Truck is dead, will start and then die

[Krlspokane12]

So I thought I'd repost this here. Yesterday I was driving down the road and the truck just died.  It threw a p1693 and then a p0122 and p0237.  Battery voltage was showing 15.1 and the IAT was showing 2.70v and the engine temp was 2.79v.  The scanner was showing no data from oil pressure sensor.  The Map and IAT and apps are all brand new. I unplugged the quadzilla and it made no difference.  I'm thinking Ecm??? Wiring?  This picture is what the scanner was reading when the truck died.  The truck would run for a few mins and then die, but now it will only run for about 5 secs.

[dripley]

Saw this in your other thread.  That info appears whacky to me, unless you were turning 4256 rpm.  I would not believe on them. Get the codes read and lets see what the truck trying to tell you. A p0606 would be a definite ECM failure, but we dont see that code tripped very often.. Mine did not trip it when it failed. but the first rebuilt one did.

[Krlspokane12]

So I just cleared the codes and now I have an additional p1694 code.  Also after the truck died and threw the p1694 code, the lift pump would shut off and restart for about 3 seconds and then turn on for 3 secs and then turn off again.  The lift pump did this with out me touching the key again, so the key was still in the start position.

These are the same codes I had 6 months ago, when I had the vp replaced and the ECM "repaired " locally.  My mechanic told me that the vp was bad and there was some issue with the ecm that a local company "fixed".  So I'm wondering if the ECM repair was just a "bandaid" and now the ecm is done.

[dripley]

It would be nice to know who rebuilt the pump and ECM. The pump to know if it got a new computer on it or not and the ECM just because they seem to be hard for folks to repair. 

The lift pump coming coming on and off is ECM controlled. Does the WTS light come on at key on? It should even just for a second or 2.

[Krlspokane12]

The WTS light comes on and goes off after a few seconds.  The pump was rebuilt by MasterTech diesel here in Boise.  Not sure of the parts they use but I had one of their pumps on my old 24v for years with out any issues.  I'm not sure who the company is that was in the ecm, but they were recommended by my mechanic. 

[dripley]

Most places deal in pumps that are rebuilt by certified rebuilders. Takes some very expensive equipment to rebuild and calibrate them properly. There are only and handful of them but many resellers. 

I got mine from DAP but it was rebuilt at either Industrial Injection or Midwest fuel injection. Cant remember which now.

Edited April 18, 2021 by dripley

[Krlspokane12]

I'm not wanting to say it's the pump, but the truck has never run right since the pump was put in and ecm was repaired.  I know these pumps are re-maned in a approved bosch facility and use bosch parts.

I dont even know where to start chasing this problem.  Damn near everything is new under the hood. MAP, IAT, CPS, VP44, BATTERIES, ALT, LIFT PUMP, ECT. 

Could this be an issue with the ALT?  When the truck idles its charging at 15.1v and then dies?? What about the oil pressure sensor, it has one wire  coming from it and it states "no data" on the scanner and quadzilla.  Im just grasping at straws here because the last time this happened it was in the shop for 3wks.

[Krlspokane12]

I want to beleive this a ecm issue.  The reason being is that these exact codes and symptoms happened last time.  The vp was said to be the culprit and it "did something" to the ecm and that needed repaired.  So whatever issue that was is back again, because the truck will run and then dies. And it will fire right back up and then die. So I'm assuming that it's the same problem that was fixed in the ecm is now broken again.  I don't think it was the pump either time. But im no expert, am I on to something or am I just whistling Dixie 

[dripley]

I would not just throw more parts at it. That seems to be a exercise in futility. Lets try to eliminate a few.

 

The oil pressure sensor is easy. You dont have one since it is an 02. It is a single wire switch that is activated at around 6 psi and then the ECM takes over and positions the needle based on RPM and engine temp. Dodge made this change because folks were thinking their oil pressure was to low at idle. There is a TSB about it from Dodge. Had me fooled for quite. Didnt even believe it when I first heard about it. Its quite convincing.

 

How did you test the charge voltage on alt to get the 15.1 volts? The photo above shows charge voltage at 9.8 volts. Either is not good. To high is harsh on the charge system and to low will make the electronics act weird. Your alternator could also be putting out to much AC voltage. This can harm the electronics. These trucks need good clean DC power to keep them running right. There is also an article by a member named WT. He has a very good article about a ground mod the cheap simple to do. He goes quite about this issue. I would link but for some I cannot access the articles section.

 

Another test for the VP is to hot wire it. This takes the ECM out of the circuit and the pump should idle only. But if the pump is fine it should idle as long as it has fuel. If it does that then the ECM would be in question. Again there is an article on how to do it here but I can access them for some reason. You can also go to Blue Chip diese.com and they have a lot of info on the vp and some good trouble shooting info including hot wiring the pump.

 

You already have a few problems point at the ECM,

 

The lift pump is not functioning properly. At key on the pump should just bump the pressure a little for a second or 2. it only does this once per key on cycle and should not repeat it until another key on cycle. Now after turning the key to on if you bump the starter, no engine start, the lift pump should run for 25 seconds or so then shut down. The ECM controls this function too.

Temp gauge pegging out is another.

 

If you hot wire the pump and idles fine that would be another.

 

The electrical system is the key part. It could frying your computers and causing electrical gremlins. I dealt with several for 3 years or so. I did WT ground mod and cleaned all my electrical connections including grounds and replaced my battery cables, made them myself a lot cheaper than buying premade which might not have been necessary  but it made me feel better. Not another electrical gremlin since.

 

If the shop you took it does not know these trucks you can and have spent a lot money already parts replacing. Time to get methodical.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Krlspokane12]

So I'm going to swap the ecm with one from a friend's truck and see where that leads me since it's a simple swap.  If it is determined that the ecm has an issue, do any of ypu guys know where I can get one? 

[dripley]

Unfortunately you cannot buy a new one anymore and you would have to get yours rebuilt. ACS, auto computer specialists, I believe, is one company others have had success with. Just dont send out the first place you see. Not everyone can fix them. I went that route back in 2010 and it was an unpleasent experience. Went thru 2 of the units, one failed out of the box and the next lasted about 1 year. Finally bought a new in 2011. IIRC  Auto Computer exchange was the name of the company.

 If you do go the rebuild route it would be good for you to get electrical system in order. That could be the main source of your problems including cooking the ECM.

 The 1694 code you mention says the ECM and PCM are not communicating with each other. You should pull those connectors inspect and clean them good and see if that helps. Electrical problems suck to say the least.

 

[Mopar1973Man]

Like myself I had my PCM burned up when my alternator shorted out. It was so bad there was no circuit board to repair the burned tracers. I went to Auto Computer Specialist and ended up buying a reman'ed PCM.

[Krlspokane12]

I will check out ACS if it is indeed the ECM.  Should I be concerned about the 15.1v I saw while the truck was running?  That was my live reading on the scanner.  Not sure if the VR is shot. The ALT is 3mths old but it was a inexpensive reman.

[Tractorman]

6 minutes ago, Krlspokane12 said:

I will check out ACS if it is indeed the ECM.  Should I be concerned about the 15.1v I saw while the truck was running?  That was my live reading on the scanner.  Not sure if the VR is shot. The ALT is 3mths old but it was a inexpensive reman.

 

I don't know where the scanner senses system voltage, so I would use a regular DVM and check voltage at each battery.  Should be right around 14.0 volts - a little higher if ambient temperature is low and a little lower if ambient temperature is high.  Each battery should be within about .03 volts of each other.

 

- John

[dripley]

@Tractorman is right. Thats why I asked a few posts back. I dont know how you got the 15.1 reading. The encore says 9.8, You are going to have slow down and not just throw another part at the problem. When my ECM failed I spent 2 months trying to figure out what the problem was. I bought a VP and a Timbo apps and neither fixed it. I quit throwing money at then. A new ECM did fix it but I was out of my league on the problem. Finally found a shop with very knowledgeable owner who helped me when the second reman died. Got luck on that one. 

[Krlspokane12]

Sorry, let me explain, the encor showed 9.8 when it died and 15.1 while it was charging.  I still need to do the wt mod so this might be the right time to do it and get that out of the way. Going to try different ecm tomorrow and see if that helps and if not, then on to checking the wiring.

[Tractorman]

1 hour ago, Krlspokane12 said:

and 15.1 while it was charging. 

 

Don't skip the step of checking battery voltage while the engine is running as outlined in my previous post.   It is a basic step, but it is important.  Let us know the results.

 

- John

[wil440]

4 hours ago, Krlspokane12 said:

Sorry, let me explain, the encor showed 9.8 when it died and 15.1 while it was charging.  I still need to do the wt mod so this might be the right time to do it and get that out of the way. Going to try different ecm tomorrow and see if that helps and if not, then on to checking the wiring.

I presume an Encore is a scanner ??  and I also presume voltages were 15.1 running and 9.8 engine stopped  if so then running is too high and stopped is too low. Stopped I'd be wanting to see 12.2 or 12.4 ish without the heater blower is on and everything electrical is also on

I'd be checking batteries/cables etc if that stopped figure is right.

If I've presumed wrong just call me stupid  

[dripley]

I have to agree with both of the above. 

[Krlspokane12]

i ended up taking an ecm off a friends truck and it fixed the issues i was having with it dying and not starting.   So, i finally to get my new ECM.  I installed the new ECM and all of my random issues went away.  The track runs better than it ever has since I've owned it. I also tested the ALT and everything looked good, so my scanner must have read the data wrong or the old ECM was throwing out weird data.  Hopefully the truck will be maintenance free for a while, I'm running out of money and things to replace LOL.  thanks for all your help this guys!!