Hello this is my first post so if I posted this in the wrong place please let me know. I am currently swapping in a gen 4 hemi into a 1999 jeep wrangler. I am near completion on this swap but currently im stuck at a stand still with a either a wiring or pcm issue. None of my relays are actuating and my fuel pump is only getting 4 volts. I have called several shops across the country and have had little help with this. Has anyone ever encountered an issue like this?
Jeep TJ Hemi Swap
- Thread starter Alexander Roten
- Start date
This is a fine place, but the only thing I see so far about this post is not enough pictures. Need some eye candy.
We will need a ton more info before we can begin to help and since this is very custom there may not be a lot of help, but we can sure try.
What PCM are you using? I am guessing the one for the Hemi? What is the voltage supposed to be for the fuel pump? Is it the correct volatge coming out of the PCM and losing it on the way to the fuel pump? Is the wire pinched somewhere? The fact that you don't have voltage to some of the relays. Do you have a good common ground? Is your battery fully charged.
You know things like that? Pictures please! This post is too wordy!
We will need a ton more info before we can begin to help and since this is very custom there may not be a lot of help, but we can sure try.
What PCM are you using? I am guessing the one for the Hemi? What is the voltage supposed to be for the fuel pump? Is it the correct volatge coming out of the PCM and losing it on the way to the fuel pump? Is the wire pinched somewhere? The fact that you don't have voltage to some of the relays. Do you have a good common ground? Is your battery fully charged.
You know things like that? Pictures please! This post is too wordy!
Sorry for the lack of information I will try to include everything now. The engine and PCM came out of a 2012 dodge ram. I had the wiring harness built by Red Rock Industries and the PCM programmed by A2 Speed. The engine is mated to a NV3550. Since Im using the gen 4 hemi instead of the gen 3 I had to install speed hut gauges. The majority of the swap parts are from Red Rock industries which include: Radiator with electric fan, motor mounts, fuel pump conversion, skinny steering, radiator hoses, pedal assembly, cross member, flywheel, starter, and their intake adapter. The jeep started life as a 99 sport with an automatic. This swap also meant changing the transmission over to a 5 speed manual. Every pin from the PCM sends the correct voltage except for one of the wires which Im beginning to believe may be the issue but Im not sure if its from the wiring or the PCM itself. The relays are not cycling and the fuel pump is only receiving 4 volts when it should be 12 volts (I believe its supposed to be 12 but will have to check to make sure). I attached a few of the pictures of the build but will have to go back and get pictures of the voltage readings. I am doing this swap at my brothers diesel shop. He recently completed a 24 valve cummins swap into a jeep CJ7.
Nice pics you made my day. I love the dash!
I am assuming you are right about the 12 volts, but I don't have first hand knowledge of the project you are taking on. I do have some wiring expertise though. It sounds to me like you need to do some wire tracing assuming your battery is not at 4 volts. Also if your relays are not cycling is something unplugged?
I am assuming you are right about the 12 volts, but I don't have first hand knowledge of the project you are taking on. I do have some wiring expertise though. It sounds to me like you need to do some wire tracing assuming your battery is not at 4 volts. Also if your relays are not cycling is something unplugged?
I'm not an electrical guy by any means, so I won't be of much help, but I'm assuming you have the FSM (with the electrical diagrams) for your year of TJ so that you know exactly what wire is what?
I've seen plenty of Chevy V8 swaps, but never a Hemi swap. I have to imagine if anyone here has done one of these swaps it would be @mrblaine or @David Kishpaugh, though even then I'm not 100% sure.
I've seen plenty of Chevy V8 swaps, but never a Hemi swap. I have to imagine if anyone here has done one of these swaps it would be @mrblaine or @David Kishpaugh, though even then I'm not 100% sure.
You might consider calling these guys. They specialize in hemi Jeep swaps.
https://jeepspeedshop.com/
They built this one.
https://sacramento.craigslist.org/cto/d/2004-jeep-wrangler-unlimited/6597467233.html
https://jeepspeedshop.com/
They built this one.
https://sacramento.craigslist.org/cto/d/2004-jeep-wrangler-unlimited/6597467233.html
ScottB
TJ Enthusiast
Get in touch with John at RPM Extreme in Gardendale, AL. These guys are Hemi to Jeep experts. Give them a call.205-631-6768.
rpmextreme.com
rpmextreme.com
Another suggestion is to find a wiring diagram for your year Jeep as Chris suggested. Here’s a couple for a 2004. Not sure if it’s close to what you have or not.
On one of the TV shows they had trouble with their Hemi swap and it turned out the PCM was looking for the SKIM key input which had been deleted from the harness.