Alright, so tomorrow afternoon I'm starting at square one for DTC codes on the Blazer.

It's throwing the following codes:
18 - Pump Cam Reference Pulse Error
35 - Injection Pulse Width Error (Time Short)
36 - Injection Pulse Width Error (Time Long)
54 - PCM fuel circuit error

What do these codes usually associate with?

I'm thinking about taking the intake off and cleaning up all the wires on the injection pump, checking all grounds, etc.

Thanks alot. The Blazer has been less than reliable for about a year now...Just trying to fix it :(

Jay

Optic Sensor codes, and lift pump code - may be wiring problems, along with bad fuel for the 35-36 - worst-case = Inj Pump cratering - clean up the wiring and grounds, check the fuel filter for dirty, drain some fuel thru the water drain, check for yukky stuff floating around in the fuel - etc

UPDATE:
Pulled the intake off and pulled the IP harness out. Checked for wear through, broken wires, etc. Found nothing so far.

Heres the problem.
In the truck is a 1994 vintage 5067 Injection Pump. I'm starting to think it is the IP that is on the way out.

Now...

We have a 2004 5521 pump sitting on the bench we got for free. We came across this because a local blew the engine in his 94 6.5TD and picked up an engine out of a 96 with a pump(the 2004 5521 IP) already on it. Put the engine in and it wouldn't start. He then returned the 5521 for the one that was on his old engine. His truck then ran, so it was assumed the pump was bad.

Does the 5067 and 5068 require a special, incompatible with other IPs, eprom in order to run?

MY personal opinion is that, ASSUMING that his truck was running a 50xx series IP, the eprom software was incompatible with the 5521. So I think the IP is still in working order.

Opinions?

Thanks alot! I owe you all beer.... :D
Jay

5067 PCM is compatible with 5521 IP - go fer it......................