Is this too many issues for one thread?
I have used this web site a lot over the last year and half but the more I do the more this truck throws at me.
I will try to give the cliff notes version. (sorry it's still long)
2001 Ram extended cab 4x4 5.2 Automatic with 80k that I bought a year and a half ago with 78k. Luckily this truck was never bought to be my daily driver.

It was running ok but used a little oil and did not have much power so I did the Hughes Plenum repair and a full tune up about 700 miles ago. While doing the plenum it seemed to have some oil gook build up so I decided to run seafoam thru the intake and some in the oil. After about 10 miles it lost oil pressure so I shut it off. Re cranked had pressure back for about a half mile and lost it again. Did this about 10 times to get it home. Changed oil and got pressure back.

It worked good for about 300 miles then went to crank it up and the oil pressure pegged out on high and was blowing lots of oil out around the oil filter. Put a new filter on and the same thing happened (it was not double gasket-ed). The high pressure bypass in the oil pump stuck. Put new oil pump and rear main seal and cleaned everything. I had better oil pressure than before (60psi when cold and 40 psi warm).

It was running really good for about 400 miles then I changed the vacuum valves to fix the blower going to defrost on acceleration. Then the temp gauge started acting weird and jumping all over the place. I drove it about 50 miles with gauge going from cold to hot. I mean it would do this in about 3 seconds so I knew the engine was not changing temp that quick. Popped the hood several times to check it and it was just warm. When I went to drive it home the gauge never moved off cold for 50 miles. I could tell it was running rich and it started running rough about the last 10 miles. Skipping under moderate load.

I changed the temp sensor next to the thermostat and it still ran rough and within 5 miles the temp gauge was doing the same thing again. Now even if the truck is cold the temp gauge pegs out to hot before I even start the truck. I also pulled the O2 sensor before the cat just in case I screwed it up running it rich for 50 miles but it made no difference still ran rough.

Now I get code 0601 Bad PCM and 0118 Temperature issue. The truck runs like crap and there is also an ignition off draw I can't figure out.

Sorry for this long explanation but any input would be appreciated.
Thanks

 

Get your multimeter out and start chasing wires. What's causing the draw?

Got good grounds everywhere?

 

The pcm needs to be replaced. Could be the source of the draw also.

 

Could the bad PCM be the issue with the temp gauge as well?


All the grounds seem good and the truck is really clean with no rust or corrosion anywhere.


The ignition off draw is in something that is controlled by the IOD fuse. If it sits for more than 3 days the battery will be dead. If the IOD fuse is pulled it can sit for weeks with no issues. Checked all interior lights, glove box light, and stereo. I am thinking maybe the issue is in the ignition switch itself.


What would running it rich do to cause the skipping? Foul spark plug or o2 sensor.

 

Acrapped out pcm could cause everything.

 

http://www.obd-codes.com/p0601 discusses the checksum error.

 

I will get a new PCM this week and see what issues go away.


O'Reilly has a Cardone Remanufactured for $148 and there are a bunch of places that you can get them online for $200 to $400. New from Dodge about $700+. Seems like everywhere has some bad reviews so it looks like a crap shoot regardless.


Thanks for the replies.

 

Getting one locally makes warranty returns easier, and faster.......

 

I got one years ago from a place that rebuilt them. It was a good used for around $200. You can look around for yourself just get the part # off your original.

 

I took my PCM to a place called MAS in Duluth Ga close to my house. They rebuild all kinds of electronic auto parts and it was going to be $119. They called 2 days later and said my PCM was not repairable due to hardware issues. So I got one for $149 from O'Reilly's put it on my truck and it acts the exact same. When you turn the ignition on as soon as it stops chiming (truck still not cranked) the temp pegs out to hot. The wires coming from the temp sensor read 5.2 volts when the ignition is turned on. When the ignition is off it reads 74 millivolts.


For the temp sensor to do this does it mean that a wire is possibly grounding where it shouldn't or a ground it should have is not working?


I also did the test on the instrument cluster by holding in the trip meter while turning on the ignition. The gauges went through their whole sequence correctly till the end when the temp gauge pegged to hot.