injector harness problems...?

uc07 · #1 (**permalink**) 03-25-2009, 03:25 PM

I'm having problems with my trusty 99 SD. It started skipping the other day and I have so far....changed the oil n filter, changed fuel filter, cleaned bowl, checked fuel pressure, replaced passenger side valve cover gasket and inner harness. I bought an OBDII scanner and of course the damn OBDII port won't communicate with it nor my hypertech ECON....figures. The damn thing skips at all RPM's.. I'm going to fix the oil cooler o-rings tomorrow. To get to the point, I washed the motor today so I could work on it and I barely made it back to the shop, it stalled numerous times, the pedal was unresponsive at times. I have washed it before and never had a problem. Also, the cigarette lighter fuse is not blown. The other day when it started skipping I plugged in the hypertech to see if I had any codes and there were no codes and it worked when I plugged it in. I'm starting to think It may be all related and a wiring harness issue. Any thoughts?

larz18 · #2 (**permalink**) 03-25-2009, 03:55 PM

well if you can get your obd port to talk then i would say program the truck back to stock for a start. Mines done that before and i just reprogram and it runs great again. its only happened to me a couple of times. check all your harness connections and fuses. i would replace the cig fuse anyway just to be sure. theres also a couple of relays related to the pcm you should verify those are working.

uc07 · #3 (**permalink**) 03-25-2009, 04:33 PM

The ODB port started acting up last year , but then I'll try it and it works so I've never gotten to the bottom of it. Now of course I really need to use it to diagnose and no talky... I'm pissed cuz I need this truck and use it every day, put 40k on it last year. Thanks.

larz18 · #4 (**permalink**) 03-25-2009, 04:50 PM

well if you cant communicate through the obd port and all fuses etc are good then that say you have a bad PCM. You can try a light reset on the PCM by unhooking the batteries for like 10-15 minutes. after the batteries are reconnected and you turn the key on your should see your gauges bottom out and flip back. That tells you it reset. Then try communicating again. i'm trying to find the obd port voltage pinpoint test for you in my ford manual but no luck yet.