Matt_the_Butcher

Hi. I have a 2wd 97 XJ SE 4.0 Aw4. When I bought it, it had several issues, most of which I fixed. It had what I thought was a simple ignition bypass with the "button start". I replaced the ignition switch & actuator & now the key works. Digging deeper I realized that it won't start without a jumper wire running from the fuel pump relay & spliced to a 3 way splitter to the green/orange wire leading to the ignition coil. Once I take the jumper off it will start but won't turn over. I replaced the ASD but no change. I ruled out the CKS b/c I don't think it would run right even if it was bypassed. I cleaned all the ground terminals. I checked all the ignition related fuses & relays in both PDC boxes. I removed the ignition switch bypass button & wiring thinking it might be a grounding issue. As far as I can tell I've got to start chasing after that green/orange wire or possibly replace PCM?

The Jeep runs like a champ with the jumper but is a lawn ornament without it. I'm not a mechanic so any advice is most welcome.

Matt_the_Butcher

Since I'm planning a 4wd conversion, am I better off buying 1 of many 4x4 99.5-01 (0331 head) blown motor XJs & just swapping my good (0630) head motor into it? I also already have the PCM, np231, AW4, shifter & drive shafts I pulled from a junk 2000 XJ.

I also found a few blown motor 99s that are rust buckets and/or have bad motors. If I have a bad harness and/or PCM in my 97, could I swap PCMs and the ignition & trans harnesses & sensors, along with the aw4 into it and trick my 97 into thinking its a 99? I noticed there's a lot less confusion with parts with 98-01 as 97.

peligro113

I'd check the wire I circled in blue. If you have power in the wire I circled in blue, I would check for power at the DG/OR wire. If you don't have power at the DG/OR wire, look for the break in the wiring. Have you checked to see if you have spark with the jumper disconnected?

Dave51

Can you clarify a couple things?
Do you mean it will turn over but not start?

Which cavity on the Fuel Relay is the jumper connector to?

A 3 way splitter has one source that splits into 3 outputs. Is this something the PO installed? If so, where do the 3 lines go?

When you Key On and/or Start, does the ASD engage?

Did you fix it already?

Dave51

BTW got a multimeter? Test lamp? Light bulb with a couple wires soldered on it?

Matt_the_Butcher

I'll have to look at the red wire that is circled in blue when I get home from work.

I do have a multi meter, its a cheapie from Harbor Freight but has worked for me. I haven't used it thus far on this problem. Last time I used it was when I replaced my NSS.

PO had to have been an electrician & not a mechanic. I do not have a light tester yet. I probably need 1.

The jumper is at the top of the fuel pump relay I believe its 86 but I'll have to double check.

Thank you all for the responses. I'll get back to this as soon as I get home.

Matt_the_Butcher

I forgot to mention that there's a 30 amp fuse spliced in the jumper from the fuel pump relay to the green/orange ignition wire.

Dave51

I have two!

And a magnetic parts dish.

And 6 tape measures.

A few 5' x 8' tarps.

A million little flashlights....

Matt_the_Butcher

I don't have all the freebies just use the 20% off coupon a lot. LOL when I take the jumper off it will not fire up. Sorry I'm not sure about the terminology b/c I've heard it both ways. When I turn the key I hear the fuel pump hum either way. With the jumper on it fires up & i can drive it. Without it the starter engages but it will not fire up.

Matt_the_Butcher

Someone correct me if I'm wrong but isn't dk grn/org a ground wire? I'm confused as to why connecting a live wire to a ground makes the system work. Maybe the coil is grounding itself out & the ASD needs some current to function?

Sorry I'm not much of an electrician or mechanic. I'm a hell of a Meat Cutter though. LOL

Thanks for the replies. Keep em coming. My break is up. Back to work...

Dave51

The problem (one anyway) is the ASD relay. peligro thinks it's the hot side. I think it's the coil side. You need to troubleshoot that first. ASD controls the coil and a couple other things so if that's the issue there should effectively 2 more circuits jumped. See if it clicks when you hit start.

Dave51

Hope SIC. Out on the lake fishing. I'd be at work too except I don't.

Dave51

Specifically the fuel injectors and oxygen sensors. If ASD is bypassed to run the coil then those two have alternative power as well. So if you fix the ASD circuit make sure any additional jumpers, splices whatever are removed. Those things don't run very well on 24V (at least, not for very long anyway).

Matt_the_Butcher

peligro113 THANK YOU!!!

That red wire that connects the ASD to the fuel pump was pushed back and not making a good connection. I pulled the pin & squeezed it closed tighter. My XJ fired right up!

I kinda feel like a tool for not being more thorough in diagnosing my XJs' issue. I've learned a few things today. I can't thank you enough! Let me know the next time you're near Fort Riley & I'll buy you a beer! 🍻

Matt_the_Butcher

Dave51, thank you for helping me understand the system better. While we're on the subject of my XJ, you mentioned o2 sensors. Could this ASD bypass be related to my XJ running like crap when I start it after its been sitting in a hot parking lot all day? It smooths out after it gets to about 190 or 200 degrees. My wife's y2k XJ acted similarly before I replaced her upstream o2 sensor.

My Jeep is black so I'm not sure if it runs rough after sitting in the sun all day b/c of vapor lock or failing o2 sensor(s). It cracks fine & doesn't act up at all in the morning.

Either way, now I can start trying to get my ac working again...