coil getting no power

Here is the latest story of the week I just rebuilt a 89 xj with the i-6 and took the etire motor out and did the full overhaul. Plugged everything back in, I did unplug everything and rap it in new plastic flex rap. I relacated his battery behind the pas. seat justblike mine and wired it up corectly and now it wont start. It turns over, has gas you can smell it from the exhaust but there is no spark from the plug wires. So I tested the coil lead wire to the distributor and it is giving no power.

So far I have replaced the coil, pick-up coil, and had the ingition modual checked evrything is good or new and it still wont start.

What did I do wrong? I has to be running tonight because he can't barrow my jeep any longer.

The large yellow wire going to the ignition control module under the coil, has to have 12-14 volts with the key in the run posisition. And usually 9+ volts while it's cranking.
The smaller yellow wire is the trigger wire for the ignition control module and goes back to the ECU. This wire is hard to test, a meter set on A/C (or sometimes D/C) will often get a little needle movent (back pinned with the connector connected), but the only real way I know to test it is with a occiliscope. I think it's a five volt square wave.
Your not the first to have this problem, there is a lot of info in search. But to tell you the truth, I don't really know if anybody has found a diffinitive answer. Langer 1 may have some helpfull hints.
If you have 12-14 volts at the large yellow wire to the ignition control module, chances are it's a fault in the small yellow wire or for some reason the ECU isn't pulsing (triggering) the ignition control module.
If the crank position sensor is cycling the injectors, chances are it's good. Making sure the thermistor (temperature sensor) on the lower left of the block is plugged up, is something else to check. I haven't tried unplugging mine to see what happens, but it has been said it being unplugged, causes iginition trouble. Same with the knock sensor. The front harness where it continues from the front of the fuel rail down the front of the motor is know to fry (even under the covering) and cause all sorts of grief.
The start signal wire from the starter relay to the ECU is also worth a look.
Check with Langer1 and see what he has to say.

Does your XJ have a Ballast Resister? They may have been still using them in '89.

Typical Chrysler Ignition is designed to make a hotter spark than the system can handle, then a huge ceramic resister is placed in the circuit to the coil to bring the power down to what the system can handle. When you crank the motor to start the engine, the switch cuts out the Ballast Resister and gives you an overpowered spark while cranking to get the motor started easier. If the resister blows, no spark, unless your cranking.

If your checking the spark while cranking, a blown ballast resister, should still spark, just when you set the key to run, the blown ballast resister will produce an open circuit and no spark.

Not sure when Chrysler dropped ballast resisters, definitely by the time they dropped distributors with DIS. It might have been sooner, like when they went to ECM's.

Rick Anderson said:

Does your XJ have a Ballast Resister? They may have been still using them in '89.

Typical Chrysler Ignition is designed to make a hotter spark than the system can handle, then a huge ceramic resister is placed in the circuit to the coil to bring the power down to what the system can handle. When you crank the motor to start the engine, the switch cuts out the Ballast Resister and gives you an overpowered spark while cranking to get the motor started easier. If the resister blows, no spark, unless your cranking.

If your checking the spark while cranking, a blown ballast resister, should still spark, just when you set the key to run, the blown ballast resister will produce an open circuit and no spark.

Not sure when Chrysler dropped ballast resisters, definitely by the time they dropped distributors with DIS. It might have been sooner, like when they went to ECM's.

Click to expand...

There is no Ballast Resister in the Ignition.
Chrysler did not own jeep back in 89 and had nothing to do with them, They were built and sold by American Motors untill 91.
American Motors is now AM General and builds Hummers.

I thought Chrysler bought out AMC in 1987? I can see that a transistion from AMC to Chrysler production was gradual over the years. Heck even my '95 XJ is way more AMC technology than Chrysler, I'm sure that Chrysler was firmly behind the helm of the production by then though.

Rick Anderson said:

I thought Chrysler bought out AMC in 1987? I can see that a transistion from AMC to Chrysler production was gradual over the years. Heck even my '95 XJ is way more AMC technology than Chrysler, I'm sure that Chrysler was firmly behind the helm of the production by then though.

Click to expand...

They were purchased in 91 and 92 year was the first changes.

langer1 said:

They were purchased in 91 and 92 year was the first changes.

Click to expand...

That's wrong.
AMC merged with chrysler in late 87, chrysler took over production in 88 using AMC parts. Major changes were made in 91.
AMC owners org recognizes 1987 as the last year for a Jeep to qualify as AMC.

As well, IIRC AMC filled military contracts for Jeeps and such, when they got in trouble and Renault went to bail them out, the only legal way for a foreign company to do that was for them to get rid of their military arm. So they split the company, into AMC for civilian and AM General for military.

AMC was absorbed by Chrysler and the name immediately killed for just Jeep/Eagle and even Eagle was dropped.

AM General went on to make HMMV's for the military and then the Civilian version of the Hummer.

So in a sense, AMC lives on in AM General and the Hummer, but technically AMC died being absorbed by Chrysler, AM General was just the military contracts from AMC. Which I guess was the same beginning for AMC 60 years ago, so maybe its best to say that AMC is being reborn again with the HMMV, like it did with the Jeep.

A few of the AMC teams still lived on. I believe the Neon was designed mostly by former AMC engineers. I think the guy responsible for the PT cruiser was also an AMC guy.

Okay, so I have replaced the computer with a reman unit with the proper software installed. It solved the reboot/shut down when the HVAC blower is moved out of the off position. However, now, after driving it for about 30 minutes, it will not restart? Again, I have no power to the coil. Is it possible that my Crank Position Sensor has also gone bad? It starts just fine when it is completely cold. Also, after it dies I still have power on two posts of the ASD Relay. Against the wall here. What do I do?

Okay. So there are two fuses under the hood that are marked for ASD. I do not get power to either one of them. Before some one asks, I did swap in a known good relay into the ASD slot.

Have you checked/tested the CKP? IIRC, a failed CKP will cause a no-spark condition. Hence, crank/no-start scenario. Disco the CKP connector, test it, reconnect it and see if it fires up?

ALos, since you did not post your specific heep specs, if you have an older model XJ, check/bypass the fuel ballast resistor. It will be on the driver side inner fenderwell, towards the front where the air box is.

The Renix has no ASD relay. The power source for the ignition module is the larger yellow wire and comes from the ignition switch. The smaller yellow wire is the pulse or trigger wire controlled from the ECU. No pulse signal or very low pulse signal from the CPS to the ECU during cranking will shut down the trigger signal to the ignition module.

You said no power to the ignition module (coil), no power on the larger yellow wire? Usually a melted connector, the connector on the steering column is the most likely, the brown wire circuit (heater blower etc,) overheats and melts the connector.

No trigger on the smaller yellow wire from the ECU is usually something to do with the CPS. Check out Cruisers CPS troubleshooting list. There is no way to measure the trigger signal to the ignition module accurately, few VOM meters will read the square wave signal it uses. Some auto parts suppliers have a special tester for the ignition module. The CPS is known to be heat sensitive, it may work cold and not hot. I've even poured a bottle of cool water on a CPS to get one more start out of it.

Don't assume that replacing the CPS is all there is to it, it may be a wiring or connector issue, either partly or in whole. Even the CPS wires cooking on the exhaust manifold.