Xcessive

Hey. Thanks for looking at this post I need as much help as possible to get my jeep back up and running since I have work in the morning.

Specs- 1996 Cherokee 4.0, automatic transmission

Problems- Will not start. No spark, no fuel, but cranks over just fine. Mil light is showing error code 42 (ASD).

Thursday after work I was driving home (had been running approx 20 minutes after giving one of my guys a jump) when I went to accelerate to be able to change lanes on the highway the jeep just died like I had turned the ignition off. Did not chug, hesitate, miss or anything. It was great then it was gone. I then coasted to the side of the highway and tried to restart, would run for about 10 seconds and then shut off. IF I gave it gas to try and keep it running it would shut off. I played with it for about 10 minutes, battery died, and then called a tow truck.

On Saturday I was finally able to mess with it. I got a scanner put on it, no codes showing. Tried starting it again and I have nothing. Cranks all day long, but still won't start. Checked Fuel- just drizzled out of the schrader valve. Put a fuel pressure gauge on it and nothing. Check the fuel pump and it's not coming on so I replaced the fuel pump. Try it again, still no fuel pressure and pump is not priming.

Next I checked the CPS. It did test GOOD but I replaced it anyways. Check fuel again and pump is still not doing anything.

Check for spark (should have done this first with the fuel pressure), no spark.

Bought new ASD/Fuel pump relays and a new distributor pickup and still no spark or fuel.

Tested the power at the PDC.

ASD relay is getting 12.9 v @ b16, 12.9 @b18.
Fuel pump relay is showing 12.9@ c16 and 12.9v @ c18.

Checked for the 5v Reference signal and circuit. Showing 5.2 volts @ the PCM, CPS, Distributor, and TPS.

Checked the o2 harness everything is good there.

Went back and tested all fuses with a test light on both posts and they are all good.

I'm now at a loss. Where do I go from here? I NEED to have this going by tomorrow morning, I'm just so brain dead and frustrated at the moment I can't think straight. Does anyone have any ideas?

Xcessive

Anyone??

Could the coil be causing all of this? The MIL 42 code would suggest something on the fuel pump side of things but sometimes these things do some weird stuff.

bubbarules1958

I think you smoked your ECU (Computer). My friend went through that with an 87. Replaced a bunch of parts and several hours before he payed someone 500 bucks to tell him it was his ECU (Computer).

Xcessive

yeah... That's where I'm leaning right now, but hoping that it's not true lol. Guess I'll hit up pick n pull tomorrow and see if I can find a compatible ECU and give it a try and see what happens. Thanks for the input bubba! BTW my 6 year olds nick name is bubba. He'll get a kick out of your name.

Does anyone know where to get a decent set of Engine control system wiring diagrams?

bubbarules1958

He will be an awesome Kid. Unplug your ECU and I bet nothing will change.. I have one for a RENIX on my desk. Half off weekend at my local pick n pull. MLK weekend. You should look into that.

Xcessive

definitely will check that out. Im lucky, I have a Pull 'n Save about 4 blocks from me Tear-a-Part is about 5 miles away and a bunch of other junk yards are pretty close. Makes the running around easy.

GreenClassic

Are you sure the CPS isn't the culprit? I know you said you replaced it, but from what I've seen on here, if you purchased a generic auto parts store CPS, they can be hit or miss.

My CPS went out on me about a week ago while going down the road at 50mph. The Jeep just shut off without warning. Cranked strong, but would not start. Replaced my CPS with a dealer part (actually cheaper than my local auto parts store). Runs like a champ again!

freegdr

Have all fuses been checked for power in and out of them ?

Xcessive

I checked the CPS before I put it in as well as I checked the one I pulled out. Both tested good. I'll go triple check the new one again in just a minute.

Checked for the 5v reference and it is good.

Checked all the fuses in the PDC and the under dash fuse panel and everything was good there. Checked both visually and with a test light.

Checked for continuity from the ASD back to the PCM (ASD output) and it tested good.

Have a strong 12v signal at both the b16 (on the ASD) and the c16 (on the fuel pump) terminals. Same with the b18 and c18 terminals (this is the switched 12v source for the relays).

RTorrez1

When my CPS went bad it was still testing good. Unfortunately when they go bad they tend to show good intermittently. I ended up changing mine out even though it read good and never had a problem with it since. Also like GreenClassic aftermarket ones are know to be garbage right out of the box. Personally I will never buy an aftermarket one again.

Xcessive

Ill send it back and go get another one from the dealership. who knows.

Xcessive

ok new MOPAR cps is in, still nothing. Im running down to tear-a-part to try and find an ecm. Any other Ideas?

RTorrez1

Have you checked the coil? There is a way to test it but I am not 100% on how to check that out. You can do a search on the forum and there are a couple of write up on how to do it. You can also check the Camshaft Position sensor in the distributor. Unfortunately the you may have to look into the ECU. With a little luck someone else will chime in with a little more info for you.

Xcessive

ok update. changed the PCM and now it TRIES to start but still nothing. Cranks and cranks with the occasional "almost started". I need to wait for a buddy to get off work so I can see if there is a strong spark while he cranks on it.

Also, the only PCM for a 96 I was able to find was a 296 and I originally had a 199. Are these two compatible?

Parsnip

Have you tried just jumping the asd relay with a wire? Happened to me and a friend both, on a 90 and a 97