dodge pickup no crank rpm

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dodge pickup no crank rpm

Postby rburgy » Fri Jun 03, 2016 1:42 am

hey guys. wanted to see if you guys would take a look at a waveform for me and give me some input.
2003 dodge r1500 4.7l. installed used engine. I have no engine rpm on scan tool. I can put the waveform up if you tell me how to move it from the waveform library to here??

I checked for 5v, signal, ground all at the crank sensor-everything looked good.
I checked it at the ECM-all that was good at the ECM was 5v.
I had erratic signal and ground was horrible. (like I said its in the waveform library)
I jumpered new wires for the signal and ground-now I have the same waveforms at the ECM as I do at the sensor, but still no RPM on scantool. The engine will backfire every once in a while through the intake. But I assume it has to do with the crank rpm??
what you guys think? any suggestions?
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Re: dodge pickup no crank rpm

Postby Fat Freddy » Fri Jun 03, 2016 5:07 am

Can I assume, since you haven't mentioned it, there are no codes???

Sorry. Don't know much about Dodge. If some one says "Dodge" to me, I think "Where's my barge pole". :wink:

One thing I would consider is weather the tone wheel for the crank is the same on both motors - number of teeth?

HTH
FF

edit: Not seen waveform
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Re: dodge pickup no crank rpm

Postby roadserpent » Fri Jun 03, 2016 3:26 pm

Here is your waveform from the library. I think you have a poor ground somewhere.
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Re: dodge pickup no crank rpm

Postby roadserpent » Fri Jun 03, 2016 3:35 pm

sorry, i had turned off channel B while looking at the waveform. it was a very good 5 volts. channel A is his signal, channel C is his ground. Pico users can turn channel B back on if you like.
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Re: dodge pickup no crank rpm

Postby rburgy » Sat Jun 04, 2016 12:42 am

The flywheel was switched pver as it was the only one i had.
I agree with the bad ground also. However, i checked all volts inputs and grounds coming into PCM. All were good. I jumped a good ground to that pcm terminal, re-checked with the scope- and all of my waveforms were perfect and still no RPM.
I have a feeling the pcm is bad. I just need to be positive before i replace it.
Thanks guys for any input.
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Re: dodge pickup no crank rpm

Postby roadserpent » Sat Jun 04, 2016 2:25 am

I am going to assume that this Ram 1500 is a pick-up truck and not a van? Then I am going to assume that it was built for USA use? Do not condemn the engine computer until you first get a crankshaft signal ! No ECU in the world could make heads or tales about anything from the waveform that you posted to the library. I found a crank waveform in the library from a 2003 durango with a 4.7 V8 and will post it here, your signal from the sensor should look very similar to this. the spacing's may be a bit different due to the fact that to my knowledge there are two different reluctor rings used on this engine. they are mounted to the internal rearward part of the crankshaft, yes inside the F---ing engine and to change them you must remove the crank from the engine. for now you need to work on getting a good looking crank signal waveform first, that is my opinion.
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Re: dodge pickup no crank rpm

Postby Fat Freddy » Sat Jun 04, 2016 11:13 am

roadserpent wrote:I am going to assume that this Ram 1500 is a pick-up truck and not a van? Then I am going to assume that it was built for USA use? Do not condemn the engine computer until you first get a crankshaft signal ! No ECU in the world could make heads or tales about anything from the waveform that you posted to the library. I found a crank waveform in the library from a 2003 durango with a 4.7 V8 and will post it here, your signal from the sensor should look very similar to this. the spacing's may be a bit different due to the fact that to my knowledge there are two different reluctor rings used on this engine. they are mounted to the internal rearward part of the crankshaft, yes inside the F---ing engine and to change them you must remove the crank from the engine. for now you need to work on getting a good looking crank signal waveform first, that is my opinion.


From what I understand, that waveform was pre repair and no longer an issue since wiring replaced but still no RPM on scan tool. :?

Really need to see post repair.

From what I understand there is a 16 (early) and a 32 (later) tooth tone wheel on the crank not flywheel as RS has mentioned. The change over is around 2002 I think.
Learned that lesson (in fact many lessons) the hard way on a Ovlov motor swap. Same model, year and month.

HTH
FF
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Re: dodge pickup no crank rpm

Postby rburgy » Fri Jun 10, 2016 3:44 am

You guys hit the nail on the head. The good engine came out of a jeep product& was put into a dodge truck. As it turns out the crank shaft reluctor wheels were in fact different. Thank you guys so much for the help. I would have put a PCM in it and then been stumped.
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Re: dodge pickup no crank rpm

Postby Fat Freddy » Fri Jun 10, 2016 2:31 pm

Great to hear you got it sorted.

And thank you for the feed back. :D So many just will just walk away, to never be never heard of again.

Appreciated
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