A cavalcade of symptoms....

[OverToyed]

Hi all.  Thanks in advance for your time and wisdom.

 

Second gen 24 valve.  Quadzilla tuner.

 

No "wait" light and no grid heater in cold weather, but from the voltage drop I can tell the grid heaters do come on after starting, even if the IAT is reading over 100 degrees (I can see what it's reading through the Quadzilla). Doesn't always come on, but most of the time it does when when the engine is hot.  Already replaced the IAT sensor and no change in symptoms.

 

Throttle position sensor (already replaced and no change in symptoms) often forgets itself.  Have to turn off, back on, press all the way down and release slowly and start.  Then works fine.

 

Something seems to be draining  the batteries (already replaced alternator).  If I don't run it every few of days it needs a jump.

 

Possible ignition switch error? ECM?

[Me78569]

no wait to start means the ecm is not booting. 

[OverToyed]

ECM not booting..... 

 

Could that be why no codes are showing?  No Check engine light either.

 

I replaced the pcm about two years ago.  That was an expensive one.

[Mopar1973Man]

Grid heater solenoids can stick and drain a battery out over night. My landlord was having this issue and was calling in a panic because the truck battery is dead. 

 

WTS light is damaged in any way will throw a P0381 code. If the ECM is having troubles booting up because of internal software errors it will lag getting the WTS light lit. The ECM will not function till the WTS light comes on. This is the first instruction that the ECM will check the IAT and set the WTS light. 

[OverToyed]

Thanks all - looks like my ECM is fried.  Sent it to "Module Experts" in Florida and stupidly paid for diags in advance.  They just called and said processor is fried so they want another 1.1k on top of the "diag fee" I already paid.

 

I asked for it to be returned to me.  Contacted Discount Diesel ECM in Davie FL and they say "Module Experts" is just a front for a junk yard with no actual ability to repair ECMs.  Discount Diesel ECM says you can't reprogram one of these without an actual vehicle and he has a stable of vehicles just for this purpose.

 

I, of course, haven't the foggiest.

 

Is there a favorite place for ECM repairs?

[Mopar1973Man]

Auto Computer Specialist in Florida. Handle many of forum members including myself. 

[OverToyed]

You guys were correct. It was the ECM.  Rebuilt one installed and seems to be working fine now.  It made a suicide pact with the driver's side battery and that was further confusing me.

 

Thanks very much for your help.

[Dieselfuture]

Make sure you do all mods needed to prevent another one from failing

[OverToyed]

I did add a wire between the two battery grounds per some thing I read long ago and I added a dedicated ground wire from the driver's battery to a mounting bolts for the ECM.

 

Is there more I should do?

[hdpwipmonkey]

On 5/6/2020 at 7:15 PM, OverToyed said:

I did add a wire between the two battery grounds per some thing I read long ago and I added a dedicated ground wire from the driver's battery to a mounting bolts for the ECM.

 

Is there more I should do?

I haven't heard of either of those two but the W-T ground mod is the important one that everyone seems to do (including me).

Or the simplified version

 

[dripley]

The ground for the ECM is internal to the ECM and not the bolts that mount it to the block. That ground is one of the grounds in WT"s ground mod. The additional ground between the batteries is a good idea and is part of WT's ground mod. I have one on my truck.

[Mopar1973Man]

THe ECM and PCM both do NOT have grounding cases. The electrical coming from the ECM is the ground connection typically goes to the passenger side battery. Here is the inside of the ECM it had no ground to the case period!