P0336 / ECM trouble beyond standard troubleshooting

[Alterego]

First off I'm new here but hope I can contribute in some fashion as well, 2ndly I hope everyone had a very merry Christmas. 

Now the truck then the issue. 1998 24v 3500 4x4 manual transmission. Mods are air box, full exhaust, hot rod vp44, air dog 2 165, edge juice CS w attitude, and the wiring harness mods listed on here. 

Ok now my problem.... driving the truck one day and it shuttered out of the blue didnt think anything of it and kept on going. A few days later it does it again and the tack dies, doesnt come back and I notice the levels on the edge dont work anymore and the truck is running bone stock. No codes or check eng during this time. Picked up wife to run some errands stopped by the auto parts store wouldn't crank back up. P0336 showed up so walked back in the parts store got a crank sensor slammed it in and truck fires up tach is back for about 30 seconds truck runs rough tach dies motor smoothes out. P0336 code is there. Shut truck off,  restart same thing starts right up tach is up for maybe 30 secs then dies and truck smooths out. So what I have done..... I removed both ECM and PCM sent them both to be tested. ECM was bad so replaced it. Removed all wiring from the engine bay, undressed it cleaned each and every connector and fixed all the grounds. Ohm'd out each wire from start to finish and validated no brakes or anything else wrong with the wiring. Put it all back together and still the same thing. I forgot to mention I have changed the crank position sensor 3 times and the cam position sensor once. I have come to the end of my rope. I would greatly appreciate some advice. I have followed every step of troubleshooting I can get my hands on. Hopefully it will be something stupid, if it is I will gladly put on the dunce hat.

 

Quick note I forgot to add that is important I think. The Edge display I have set up to show RPM and it never drops to zero it is following the engine and is correct. 

 

Thanks in advance 

Alton 

Edited December 26, 2018 by Alterego
Add info

[Marcus2000monster]

9 minutes ago, Alterego said:

First off I'm new here but hope I can contribute in some fashion as well, 2ndly I hope everyone had a very merry Christmas. 

Now the truck then the issue. 1998 24v 3500 4x4 manual transmission. Mods are air box, full exhaust, hot rod vp44, air dog 2 165, edge juice CS w attitude, and the wiring harness mods listed on here. 

Ok now my problem.... driving the truck one day and it shuttered out of the blue didnt think anything of it and kept on going. A few days later it does it again and the tack dies, doesnt come back and I notice the levels on the edge dont work anymore and the truck is running bone stock. No codes or check eng during this time. Picked up wife to run some errands stopped by the auto parts store wouldn't crank back up. P0336 showed up so walked back in the parts store got a crank sensor slammed it in and truck fires up tach is back for about 30 seconds truck runs rough tach dies motor smoothes out. P0336 code is there. Shut truck off,  restart same thing starts right up tach is up for maybe 30 secs then dies and truck smooths out. So what I have done..... I removed both ECM and PCM sent them both to be tested. ECM was bad so replaced it. Removed all wiring from the engine bay, undressed it cleaned each and every connector and fixed all the grounds. Ohm'd out each wire from start to finish and validated no brakes or anything else wrong with the wiring. Put it all back together and still the same thing. I forgot to mention I have changed the crank position sensor 3 times and the cam position sensor once. I have come to the end of my rope. I would greatly appreciate some advice. I have followed every step of troubleshooting I can get my hands on. Hopefully it will be something stupid, if it is I will gladly put on the dunce hat.

 

Thanks in advance 

Alton 

Welcome to the forum! A 1998 truck will have a crankshaft position sensor and not a camshaft position sensor. The 01-02 trucks had the cam sensors. Make sure you are actually getting a crank sensor for the correct year. It appears that possibly the crank sensor failed immediately have you tried another one yet? Also I suggest completely disconnecting the edge tuner from the truck for diagnostics. Hope this helps somehow and I’m sure someone else will chime in and help! 

[Mopar1973Man]

Have removed the Edge Juice? Want to make sure the Edge Juice isn't fouling the signal.

[dripley]

55 minutes ago, Marcus2000monster said:

Welcome to the forum! A 1998 truck will have a crankshaft position sensor and not a camshaft position sensor. The 01-02 trucks had the cam sensors. Make sure you are actually getting a crank sensor for the correct year. It appears that possibly the crank sensor failed immediately have you tried another one yet? Also I suggest completely disconnecting the edge tuner from the truck for diagnostics. Hope this helps somehow and I’m sure someone else will chime in and help! 

I believe the early model 24v have both. Not sure on years though.

 

I would ask who tested and rebuilt your ECM?

[Mopar1973Man]

It changed in 2000 (IIRC) when it went to a single cam sensor and no crank. 

 

9 minutes ago, dripley said:

I would ask who tested and rebuilt your ECM?

Might be time for a call to them and see if the ECM failed again or was it fixed correctly. 

[Alterego]

Thanks for the replys. Yes I have completely removed the edge. And it did the same thing. This truck has both sensors the crank behind the starter and the cam under the vp( what a pain to get to). I have changed the sensors. The ECM and PCM where tested by SIA electronics and the new PCM came from Auto Module Source in Florida. I have checked all the references and they are 5 volt plus or minus 0.1 volt used a test light on the signal and it shows good. I was told the signal from the CPS goes to the PCM but from the wiring I can see it goes straight to the ECM 2 wires on one side of the connector and 1 on the other I think it was pin 6 and 16 and pin 2 if I'm not mistaken. I'm crossed eyed from pinning the whole harness out the past 2 days. What really gets me it happened all of a sudden like a white snapped or component just failed which from my experience doesn't happen very often.

[Mopar1973Man]

 

 

[Alterego]

I am luck I have access to a plotter and have those prints on large scale. I printed them from the electrical section and that is how I checked the wiring from the pinouts to the harness everything seems ok. I cant really use my TDR on it except for the CAN BUS twisted pairs, and to use a megger on it would be detrimental to the harness. So I used a fluke 78 to ohm out the harness. I was going to o-scope the signal but not sure what the pattern should look like. My o-scope has 4 channels so I could do the crank and cam at the same time.... this is why I'm at a loss. I am reaching out to the experts. I'm at the point to just replace the whe harness and both boxes again, but I have a feeling this wouldn't fix it as I have already checked it all out. 

Also I have move the grounds that dodge spliced all together to the LH side of the timing cover and ran 2 8 gauge ground wire directly to the battery. The PCM ground was checked and I removed the plugs and ran straight to the negative terminal of the battery. All the battery wiring is 1/0 stinger battery cable and both power and grounds of the batteries have been redone that way and both batteries are interlinked with 1/0 cable all terminals are soldered and have environmental heat shrink that completely seals them. 

[Alterego]

So after several hours of staring at wiring schematics. And everything else I've done I think I'm going to go after the wires under the dash. It's the only thing that makes sense to me now. Please jump in a correct me if I'm wrong but a short to say the tach behind the instrument cluster could feed back into the ECM and cause my issue. Has anyone else had issues with wiring under the dash. 

[dripley]

8 I would be suspect of the ECM rebuild. I went thru 2 from Automotive Scientific Inc out of Florida. The first tripedthe 606 code that the OE one did not tripand the second under warranty that lasted about one year. It just died driving down the highway, no warning what so ever. If the wiring checked as good as you say it did, will a new harness do any better? 

 I did a little research into Auto Module Source. I found glowing reviews and really negative reviews. The ones that caught my attention were on the BBB site. They went back to 2016. In 2016 they were very buisness like and apolagetic for the problems in the responses, but 2018 the were blaming the customer and un apolagetic. In fairness to them some of it was the customers fault. The one that boggled my mind was the gentleman that recieved two PCM's that he was sending back to them for refund. Upon receipt of the package they said they weighed and it was not heavy enough to be 2 PCM's, so they tossed the box in the trash without opening it and would only credit him for one.

 In fairness to AMS I realize that negative reviews are most times easier to find than positive. And the reviews I found did not state what kind of vehicle these modules were for. I am just naturally suspicious of electronic rebuilders in general unless I know some real history on their products.

 @pepsi71ocean has been working on and has posted an article on this very subject.

 

[IBMobile]

11 hours ago, Alterego said:

The PCM ground was checked and I removed the plugs and ran straight to the negative terminal of the battery.

 

The PCM grounds are the black/tan 14 AGW at C31 and C32.  They are spliced with the black/tan 18 AGW from the datalink connector and another black/tan wire that is not used.  These all join at splice S126 to a black/tan 10 AGW. It goes to the gray connector, which I think, you have removed at the right battery.  

 

 

When I did the ground modification I soldered all those wires together.

I

Edited December 27, 2018 by IBMobile

[pepsi71ocean]

I suspect we may have another one to add to the list. It sucks that this happens with peoples money and time, but I'm glad we're adding to it constantly.

[Alterego]

First off thanks for all the replies.. so here we go... problem is still here. I have swapped the ECU out several times now with several different units. Even borrowed a buddies truck that has the exact same drive train and put my "new" unit in his and his in mine. His truck ran fine with either unit, mine on the other hand still has crank sensor code, tach dies after 10 secs. I completely removed my edge before any of that. All of the Under good harnesses have been removed and checked completely for shorts pushed pins. Ground mod is done. Alternator mod is done with the field fuse installed. I'm thinking about going and buying a mopar brand crank sensor to see if maybe the air gap might be the issue, but with a test light I can see it pulsing and the sensor is getting the correct 5v reference. I'm totally frustrated with this now and the whole keep throwing parts at it is not my style. I did also check all the under dash wiring and also removed the cluster just in case. The cluster did check good with it's own test. Thanks to everyone. When I get it figured out I'll post the solution for sure. 

[Mopar1973Man]

That sensor needs 3 wires to work right. Being the ECM is not the cause this means either the wiring or the sensor. One last possible failure is the tone ring is loose on the crank.

1. +5V supply
2. Sensor return
3. Sensor ground

Did you ohm form end to end? This should give you 0 ohms for all three wires. Requires both ECM and Sensor unplugged.

 

Did you ohm from pin to ground? This should give infinite ohms or open circuit. Just checking for wires grounded to body. Requires both ECM and Sensor unplugged.

 

Did you check for good +5V signal?

Did you check for good sensor ground?

 

Output of the sensor is AC voltage. It a square wave signal and the ECM counts the frequency of the square wave for the tach reading. This is why the AC noise has to be ruled out for sure. If you want to you could either just pull the belt for testing or pull the field lead from the alternator so its not active. 

 

As for the tone ring. You'll see its got a removable section for installing to the crank.This is the early crank sensor in the block near the starter.

 

If the engine has ever been swapped this article might explain some of your headaches.

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/swapping-vp44-cummins-engine-between-985-00-01-02-r429/

[Alterego]

Yes sir. I did the above checks. With the harness out of the truck and again with it back in. Perfect continuity from end to end. No shorts pin to pin. 5v coming to the sensor and a good ground back. With the O-scope hooked up the sensor seems to be working as it should. I felt in the hole to see it the ring is loose but really can tell so it looks like the pan will be coming off. Not sure if it is possible with the engine in the truck. The thing that really bothers me is that with the Edge hooked up I get a tack reading on the display. And once the cluster tach goes to zero the truck runs stock as a stock truck. 

[Mopar1973Man]

Hmmm... ECM been swapped. P0336 code is crank sensor performance error. 

 

Can you drive with the o-scope hooked up? I wonder if the signal is getting dirty or dropping out.

[Alterego]

I'm going to order longer leads this morning for my o-scope should have them by tomorrow afternoon then yes I can drive with it hooked up. This is the events as they happen. It doesnt matter if the edge is hooked up or not and keep in mind it's the same thing with multiple ECMs and all the wiring has been removed from the truck and checked end to end all sheathing removed and wiring completely inspected. All the crimp splices have been replaced with solder sleeves then have adhesive heatshrink on top to completely seal them. Ok now for the events as they happen. Key on air dog comes on for a second. Preheat light comes on and then goes off approx 10secs. Clutch depressed key to start. Truck fires right up. Sounds like it's missing or timing is off. Tach is active for about 20 seconds. Tach then dies and torch smoothes out and runs normal. As all this happens with meters and o-scope hooked up. The 5v input is constant, on a second meter measuring resistance the ground is constant. On the o-scope the signal and frequency remain constant. With the edge hooked up the rpm displays and it is correct and matches the engine rpm. It matches the external optical tach. Today I'm going to drop the starter and check the reluctor ring. If I can get the oil pan off I will check the air gap. I'm looking for a spec for that now. 

[Mopar1973Man]

What I'm thinking is like my ABS issue. I had my ABS module rebuilt. Then tested all the wiring and 0.01 Ohms end to end. As for pin to ground was infinite. What I found out was the tone ring broke and spun in the hub. Very detectable with @Chris O. CCD network tool. The tone ring did not show any speed below 30 MPH but rises above that it snapped to speed and was true. I'm wondering if the tone ring is slipping or out of index. Remember there is the cam sensor that is a single tooth denoting TDC #1 so if the index of the crank is not in time it might (guessing) throw the P0336 code. I heard of a few stories of the tone ring coming loose but not sure if it was true ore not. 

 

We can rule out ECM, wiring and sensor. This only leaves the timing of the tone ring or is the tone ring slipping. 

[pepsi71ocean]

On 2/2/2019 at 12:50 PM, Alterego said:

Yes sir. I did the above checks. With the harness out of the truck and again with it back in. Perfect continuity from end to end. No shorts pin to pin. 5v coming to the sensor and a good ground back. With the O-scope hooked up the sensor seems to be working as it should. I felt in the hole to see it the ring is loose but really can tell so it looks like the pan will be coming off. Not sure if it is possible with the engine in the truck. The thing that really bothers me is that with the Edge hooked up I get a tack reading on the display. And once the cluster tach goes to zero the truck runs stock as a stock truck. 

 

I believe you may have a bad pin on the cluster pin that goes to the instrument cluster. There is a TSB out for this, and i know of this because that was what the shop that installed my built automatic said was the issue (which was irrelevant). But It maybe worth pulling the instrument cluster cleaning and hen looking at the pins.

I worked on a jeep that stared with the tack dieing intermittently, bu then ended up becoming the whole cluster. It ended up being the plug on the back of the cluster.

I'm unsure of the edge receiving the tach signal from just the CKP, as here is also a cam sensor and a sensor inside the VP-44 And all 3 must match.

Edited February 4, 2019 by JAG1

[Alterego]

@pepsi71ocean I did check the cluster as you suggested a couple weeks ago. I even pulled it from the truck and ran the truck with it out, still runs the same. I have checked it fully. 

@Mopar1973Man the more I learn the more I understand the logic in the ecm. I haven't found a logic tree for the ECM yet but. I think I have figured out. That the truck has 3 timing signals; crank, cam, and injection pump. The truck will run if it can denote that the injection pump is in time with the cam but with the crank sensor being "off" it nulls that signal, which is when the tach dies and the engine then runs off the 2 signals that match. There must be some sort of "or" gate in the logic that allows this to happen if one of the signals is lost..... So I have come to the conclusion that the reluctor ring on the crank has slipped and is now slightly off, thus the engine running ruff on start up until the logic nulls that signal out due to the mismatch. Please correct me if my thinking is wrong.