BMC330

Got new PCM in today. Cleaned ground and installed the new PCM. I still have no change in the truck. No power above about 1/8 peddle. I do not have the scanner to plug into the truck at this time, it belongs to my nephew and he has to use at his shop during the week. It will be this weekend before I can get it back. I have new codes with the new PCM by key display. P0122 P1698 P0522 P0123 P1295 Still chasing the problem. Completed APPS voltage to high test. At the end I got to replace ECM. I was allowed to borrow an ECM from a truck very close to mine. Only thing I could find was 2WD where mine is 4WD. The other ECM did not change anything on my performance. I purchased a Load Pro. I am about to start load testing ground wires. Maybe I will find the problem today.

Got new PCM in today. Cleaned ground and installed the new PCM. I still have no change in the truck. No power above about 1/8 peddle. I do not have the scanner to plug into the truck at this time, it belongs to my nephew and he has to use at his shop during the week. It will be this weekend before I can get it back. I have new codes with the new PCM by key display. P0122 P1698 P0522 P0123 P1295 Still chasing the problem.

It is a 6 speed truck not auto. Im at the point i will replace both if needed. I will call them back and specify i have a 6 speed truck. Thanks for the reply.

I called auto computer spectlist. They said the PCM had no bearing on the APPS voltage being erratic. It was the ECU that controlled the APPS. Im confused as to is the issue in the PCM or the ECM. I know PCM has something to do with the APPS due to unpluging the PCM corrects my erratic APPS. Which should i be looking to replace PCM or ECU?

I have learned a lesson on this adventure. Mechanical problems are much more enjoyable to work on. Wiring issues are really a pain. I have used a Fluke Meter more in the past two days than in my entire life.

Ok. Im not sure if it has all the options as my truck as mine is loaded and the other is a work truck. I will order a new one and go from there. Thank you.

PCM is what we are thinking also. I have a friend who has a truck we may be able to borrow a PCM from to see if our symptoms go away. If he will allow us we are also going to get the ECM. I will advise when we have the PCM changed.

We unplugged the first wire bundle closest to the drivers side and apps is smooth. The graph looks perfect between apps percent and apps voltage. And we are getting 100 percent on apps. Not sure where to go from here.

PCM abnormal is all i am getting. Graph of apps sensor percent. Wide open is 65%

PCM abnormal is all i am getting.

No codes. I am scanning again now. I will advise asap IMG_0561.3gp

On the live data we found the TPS all over the chart. Looked like watching a heart monitor when I put it on the graph mode. Replaced the TPS and we are getting the same results. The TPS will read constant when only about 1/8 of the way depressing peddle. The truck seems to run fine at that point. If you mash the peddle any further the readings go all over the chart. I am only getting one code and it is a PCM fault/3. I have checked the grounds and found no issues. I also unplugged the wiring going to the ECM to check for corrosion but it looked new.

Alternator noise is .025 vac on fluke meter. Going to OHM the throttle position sensor now.

Ok, pulled the alternator and had tested at the local Autozone. Test was good. Going to borrow Fluke multi meter to check AC noise again. If AC noise checks ok will move on to the ECM and VP grounds. Thanks for all the advice. Will advise if i find my issue. One thing i noticed yesterday is throttal response is good until about a quarter of the way when accelarating. After that the truck pretty much will go flat until it reaches around 2000 rpm and the boost starts raising up. Also i noticed the oil pressure guage moves to around 40 psi when the key is on. Not sure if this matters just something I seen yesterday.

I hooked the truck up to a Matco Scan Tool this afternoon and drove it around 50 miles. I had it on the live scan mode while driving. The voltage to the ECM would go between 12 volts to 9.88 back and forth. When the truck was at its lowest power point I was only showing 9.88 volts. Could this be a ground issue? The MAP was pretty much all over the chart also. My boost gauge would show 10 psi and the scanner would go between 0 to 10 back and forth. I also had 6 pounds of boost showing with the truck not running. Im going to pull the alternator off in the morning and have it tested. Are there any more things I can check in live scan mode that may help narrow my problems?

The fuel pressure stays on 15psi. I have a new fass fuel pump installed on the truck. I have watched your videos and completed a AC noise test and it was within specs. The will not start when engine is warm is back. I am really lost.

Ok guys sorry it has been so long. Got around to replacing my VP44 today. I have the same issues as before other than no hard starts when motor is hot. The VP is from Pro Diesel. Any ideas where i should look next for my next to find the issues?

Thats what i will do in the furtute. Thanks for your help guys. Im going to pull the VP44 off the truck this weekend.

Thanks Mopar Man. I was just typing what the scanner said on the code. You have been a big help. I will get a new VP44 on the way and replace it. I will post the outcome of this problem. Almost all threads stop without telling what corrected the problem. It drives me nuts lol.

Ok guys sorry it has taken me so long today. Checked the alternator noise with a fluke meter and got a reading of 0.035V ac Have checked for the timing key. It is there but it is the first time I have looked at the front gear of a pump but all looks good. My codes are P0216 P0230 p1693 in companion JTEC Mod P1698 CCD/J1850 Message from TCM/PCM My hard start issues have gone away. The truck started fine this morning and after a 90 mile drive to my brothers shop.

My fuel gauge is electric so when starting the engine it zeros out. I was paying special attention to the gauge as I turned on the key to make sure I had fuel pressure before attempting to start the engine. It never showed to be on zero at anytime before attempting to start it. When towing with the truck yesterday I had to run the truck at a much higher RPM than I ever have due to down shifting to pull hills. I have never ran the truck at that high rpm in the past. Not sure that it had any bearing on the issue but I just thought I would mention it. My fuel pressure was never under 15 psi when at the higher RPM. I will have to go to my nephew's shop to have access to a quality OBII scanner. He has a new version from MATCO I only have a cheap one from Autozone. I will advise if I have new codes as soon as I get ti hooked up. I will also perform the alternator AC noise test and check my VP44 timing key today.

I will check it in the morning with OBDII computer. Fuel pressure was 15 pounds.

Today I developed a new symptom with the truck. I had to use the truck to pull my tractor about 50 miles. Everything was fine with the acceptation of the no power issue. When I got unhooked from my trailer the truck did not want to start. After nearly running down the batteries it finally started and ran fine. I drove the truck for around a 20 mile trip to charge the batteries. When I returned home I once again had the hard start issue. I will try again in the morning and see if the hard start issue is still there. I will also check the fuel filters on the Fass Pump I installed last weekend to make sure I am not getting air in the system.

It will be this weekend before I will be able to work on the truck again. I will start with testing the alternator and check the timing key. I will advise of my findings. Thanks for your help.

Thanks for the reply. The warranty will have ran out on the pump by now. The pump replacement was around 5 years ago. When the truck did not perform as it did in the past he bought a new truck to replace it. The truck has pretty much sit for around 5 years until I finally talked him into selling it to me. My brother in law replaced the pump. He is a 18 wheeler mechanic. I am unsure about the key way. I was going to check it yesterday but I was unable to find my mirror. My 9 year old likes playing with it for some reason. LOL If the key was pushed off or crushed can it be replaced or do I just need to be looking to replace the pump? If I replace the pump do you guys recommend any of the pump re builders? I bought the truck extremely cheap so I have plenty of room money wise to get the truck back running right. The wait to start light does not have any delays. It comes on as soon as the key is turned on to the on position.