Stranded in New Mexico - opinions and ideas certainly welcome

[edroelle]

Greg,

I had a similar, but not identical problem with my DDEC III (Series 60).  I would be driving and the engine would go to idle.  (Quite nasty when it stopped on an exit ramp!)    A DD dealer could not identify or reproduce the problem although throttle codes were flashed.  Throttle position sensor appeared to work fine when hooked to computer.  But, since nothing could be confirmed, they replaced the most likely component, the TPS.  It works fine now, so that must have been the problem.  To me, it acted odd in that if there was a glitch in the resistance of the TPS, the engine would go to idle.  Sometimes after the idle incident, it would work OK for a time.   It was not consistent.

Just another idea in the event it is not fuel.  Likely, other DDECs will have there own peculiarities.

Ed Roelle
Flint, MI

[ArtGill]

Greg,
         I had a problem with my Model 20 that it would not produce power over 20 mph.  After a tow and several hours at the dd dealer, new injectors, they found the pulg that goes to the injectors off the DDEC was loose and several of the injectors were not operating.  So, make sure, if you haven't already, that all the plugs on your DDEC are well seated.
          The fuses that BK referred to are near the battery disconnect beside the batteries.
        I wish you the very best and good luck.

Art

[gyrocrasher]

Greg:
Any progress on your problem? We all wish you the best. Mitch

[NJT 5573]

Greg,

There is a lot of info on trouble shooting your DDEC 2 in the manual. There are 4 possibilities that start with the check engine lite for diagnosis without a DDR tool.

(1) lite comes on and stays on-chart 2
(2) lite comes on for up to 5 seconds and then goes out- chart 2
(3) lite is off- chart 4
(4) flashing lite- chart 8

Chart 2, Hold up switch to read codes
(1) flashes codes- go to chart 3
(2) check engine lite is always on but does not flash codes- go to chart 6 page 69
(3) check engine lite never comes on- go to chart 6

Chart 3 relates to codes and you don't have any

Chart 6,1 page 69, note this chart is only to be used if
(1) all basic mechanical and physical inspections have been performed and no problem found and,
(2) Diagnosis of DDEC 2 was started at step 1 and you were referred here!
Turn Ignition off
check both fuses and circuit breakers to the ECM
Fuses and c/bs are ok- go to chart C6-2
Fuses or c/bs are blown, replace and reset, then go to C6-30, the fuse may blow again if an intermittent short to ground exhists in either circuit 240 or 241.

Chart 6-2 check for open in DDL connector,
(1) check resistance between cavity A of the DDL connector and a known good ground- any resistance, reading greater than 3000 ohms, repair open in circuit, go to C6-30
(2) disconnect vehicle harness connector at ECM
(3) check resistance between cavity M of the DDL and cavity E-1 of the ECM 30 pin connector
(4) check resistance cavity J of the DDL connector and cavity C2 of the ECM 30 pin connector
(5) check resistance between cavity K of the DDL connector and cavity C1 of the ECM 30 pin connector
If (3), (4), and (5) resistance readings are less than 3000 ohms, go to chart C6-3, if greater, repair open in circuit

Chart 6-3
(1) Disconnect the vehicle harness connector at the ECM
(2) Turn Ignition on (engine not running) while at the same time observing the Check engine lite
a, check engine lite comes on and stays on, driver line #419 is shorted to ground repair short, then go to C6-30. The DDR system also needs repair, go to C7-4
b, check engine lite stays off, Go back to C6-3

Chart C6-4
(1)Turn ignition off
(2) Check terminals at the vehicle harness connectors, both the harness and ECM side for damage; bent, corroded and unseatable pins or sockets. Pay special attention to the terminals and sockets on the 6 pin power connector and sockets B1 and B3 of the 30 pin vehicle harness
a, if terminals and connectors are OK, replace ECM, then go to C6-30
b, problem found, repair terminals/connectors; then go to C6-30

Chart C6-30
(1) Turn ignition off
(2) Reconnect all connectors
(3) Turn ignition on
(4) Clear codes
(5) Turn ignition off
(6) Turn ignition on while at the same time observing the check engine lite
(7) If check engine lite stays on, read the historical codes
a, check engine lite comes on for 5 seconds then goes out, repairs are complete
b,check engine lite does not come on at all, go to C4-1
c,check engine lite comes on, stays on but codes don't flash, all system diagnostics are complete. review this section from the first step to find the error
d, codes other than code 25, go to start-1 to service codes

If you need chart 4 information, let me know. Make sure that your CEL bulb is good.

[Greg Roberts]

Wow! You guys are really helpful. I am taking a few days with family and then I will get back on the trouble shooting with vigor. I have some really good ideas here of things to do and check. Certainly the low full pressure is something that I will address as well. I will update you guys by Wednesday next week if not sooner. I hope to get back on the trouble shooting that morning. Thanks!

[Greg Roberts]

The verdict is in: I replaced the fuel pump and improved the pressure a good deal, however, not as good as the book numbers and the pressure was falling back at the highest RPM. I had a new fuel line made up and replaced the line from the tank all the way to the primary filter and pressure went to the book number and stabilized with no fall off at all. The original installation had 8 connections and went from hose to tubing and then back to hose again and also had one bulkhead fitting. My new installation has one connection at each and that is all so removing a lot of potential leak points. I now carry a spare fuel pump and drive fork by the way.

Thanks to all of you for your suggestions and help!

Question for all of you: What spare parts do you carry and what is your philosophy regarding your choices?

[Songman]

Glad to hear you got that good looking bus back on the road, Greg. That means we'll see you in Quartzsite now, right?

[Dreamscape]

Great News Greg!

I carry duct tape and baleing wire!

Seriously, a spare compressor gov., assorted sizes/lengths of hose and clamps, reverse solenoid and odds and ends. Nothing major. I figure Napa will have what I need!

Hoping you have a wonderful New Year!

Paul

[Kwajdiver]

Glad to hear your back on the road....

I care a spare belt, and lots of tools.

Your never going to have the correct part when you break down, are you? 

Bill

[rv_safetyman]

Greg, that bulkhead fitting was probably a check valve.  That valve is there to keep you from loosing your prime.

If it was a check valve, I would buy a new one and install it in the line you fabricated.

Like you, I installed all new line, but left the check valve (new). 

Jim

[Greg Roberts]

Jim,
You are probably right. It looks like a simple coupling that is welded as a bulkhead and then has a flare fitting screwed into one side and a tubing fitting screwed into the other. I am thinking that the fitting on the tubing side could be where the check valve is located but I will have to investigate further. Either way, I should go ahead and install an inline check to keep the system happy. Thanks for the heads up!

[Greg Roberts]

Well it is looking like I have too much going on and am not going to make it over there doggone it. I really want to go but things just are not lining up for me. I will certainly make it a goal to be there next year!

Glad to hear you got that good looking bus back on the road, Greg. That means we'll see you in Quartzsite now, right?