So it's throwing codes for different injectors? Is it randomly? Try this: On two injectors right next to each other, unplug the electrical connectors from both, and SWAP them so that they are on the wrong injectors. If the PCM is going bad, the engine will continue to run fine. Why? Inside the PCM is a part called the Injector Driver. When this part fails, it will throw injector circuit codes seemingly random. When you swap those wires, the injector driver is not functioning properly so the engine will continue to run the same as before (not worse, sometimes even better for a time). Note: Do NOT drive the vehicle with the injector wires swapped. Only idle the engine.

 

I cut away most of the convolute so I could trace individual wires. I didn't find any faults in the harness. I noticed some bad corrosion on the PCM enclosure. It looked like water may have made its way inside.

The new PCM will be here tomorrow. I'll be sure to update.

 

have you checked the connections at the PCM? If it is corroded, chances are good so are the connectors.....

 

I started with the connectors, that's how I discovered the corrosion on the bottom / top of the PCM. I removed the connector boots when I was checking resistance on the injector wires and a few sensors.

The new computer was delivered yesterday, mounted and connected as of today. I also installed new cam and crank sensors. The old crankshaft sensor was a pain to remove. I finally realized they were allen bolts after I got the first one out (too much grime). I discovered a cracked coolant temperature sensor, though I forget if it was for the dash or PCM (I'll be checking that tomorrow). With the battery charging and only a few minor connections left, the truck should be on the road this weekend.

NOTE: Still need to non-foul downstream O2 (using this thread as a list)

 

Yesterday morning I finished taping / routing the wires. I replaced the cracked coolant temperature sensor, complete with Teflon (it was the PCM's-- two prong). It started up on the first try and was running very smooth. I drove it around the neighborhood for a while to bring it up to temperature, it felt great. When I got home and gave the oil a check-- chocolate milk.

I let the truck cool for a few minutes and then removed the radiator cap. I started the truck and didn't see any bubbles, nor did coolant appear to be coming out of the exhaust. That coupled with a history of passing recent compression tests, I'm ruling out a blown head-gasket. The oil smelled heavily of gasoline. I'm pretty sure gasoline mixed with the oil in the sump caused by the previous injector driver failure. I've also read that condensation can build up in the engine. The temperature has been swinging wildly here (10F one day and 45F the next). This truck really hasn't moved for the better part of a month. In any event, I'll be changing the oil Monday (0w-30, here I come!).

Today I gaped the plugs and gave the threads a generous coating of anti-seize. The plug tips themselves looked awesome, even troublesome cylinder three! I crawled under the truck and did the same for the O2 sensors (anti-seize). I decided while I was under there, I would also tackle the half-assed band clamp from a few weeks prior. I applied a liberal bead of exhaust sealant around the pipes to be connected and the clamp / accessories themselves. I used my knees to align the tubes and two ratchets to make quick work of the clamp. The result is no less than awesome in my eyes.

I was thinking of coating the metal PCM exterior with some sort of rubberized aerosol paint (think-- bed liner, frame coating) to make it more corrosion-resistant. Does anyone know if PCMs typically use their metal exterior for heat exchange purposes? Eventually I'd like to reroute it behind the firewall (protection from elements).

I'll be posting some pictures tomorrow afternoon.

 

PCM does indeed shed heat thru its metal exterior. Don't insulate it. Moving it INTO the cab sounds like a really good idea.

You may have a leaking intake gasket. That would account for coolant in the oil, but, no other signs of a problem.

 

I've been keeping a close eye on the coolant level because I flushed it not too long ago, the level hasn't dropped. The intake gasket is also brand new (replaced during hughes fix).

I'm convinced it was from the injectors dumping fuel into the cylinders.

 

Gas in the oil won't make it look like a chocolate shake though.... will just make it thin, and stink.

Change the oil, go for a drive, (enough to get the engine nice and warm) and then check the oil again.

 

I'm pleased to announce that everything seems to be on the up-and-up. I changed the oil this morning after idling to warm (didn't want to load the engine with wet oil), Mobil1 5w-30 paired with a Wix oil filter.

After a few hours of run-time, the oil is-- normal!









... yes, those wires will be covered soon.

 

The CEL is once again illuminated, as expected.

• P0141
• P0138

It's a relief to finally see that eternal P030X (misfire) code gone-- much like emerging from the Callahan (big-dig) unscathed. A new downstream oxygen sensor is en route. A trip to Autozone later this week should net me two non-foulers, and an end to this light.

As always, updates will follow.