will ecm defuel if it doesn't see a speed signal

[KellyClark]

I transplanted an '04 cummins into my '77 Ford. It runs great but seems to lack power. I have an Edge Juice with Attitude, however it doesn't change the engine's output at all. It seems like the ecm is defueling and overriding the Juice.



I don't have a speed sensor in it right now, could that be the problem? Will the ecm defuel the motor if it doesn't have a speed signal?



Thank you in advance for your replies.



Kelly

 

[RobertP]

i have never ran into that situation myself but i would assume that the speed sensor would set a code. possibly putting the engine in limp mode causing it to defuel.

 

[TCDiesel]

I transplanted an '04 cummins into my '77 Ford. It runs great but seems to lack power. I have an Edge Juice with Attitude, however it doesn't change the engine's output at all. It seems like the ecm is defueling and overriding the Juice.



I don't have a speed sensor in it right now, could that be the problem? Will the ecm defuel the motor if it doesn't have a speed signal?



Thank you in advance for your replies.



Kelly

Is it Auto ECM/PCM combo, or stick

 

[Reb.B]

it will not defuel. The reason i say this is when you cut the abs/speed sensor for more MPH, the engine will not defuel.

 

[KellyClark]

I'm not running the pcm, just the ecm. It has a manual transmission and it has set a speed sensor code.

 

[TCDiesel]

Have you check the ohms on the APPS. TPS on 03/04

 

[KellyClark]

No, I havent checked the APPS. What should it be? Also, does anyone know the correct input voltage range for the speed signal?



Thanks again for your help.

 

[cerberusiam]

I have a suspicion, manul or auto, the ECU will limit fuel if the rpms are under a certain level. I know the autos will limit rpms and defuel if it doesn't see a speed sensor signal and I suspect the same fuel maps are in the manual ones also. That could be limiting the fuel the ECU will allow.

 

[KellyClark]

Anyone know what signal the Dodge speed sensor sends? (Pulses per revolution?) Does it get converted to digital in the abs controller? What does it send to the ecm? Right now my Edge Juice w/Attitude is nothing more than a $900 tachometer.



ANY help would be appreciated. Thank you,



Kelly

 

[KellyClark]

Edge won't help me since the Juice isn't in a stock Dodge. Would anyone with an Edge be willing to disconnect the speed signal from their ecm to see if it changes the performance?

 

[KellyClark]

Can anyone help me?

Buehler?

Buehler?

Buehler?

 

[KZimmermann]

I have an 03 Cali SO in my Superduty with no vss to motor and mine does not defuel.

 

[KellyClark]

kzimmerman,



Do you have any other computers or modules besides the ecm? are you running with an abs computer? Does your ecm have any trouble codes?



thank you in advance.

 

[KZimmermann]

I run a PCS trans controller, I have the Ford pcm in place for my dash, abs, etc. . There is no communication between the Cummins ecm and the Ford pcm. I am also running a VA C5 Beta Test box for duration, timing, and pressure. My ecm has codes but they are only codes related to items not hooked up, they do not affect the way the motor runs.