No vehicle speed on IQuad

[martinique78]

I just finished up my Fummins swap on my 2004 Excursion v10 gasser.  I installed a 2001 24V along with the 47RE transmission being controlled by the Dodge PCM.  I installed all the required wiring and the truck runs and shifts fine however I dont have MPH on my Quadzilla iQuad display.  Does the iQuad get the vehicle speed from the cluster that is no longer attached or does it get it from the transmission speed sensor?

 

In the beginning i couldn't get the trans to shift. I started poking around on the trans harness and found that one of the wires going to the transmission speed sensor was cut.  I repaired that and now the trans shifts like it should however I'm still not getting a MPH signal to the iquad.  

 

I'm running V2 base tunes on my Adrenaline.

[Mopar1973Man]

Speed is reported by the Dodge ABS computer not the the PCM. You would have to setup the Dodge ABS computer just to get speed. The speed sensor in the transmission is only for shifting not road speed. Be aware this will make the grid heater run longer than normal since there is no speed signal there is no way to cancel at road speed.

Edited May 9, 2017 by Mopar1973Man

[Me78569]

Exactly,  no Dodge ABS computer = no Iquad MPH reading.

[martinique78]

Ok, that makes sense.  I'm not worried about not having it on the iQuad, i just wanted to make sure nothing else was wrong.

 

Is it a big deal to have the grid heater run longer at road speeds?  Only thing I could see it affecting is a draw on the electrical system for longer.

[Me78569]

The only thing you won't get without MPH is cruise state timing.  not a huge deal as you can just make your rpm timing curve work for that as well.  

 

How long as you talking about?

[martinique78]

I'm not asking to keep it on longer, I'm just wondering how long will it stay on with no road speed canceling and will it have any negative impact?

[Me78569]

until temps come up.  I wouldn't think it's a good for the system the grid heaters draw a TON of amps.  

 

might need to wiret the relay into a switch on the dash or something.

[Mopar1973Man]

It will throw codes if you wire in switch for the relay.

[Me78569]

dunno if he cares.  

[martinique78]

I don't have a check engine light for my setup so no worries on it throwing codes.

 

another question is does the pcm use the vss from the abs for torque converter lock up as well?  I was on the freeway today for the first time and the converter didn't lock up once on my 30 mile drive.

[Me78569]

Does the PCM see your brake pedal switch?

 

I am pretty darn sure the pcm looks at the trans speed sensor for lockup.  I might be able ot test that for you at some point when things slow down.

[martinique78]

I still have to bring that wire inside the truck.  I'm pretty sure the brake pedal switch is a negative trigger while the ford is a positive trigger so i'll have to install a relay to get the proper ground trigger for it.

[martinique78]

I noticed that the VSS comes from the ABS unit only because that's where the speed sensor on the rear diff goes to.  I'm wondering if I can tap off the VSS on the rear diff of my ford and tie it into the VSS in wire on the PCM and everything will work like it did on the dodge.

[Me78569]

Break pedal sense and speed is needed for the TC to lockup.

[martinique78]

Ok.  I've looked at a couple of electrical diagrams and some are conflicting.  One shows the brake sense being connected to ground when the pedal is depressed and others show it being connected to ground when the pedal is not depressed.  I'm guessing its supposed to be grounded when the pedal is not depressed because not having the wire hooked up at all would be the same as open from the ground connection and i'm not getting lockup.

 

When you say speed your talking about transmission speed right? not speed from the ABS computer?

[Me78569]

 

 

yep talking the side of the trans

[martinique78]

Thanks for the link, wish i had found that earlier.  Looking at it however shows the same contradiction i've been talking about.

 

Look ant the brake switch on ABS system page, it shows pin 1 open to pin 2.

 

Look at Automatic transmission system page 1, it shows pin 1 closed to pin 2.

 

Both have the same white/pink wire so it's not two different switches.

 

Are these diagrams just showing it this way cause the ABS is looking for an open signal and the trans is looking for a closed signal?  Sorry for all the questions, I really appreciate all your help.

[martinique78]

I got my brake switch sense connected so that when the brake is not depressed the sense wire is connected to ground.  Still no lockup according to the iquad display.  I haven't had a chance to check the AC voltage from my alternator yet but its next on my list of things to check.

[Mopar1973Man]

On 5/11/2017 at 0:22 PM, martinique78 said:

Thanks for the link, wish i had found that earlier.  Looking at it however shows the same contradiction i've been talking about.

 

Look ant the brake switch on ABS system page, it shows pin 1 open to pin 2.

 

Look at Automatic transmission system page 1, it shows pin 1 closed to pin 2.

 

Both have the same white/pink wire so it's not two different switches.

 

Are these diagrams just showing it this way cause the ABS is looking for an open signal and the trans is looking for a closed signal?  Sorry for all the questions, I really appreciate all your help.

 

 

I'm going to assume that like typically applied brakes should be grounded. 

[martinique78]

So youre saying i should switch it to when the brakes are applied its grounded and when they are not it's open?