Aloha - I am back from Hawaii!  And apologies if this was answered already somewhere else.  Here is what happened:

It's a gen II 2002 24 valve diesel 3500

Changed VP44 and ECU in Jan 16 - truck ran fine other than issue with TPS - which we changed as well (sometime spring 16).

 

Had "no-start" issue with error 1689 a couple of weeks ago and swapped out the fuel relay for a new one - truck ran fine but pretty rough - felt like missing cylinder.

 

Today truck started, drove around for a bit (but ran rough); we shut it down, tried to restart a while later and now, no start again.

Pulled codes and it is now reading 1689 and 1690 - swapped relay out for another one - but truck is dead - (well, semi-dead) - starter works, lift pump works (has pressure), but no fire.

We had a ton of rain and moisture (live in hurricane country) - could it be wiring, i.e. between ECU and VP44?

Any help/ideas are greatly appreciated!

I think first, for the 1689, I would check your ECM and VP wiring connectors and be sure they are clean and tight. Some dielctric grease on the connectors will help protect them from future corrosion.  The 1690 is pointing to the cam shaft positioning sensor. A bad one will make the truck run rough. It is not expensive but is located behind the VP. I have heard of folks replacing with the vp on but is back there pretty good.

 It is possible your VP computer has failed. But dont condemn it on the one code. The above measures are cheaper to try without throwing expensive parts at the problem. It never hurts to clean up all of your ground connection also. If you look under the articles tab at the top of the age, 2nd gen, engine, then OBD codes you find the codes listed with diagnostic info. 

 As a member of the electrically challenged here others should weigh in on the subject also.

Rrrgh- I did not want to pull the VP off again - so will start with grounds & wiring, although I already put dielectric grease on any possible connection, but none-the-less, it has been really wet & moisture gets in everywhere.  Thanks a bunch for help.  If someone else has any other thoughts - they'd be super appreciated.  Thank you!

P1689 is a communication issue. So there is a few things to check like ohming from end to end of the wiring from the VP44 to the ECM and check and see if there is more than 5 ohm of resistance if so repair the weak connection or wire. Then other is excessive AC noise fouling the communication. If you measure more than 0.1 volts AC on the alternator BATT terminal will running you've got a bad alternator. 

Thank you Moparman.  Will give the wiring another once over.  I still have those voltages & ohm settings somewhere when I tested the VP 44 in Jan - I don't drive this beast, I am just the dedicated fixer of it - belongs to hubby who is about ready to drive it off the cliff - the truck seems posessed - belonged to Jimmy Stewart (well his estate) and it would just come on at night and play country western music - certainly not a station we'd listen too.  He'd have to go out and turn radio back off and mind you, the truck was locked the whole time!  I am not that ghost oriented, but makes for interesting conversation?.  It's the stinking wiring on this thing, and I have some sentimental attachment to it.  So will try to keep running as long as I can.

will update on progress - got a chemistry lab to teach today, though.  Weekend will be happy wiring mad prof style.

If there have been electrical modifications or repairs you may want to look there for electrical issues.  Most people don't put a lot of effort into "clean" and "neat" wiring repairs.  They can often time be a great place for corrosion, cold solder joints, or loose  connections. 

10 hours ago, MadProf said:

Rrrgh- I did not want to pull the VP off again

You can change the cam sensor without touching the VP. Just loosen the vacuum pump, then just take a little time. I changed mine that way, much easier the messing with the Vp.

11 hours ago, klcammie said:

You can change the cam sensor without touching the VP. Just loosen the vacuum pump, then just take a little time. I changed mine that way, much easier the messing with the Vp.

I changed my cam position sensor not to long ago, I used a 1/4 inch drive and a long extension and went right behind the VP.  All done by feel but whole process was only about 30 min. 

Ohhh - fabulous - thanks a lot for the detail with the wrench - I can do that!  Fortunately, my hands and arms are relatively small but I got good strength - will give it a whirl.  Been raining for last two days, so have not had chance to check.

On 9/23/2016 at 6:16 AM, Hawkez said:

If there have been electrical modifications or repairs you may want to look there for electrical issues.  Most people don't put a lot of effort into "clean" and "neat" wiring repairs.  They can often time be a great place for corrosion, cold solder joints, or loose  connections. 

Yep - and there were lots of them done by previous owner - that person's favorite type of connection: butt connectors - yippie!  Been tearing them out whenever possible and solder/shrink wrap or just replace with proper wire.  Thanks for suggestion as well!