Need a hand with engine speed signal

[Sugmadique]

Does anyone know, or can anybody check what the voltage on C1 Pin8 on the PCM is at idle? I am trying to figure out if the ecm modifies the CKP sensor signal or if it just sends the same signal. I suspected I had a bad ECM and I sent it out for a rebuild from auto computer specialist and they did a full rebuild but I’m still having the same issues. I replaced the CKP sensor a few years ago due to the tach dropping out and a no start issue but I couldn’t get a cummins part so I used an eichlin sensor. When I hooked up a scan tool I had CKP signal and CMP signal but no engine speed at the PCM. For testing purposes could I jump the signal wire from the CKP sensor to the engine speed input for the PCM? At that point if I don’t have engine speed would that be a bad PCM? It’s a replacement unit from car computer exchange from less than a year ago. 

[wil440]

In truth I don't know, but I will say one thing ..... a CKP sensor really does not output volts it outputs a sine wave which is not measureable with a normal voltmeter

What scan tool did you use ??

If you have CKP and CMP signals where were these ? were these reported by the ecm but not reported by the pcm,   or vise versa  @Mopar1973Man will likely be along and add wiring diagrams

I wouldn't be jumping nothing from anywhere

eichlin .... where's that made ??

[Sugmadique]

14 minutes ago, wil440 said:

In truth I don't know, but I will say one thing ..... a CKP sensor really does not output volts it outputs a sine wave which is not measureable with a normal voltmeter

What scan tool did you use ??

If you have CKP and CMP signals where were these ? were these reported by the ecm but not reported by the pcm,   or vise versa  @Mopar1973Man will likely be along and add wiring diagrams

I wouldn't be jumping nothing from anywhere

eichlin .... where's that made ??

I used a snapon Verus pro, using the OBD2 generic function. It showed Engine speed at CKP sensor and CMP sensor when accessing the ECM but when connected to the PCM the was no engine speed signal. Eichlin is the house brand of Napa I think. I’m sure it’s made in China. 

[wil440]

The Snap On Verus Pro ought to connect not on OBD2 generic, my first check would be to make the Verus ID the truck and scan properly.

Generic is what it was always supposed to be ...., as in all makes all faults but I'd want to be seeing a vin connect as some manufacturers don't follow the spirit of things, Dodge is one

[Tractorman]

59 minutes ago, wil440 said:

eichlin

 

I believe he means Echlin.  They are a major brand name in electrical components.

 

- John

[wil440]

7 minutes ago, Tractorman said:

 

I believe he means Echlin.  They are a major brand name in electrical components.

 

- John

John

Here https://www.encyclopedia.com/social-sciences-and-law/economics-business-and-labor/businesses-and-occupations/echlin-inc

Seems to have a good history

I'm in the position of using various mobile plant manufacturers parts including Cat, Komatsu, Volvo, Hyundai, JCB, Bobcat ETC ETC and certainly electrical sensors are not always good out of the box

[Tractorman]

A good read.  I didn't realize just how diversified Echlin is.

 

- John