Any thoughts on random stalling?

[94blazer]

So, I recently picked up a 94 Blazer with the 6.5. Obvious issues are - It stalls seemingly at random, the transfer case plug ins don't match the harness on the truck, and what looks like oil cooler lines and rear main seal leaking.

The truck has been sitting for the last year, the PO says he didn't have the money for tags and insurance. I have receipts for a transmission rebuild at the dealer 40k miles ago, a new IP 10k miles ago, and a GM Crate 6.5 installed 80k miles ago.

My first thoughts were the PWM on the IP, OP sending unit, and or lift pump relay. Happen to have a 94 suburban sitting here, so I swapped the FP relay and remote IP driver over, and replaced the OP sending unit. *Edit* I also changed the fuel filter, but have NOT drained the tank or added any fresh fuel *Edit*

The truck still dies at random, sometimes just sitting at idle it will die. So now I am tracing down all the grounds, and replacing the battery cables.


Anyone have other ideas?


Also, the transfer case is manual shift correct? If I got rid of the motor on the front axle to engage the 4x4, and went with a manual cable setup, would I even need to worry about the switch/sensor whatever it is on the transfer case that doesn't mate with the trucks harness?



Thanks
Casey

 

[bk95td]

The transfer case ties into the ecm[computer] When in 4-low it changes the shift speeds. Very unlikely the rear main is leaking if the cdr valve is functioning. Any leaks into the valley end up looking like rear main because the valley drain dumps on the torque converter or in that area. You need to do a fuel pressure test to determine if the stalling is a fuel problem or electrical problem.

 

[WarWagon]

PMD of course esp. in the heat out here.
Diesel over 1 year old is bad fuel. Add some fresh fuel. Transfer case has the VSS speed sensor.

 

[buddy]

What you need to check is if when it stalls, is there still fuel in the filter manager, meaning did the IP suck the fuel out of it and cranking and running it allows the IP to suck more fuel from the tank.

You need to know how the Lift Pump works in your truck and verify its operating correctly. There is a good thread in the tech library area, specifically on lift pump operation. And if it is operating but no fuel, then the tank must be clogged.

If you know the PMD is good, and grounds are good look for air in the fuel lines, rusty lines on top of the fuel tank, fuel lines between filter manager and IP and filter drain valve in the valley, and improperly installed filters are common air or fuel leak areas. A clear fuel hose on the return from the IP is a good trick to see if you have bubbles. or a clear line from filter to the IP and watch it real close, even with a magnifying glass.

 

[Burning oil]

Welcome to TTS

Does your Suburban run fine with the PMD on it?

 

[94blazer]

Quick update, The Suburban runs great.

With the blazer running at idle, opening the filter drain valve results in the drain line gushing diesel fuel, and the truck idles fine. I don't loose gauges radio or lights when it dies, and it starts right back up.

 

[buddy]

Check the filter manager after it stalls.

If nothing else is working, pull the Engine shut off solenoid off the IP and with a snap ring pliers you can remove the plunger and put the body back on. It isnt necessary and would confirm that is or is not causing the issue. The plunger can be put back in later.

 

[94blazer]

Quick question, the previous owner had installed a new injection pump.... would the pump not having a resistor installed make any difference? I thought I read somewhere this could cause stalling.

 

[buddy]

The resistor isnt going to be your problem. It would cause a DTC for that.