2007 5.7 Hemi in 73 Plymouth Duster (pedal cuts out)

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Thaddeus

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Hello,

I recently put a 2007 Chrysler Aspen 5.7 Hemi in my 73 Plymouth Duster, with a Durango 545 RFE transmission (4x4 but running it as RWD only), 8 3/4 rear end. It has the Digital instrument cluster outta the Aspen, and a fly by wire pedal.
Ive had an issue for months that I cant seem to solve.
When Im holding constant acceleration at higher speeds my accelerator pedal cuts off, and I can no longer accelerate (total loss of pedal). Its also not giving me a speed reading. The only way to get it working again is by turning car off, then back on. If Im driving the car and only gas it for a few seconds at a time I can normally avoid this issue (no constant acceleration).

*I have tried 2 new accelerator pedals, changed transmission speed sensor, and made a whole new wire harness. I still have the issue.

I was told that this issue could be caused by the fact I dont have the ABS hooked up in the vehicle. That I also need the speed sensors off the ABS system.

Has anyone had this issue? Or might know whats going on? Thank you!
 
Last edited by a moderator:
Thaddeus said:
Hello,

I recently put a 2007 Chrysler Aspen 5.7 Hemi in my 73 Plymouth Duster, with a Durango 545 RFE transmission (4x4 but running it as RWD only), 8 3/4 rear end. It has the Digital instrument cluster outta the Aspen, and a fly by wire pedal.
Ive had an issue for months that I cant seem to
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You will need to continue your question. You posted in how-to articles which is the wrong location. Thanks
 
Thaddeus said:
Hello,

I recently put a 2007 Chrysler Aspen 5.7 Hemi in my 73 Plymouth Duster, with a Durango 545 RFE transmission (4x4 but running it as RWD only), 8 3/4 rear end. It has the Digital instrument cluster outta the Aspen, and a fly by wire pedal.
Ive had an issue for months that I cant seem to solve.
When Im holding constant acceleration at higher speeds my accelerator pedal cuts off, and I can no longer accelerate (total loss of pedal). Its also not giving me a speed reading. The only way to get it working again is by turning car off, then back on. If Im driving the car and only gas it for a few seconds at a time I can normally avoid this issue (no constant acceleration).

*I have tried 2 new accelerator pedals, changed transmission speed sensor, and made a whole new wire harness. I still have the issue.

I was told that this issue could be caused by the fact I dont have the ABS hooked up in the vehicle. That I also need the speed sensors off the ABS system.

Has anyone had this issue? Or might know whats going on? Thank you!
Click to expand...
You should have the OBD conector in that harness scan it with a scan tool post the codes , normally if it sees gas and brake signals at the same time is one issue ?
 
Biff said:
You should have the OBD conector in that harness scan it with a scan tool post the codes , normally if it sees gas and brake signals at the same time is one issue ?
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Thank you. Yea I only noticed that its not getting a vehicle speed reading, and app 2 bleeps out. app 1 reads fine
 
Thaddeus said:
Thank you. Yea I only noticed that its not getting a vehicle speed reading, and app 2 bleeps out. app 1 reads fine
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Yup needs to see app 1&2 . If your friends with an auto wrecker they may lend you one to try .
 
Did you figure your problem out. Sounds like it’s going into limp mode. Mine has done this a few times over the years. Not figured it out.
 
loganscuda said:
Did you figure your problem out. Sounds like it’s going into limp mode. Mine has done this a few times over the years. Not figured it out.
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not yet but I have a plan Im gonna try. Im gonna route in a SGI-100 and a Rostra. going to steel the speed signal off the output speed sensor so it gets a reading
 
Thaddeus said:
not yet but I have a plan Im gonna try. Im gonna route in a SGI-100 and a Rostra. going to steel the speed signal off the output speed sensor so it gets a reading
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Did your plan work? I’m having the same issue and need a solution. Wondering if the Ford 8.8 sensor will work.
 
It’s an abs thing I’m reading up on it else where and will link later one of the speed inputs comes from the abs wheel speed I think it was, it may require a modified signal? Haven’t completely got it but I know it only happens to me when I give it all the beans, I have a video of a beautiful burnout but feather on and off the pedal and it’s drivable but I step on it she launches then dead pedals me.
 
What ECU are you using. And what harness do you have. If you are using an 07 ECU that may be your problem. Did you use the factory harness?
 
I have 04 5.7 with 545rfe and an 05 ECU. I don’t use any ABS outputs. My harness I got from Hotwire. You may call and ask them what the bypass pin is.
 
Swap specialties harness worst harness ever!!!! I wouldn’t even be surprised if I had more wiring issues but I think I checked all the trans and sensor wires for speed so idk? Blake from diy hemi says maybe I have a short? Maybe in the pedal? I am using a 05 hemi 5.7 545 rfe 05 computer but ecu was 4x4 so I think it had extra wheel speed input but said it was all the same when I got information from what I thought were credible sources
 
5F300A92-380B-46F5-8E18-3991A56E1999.png
DD497C1E-F8F5-4578-87D4-8726F0E85C86.png
 
I used a Speedhut GPS Speedo gauge. So I can’t help with that. Just throwing this out there, have you cleaned the throttle body. I know it will cause some crazy stuff to happen. My son just had that problem where it would go into limp mode on his 2015 Ram. I told him to clean the throttle body and it fixed his fault.
 
Also did you do a learn on your pedal. Disconnect battery reconnect hold pedal down and turn key to on. Not start. Then let off and turn to start
 
You actually got a harness from swap specialties? I've lost all hope getting my OEM 05 harness and PCM back from them. I was helping them make a swap harness years ago but they ghosted and never sent me back my property.

Also they never had a harness that worked correctly. WE were close but they always had issues.

Riddler
 
Riddler said:
You actually got a harness from swap specialties? I've lost all hope getting my OEM 05 harness and PCM back from them. I was helping them make a swap harness years ago but they ghosted and never sent me back my property.

Also they never had a harness that worked correctly. WE were close but they always had issues.

Riddler
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Yes they have many many issues the same, Andy has scammed many out of stock harnesses and ecu’s sorry to hear that, I worked my *** off so been driving as is but soon going back into the project stage so I can complete and compete the car in time attack tracks and local car shows. Seems like we combined are better than any tuner in California or performance shh hbu op for that matter too, so again I turn to you all..
 
Bump I’ve gotten further into tuning on another one of my cars are am going to explore some pedal tunes and look for some apps 2 info and finally solve this, if @loganscuda would help me with a pin confirmation I’ll dig out some pin out info
 
C1
Pin 8 vehicle speed signal #2
Pin 13 vehicle speed signal #1

C2
Pin 15 tp sensor return
Pin 21 tp #1 signal
Pin 23 map signal
Pin 28 tp #2 signal


c3

Pin5 speed control vac vent sol
Pin 7 speed control supply
Pin 12 speed control vac sol
Pin 14 brake switch #2 signal
Pin 15 speed control switch return
Pin 16 apps 1 return
Pin 17 apps 2 return
Pin 18 speed control switch signal #2
Pin 23 brake switch #1
Pin 25 apps #1 signal
Pin 34 speed control switch signal #1
Pin 36 apps #2 signal

C4 has a lot of the trans stuff lemme sort thru
 
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I’m not with the car I gotta scan it and update for the 4th pin on ecu too

I’m really trying to make pulls with his car so I wanna be able to slam that pedal

I know that my hp tuners doesnt catch my mph
 
I can't help much with this but keep in mind it might be a shielding/ RFI/ EMI issue and or improper grounded/ ground loop. You have completely changed the system (and harness) from OEM, even though (I guess) you are using the OEM system components.
 
67Dart273 said:
I can't help much with this but keep in mind it might be a shielding/ RFI/ EMI issue and or improper grounded/ ground loop. You have completely changed the system (and harness) from OEM, even though (I guess) you are using the OEM system components.
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Issue only presents itself in gear, in park I get full pedal.
 
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