Ecm and Injector pump voltage varies, engine runs rough??

[Tim Waldo]

Alternator output solid at 14v.

ECM voltage output varies, Injector pump voltage varies. Is this normal, if not, what should I do?

 

Thanks in advance, I've ordered the scan tool that was being used so I can check whenever.  The problem is I don't know what the typical values should be.

 

Tim

[Mopar1973Man]

Time to do a W-T ground wire mod if it has not been done. Ground on the VP44 and ECM are ran right beside the alternator lead and AC noise issues don't help either. Seriously I would look at doing the W-T ground wire mod and then look at the +12V side for corroded pins or sockets. VP44 get power from the fuel pump relay. ECM has constant +12V and keyed +12V double check both too.

 

 

[Tim Waldo]

What I was thinking... just wanted someone to tell me :P I picked up the supplies to do the WT mods this weekend...   

THANK YOU.

[Tim Waldo]

So I did the W-T mod for grounds (mostly, not quite done with that)  ECM and Injector pump voltages came up (ECM to 12-14 volts, Injector pump holding around 9volts)  but I'm still getting white smoke and a heavy diesel smell from the exhaust , is there anything OTHER that the VP44 timing is off that you can think of that would cause it?

[Mopar1973Man]

W-T Ground mod. Bad fuel pump relay. Would be my first two thoughts for low voltage at the VP44. Double check the main power lead to the PDC. 

[Tim Waldo]

SO the voltage the scan tool is getting is some not standard report.... Checking Pin 7 with a DMM I get 12ish volts.  I don't know where the scan tool is getting it's voltage from.

 

I apologize for the confusion, it took being on the phone with Thoroughbred to have me actually check the plug at the back of the vp44.  They suggested it might very well be the injector lines not quite seated on the injector(s) or possibly one or more injectors just don't like the new pump... Truck does have 430k+ miles and the injectors have not been touched since I have owned the truck (right at 220k miles)

 

Edited February 6, 2023 by Tim Waldo

[LorenS]

210k miles on injectors, I'd start there if you are financially able to do so - at least get them checked out. I changed mine at maybe 290k miles (no idea if they'd been changed before) and one couldn't hold even 100 PSI! None of the others were anywhere near specification.

[Tim Waldo]

8 minutes ago, LorenS said:

 at least get them checked out.

 

What are your suggestions on getting them checked out?  Dealership?

[LorenS]

I certainly wouldn't go to a dealer. Looks like you're not far from Knoxville, so if I were you I'd call these guys since they're a Bosch shop - at minimum they may know a reputable local shop to test and clean injectors. If not, or you have the time send them to @dieselautopower.

 

The Knoxville guys:

https://cdkdiesel.com/common-rails/injectors/

 

Edited February 7, 2023 by LorenS

[Mopar1973Man]

I've sent injectors back to Diesel Auto Power for pop testing. Fair prices and you can even do custom pop pressure setups. Like I sent my OEM injectors in and had 7 x 0.010 nozzles installed and pop at 320 bar. After 150k miles my stock injectors were 260 bar. Hence why I will tell anyone to replace injectors at 100k miles.

[dieselautopower]

Turn around time is generally 2 days.  Then Fedex 2 day return shipping is less than $15