Question on speed sensor & standard trans

[chasmosis1]

Obviously I'm new here, however I am far from new to the scene. I am actually in the process of installing an 04 Ram 5.7 into a Jeep YJ. I am going to build/modify the factory harness myself. I have already identified all of the needed pinouts with the FSM. I am using an AX15 connected through a 3.9 bellhousing. Question is whether I need the speed sensor signal for the PCM or is it strictly for shifting the trans? I would like to completely remove the C4 connector, but want to confirm that the speed sensor is unnecessary. I will either be using the AX15 speed sensor to send the signal to the factory electronic dash (using a 5v signal from the 5.7 PCM) or I will use a cable driven speedo. Programming is not an issue as I have the equipment and knowledge for that and will be shutting off the trans, rear O2's, & EGR. I am seeing nothing in the PCM that would require the signal, but I also know that today's programming only shows a limited portion of what the Dodge PCM is capable of.

 

[Hemi Rebel]

You are using the 04 ram pcm? I dont think the ax15 has the capability to handle 5.7 hemi power.
The 04 ram pcm uses vehicle speed sensor input to adjust timing and idle speed

 

[chasmosis1]

Thank you for the reply Hemi Rebel. Yes I am using the 04/05 PCM. I was unaware that the speed sensor adjusted the two, that is why I'm checking. Is this personal experience or did you see it posted? I have seen posts where guys running standards had issues with stalling when stopping, but to be honest I've seen posts where that is common in stock form as well.

I'm aware of the 300# rating of the ax15 and the 375# hemi rating.........however in my opinion (and I'll find out) they tend to be under-rated as they stand up to LS motors in the Jeeps and Novak themselves have actually installed them behind LS's. I am not a hardcore wheeler, just a guy that likes to build toys. Besides I have a fair collection of them laying around.....lol

 

[chasmosis1]

Just to keep this thread updated, I have found a member on FABO who is using a Hotwire produced standard shift harness and he has no C4 plug (plug to the trans & VSS side of the PCM) and has no wires coming from positions 8 or 13 on C1 which are the signals from the wheel speed sensors. His vehicle is running fine which leads me to believe that, though it may possibly be used to adjust timing/fuel on an automatic vehicle, it is not necessary on a standard shift vehicle for anything other than an electronic speedometer.

Chas

 

[Hemi Rebel]

Here is a thread i started. Yet to finish though.

http://www.forbbodiesonly.com/moparforum/showthread.php?94073-speed-sensor-for-727-A833

I haven't gotten there yet, i was just trying to plan ahead. I need to do more research on mine. Factory info needs to be deciphered. They dont come right out and explain how the pcm gets its VSS signal. But looking into yours, the VSS is the rear axle abs sensor of a 2004 ram. The abs controller then shares that info on the bus for the pcm to see.
I have a 2006 srt controller (no c4 connector) and will try with no speed sensor. If i have issues I will deal with them when they pop up. I doubt it will give me any being speed density.
What are you using to reprogram the PCM? I have hp tuners. With that I can program the pcm to ignore missing modules and inputs.

 

[chasmosis1]

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Here is a thread i started. Yet to finish though.

http://www.forbbodiesonly.com/moparforum/showthread.php?94073-speed-sensor-for-727-A833

I haven't gotten there yet, i was just trying to plan ahead. I need to do more research on mine. Factory info needs to be deciphered. They dont come right out and explain how the pcm gets its VSS signal. But looking into yours, the VSS is the rear axle abs sensor of a 2004 ram. The abs controller then shares that info on the bus for the pcm to see.
I have a 2006 srt controller (no c4 connector) and will try with no speed sensor. If i have issues I will deal with them when they pop up. I doubt it will give me any being speed density.
What are you using to reprogram the PCM? I have hp tuners. With that I can program the pcm to ignore missing modules and inputs.

I had previously looked at this thread, though I didn't realize it was yours, as that is one way I had considered going. The Jeep YJ's had years where they had gone from cable to electronic drive speedometers, so I have the option of using a cable driven speedometer with that VSS that you showed, the electronic speedometer here http://www.rockauto.com/catalog/moreinfo.php?pk=40822&cc=1185207&jnid=409&jpid=0 and trying to use the signal for both, or trying to use the VSS signal from the Ford 8.8 http://www.rockauto.com/catalog/moreinfo.php?pk=1268469&cc=1354553&jnid=534&jpid=1 that I replaced the weak Dana 35 with. I'm just not sure if the signals will work together with the PCM or not.

Chas

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Here is a reply from the thread I started over on FABO:

In general, a speed sensor is part of the idle speed control. If the throttle is closed and speed is zero, the PCM regulates idle speed. Idle speed, is not adjusted when coasting, where speed is not zero. If the PCM thinks the speed is zero at coast, idle control cuts back on by pass air attempting to bring engine speed down, but results in stall when coming to stop, due to delay in control to raise speed again, from over speed cut.

If there is a TB bypass air adjustment, it can be set where the minimum idle speed is maintaned, when idle control is at minimum. That will avoid stalling, yet control idle speed for other loading conditions.

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I am using HP Tuners as well, though I am not very experienced with it yet I can enable & disable certain items, remove skim, etc. I would like to go to their training, even though it is for GM's it would give me the general idea of how to adjust parameters, however it is in Vegas on November 1st and I have a family that loves Halloween.

 

[Hemi Rebel]

There is no bypass on a modern hemi. Drive by cable throttle bodies use an idle air control valve. No need on a completely computer controlled t body. I predict if it stalls at all, the pcm will adapt and make corrections.