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P0336 / ECM trouble beyond standard troubleshooting


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  • Owner

Close enough. 

 

Cam signal is just a TDC pulse. VP44 has it's own tone wheel and pulse teeth. Then the crank has that multi-tooth wheel. 

 

Now with the later series the cam sensor was dropped. The crank sensor was moved to the cam. Exact same pins used as the early series. Just routed the sensor to the cam tone wheel. 

 

The weird part... What you describing is what normally happens with a block change. Wrong cam gear is used and the cam sensor hole of the gear case is in a different location from early to later. Your problem matches exactly. I'm going to assume though that you have not changed blocks. 

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@Mopar1973Man it is the original block in the truck no motor or cam change. It just happened one day. Drove to the store, truck wouldn't start, grabbed a CPS and changed it truck started but tach died thought is was a bad CPS changed it again same thing. Sent ECM off to have it tested was found bad, changed ECM now 3 times and the same issue. Didnt realize the reluctor ring was able to move or I would have checked it. Truck ran fine until this event. The reluctor ring is the last part of the equation. I was looking at the other link you sent me with the swap problems and saw the 36 minus 1 external pickup I'm going to give them a call in the morning and see if that will replace the internal ring. If it does I will go that path till I get time to go into the motor and reset the internal one. 

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2 hours ago, Alterego said:

@Mopar1973Man it is the original block in the truck no motor or cam change. It just happened one day. Drove to the store, truck wouldn't start, grabbed a CPS and changed it truck started but tach died thought is was a bad CPS changed it again same thing. Sent ECM off to have it tested was found bad, changed ECM now 3 times and the same issue. Didnt realize the reluctor ring was able to move or I would have checked it. Truck ran fine until this event. The reluctor ring is the last part of the equation. I was looking at the other link you sent me with the swap problems and saw the 36 minus 1 external pickup I'm going to give them a call in the morning and see if that will replace the internal ring. If it does I will go that path till I get time to go into the motor and reset the internal one. 

 

And you said SAI tested the 3 ECM's?

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@pepsi71ocean yes SAI electronics did test my original ECM. They do not sell replacement parts so... I started looking and found automotive module source.. I ordered a replacement and same issue so I assumed by everything I heard that ECM was not right, so sent it back got another and still same thing. The 3rd ecm came from a friends truck that I swapped in to see what would happen. I do have to say AMS didnt give me a single issue swapping out the ecm and did everything they can to make sure it was right. I know the ECM they sent me is good because it runs great in another truck. I've think with the help of this forum, it has been narrowed down to the tone ring on the crank. I'm going to explore an external option and completely remove the internal one completely. 

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What a lot of work your going thru to find the issue. Before dropping the oil pan, isn't there any other possibilities for something simple?. Anything can be easily overlooked.

 

Yesterday I was messing with the two alternator leads, the black two pin connector on the Nippon Denso. After disconnecting I noticed a lot of black dirt on the face of the connector which can cause, sometimes called, 'Earth leak' across the pins. Cleaned up the face and blew air inside around the two pins, inspected where the factory put hard bend on the two wires at the connector, (looked like the insulation may have deteriorated, couldn't tell for sure, so I taped them anyway separately at that bend and placed lots of dialectic grease on the face and around connector. Plugged back in, started the truck and seemed to be running surprisingly better.... smooth as glass really.

 

I know I'm shootin from the hip w/o any practice here but I'm hoping it something simple.

Edited by JAG1
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6 hours ago, Alterego said:

@pepsi71ocean yes SAI electronics did test my original ECM. They do not sell replacement parts so... I started looking and found automotive module source.. I ordered a replacement and same issue so I assumed by everything I heard that ECM was not right, so sent it back got another and still same thing. The 3rd ecm came from a friends truck that I swapped in to see what would happen. I do have to say AMS didnt give me a single issue swapping out the ecm and did everything they can to make sure it was right. I know the ECM they sent me is good because it runs great in another truck. I've think with the help of this forum, it has been narrowed down to the tone ring on the crank. I'm going to explore an external option and completely remove the internal one completely. 

 

So does SAI rebuild computers then? Or what exactly do they do?

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  • 2 weeks later...

@JAG1 first off all input is much appreciated. I know sometimes as a life long mechanic we tend to dive right in and overlook the obvious. To answer your question yes sir all connections have been checked cleaned and "bond checked" to their respective components. All the harnesses have been removed disassembled inspected cleaned checked end to end for any failures, then reassemble to aircraft specs all bend radius of wires have been set to 6D or better. Then everything was loomed up and taped all the joints that could have been an issue have been changed out for solder sleeves then adhesive heatshrink on top of that. It has come down to the last thing in the equation, which is the tone ring. I wasnt aware it was a bolt on ring until @mopar1973man brought it up. But with the logic of the ECM and a signal that doesn't agree with the other inputs. I'm confident that once I drop the pan I will either find pieces of the ring in the bottom or the small removable section sitting there. I will post pics and updates once I get into the bottom end. Once again thanks to everyone for all the information and input 

Ok everyone so after getting the oil pan loose enough for me to see inside the tone ring is broken. It has sheared in half. So got a new tone ring and will post pics once I get the pan off 

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Do you have any suggestions on the installation. I'm trying install without pulling the crank. I've got the cap off but there doesn't seem to be a way to install it without pulling the crank 

Edited by Alterego
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Yea I got all the parts in the bottom of the pan. Everything is accounted for. The issue now is getting it back on without pulling the crank 

@JAG1 I have tried to find a way around it with no luck. Destrocked diesel has a 35 minus 1 tone ring kit that mounts to the balancer but According to them it wont work as a replacement for the internal ring 

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  • Owner
15 minutes ago, JAG1 said:

Is there a way to get around not having one?

 

No. Engine won't run without a tach signal.

 

16 minutes ago, JAG1 said:

Some kind of a fooler on the sensor?

 

No. There is no way to fool the crank sensor.

 

16 minutes ago, JAG1 said:

You can hit me if it's a dumb question :punish:

 

Naw... I'll drop a bolt in your manifold... :whistle:

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Found it in the ram forum.... You have to pull #6 main bearing cap off, then pull #6 rod cap off. You might have to rotate the engine to get the cap off. The ring is in 2 pieces with 5 screws holding it all on. Take the small section out first, then rotate the engine so the gap where the small section was is facing up. Then you have to manipulte the large section out.  Assemble in reverse order...The tone ring screws torque to 71 in lbs...and use blue loc-tite on them. Main bearing cap...45 ft lbs, 66 ft lbs, then turn bolts 90*. Rod cap...22 ft lbs, 44 ft lbs, then turn bolts 60*. Oil pan bolts 18 ft lbs. I'll let everyone know how well it works out hopefully will be up and running by lunch tomorrow... 

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