Hi drove my 1999 3500 24v truck to work the other day and parked came back to it in the evening and whent to start it, first thing i noticed was no wts light.It turned over but fail to start and no fuel pump and no bus showing in odometer. Popped the hood and could smell burnt wires. The joint connection 2 in the pdc burned up the local dodge dealer told me that usually the pdc gives out 90% of the time the pdc shorts out its self and causes this but I'm not sure about that. I got a good used one from a local parts truck my plan is to clean all the grounds and check for shorts then I will hook the batteries back up and pull what codes i can. Just wondering what else i should do to prevent it from happening again or does anyone have an idea what might have caused it in the first place.would be thankful for any feed back.

Dale

46 minutes ago, Daleb said:

I installed a Fass a couple weeks ago and it is running from the oem fuel pump plug to the relay that came with the Fass harness. I think when I get the truck back together I’m going to run the Fass off a switch and leave it out of the pdc altogether 

I would advise against the switch. I you end up in wreck the pump will keep running and pumping fuel until you cut it off. If you are incapaciated you wont be able to. And if you are on fire with a ruptured fuel line the end results could quite bad. The ECM takes care of that for you. 

 You can pull the power from a battery or the alternator for that matter. But let the ECM control it.

 I dont believe the fass is causing your issue. Though it is possible if something is wrong with the pump. I also dont believe the fass would cause that joint to over heat unless you were able to connect the pump to that joint connector. 

Surprising the replacement has indications of too much heat as well. I'm going to start up my truck, Raptor pump is hooked to the battery (controlled by the ECM) and see if I can feel any warmth or heat in that area.

 

No daylight and not enough coffee just yet though. Will report back in awhile.

Thanks

If its a DDRP yes its possible to have this issue. 

 

IF its a full FASS or AirDog no this problem doesn't exist. Being that the full series has a power relay that is triggered by the ECM and powered from battery power. Where the DDRP is power directly from the ECM so if the pump is locked or having issues the full load is past through the ECM putting it at risk of damaging the ECM and then also adding load to the PDC.

1 hour ago, Mopar1973Man said:

If its a DDRP yes its possible to have this issue. 

 

IF its a full FASS or AirDog no this problem doesn't exist. Being that the full series has a power relay that is triggered by the ECM and powered from battery power. Where the DDRP is power directly from the ECM so if the pump is locked or having issues the full load is past through the ECM putting it at risk of damaging the ECM and then also adding load to the PDC.

Wow! we found something here.

 

I started my truck let it idle for about 3-4 mins and felt my fingers down on that area. No warmth at all. Thanks to Mopar1973Mans understanding he is the one that taught us all so very well about this possible problem of the lift pump being run direct off the ECM. Now we see its effect.

 

I hope you get it repaired and all goes well.

Edited October 10, 20186 yr by JAG1

yes its the full fast titanium. and it plugs into the regular harness at the old location on the block. Then it goes directly to a relay that came in the fast wiring harness

Its called 'Fass' Dale. So it is powered off the batteries then? Activated by the ecm?.

 

I was hoping we found why the burned electrical so the repairs aren't in question.

18 hours ago, Daleb said:

yes its the full fast titanium. and it plugs into the regular harness at the old location on the block. Then it goes directly to a relay that came in the fast wiring harness

Your phone is fast to correct you, mine does the same thing, very annoying, stupid AI

Yes it is operated off the ecm and plugged into the plug for the original fuel pump. Is that plug powered by the batteries?I do hate auto correct.

Not sure I'm understanding..... are you saying Dale, that a new fuel lift pump (recently bought yet to be installed) is set up with a relay to run off the batteries? And the old lift pump is not set up with a relay and runs off the ECM (factory lift pump power)?

 

It needs to run off the batteries.

 

3 hours ago, Dieselfuture said:

Your phone is fast to correct you, mine does the same thing, very annoying, stupid AI

Whenever I get the wonderful opportunity to talk with Mike he always ends the call with, ''I'll catch you on the flip''. He he.... has no idea what that means since I'm still on an old flip phone when talking to him.

4 hours ago, Daleb said:

Yes it is operated off the ecm and plugged into the plug for the original fuel pump. Is that plug powered by the batteries?I do hate auto correct.

Did you install the FASS or was it on the truck when you bought it?

The fass was installed by myself. The old lift pump on the side of engine has been removed and the fass harness plugs into the old fuel pump plug as per instructions. The harness then goes to a relay then from relay + &- go to battery and the other wire goes to the fass pump behind the cab. I was not thinking so yes it’s ran off the battery and controled by the ecm. 

Edited October 11, 20186 yr by Daleb

Was the engine block lift pump running off the ecm when the PDC burned? 

No the fass was installed powered off the battery controlled by the ecm.

5 minutes ago, Daleb said:

No the fass was installed powered off the battery controlled by the ecm.

Dang, I really want to know what caused it.

So do I. I'm going to start buying all the PDC I run across because they are getting scarce up here not to many scrape yards hold trucks or cars for parts anymore they crush them as they come in.

2 hours ago, Daleb said:

So do I. I'm going to start buying all the PDC I run across because they are getting scarce up here not to many scrape yards hold trucks or cars for parts anymore they crush them as they come in.

 

Here in Idaho if a Dodge Cummins comes to wrecking yard its sold before it even hits the dirt. I don't have a salvage yard to even go play in. I check the network for local yards and the truck is sold before it hits the dirt. Sad but true!

Mopar1973Man, do you think Dale should decrease the size of number 3 fuse as a precaution?

I would be looking at the measured amperage draw on that circuit more so than changing the fuse. Something is drawing more power through that circuit and had a weak spot and so it melted and burned up. Look at it this way you reduce the fuse size you most likely keep popping them. If you leave it stock sized it will possibly do the same damage again. You come back to fixing the circuit load and not the fuse. 

This is one of the main grounds for the pdc was nothing but black tap holding the wires to the ring connector. One of the heavy equipment mechanics at work said this would cause extra draw through the pdc. As I remove the old wire harness I will see what other surprises await.