Truck in my sig......

This truck has had a FASS 150 on it for @10 years, has and still does work correctly. Up until yesterday, key "on", pump ran a couple of seconds, or bump the starter and pump ran for @20 seconds. Yesterday, key "on", no pump, bump the starter, pump runs a few seconds and shuts off. The FASS is run with a relay plugged into the factory lift pump harness. The truck starts and runs, and maintains @14 psi constant after being started. I unplugged the FASS harness, tested the relay and the harness, checked out ok, and the pump runs with 12v direct to it. Key "on", the factory lift pump harness shows 7v, bump the starter it goes to 9v-10v for a few seconds, then back to 7v ( I neglected to check voltage there with the engine running). The factory pump harness appears to be intact. The CEL is not on, though my scanner picked up a companion code P1693, but it didn't specify what the problem is. Also, I cannot clear this code. Any ideas on what has failed?

Edited March 18, 20187 yr by mrclean

What is your WTS light doing? On at key on or delayec?

4 hours ago, dripley said:

What is your WTS light doing? On at key on or delayec?

I really can't say, didn't see it, but the truck had been plugged in and it was actually very warm outside. I left it unplugged for tonight, and will check in the morning when I know it'll be cold enough to run the grids........

You ought to see it at key on no matter what. It will come on briefly no matter what the temp is.

Yes check that first ^^^ sounds like a possible ecm problem, which leads to checking alternator for excessive ac noise. 

Also relay that comes with fass or air dog is not a protective one, you need to get one that has a resistor or diode for when it's denergized and doesn't send current spike back to ecm

No WTS light. Waited @2 minutes, no light, and no grid heaters. Possible solutions short of replacing the ECM? I'll replace it if needed, but I'd rather cover all the bases before doing that........

I've seen a lot of posts ( here and other sites ) where folks with this issue are not able to start the engine at all, and mine starts and runs normally. Any idea why?

Also saw some posts that say that 1693 code cannot be seen by itself.......but it's the only code showing on my truck.

Edited March 19, 20187 yr by mrclean

If you left it plugged in overnight it is possible the truck was warm enough that it only stayed on briefly, like a couple seconds. Easy to miss if you are not looking right at it. .

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I've seen a lot of posts ( here and other sites ) where folks with this issue are not able to start the engine at all, and mine starts and runs normally. Any idea why?

 

Mine always started. Just had to wait for the ECM to boot up indicated by when the WTS light came on.

I had the delayed WTS light for years. Finally got a new ECM all problems were fixed

 

 

.Rick

3 hours ago, dripley said:

If you left it plugged in overnight it is possible the truck was warm enough that it only stayed on briefly, like a couple seconds. Easy to miss if you are not looking right at it. .

No, left it unplugged to be sure.........no WTS light.

Okay, in the event I need a new ECM, where is a good source for one?

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Okay, in the event I need a new ECM, where is a good source for one?

 

After a lot of research, I bought my ECM here:

http://www.remanautoelectronics.com/dodge/cummins-78.aspx

ts a partner company of Flight Systems

https://www.fseg.net/

 

Its a Known good company

I am very pleased with the ECM I got from them.

 

It is completely re-manufactured, software upgrade and extensively tested

 

Watch out for places that say "lifetime warranty".

 

 

.

Edited March 19, 20187 yr by GSP7

I can only add this.

cummins/articles.html/24-valve-2nd-generation_50/51_engine/electrical/list-of-verified-and-reliable-pc

 

The link did not work but the article is in the articles section under 2nd gen, electrical.

Edited March 19, 20187 yr by dripley

What @dripley attempted to post...

 

Then since there is a ECM failure I need you to check the AC noise output from the alternator. Most likely the alternator killed the ECM. 

 

 

 

AC noise test is on the agenda for tomorrow, I'll update the post after. Thanks for the info guys!

Updating the thread.......

Looks like I need an alternator AND an ECM. Sometimes I wonder why we keep these old trucks. Fix one problem and find two more............

Thanks for all the input guys!

2 hours ago, mrclean said:

Updating the thread.......

Looks like I need an alternator AND an ECM. Sometimes I wonder why we keep these old trucks. Fix one problem and find two more............

Thanks for all the input guys!

 

I heard that,  My 81 K20 chevy is a piece of cake and cheap$$ to maintain compared to all the damn new fangled electronic/computer/senser bull sh*t on my dodge

 

Computers on vehicles suck !.. Ill take a pre '73 vehicle restored before I buy a new truck

 

 

.

 

Edited March 25, 20187 yr by GSP7

These truck aren't bad. I look at mine with 15 years of age and 338k miles on the clock and still got all the electronics working just fine. It, when people ignore warning signs like the torque converter lockup and then toil foil and modify the electrical attempting to shield the power, leads from AC noise come to find out the alternator is the cause. I'm now on the path of figuring out the cause of alternator failures which actually stems from the grid heaters. So the computers have nothing to do with it. It the fact the Dodge did a crappy job of wiring the truck and used a under par alternator for such heavy load like the grid heaters. So if you want to blame something blame the alternators, Dodge and the grid heaters that is what is creating the problems. 

Do you think the grid heaters heavy draw is a cause of the alternator diodes failing?

 

I finally disconnected my grid heater a few months ago. Made it through winter with out it

1 hour ago, GSP7 said:

Do you think the grid heaters heavy draw is a cause of the alternator diodes failing?

 

Yes and no. The first 10 years of my truck have been totally trouble free never had an alternator issue ever. Then now I can't keep an alternator longer than 4 months with the grid heaters hooked up. As long as the grid heaters are disconnected the alternators don't seem to have issues. So I'm betting that the grid heaters are increasing amperage draw as they age. That is the only theory I've got right now. 

1 hour ago, GSP7 said:

I finally disconnected my grid heater a few months ago. Made it through winter with out it

 

I disconnected my grid heaters in December when I lost my last alternator at 4 months of age. No issues to report. Still only in the 0.030 range for AC noise. 

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Then now I can't keep an alternator longer than 4 months with the grid heaters hooked up.

Are you using Napa rebuilt alternators? 

 

If so, that is the problem.

 

Ive used both alternators and starters from Napa auto that were junk and didnt even last a year. On other trucks not my cummins. . I did use a Napa starter on my CTD and it went bad in less than a year (bad armature or field windings)

 

Im not impressed with what Napa peddles even if does have lifetime warranty

 

I think the best way to confirm if its the grid heaters it to see how the alternator does this year, if they're still good by the time next winter comes, connect the grid heaters back on, then test the alternator regularly. If the ac numbers start to climb, it would be a fair confirmation that the grid heaters are the cause of our alternators failing.