boost solenoid/leaking vac line/bad pump cause a de-fuel?
On the '95 excess boost will cause de-fueling. If low boost will cause it, it has to be really low. I had a total vacuum failure and never set a code. High load boost was down around 2-3 psi. Maybe with a stock exhaust it'll go lower and code, but I never saw it.

[DennisG01]

Gotcha. Thank you, John.

[AVM62]

You might want to check the lift pump & oil pressure switch. That was my problem on my 1994 ran fine at lower speeds just would not go much over 65 up hill.

[psaracino]

i am under the impression that the truck is an old tow truck and they had governers on them i suppose to not drive fast with a car on back. do you think chipping it would override the possible governer. i would like to check the codes anyway, could be something stupid .