Need Cooling Help for Hemi Swap

[Wildman]

Mark at Wranglerfix says he's got the ECM I need!

The Jeep starts, but it's got no cam signal, so it takes a bit of cranking before starting. It's receiving zero signal from the pedal assembly, including having tried a brand new pedal. All grounds have been traced, etc.

The nice thing is he can test it and verify if it is the PCM that's causing your issues or not... That seems like a lot to be going wrong all at once.
I hope you can get it all figured out.

 

[Agar426]

The nice thing is he can test it and verify if it is the PCM that's causing your issues or not... That seems like a lot to be going wrong all at once.
I hope you can get it all figured out.

There were some wires that appeared to be chewed on that go directly to the throttle body. They repaired the wires, but they are thinking the short that occurred might have damaged the ECM. Fingers crossed.....

 

[Wildman]

There were some wires that appeared to be chewed on that go directly to the throttle body. They repaired the wires, but they are thinking the short that occurred might have damaged the ECM. Fingers crossed.....

Damn mice... I had to replace a few engine wiring harnesses on RV's when I worked in a shop due to mice chewing them up.

 

[Agar426]

Damn mice... I had to replace a few engine wiring harnesses on RV's when I worked in a shop due to mice chewing them up.

Exactly! Damn mice.....

 

[Wildman]

Exactly! Damn mice.....

If it's going to be parked for a length of time put pieces of Irish Spring bars of soap on the engine & in the engine bay. Mice don't like the smell of it. There are other rodent repellant options also. But that was a cheap & easy way that I found.
I use shaved off pieces in my motorhome.

 

[Agar426]

If it's going to be parked for a length of time put pieces of Irish Spring bars of soap on the engine & in the engine bay. Mice don't like the smell of it. There are other rodent repellant options also. But that was a cheap & easy way that I found.
I use shaved off pieces in my motorhome.

Great tip, thank you! My plan, if it all goes through, is for this to be my daily, or at least my most of the time rig. My father in law started using peppermint spray. I'll pulse him as to the success of that as well.

 

[NashvilleTJ]

If it's going to be parked for a length of time put pieces of Irish Spring bars of soap on the engine & in the engine bay. Mice don't like the smell of it. There are other rodent repellant options also. But that was a cheap & easy way that I found.
I use shaved off pieces in my motorhome.

Strong enough for a mouse, but I like it too...



(We'll see who gets that reference...)

 

[Agar426]

Update:

Wrangler fix came through with a computer, quickly I might add, and the Jeep is running great! The new cooling setup is spot on so far, all is good with a couple of gremlins, one of which has them stumped.

1. A/C and Cruise - AEV used the little "jumper computer" they developed, which I'll call the "black box" from here on out, to control the cruise control and the A/C. This allowed AEV to use the OEM dash, gauges, switches, etc. I probably have that wrong, but somehow, but suffice it to say the black box makes it so the A/C and Cruise work, which right now......they do not.
2. Temp Sensor - With both ECMs, old and new, the temp sensor isn't reading right. They have swapped out the temp sensor multiple times, and it's just not reading right until it's been driven around, then it settles in. They showed me.....it's hooked up to the computer, and you can see both the temp reading, as well as the associated voltage readings. The temp reading starts out very low, well below zero, when the Jeep is indoors and it's 48* outside. It creeps along, then it spikes, jumping up to around 17*, then it spikes again up to about 60*. From there, it seemed to steadily climb to about 160* on the scanner, as well as the gauge on the dash. During the initial spike to 17* the CEL comes on. The Jeep runs rich until it starts to come up to running temp, then everything settles in nicely, great idle, cooling is working great, etc. Wondering if it's the black box? Something they did to get the OEM integration up to par? I've reached out to AEV, hoping they can shed some light. Thoughts?

 

[Wildman]

Update:

Wrangler fix came through with a computer, quickly I might add, and the Jeep is running great! The new cooling setup is spot on so far, all is good with a couple of gremlins, one of which has them stumped.

1. A/C and Cruise - AEV used the little "jumper computer" they developed, which I'll call the "black box" from here on out, to control the cruise control and the A/C. This allowed AEV to use the OEM dash, gauges, switches, etc. I probably have that wrong, but somehow, but suffice it to say the black box makes it so the A/C and Cruise work, which right now......they do not.
2. Temp Sensor - With both ECMs, old and new, the temp sensor isn't reading right. They have swapped out the temp sensor multiple times, and it's just not reading right until it's been driven around, then it settles in. They showed me.....it's hooked up to the computer, and you can see both the temp reading, as well as the associated voltage readings. The temp reading starts out very low, well below zero, when the Jeep is indoors and it's 48* outside. It creeps along, then it spikes, jumping up to around 17*, then it spikes again up to about 60*. From there, it seemed to steadily climb to about 160* on the scanner, as well as the gauge on the dash. During the initial spike to 17* the CEL comes on. The Jeep runs rich until it starts to come up to running temp, then everything settles in nicely, great idle, cooling is working great, etc. Wondering if it's the black box? Something they did to get the OEM integration up to par? I've reached out to AEV, hoping they can shed some light. Thoughts?

WOW

Fix one thing and another pops up.

OK I'm wondering how Hotwire gets the HVAC & Cruise to work? Because as far as I know they aren't using any type of interface box. @NashvilleTJ can you comment on this?
I'd think that it not running properly until it's getting a correct temp reading. Now as to Why? I'd say you might be correct that it's the black box.

And so since I brought it up I'll suggest a possible conversation with Hotwire and see what they'd need to make you a new wiring harness. I'm guessing that AEV made their own wiring harness? Hate adding more expense to all this.

 

[Agar426]

WOW

Fix one thing and another pops up.

OK I'm wondering how Hotwire gets the HVAC & Cruise to work? Because as far as I know they aren't using any type of interface box. @NashvilleTJ can you comment on this?
I'd think that it not running properly until it's getting a correct temp reading. Now as to Why? I'd say you might be correct that it's the black box.

And so since I brought it up I'll suggest a possible conversation with Hotwire and see what they'd need to make you a new wiring harness. I'm guessing that AEV made their own wiring harness? Hate adding more expense to all this.

I'm all for whatever makes it reliable! To me, everyone talks about more flex, more power, more this, more that. That's all awesome, but none of it is any good if it doesn't start when you turn the key. The most important thing any vehicle can do is run. Right now, the Jeep is running great, but it has to come up to temp before it the temp sensor behaves normally. When it's cold, the temp reading is well below zero. When they showed it to me, it was -11* on the scanner. The gauge on the dash is reading consistently with the sensor output. I live in northern NM, and while I am at 7,400 feet, and it can get cold here, it's 48* outside today, and likely 60* inside the shop. It hasn't been -11* here since probably 2009-ish. Earlier, they were seen temp readings well below that.

 

[Wildman]

I'm all for whatever makes it reliable! To me, everyone talks about more flex, more power, more this, more that. That's all awesome, but none of it is any good if it doesn't start when you turn the key. The most important thing any vehicle can do is run. Right now, the Jeep is running great, but it has to come up to temp before it the temp sensor behaves normally. When it's cold, the temp reading is well below zero. When they showed it to me, it was -11* on the scanner. The gauge on the dash is reading consistently with the sensor output. I live in northern NM, and while I am at 7,400 feet, and it can get cold here, it's 48* outside today, and likely 60* inside the shop. It hasn't been -11* here since probably 2009-ish. Earlier, they were seen temp readings well below that.

I'm of the same persuasion when it comes to my rigs. I don't want to have to fight it.

 

[GoldenGorilla]

Update:

Wrangler fix came through with a computer, quickly I might add, and the Jeep is running great! The new cooling setup is spot on so far, all is good with a couple of gremlins, one of which has them stumped.

1. A/C and Cruise - AEV used the little "jumper computer" they developed, which I'll call the "black box" from here on out, to control the cruise control and the A/C. This allowed AEV to use the OEM dash, gauges, switches, etc. I probably have that wrong, but somehow, but suffice it to say the black box makes it so the A/C and Cruise work, which right now......they do not.
2. Temp Sensor - With both ECMs, old and new, the temp sensor isn't reading right. They have swapped out the temp sensor multiple times, and it's just not reading right until it's been driven around, then it settles in. They showed me.....it's hooked up to the computer, and you can see both the temp reading, as well as the associated voltage readings. The temp reading starts out very low, well below zero, when the Jeep is indoors and it's 48* outside. It creeps along, then it spikes, jumping up to around 17*, then it spikes again up to about 60*. From there, it seemed to steadily climb to about 160* on the scanner, as well as the gauge on the dash. During the initial spike to 17* the CEL comes on. The Jeep runs rich until it starts to come up to running temp, then everything settles in nicely, great idle, cooling is working great, etc. Wondering if it's the black box? Something they did to get the OEM integration up to par? I've reached out to AEV, hoping they can shed some light. Thoughts?

I'm assuming you are talking engine coolant temp, not intake air temp. Both have important impacts to the spark and fuel calculations.

I'm not as comfortable in the NGC3 PCM of the 05/06 TJ as I am on my 04 JTEC+ files, but recently tuned my dad's 06 LJR for him. I don't see anything in that file directly related to fuel that seems related to that temp, but it's not uncommon for these to run in open loop on startup intentionally rich for a little while to get the cats fired up. Once engine temp comes up to operating or a certain time has passed, then the engine will switch over to normal spark timing and closed loop fuel.

No idea why this temp would associate with a CEL. It really sounds like a bad sensor to me, but there are so many other possibilities like wiring harness issues, or voltage or ground issues that could come into play. They don't make a ton sense as possible causes when warmup solves them though.

 

[Wildman]

I'm assuming you are talking engine coolant temp, not intake air temp. Both have important impacts to the spark and fuel calculations.

I'm not as comfortable in the NGC3 PCM of the 05/06 TJ as I am on my 04 JTEC+ files, but recently tuned my dad's 06 LJR for him. I don't see anything in that file directly related to fuel that seems related to that temp, but it's not uncommon for these to run in open loop on startup intentionally rich for a little while to get the cats fired up. Once engine temp comes up to operating or a certain time has passed, then the engine will switch over to normal spark timing and closed loop fuel.

No idea why this temp would associate with a CEL. It really sounds like a bad sensor to me, but there are so many other possibilities like wiring harness issues, or voltage or ground issues that could come into play. They don't make a ton sense as possible causes when warmup solves them though.

From the way he's describing things in the 1st update post it sounds like it's somehow connected to this "black box" that AEV used to make the HVAC & Cruise Control to interface with the PCM. Back when this swap was done I don't think they'd unlocked them yet so they had to make a go between.
https://wranglertjforum.com/threads/need-cooling-help-for-hemi-swap.87649/post-1844027
As far as I know Hotwire doesn't need this but since my TJ is a 97 I don't have CC and my HVAC is the old slider type.
Which is why I suggested he talk with them and see if there is a work around that might help now.

 

[Agar426]

I'm assuming you are talking engine coolant temp, not intake air temp. Both have important impacts to the spark and fuel calculations.

I'm not as comfortable in the NGC3 PCM of the 05/06 TJ as I am on my 04 JTEC+ files, but recently tuned my dad's 06 LJR for him. I don't see anything in that file directly related to fuel that seems related to that temp, but it's not uncommon for these to run in open loop on startup intentionally rich for a little while to get the cats fired up. Once engine temp comes up to operating or a certain time has passed, then the engine will switch over to normal spark timing and closed loop fuel.

No idea why this temp would associate with a CEL. It really sounds like a bad sensor to me, but there are so many other possibilities like wiring harness issues, or voltage or ground issues that could come into play. They don't make a ton sense as possible causes when warmup solves them though.

Correct, the reading is referring to the engine coolant temp. It got up to 48* today, a beautiful late December day. There's no way the coolant temp could have been -11*, but that's what the sensor was saying it was, and it was a brand new sensor. When it's reading that cold, the engine is running rich. The CEL comes on with the first spike in temp reading. Looking at the scanner, it graphs output, and you can see the spike in the graph when it jumped from -11 to 17 degrees. When that spike happened, the CEL came on. The code it's throwing is P2181 "Cooling System Performance." The ECM is from Wrangler fix and is for a 2005 Ram 1500 with 5.7 Hemi. They thought it might be the ECM, so they installed the original ECM, and it was doing the same thing. For some reason, the sensor thinks the coolant temp is way colder than it actually is.

 

[Agar426]

From the way he's describing things in the 1st update post it sounds like it's somehow connected to this "black box" that AEV used to make the HVAC & Cruise Control to interface with the PCM. Back when this swap was done I don't think they'd unlocked them yet so they had to make a go between.
https://wranglertjforum.com/threads/need-cooling-help-for-hemi-swap.87649/post-1844027
As far as I know Hotwire doesn't need this but since my TJ is a 97 I don't have CC and my HVAC is the old slider type.
Which is why I suggested he talk with them and see if there is a work around that might help now.

I heard back from AEV, and there was a good amount of back and forth, with suggestions to check for corrosion in the sensor, broken/damaged wires, etc. I asked about the black box, as I knew it was related to the cruise and A/C, neither of which are currently working, so the odds are high that the black box is not working. The shop disconnected the black box, and it had no effect on the temp sensor reading but it did affect the voltage readings, I'm guessing because the amount of resistance in the system is now different with it unplugged?!? I asked if the black box could be the cause of the temp sensor issue, and they replied with "The box just converted the cruise control from a four button to a five button version so one side of the box is a cruise control button converter, and the other side of the box turns on the air-conditioning system the same way the ram does." They also acknowledged that maybe there is a sensor ground that is shared with multiple sensors, so he suggested unplugging the black box, which the shop had already done, with no change to the temp reading.

 

[Wildman]

Correct, the reading is referring to the engine coolant temp. It got up to 48* today, a beautiful late December day. There's no way the coolant temp could have been -11*, but that's what the sensor was saying it was, and it was a brand new sensor. When it's reading that cold, the engine is running rich. The CEL comes on with the first spike in temp reading. Looking at the scanner, it graphs output, and you can see the spike in the graph when it jumped from -11 to 17 degrees. When that spike happened, the CEL came on. The code it's throwing is P2181 "Cooling System Performance." The ECM is from Wrangler fix and is for a 2005 Ram 1500 with 5.7 Hemi. They thought it might be the ECM, so they installed the original ECM, and it was doing the same thing. For some reason, the sensor thinks the coolant temp is way colder than it actually is.

WOW.... It's cold here at my place but not that damn cold.

I heard back from AEV, and there was a good amount of back and forth, with suggestions to check for corrosion in the sensor, broken/damaged wires, etc. I asked about the black box, as I knew it was related to the cruise and A/C, neither of which are currently working, so the odds are high that the black box is not working. The shop disconnected the black box, and it had no effect on the temp sensor reading but it did affect the voltage readings, I'm guessing because the amount of resistance in the system is now different with it unplugged?!? I asked if the black box could be the cause of the temp sensor issue, and they replied with "The box just converted the cruise control from a four button to a five button version so one side of the box is a cruise control button converter, and the other side of the box turns on the air-conditioning system the same way the ram does." They also acknowledged that maybe there is a sensor ground that is shared with multiple sensors, so he suggested unplugging the black box, which the shop had already done, with no change to the temp reading.

If it was a ground you'd think it would act up all the time but then if it's an intermittent short/connection I'd guess it could connect once it get warm? Short of going back and tracing every wire and doing wiggle tests along the way I don't know how to trace it down.
But then the other option I see is to have a new wiring harness built? I don't know which would be cheaper? Or if it's going to solve your issue either.
One way would be to add some new grounds and temporarily plug them into the harness near the PCM to see if it help?
Maybe add a new wire to the sensor also to see if that helps?

I haven't been able to find a good free PDF of the FSM or wiring diagrams for a Ram so I can't help there.

Again I don't know that it would help any but it might just be worth it to reach out to Hotwire and see if he can help you any.

 

[Agar426]

WOW.... It's cold here at my place but not that damn cold.



If it was a ground you'd think it would act up all the time but then if it's an intermittent short/connection I'd guess it could connect once it get warm? Short of going back and tracing every wire and doing wiggle tests along the way I don't know how to trace it down.
But then the other option I see is to have a new wiring harness built? I don't know which would be cheaper? Or if it's going to solve your issue either.
One way would be to add some new grounds and temporarily plug them into the harness near the PCM to see if it help?
Maybe add a new wire to the sensor also to see if that helps?

I haven't been able to find a good free PDF of the FSM or wiring diagrams for a Ram so I can't help there.

Again I don't know that it would help any but it might just be worth it to reach out to Hotwire and see if he can help you any.

They're my next call!

 

[AjordanH]

Didn’t this Jeep have an electric fan? If so I wonder what kind of fan controller or switch it used and especially what kind of temperature sensor it used. If it is tied into the stock coolant temperature sensor then that could explain the voltage therefore the temperature errors. It may have a resistance to either voltage or ground that is changing the voltage which the PCM is seeing.

 

[Wildman]

They're my next call!

I hope he can help you out...

Didn’t this Jeep have an electric fan? If so I wonder what kind of fan controller or switch it used and especially what kind of temperature sensor it used. If it is tied into the stock coolant temperature sensor then that could explain the voltage therefore the temperature errors. It may have a resistance to either voltage or ground that is changing the voltage which the PCM is seeing.

It did but was swapped out for a mechanical fan if I remember the conversations correctly.

 

[AjordanH]

I thought so but I wonder if the wiring and control is still there. With the same voltage irregularly from 2 sensors it sounds like a wiring issue.