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Cruise Control for Mechanical Injection Pump

16K views 6 replies 6 participants last post by  Kriesel  
#1 ·
I've been looking around here, and other forums, for a few weeks now, and I'm having a hard time finding where to get an aftermarket cruise control. So, just short of buying the book from thedieselpage.com, does anyone know what I need to do in order to get my cruise control working after switching to a mechanical pump, whether using factory parts or aftermarket?

To better explain what my truck is:

1994 K3500, has all the cruise control equipment that I can tell, except the 6.5L engine... (has a cummins in its place now :p: which is a mechanical pump)

I can find all kinds of people stating that it is possible to get an aftermarket solution when switching the 6.5L from electric to mechanical, but I cannot find an aftermarket solution. Or, would it be easier some other way? Am I being an idiot and don't even need an aftermarket thing? Maybe a vacuum line is missing or something? Does it run off of vacuum? Is there anything I should check that would possibly make it work again that may be broken? Sorry for being such a noob, just don't know much about the cruise control on this truck... I would rather use factory parts if I could, and I can't imagine that it would be hard to get working since the truck came with cruise to begin with, but the engine swap gave the truck a mechanical pump instead.

Here are some of the examples that I've found, which are not super helpful:

From http://www.dieselplace.com/forum/showthread.php?t=394852:
You would find it hard to keep the cruise.
From http://www.dieselplace.com/forum/showthread.php?t=68264&page=2:
instarx said:
I had to get an aftermarket electric cruise control for it.
From: http://www.dieselplace.com/forum/showthread.php?t=293080
Jodean said:
your cruise aint going to work either, unlesss you get the 93 cruise setup, which also might involve some wiring.
 
#2 ·
6.5 mechanical has a second cable at the trottle lever for the cruise
 
#3 · (Edited)
The factory injection system was drive by wire with no throttle cable. As such, cruise was controlled by the PCM to try to maintain a set speed. For your Cummins application, I'd suggest finding a factory electronic cruise module from the same era truck that runs a cable. I know they were used on 6.2's and 6.5's before the electronic injection (but the OOBS still had vacuum cruise and I'm not sure if the electronic cruise came with the OBS in 88, or if it held off until 92). I have also seen them on a couple of gas trucks. It will possibly require some re-wiring. Late Model Restoration has the module for 88-91 and 92-95 trucks.
 
#4 ·
The 88-99 cruise control box would be a the best option. It's a stand alone unit and will work on any vehicle in the world...as long the wires are connected and a VSS.

I did a 4BT cummins swap into a 93' Suburban and I used that same unit that came with the suburban and hooked right to the throttle lever and thats it! Check my sig for the cummins swap.

Was your truck originally a 6.5 diesel? If so then you will need the cruise control box off a 88-99 Chevy truck, Suburban and Tahoe. You will see the "dimples" on the engine firewall where the factory holes to be drilled for cruise box. A harness went from it to the inside plugged into the cruise switch(not sure how) and the then there is a few wires that needed to be connected like to VSS and power, ground not sure for the rest but it will work on your cummins because it worked great on mine;)

A friend put one of those factory CC box on his 1940's converted bus motorhome and it functions like factory.
 
#7 ·
Was your truck originally a 6.5 diesel?
Yeah mine was originally the 6.5, and it had cruise. I'll look over your swap. Thanks for the info!

I have a cruise control box for a 1993 mechanical 6.5 That I am not using
I will let you know if I end up needing it. Want to research this a little more, and make sure I need it first. Thanks!
 
#5 ·
I have a cruise control box for a 1993 mechanical 6.5 That I am not using
 
#6 ·
Actually as silly as it may sound, you could just put a good "choke cable" on it.

A PTO cable would hold up quite well. Just use a small chain on the end so it would flex with the travel and pull it to engage. The governor in the pump would sense the load going up a hill to a certain degree.
Cable would work well as a hi idle as well.