Gr8Dain's 4.0/aw4 swap from a 97 XJ

[gr8dain]

Last night I picked up an ECM to test out to see if the problem stays or not. Too bad it was snowing. Hopefully I will get to test it out soon. I also bought an O2 sensor to plug in (still no headpipe yet) and a new upper radiator hose. I do not like the bend this one has in it.

 

[gr8dain]

So after talking to @jims chop shop he thinks it may be a bad ignition switch since it shows 12v in on position, then drops to nothing at start and back to 12v when I release and back to on. If so, that will be good and mean the computer is fine. Now to drop the steering column to get to it and see what condition it is in. I probably did something when I swapped the pedal boxes. And I need to get in there anyway to adjust the old brake light switch and add the new one anyway. But I hate getting to the stuff under the dash. Not comfortable at all.

 

[bigwalton]

So after talking to @jims chop shop he thinks it may be a bad ignition switch since it shows 12v in on position, then drops to nothing at start and back to 12v when I release and back to on. If so, that will be good and mean the computer is fine. Now to drop the steering column to get to it and see what condition it is in. I probably did something when I swapped the pedal boxes. And I need to get in there anyway to adjust the old brake light switch and add the new one anyway. But I hate getting to the stuff under the dash. Not comfortable at all.

Glad you got that much figured out.

Just take the time to pull the driver's seat out. You have enough going on in there it's worth the time.

 

[gr8dain]

Glad you got that much figured out.

Just take the time to pull the driver's seat out. You have enough going on in there it's worth the time.

I know I should. But I am also lazy enough to make my life miserable. Haha. Thanks for the reminder. It is only 4 bolts

 

[bigwalton]

I know I should. But I am also lazy enough to make my life miserable. Haha. Thanks for the reminder. It is only 4 bolts

of all the times I’ve been under there, I only pulled the seat once and should have every time

 

[Belizeit]

And add a blanket or towel for padding. I hate laying up under there.

 

[gr8dain]

Well I went through the fun of replacing the ignition switch. While there I adjusted the brake pedal switch to try and get the button to make contact with the pedal. And after all of that, it did not solve my problem. Grrrr.

So I swapped in the other ECM I have and still nothing.

The only way to get the Jeep to start is to bypass the ASD relay. Back to the drawing board.

 

[bigwalton]

Well I went through the fun of replacing the ignition switch. While there I adjusted the brake pedal switch to try and get the button to make contact with the pedal. And after all of that, it did not solve my problem. Grrrr.

So I swapped in the other ECM I have and still nothing.

The only way to get the Jeep to start is to bypass the ASD relay. Back to the drawing board.

Does the engine start normally now with the new switch when you have the relay bypassed? No more "partway to run" start?

 

[gr8dain]

Ugh. So today is not going so well. As stated above, no luck in getting it to start without using the jumper wire. But I decided to keep plugging away and found my old temp sensor I was using on the 258. Pulled out the new one and i stalled this one. I let it idle and get up to temp. Reads perfectly. So it stays.

Now the bad news. After it warmed up and let the thermostat open, I discovered that my radiator is misting from the fins. Grrrr. I guess it got banged up sitting around the garage. New radiator will need to be ordered.

And when I went to out the plastic cover around the steering wheel opening in the dash, it broke into 2 pieces. I guess it is too cold. Dang it. Not my day today.

 

[FLCJ8]

I put the computer on the drivers fender...

The only way to get the Jeep to start is to bypass the ASD relay. Back to the drawing board.

When you mounted the PCM on the fender did you assure a good ground to the case?

I'm not sure of the '97 (no reason to think it would be different) but the '03's require a good ground connection of the mounting tab to the STEEL tub.
The proper sensor inputs to the PCM is what ultimately causes it to signal the ASD to close and provide 12v power to the coil, injectors, and O2 sensor heaters.
The signal from the PCM to the ASD relay is GROUND (-12vdc)

If by jumpering you mean the comm. to N.O. of the ASD relay you are bypassing the coil power.

Have you tried jumpering ground to negative terminal of the ASD relay?
This would let you know if the relay is functioning.

Also, if you remove the ASD relay and jumper to run the engine you could check from +12vdc to the grd terminal port for the relay to see if it is present.

Sorry if some or all of this has been already addressed... I'm just trying to help, I feel your frustration.

 

[gr8dain]

When you mounted the PCM on the fender did you assure a good ground to the case?

I'm not sure of the '97 (no reason to think it would be different) but the '03's require a good ground connection of the mounting tab to the STEEL tub.
The proper sensor inputs to the PCM is what ultimately causes it to signal the ASD to close and provide 12v power to the coil, injectors, and O2 sensor heaters.
The signal from the PCM to the ASD relay is GROUND (-12vdc)

If by jumpering you mean the comm. to N.O. of the ASD relay you are bypassing the coil power.

Have you tried jumpering ground to negative terminal of the ASD relay?
This would let you know if the relay is functioning.

Also, if you remove the ASD relay and jumper to run the engine you could check from +12vdc to the grd terminal port for the relay to see if it is present.

Sorry if some or all of this has been already addressed... I'm just trying to help, I feel your frustration.

I honestly need Eric’s help here. I did run a dedicated ground from the neg bus bar to a ring terminal that is around the bolt between the fender and the back of the ECM and I validated that it has good continuity.

By jumping, I have pulled the ASD relay out and run a jumper wire from the 30 pin socket to the 87 pin socket. Eric and I ran a bunch of tests of volts and continuity on various sockets for the relay. But right now my mind is a mess trying to remember all that we did.

If my fuel pump is getting power through the circuit, would that confirm that I am getting a god ground? If it can ground the pump circuit, it should be able to ground the ASD, right?

And I appreciate the help. It sucks trying to do this over the internet. So no worries about saying something that I/we have already tried.

I am going to see about getting Hotwire (the guy that built it) on the phone and walk him through it all. I have been emailing, but a call will be better.

With a snow storm coming Sunday into Monday, and my radiator and drive shafts showing up early next week, I have some things to keep me busy. Maybe I will take the grill apart tomorrow and put it in the garage so that I can remove the old radiator and install the new one in the garage while there is snow on the Jeep.

 

[FLCJ8]

If my fuel pump is getting power through the circuit, would that confirm that I am getting a god ground? If it can ground the pump circuit, it should be able to ground the ASD, right?

The grounds for the fuel pump and the ASD are spliced in different locations, (of course they do eventually connect to battery ground)

I recommend doing these tests while the engine is running since some PCM's shut down the power if the the engine sensors don't get the expected signal in a certain amount of time.

Confirm pin socket 86 (+12vdc) to battery ground is ~12 vdc
(I believe this is the same circuit as the fuel pump relay, so it should be hot)

Check pin socket 85 (-12 vdc switched) to battery + 12vdc. You want to see battery voltage between these two leads.
This is what is supposed to energize the coil of the ASD relay.

On or the other is open (assuming the relay tested good)

Depending on the results of the tests it is just a matter of determining where the open or high resistance connection is.

 

[gr8dain]

Since my radiator sprung a leak, I decided to order a new one and remove the grill and old radiator before the 12” of snow starts tomorrow. I hate going backwards. But at least I gad not put the front bumper and winch back on yet.

I am not sure if the radiator got nicked when it was in the garage for a year or if it was due to the plastic zip tie like things that I used to attach the trans cooler to it. I am hoping the former as I don’t know how I would install the trans cooler this next time. Maybe attach it to two long bands that span the front of the radiator and attach to the mounting points that the radiator uses on the grill? Hmmm

 

[PetesCj-8]

Since my radiator sprung a leak, I decided to order a new one and remove the grill and old radiator before the 12” of snow starts tomorrow. I hate going backwards. But at least I gad not put the front bumper and winch back on yet.

I am not sure if the radiator got nicked when it was in the garage for a year or if it was due to the plastic zip tie like things that I used to attach the trans cooler to it. I am hoping the former as I don’t know how I would install the trans cooler this next time. Maybe attach it to two long bands that span the front of the radiator and attach to the mounting points that the radiator uses on the grill? Hmmm

I had the same thing happen to mine when I had it out for awhile. I figured I did something to it in the time it was out. I used zip ties( only heavier) through the fins on my current Cj to secure the temp probe for the electric fans. The probe itself goes through the fins and I had no problems. Doubting you did it attaching the trans cooler.

Wish I could help with the starting issue but Id probably be worse off if I was in your situation. Probably wouldve given up and took it to a shop.

 

[gr8dain]

I had the same thing happen to mine when I had it out for awhile. I figured I did something to it in the time it was out. I used zip ties( only heavier) through the fins on my current Cj to secure the temp probe for the electric fans. The probe itself goes through the fins and I had no problems. Doubting you did it attaching the trans cooler.

Wish I could help with the starting issue but Id probably be worse off if I was in your situation. Probably wouldve given up and took it to a shop.

The thought of tossing the Scrambler has crossed my mind a few times recently. But I will get through it. And it better happen before the nice weather. Or I will be running it with a jumper wire.

And I bought some aluminum strips to use as mounting brackets. When the radiator comes, I will decide how I run it.

 

[Belizeit]

No giving in or up ! You got this !

 

[gr8dain]

The driveshafts arrived. And yes, we still have our tree up. I am a child.

 

[TravelnMan]

I read through some of this but admittedly not all- are you sure the ASD relay is good? Looks like you tested for switched voltage and have a proper ground installed. Installing a jumper and to make it run indicates that you have a good power source. If the signal is good I'd be looking to see if the relay itself has high internal resistance or not making contact - does it click when energized/actuated?

 

[gr8dain]

I read through some of this but admittedly not all- are you sure the ASD relay is good? Looks like you tested for switched voltage and have a proper ground installed. Installing a jumper and to make it run indicates that you have a good power source. If the signal is good I'd be looking to see if the relay itself has high internal resistance or not making contact - does it click when energized/actuated?

I hear it click. And I swapped it with the fuel pump relay and no change in reactions. But thanks

 

[gr8dain]

Waiting on my radiator to show up. Then I will start mocking it up. I think I will mount it with the mounting tabs inside of the grill like I had it on my 258. I still think the fan is too close to the radiator, and since it is out, now is the time to move it. I am also considering painting the grill while it is off. It is gray now. And I have gotten used to it. But I am considering black or white, although i won’t be able to match the white and it may look off like the doors do.