no voltage to coil 1995 4.0 5spd

[8Mud]

You really have to get a wiring digram and check your ASD circuit, that dark green wire with the orange stripe.
My last major malfunction (in my 96) was a flacky connection in the ASD circuit under my dash.
Power to activate the ASD relay is a yellow wire from the key (run/start), then to ground at the ECM PCM or whatever you want to call it. The main (activated) circuit for the ASD relay is a dark green wire with an orange stripe, that runs to the coil and the alternator among other things (like the injectors), there are splices in the system. If the ASD relay is closing while the motor cranks, it's likely in the wiring, if it doesn't close while cranking, it's likely a sensor input to the ECM or in the wiring. Only one or two senors will keep the ASD relay open that I know of, the CPS or the Sync sensor (maybe, as I've never tested it myself, just heard this is true). Most other sensor failures will let the motor run, though often poorly.
Sometimes there are no shortcuts and you have to test most every wire in a harness for continuity. A systematic approach may be harder, but will likely be more successful in the long run. I often start in the middle and then work towards both ends, just my way.

 

[Ralph]

x2 on the fuses. I had a similar problem and it was a blown 20 amp fuse. The problem was a caused by a shorted wire, but that's another story.

 

[DonnMcc]

You really have to get a wiring digram and check your ASD circuit, that dark green wire with the orange stripe.
My last major malfunction (in my 96) was a flacky connection in the ASD circuit under my dash.
Power to activate the ASD relay is a yellow wire from the key (run/start), then to ground at the ECM PCM or whatever you want to call it. The main (activated) circuit for the ASD relay is a dark green wire with an orange stripe, that runs to the coil and the alternator among other things (like the injectors), there are splices in the system. If the ASD relay is closing while the motor cranks, it's likely in the wiring, if it doesn't close while cranking, it's likely a sensor input to the ECM or in the wiring. Only one or two senors will keep the ASD relay open that I know of, the CPS or the Sync sensor (maybe, as I've never tested it myself, just heard this is true). Most other sensor failures will let the motor run, though often poorly.
Sometimes there are no shortcuts and you have to test most every wire in a harness for continuity. A systematic approach may be harder, but will likely be more successful in the long run. I often start in the middle and then work towards both ends, just my way.

Thanks,I was lost and frustrated.I'm gonna keep checking before I go throw parts at it.I just needed a direction to go in.we will see what happens.

 

[OLAK]

Friend gave me a jeep to work on that was dead. He had replaced cps etc. I got stuck thinking there was something wrong with asd circuit: turned out to be the stator /camshaft pos sensor magnet had come loose - had to replace the sensor and that cured it. the asd circuit needs input from both the crank sensor and the camshaft sensor in the distributor to cause the asd relay to close. no close, no spark or fuel

 

[DonnMcc]

Friend gave me a jeep to work on that was dead. He had replaced cps etc. I got stuck thinking there was something wrong with asd circuit: turned out to be the stator /camshaft pos sensor magnet had come loose - had to replace the sensor and that cured it. the asd circuit needs input from both the crank sensor and the camshaft sensor in the distributor to cause the asd relay to close. no close, no spark or fuel

know of a way to test it?I know it's cheap,I just would like to be sure.Along with learning how to check it.

You know I bought a 1990 dodge dakota 3.9 that had no spark no fuel,the kid threw parts at it I put a stator/cam sensor on it and it ran.Lol,only reason I put it on was it was about all that was left.gotta be a way to test it.

 

[OLAK]

from 1993 fsm ( ymmv
Camshaft Position Sensor
1) Use an analog voltmeter. DO NOT remove distributor
connector from distributor. Insert voltmeter leads into backside of
distributor wiring harness connector to make contact with terminals.
Ensure connector is not damaged when inserting test probes.
2) Insert positive voltmeter lead into camshaft position
sensor signal output circuit (Tan/Yellow wire on Cherokee and
Wrangler; Gray/Black wire on Grand Cherokee) at distributor wiring
harness connector. Insert negative voltmeter lead into ground circuit
(Black/Light Blue wire) at distributor wiring harness connector. Set
voltmeter to 15-volt DC scale.
3) With distributor cap removed, manually rotate engine until
pulse ring enters sync signal generator on camshaft position sensor.
Distributor rotor should be at 9 o’clock position. Turn ignition
switch to ON position. With pulse ring positioned in the sync signal
generator, reading should be approximately 5 volts.
4) If no voltage is present, check voltmeter leads for good
connections. If connections are okay and there is still no voltage,
check for voltage at supply circuit (Orange wire on Cherokee and
Wrangler; White/Black wire on Grand Cherokee).
5) If no voltage is present at supply wire, remove PCM
connector. Check voltage at PCM pin No. 7 and ground with wiring
harness connected. PCM is located on left side of engine compartment.
If there is no voltage at PCM, see appropriate camshaft position
sensor circuit tests in G - 2.5L & 4.0L TESTS W/ CODES article in this
section.
6) If voltage is present at supply wire, replace camshaft
position sensor. If voltage is present at PCM pin No. 7, but not at
supply wire, check continuity of supply wire between the distributor
connector and the PCM. If no continuity exists, repair wiring harness
as necessary.
7) If supply wire is okay, check continuity between camshaft
position sensor signal output wire at the distributor connector and
PCM pin No. 44. If no continuity exists, repair wiring harness as
necessary.
8) If camshaft position sensor signal output wire is okay,
check continuity between ground circuit wire at the distributor
connector and ground. If no continuity exists, repair wiring harness
as necessary. If ground wire is okay, go to next step.
9) While observing voltmeter, crank engine. Voltmeter needle
should fluctuate from 0-5 volts while the engine is cranking. This
verifies that camshaft position sensor in distributor is operating
properly and that a sync pulse signal is being generated. If voltmeter
does not fluctuate, replace camshaft position sensor.

 

[DonnMcc]

anyone got a suggestion on a diagnostic/code scanner?I want one that reads and resets the ecc.Unless it"s too much.

Thanks OLAK,I've been looking for that.


damn,no batteries and my extension cord is too short.Have to wait till morning.

 

[xj88superjeep]

You can look at this one of two ways... I like the way you are looking at it... I went through this with my 97 that went from intermittent no start to just no start at all, and it ended up being a short in the wiring that I could not track down. I poured over wiring schematics and traced circuits for 2 weeks before giving in and paying a tech. The guy asked me why I waited so long and didn't just bring it to him in the first place and save myself the headache, and I calmly said "because I learned a lot even though I didn't find the short"

If you have the money, an EXPENSIVE scanner can test things like the starting circuits and things like that, live while you are cranking the engine. It will tell you exactly what the PCM is seeing, and where the roadblock is... they can also run their OWN diagnostic scans and tests outside what the PCM is telling it... I don't know which scanners can and can't do that, or how much they cost, but a basic scanner is pretty cheap (around 100 clams) and can read and reset your codes. Check out harborfreight.com for cheap scanners

 

[Matthew Currie]

I got a 95,rebuilt motor,new clutch,all new sensors(lol),plugs,wires,cap,clutch,etc everything but the ecc and distributor(which has 1/8 play if you wiggle it.)I can see where the harness has been probed so I'm not the only one to go thru this.The harness has been unmolested and all the wires look good.no crummy decayed ones.I'm about to buy a ecc.I just hate wasting money and not knowing for sure.
lol,my meter was junk also,no more cheapies for 10bucks.

Before you get the ECC (or ECU or PCU or whatever they call it this year), I'd get an ohmmeter and hunker down and check every single circuit, plug to plug. Any number of problems could be lurking in that harness.

I have never heard of having to reset the PCU as you were told, and nothing in the '95 FSM mentions this. Codes are stored for a number of restarts, then automatically cleared, but fixing a malfunction should be enough to get you running fine even if the code stays stored for later reading.

A bad Cam position sensor should throw a code, but it's still worth looking at. It will definitely prevent the engine from starting. But here's a funny thing about that, which has worked twice for me, on a 93 and a 95. It seems that when the cam position sensor goes bad, it prevents the PCU from booting up, but if you turn on the ignition first, then unplug and replug the distributor, it will start. When you replug it, you'll hear some clicks and whirs as the idle solenoid and a relay or two kick in, and it will be good for one start. It will run, but not perfectly, because the fuel injection timing is screwed up. It may overheat, and you'll need to go through the procedure every time you start. But it can get you home. If that procedure works, it is also a sure diagnostic for a bad cam sensor.

 

[winterbeater]

anyone got a suggestion on a diagnostic/code scanner?I want one that reads and resets the ecc.Unless it"s too much.

Another possibility is to check your local autoparts franchise. I think Autozone will scan it for you for free, and Murray's will sell you one and buy it back when your done. I've used that service for specialized pullers, etc. that you probably only need once.

 

[DonnMcc]

I'm a tard.I was looking in the pdc and I noticed that the cover says there are mini fuses also.yeah,yeah they weren't there.haven't got any in it yet but it might just be running here when I do.I hope that's what it is.I feel like a idiot.

 

[DonnMcc]

I put the fuses in but I still get no power to coil and Now I only get code
22
23
24
Does that mean my computer is good?I was getting 2 others before.

 

[xj88superjeep]

Don't feel too bad! We've all done those things that we hate to admit, but few actually have the pair to post up what they found if it makes them look bad. Kudos

 

[xj88superjeep]

• 22* Coolant sensor signal out of range
• 23* Incoming air temperature sensor may be bad
• 24* Throttle position sensor over 4.96V

I would start with the TPS from here... test it and or replace it... I think that would at least let you start the truck, but that's just my thoughts...

 

[DonnMcc]

I did the cam sensor test(thanks again olak),and It shows it's bad.got power to it,good ground,but when I check while cranking it goes nowhere.A little negative actually.I'm gonna pick one up and see what happens.

 

[DonnMcc]

• 22* Coolant sensor signal out of range
• 23* Incoming air temperature sensor may be bad
• 24* Throttle position sensor over 4.96V

I would start with the TPS from here... test it and or replace it... I think that would at least let you start the truck, but that's just my thoughts...

the tps is bad I will be replacing it.I think the fuel pump may be bad also.I put a jumper wire on the relay 87 and 30,got power all the way back and no fuel pump working.Kinda hard to believe all these things can be bad.

 

[xj88superjeep]

Sounds like they swapped a new motor into a completely unmaintained Jeep thinking it would fix all these problems, and it didn't so they sold it to you... You are doing the right things though... Soon you will have a great running XJ!

 

[Matthew Currie]

Another possibility is to check your local autoparts franchise. I think Autozone will scan it for you for free, and Murray's will sell you one and buy it back when your done. I've used that service for specialized pullers, etc. that you probably only need once.

I'm not sure that's true for OBDI. It might be, but Don has a little logistical problem, in that if he can get his Jeep to an Autozone it will be because he's already fixed it! :doh:

 

[DonnMcc]

I'm not sure that's true for OBDI. It might be, but Don has a little logistical problem, in that if he can get his Jeep to an Autozone it will be because he's already fixed it! :doh:

lol,so true.

 

[DonnMcc]

I started a new post about the results of my pin testing.I would still like to know about the computer,seems like it would be good if the codes change.