no OD, flickering headlights. Bad PCM?

Does it have spark? And other questions...

Moderators: Greenleaf, BC847, Richie O

no OD, flickering headlights. Bad PCM?

Postby mperryb » Mon Nov 20, 2017 10:44 am

Hey guys I am having some problems with my overdrive and headlights and dash lights flickering like crazy.

The overdrive stopped working recently. I installed a potentiometer in place of the TPS, no luck.
I was able to jump it and get to work with a switch, less than ideal.

I was going to install a pressure switch but the 4x4 shifting mechanism seems to be in the way of the pressure port needed. So I am back to square 1.

I adjusted the cps and it seems to have good ground, 5v refrence and proper signal voltage depending on where the air gap is.

I hotwired the power side and let the computer control the ground. I tapped into pin 55 ran a wire from pin 55 to the cab. I used this wire to force a ground for the od solenoid, that didn't work. Odly enough after I removed the pin55 jumper and wire it started working. I had to adjust the TPS(now a POT) and kickdown cable to get it to work properly but it shifted in and out of OD for a good 3 days.

Sweet, problem solved.

No such luck, this morning on my way to work, again I had no overdrive. The headlights and dashlights have always flickered and the gauges bounce like crazy but this morning was much worse than before.

Im thinking my PCM has had enough and needs replaced.
Oh and the speedo and AC work.
mperryb
fuel screw!!!!
 
Posts: 26
Joined: Fri Dec 12, 2014 12:17 pm

Re: no OD, flickering headlights. Bad PCM?

Postby thrashingcows » Mon Nov 20, 2017 1:58 pm

Have you cleaned and inspected all your grounds? Should be a yearly thing IMO...without "good" grounds all kinds of problems can arise as the circuits back feed through other wiring circuits looking for a ground point.
1984/93 Dodge Crewcab, W350, 1 Ton SRW, long box, 330K Km's, M&H spacer, 366 spring, fuel pin to deep side, 14cm housing, Piston LP, PS IC, Isspro Boost, Pyro and tach, NV4500, 29 spline NP205, 3.54's.


Check out the build....http://www.dieseltruckresource.com/dev/ ... 05923.html
thrashingcows
14mm rotor
 
Posts: 567
Joined: Wed Nov 02, 2011 12:00 am

Re: no OD, flickering headlights. Bad PCM?

Postby mperryb » Mon Nov 20, 2017 4:02 pm

Yeah I cleaned the ground on the core support. I did a resistance check between the ground pins on the pcm and the negative battery and found no resistance between the two. Same story with the pcm pins to the core support ground, so I didn't move forward with cleaning all grounds.
mperryb
fuel screw!!!!
 
Posts: 26
Joined: Fri Dec 12, 2014 12:17 pm
Top


Return to Electrical

Who is online

Users browsing this forum: No registered users and 1 guest

cron