Gr8Dain's 4.0/aw4 swap from a 97 XJ

gr8dain

Scrambler Junkie
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Ashburn
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Think thats the windshield wiper breaker, and i believe its main job is to protect the motor from burning out on those icy days when the wipers are frozen to the windshield and you turn the wipers on (probably not applicable to all forum members! :D)
That is what I am finding from research, but I have a 20amp blade fuse there. I will swap them, but wondering where that one came from. Maybe it was in the rats nest of wires under the dash and fell when I was trying to reattach the plug on the brake switch. Who knows
 

gr8dain

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That’s a breaker, most likely for the headlamp power feed.

I’m about to start building my harness tomorrow...
If it is for the headlights, where would it go? Is it on the fuse panel or connected to wires under the dash somewhere?
 

gr8dain

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Well, I added the trans fluid, oil and coolant. And grounded the wiring harness under the coil bracket so it has a better ground. That seemed to help as now the fuel pump
Is making noises when I put the key to on. I cranked it but no start. Also, my battery is shot. I was using a jumper. I will be getting a new AGM battery tomorrow.

I do not have a wire on my harness to attach to the charge return post on the alternator. Do you guys think I should just run a cable from that post directly to the battery so that the alternator charges the battery?

Oh and while I have the fuel pump sounding like it is getting power, I do not have lights or horn yet. But I tested the horn on the jump box and it works. So it is in the wiring somewhere.

How many times do you think I need to engage the fuel pump before there is enough fuel and pressure in the rail?
 

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tower210

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I'd fix the battery first.....

And then get a code reading tool to see if it's throwing codes (oreily's will let you borrow in their parking lot).

If it persists I'd put a fuel pressure gauge on the fuel rail. I tried using the OE fuel return and the way mine was setup (which was the same as many other 4.0 CJ conversions) didn't like that setup... I was getting like 90 psi. We ran the return fuel line into a catch can and it fired right up (and it fixed the fuel pressure). Eventually we ran a new return line to the tank.

By now I'm wishing I'd have just bought one of the Bosch code tools; works so well. I'm OBD1; so not as good as the OBD2 readers; wish I could have a scan gauge in the jeep.

KK
 

gr8dain

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Ashburn
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I'd fix the battery first.....

And then get a code reading tool to see if it's throwing codes (oreily's will let you borrow in their parking lot).

If it persists I'd put a fuel pressure gauge on the fuel rail. I tried using the OE fuel return and the way mine was setup (which was the same as many other 4.0 CJ conversions) didn't like that setup... I was getting like 90 psi. We ran the return fuel line into a catch can and it fired right up (and it fixed the fuel pressure). Eventually we ran a new return line to the tank.

By now I'm wishing I'd have just bought one of the Bosch code tools; works so well. I'm OBD1; so not as good as the OBD2 readers; wish I could have a scan gauge in the jeep.

KK
Thanks. I have a couple of code readers. And I had a fuel pressure tester on it, but it was showing zero. But I have a plan on the fuel. I can easily pull the lone off the back and run it into a fresh tank of gas and see if it pick up any fuel or not. I had not thought of the return. I will keep that in mind as well.
 

gr8dain

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So I went out to the driveway this morning to rake the trash out and was greeted to a lot of coolant on the ground. Opened the hood and saw it collected on the bottom of the radiator. Then opened the door to see why it was pooling under the passenger seat area of the Jeep. It is running down from the lines feeding the heater core. Grr. Hopefully that is just a matter of loose hoses there. Not sure about the radiator itself. It was not leaking before I took it off. But it may have been damaged living in the garage for a year. We will see. Just not happy about it.
 

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gr8dain

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I tightened the hose clamps for the heater core and the radiator. They seemed pretty tight, but who knows. Moved on to other things.

I got a couple of little things done before the rains started. I was able to drain the gas tank using a hand pump. It looks like around 9 gallons came out. The gauge read 1/8 tank. I guess the sending unit does not go all of the way down. The I installed the new AGM battery. Then replaced the plug for the VSS (speed sensor) on the t-case to work with the sensor I am using. It handles the mechanical speedo gauge as well as sending the signal to the ecu.

Ignore the wiring in the pic of the battery. I have not finished stuff so a lot is still just laying around.
 

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gr8dain

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So I am trying to see why the Scrambler won’t start. So I went to check to see if fuel was making it to the rail. Gauge says Zero pressure. Ok. Separate the pump from the filter/regulator and fuel sprays out at that connection. No fuel coming out of the filter. Hmmm. Run a bypass hose and now I have pressure at the rail. Without the regulator I have too much. But I now know I have fuel making it.

How to tell if the fuel filter is bad? It is brand new. But whatever. Are you supposed to be able to blow through it? Because I am not getting any air through it. It is like blowing into a solid dowel rather than a tube. This is for a 2001 Grand Cherokee by the way.
 

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gr8dain

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Will the computer keep the Jeep from starting if the fuel pressure is too high? Or will I be chasing a spark issue as well?
 

gr8dain

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Ugh. Never mind. My mistake. I had the supply and return lines on the wrong ports. Switched them and now my fuel makes it and is at a good pressure. Now on to test spark
 

gr8dain

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Still not running. And I have a few codes. I know I do not have an O2 sensor hooked up yet. And maybe my TPS is bad. I am reusing the one from the donor, I think.

I think I have a ground issue still since I do not have lights or horn either. I will play around more tomorrow if the weather is decent again.
 

jims chop shop

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Think thats the windshield wiper breaker, and i believe its main job is to protect the motor from burning out on those icy days when the wipers are frozen to the windshield and you turn the wipers on (probably not applicable to all forum members! :D)
That’s what’s in mine, and in Several of my other spare fuse panel’s
 

tower210

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Olathe
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Still not running. And I have a few codes. I know I do not have an O2 sensor hooked up yet. And maybe my TPS is bad. I am reusing the one from the donor, I think.

I think I have a ground issue still since I do not have lights or horn either. I will play around more tomorrow if the weather is decent again.
I think if you don't have an O2 it won't run...... It wants to closed loop fuel; with no O2 sensor thats impossible... I might be wrong
 

gr8dain

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I think if you don't have an O2 it won't run...... It wants to closed loop fuel; with no O2 sensor thats impossible... I might be wrong
Interesting. That is not what I was told. I was hoping to have it running before doing the exhaust work.
 

gr8dain

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As for an update, it is cold and rainy. And year end close is taking all of my time. But I ordered a bus bar and got some wiring to help clean up the battery wiring. And got a cable to run from the starter to the alternator. Hoping to be able to do that and some “ground work” when the weather is better and I get a few minutes.
 

93_Fummins

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Edmond
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OK
I think if you don't have an O2 it won't run...... It wants to closed loop fuel; with no O2 sensor thats impossible... I might be wrong
Typically it should still run in open loop....it'll just run very poorly because the logic assumes "warm up" parameters until it registers the O2 reading and goes closed loop. However, there may be a ground reading to determine no sensor versus faulty sensor...I'm not sure....but in that case its very possibly that it would not run at all with an empty plug.
 

gr8dain

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Typically it should still run in open loop....it'll just run very poorly because the logic assumes "warm up" parameters until it registers the O2 reading and goes closed loop. However, there may be a ground reading to determine no sensor versus faulty sensor...I'm not sure....but in that case its very possibly that it would not run at all with an empty plug.
Well, I will find out more once I don’t have to work until midnight every day and can get out there and tidy up the wiring. And I will do a little research on that issue. I was told it will run without them, but I will validate that.
 

tower210

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Olathe
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Well, I will find out more once I don’t have to work until midnight every day and can get out there and tidy up the wiring. And I will do a little research on that issue. I was told it will run without them, but I will validate that.
Worst case get one and plug it in. I'm sure it will run open loop (badly) for a bit. You have hear that you want to buy the OEM brand for the 4.0 O2 sensors. Lots of people have had issues with Bosch and others...
 
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