"1994 B2300 Timing issue-Possible PCM system problem"

[jstelmack]

Fuel Pump installed - back to original problem.

Pump installed and working. Now I am back to the beginning. It kicks over for 2-3 seconds and then dies out. If I hold the accelerator just barely above idle it will run for 3-4 seconds. Any movement in the accelerator and it immediately dies. Will not kick over if accelerator is held open more than just a smudge. I suspect no progress until I find where the rubber vacuum cap came from and re-install it.

 

[Tbars4]

...Do you have the vacuum diagram by the radiator on the core support?

..If not, there is a sticky at the top of this section that should have it.

..BTW...If you update your post, no one gets notified..

 

[jstelmack]

I have the diagram and the service manual. I can identify all vacuum circuits on the diagram(and manual) and they are in tact. When the backfire happened, I saw (out of the corner of my eye) the cap fly up and bounce off the hood. It seemed like it came form behind the intake manifold, but am not sure. Even feeling where my eyes can't see there is no obvious place for this cap to live. I cannot believe that something this simple has me stumped.

What am I doing wrong that people do not see my updates?

Thanks again for helping.

 

[Tbars4]

...They will be notified of a new post...Updating an existing post results in no notification..

..It's just how these board's work and it takes a little getting used to..

..Look under your upper intake..Either there or iin the back by the PCV..There may have been a spot just for an auto tranny vacuum line that was capped..

 

[jstelmack]

What you said makes sense. I have the 5 speed. The service manual depicts a "thicker" vacuum line to the auto trans. I'll search for that tomorrow.

Thanks!

 

[jstelmack]

Got it running. Idles OK but no power. Pressing on accelerator the engine boggs down and struggles to gain RPM. Cannot locate an open vacuum port for the mysterious "cap". Timing belt tight and notches line up. Looks like a fuel/air mixture problem. I put some "SeaFoam" in the tank. Possible that the injectors are clogged from the previous fuel tank gunk. Will check codes again today. (forgot to do that yesterday.)

 

[jstelmack]

PROGRESS! Put some SeaFoam clearer in the fuel tank and ran engine for a while. Had error code 214. Had camshaft sensor connector disconnected (OOPS). Reconnected it, reset codes, drove around - no more codes. Still low on power but no more backfires. One issue that baffles me... I noticed that I had left the test jumper installed in the diagnostic connector. When I pulled the jumper out the engine immediately dropped RPM. Drive tests with jumper removed vs jumper installed = Runs MUCH BETTER with jumper INSTALLED! I cannot figure out why this is. Still no codes. Remove jumper, and truck drives but with far less power and more bogging down under throttle then when the jumper is installed. Any suggestions?

 

[jstelmack]

I'm starting a new thread since so much has changed. Title will be:
1994 2.3L Engine runs better with diagnostic test jumper installed - why?