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Complete yj swap


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2 hours ago, Eagle said:

 

No, I'm suggesting exactly the opposite. I'm suggesting using the '92 YJ engine harness to run the engine, and leaving everything else alone. If Chrysler can separate out the HO engine harness and sell it as an aftermarket upgrade for the 4.2L, there's no reason why you can't use it as a stand-alone. I just don't understand why you seem to be fixated on messing with wiring that isn't part of the engine harness.

 

"If it ain't broke ... don't fix it."

That's what I'm saying. Or like I said maybe I'm overthinking it. So lets make this simple. If I use yj engine harness and the original mj dash harness. And plug them together at the bulkhead everything will be fine? I'm just getting mixed responses on all of this hence why I'm trying to simplify it and save myself a headache. Only thing at the point I won't have would be the guages then correct? And then down the line I get a h.o xj dash harness and guages everything will be good?

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1 hour ago, Jeeperscreeper said:

That's what I'm saying. Or like I said maybe I'm overthinking it. So lets make this simple. If I use yj engine harness and the original mj dash harness. And plug them together at the bulkhead everything will be fine? I'm just getting mixed responses on all of this hence why I'm trying to simplify it and save myself a headache. Only thing at the point I won't have would be the guages then correct? And then down the line I get a h.o xj dash harness and guages everything will be good?


 

the bulkhead connector provides very little to actually run the engine. Unless you are very comfortable with electrical, just leave the bulkhead alone and for that matter all your MJ wiring. You need the engine harness only. It is bundled with all sorts of other wiring from the YJ. Look at a pinout for that bulkhead connector. You will see that it doesn’t really run anything engine-wise. The ecu needs very little from that bulkhead connector to run the engine. What it needs are those 5 wires (sometimes even less depending on how far you strip down the harness). I’ve stripped these harnesses down several times now for engine swaps and it’s pretty simple now but the first time it was a daunting task when you are looking at all those wires. Another option is just grab a Howell/fitech/sniper tbi setup and install a regular distributor (like an hei from dui). That is about as stand alone as it gets. Just provide power and fuel.

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1 hour ago, Jeeperscreeper said:

That's what I'm saying. Or like I said maybe I'm overthinking it. So lets make this simple. If I use yj engine harness and the original mj dash harness. And plug them together at the bulkhead everything will be fine?

 

Plug what together?

 

Do you understand what "stand-alone" means? You do NOT need to connect the YJ engine harness to anything at the firewall (what you call the "bulkhead"). The '92 computer mounts on the inside of the driver's side fender, under the hood.

 

And then down the line I get a h.o xj dash harness and guages everything will be good?

 

Why would you want to get an HO dash harness for a Renix vehicle? If you do that, your fuel gauge will read backwards. Leave the dash harness alone.

 

"If it ain't broke ... don't fix it."

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3 hours ago, Eagle said:

 

No, I'm suggesting exactly the opposite. I'm suggesting using the '92 YJ engine harness to run the engine, and leaving everything else alone. If Chrysler can separate out the HO engine harness and sell it as an aftermarket upgrade for the 4.2L, there's no reason why you can't use it as a stand-alone. I just don't understand why you seem to be fixated on messing with wiring that isn't part of the engine harness.

 

"If it ain't broke ... don't fix it."


exactly, the Chrysler MPI kit did not even connect to the bulkhead connector. Here are the install instructions for that kit: https://www.quadratec.com/sites/default/files/installation_instructions/2688.pdf

 

since you are swapping in an HO 4.0 there is no need to mess with the alternator regulation. Just let the ecu handle the regulation like it always does on the 4.0. Alternatively, you can get an external regulator which is what I’ve installed when running high output alternators.

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9 minutes ago, Eagle said:

 

Plug what together?

 

Do you understand what "stand-alone" means? You do NOT need to connect the YJ engine harness to anything at the firewall (what you call the "bulkhead"). The '92 computer mounts on the inside of the driver's side fender, under the hood.

 

 

 

 

Why would you want to get an HO dash harness for a Renix vehicle? If you do that, your fuel gauge will read backwards. Leave the dash harness alone.

 

"If it ain't broke ... don't fix it."

It's not a renix vehicle anymore that it's h.o. and I want to rid the dummy lights and have actual guages. For temp and oil and gas mainly. A speedo too. I understand that I can make the motor run simple. I guess I'm just not understand. I get what stand alone is. I guess I'm just not understanding if it's stand alone how would I run power to the fusebox. That's what I'm calling the bulkhead. When the engine harness 'enters the cab'

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I know this can all be very confusing. If you study all you wiring diagrams and pinouts carefully you can make it work. The engine harness does not actually enter the cab, it just appears that it does. As for gauges, you will be in for a major headache if you want to swap over the entire HO harness including gauges. I am speaking from personal experience here. As for the relay box, if you notice in the instructions for the Mopar kit you will see that it only has a couple of separate trays mounted to the firewall. It does not utilize the pdc.

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For gauges, if you must have updated ones, you can grab a gauge cluster from an HO XJ along with the connector for it and just splice them into your harness. You will need to replace the vss on your transfer case to the later style so you can run the new electric speedo.

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11 minutes ago, ghetdjc320 said:

I know this can all be very confusing. If you study all you wiring diagrams and pinouts carefully you can make it work. The engine harness does not actually enter the cab, it just appears that it does. As for gauges, you will be in for a major headache if you want to swap over the entire HO harness including gauges. I am speaking from personal experience here. As for the relay box, if you notice in the instructions for the Mopar kit you will see that it only has a couple of separate trays mounted to the firewall. It does not utilize the pdc.

So simpy use the yj engine harness and mj dash harness and all will be well. But I won't have the sender for oil and temp and no speedo the yj is electric speedo

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1 hour ago, Jeeperscreeper said:

It's not a renix vehicle anymore that it's h.o. and I want to rid the dummy lights and have actual guages. For temp and oil and gas mainly. A speedo too. I understand that I can make the motor run simple. I guess I'm just not understand. I get what stand alone is. I guess I'm just not understanding if it's stand alone how would I run power to the fusebox. That's what I'm calling the bulkhead. When the engine harness 'enters the cab'

 

You can get a gauge cluster with full gauges and a tachometer from a 1984 through 1990 Cherokee and it's plug-and-play with the MJ chassis harness. Your '92 engine should still have a temperature sender on the back corner of the head -- that feeds the temp gauge. The oil pressure sender is a no brainer. And the fuel gauge in a Renix cluster will read correctly, whereas if you pop in an HO cluster the gauge will read full when the tank is empty, and it will read empty when the tank is full. Plus -- an HO cluster has an electronic speedometer, so then you have to deal with wiring that up.

 

The engine harness doesn't enter the cab with an HO system. The ECU is under the hood.

 

You're making a simple job much more complicated than it needs to be.

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59 minutes ago, Jeeperscreeper said:

So simpy use the yj engine harness and mj dash harness and all will be well. But I won't have the sender for oil and temp and no speedo the yj is electric speedo


Use a vss from a 1991 yj. It has both the electrical out for the ecu and a cable drive for your speedometer. 

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9 minutes ago, Eagle said:

 

You can get a gauge cluster with full gauges and a tachometer from a 1984 through 1990 Cherokee and it's plug-and-play with the MJ chassis harness. Your '92 engine should still have a temperature sender on the back corner of the head -- that feeds the temp gauge. The oil pressure sender is a no brainer. And the fuel gauge in a Renix cluster will read correctly, whereas if you pop in an HO cluster the gauge will read full when the tank is empty, and it will read empty when the tank is full. Plus -- an HO cluster has an electronic speedometer, so then you have to deal with wiring that up.

 

The engine harness doesn't enter the cab with an HO system. The ECU is under the hood.

 

You're making a simple job much more complicated than it needs to be.


it is a simple swap once you do it. It may be difficult to wrap your head around it the first time. Let us know if you need help with specific items

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5 minutes ago, ghetdjc320 said:


Use a vss from a 1991 yj. It has both the electrical out for the ecu and a cable drive for your speedometer. 

Like this.

 

I ran the MOPAR 1994 4.0HO conversion kit on a 1991 XJ motor installed in my 83 CJ7 for over 10 years.

IMG_2622.jpg

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11 minutes ago, schardein said:

Like this.

 

I ran the MOPAR 1994 4.0HO conversion kit on a 1991 XJ motor installed in my 83 CJ7 for over 10 years.

IMG_2622.jpg

That’s it! 92 was the year the yj switched to an electric speedo. You will need to provide the ecu with the speed signal from this sender otherwise it will try to stall when you come to a stop.

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42 minutes ago, Jeeperscreeper said:

Ok so make a stand alone. And use the dash mj harness and only thing I won't have is gauges till I can get xj h.o dash harness and guages. I can live without for a bit on guages but need heat because winter is upon us.

 

YOU DO NOT NEED AN H.O. DASH HARNESS! How many times do we have to tell you this?

 

Your existing harness has a connector for the temperature sender in the back corner of head. That's what feeds the temperature gauge on the dashboard. The temp sender in the thermostst housing feeds the ECU.

 

Your existing harness has a connector for the oil pressure sensor. Your '92 engine has an oil pressure sensor. Put the wire on the sensor and you get an oil pressure reading. Use a gauge cluster from a 1990 or older Cherokee. If you use a cluster from a 1991 or newer XJ, the gas gauge will read backwards.

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1 hour ago, Eagle said:

 

YOU DO NOT NEED AN H.O. DASH HARNESS! How many times do we have to tell you this?

 

Your existing harness has a connector for the temperature sender in the back corner of head. That's what feeds the temperature gauge on the dashboard. The temp sender in the thermostst housing feeds the ECU.

 

Your existing harness has a connector for the oil pressure sensor. Your '92 engine has an oil pressure sensor. Put the wire on the sensor and you get an oil pressure reading. Use a gauge cluster from a 1990 or older Cherokee. If you use a cluster from a 1991 or newer XJ, the gas gauge will read backwards.

Well sir. Noone has explain the the idiot light cluster and the real guage cluster are plug and play. And everything I have seen they are not plug and play without the correct senders

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3 hours ago, Jeeperscreeper said:

Well sir. Noone has explain the the idiot light cluster and the real guage cluster are plug and play. And everything I have seen they are not plug and play without the correct senders

 

2 hours ago, Pete M said:

the clusters are indeed plug-n-play with the caveat that you need to swap out the temp and oil pressure switches with their appropriate sensor counterparts. :L:   

 

 

Yes, Pete is right. Just swap in the appropriate sensors. There are two versions of most switches, one is for a light and the other for the gauge. 

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25 minutes ago, ghetdjc320 said:

 

 

 

Yes, Pete is right. Just swap in the appropriate sensors. There are two versions of most switches, one is for a light and the other for the gauge. 

Ok. Are plugs the same? Say I left that on the yj engine harness and got the correct sensors and plugged them to the yj harness that would work?

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7 hours ago, Jeeperscreeper said:

Well sir. Noone has explain the the idiot light cluster and the real guage cluster are plug and play. And everything I have seen they are not plug and play without the correct senders

 

You didn't ask. You started off insisting that you need an HO cluster, and that you need an XJ HO under=dash harness.

 

Did the YJ have gauges? If so, the engine already has the correct sensors for the gauges.

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