Sudden Crank/No Start condition - also no accessories in On/Run?

[Johnny6guns]

Hey folks. I joined because all my internet searches lead me to here. I have a 1988 XJ with Renix 4.0 and the AW4.

So the Friday before last, I parked my Jeep after work like usual. Got into it Monday morning, and it would crank but not start. I also noticed that I had no power at the accessories - my 12v cig outlet, blower motor, turn signals, and everything else I would usually have in "On" position are dead.

First I thought it was an ignition switch or dead spot in my ignition cylinder. Changing those did nothing. Then I moved on to the ignition coil, then CPS. Still nothing. I have fuel pressure, and my CPS reads the correct resistance but no voltage (0.0v) when cranking. I cleaned my grounds and C101 thoroughly, and Im still getting no change. Ive also checked my fuses and swapped relays around and theres no difference.

Is there something Im missing here? The thing that really stands out to me is that I have no accessories. Turning the key just goes from nothing to straight cranking, but no fire. Ive read that the Starter Relay Solenoid behind the battery supplies power to a lot of different things - could this be the issue?

Ive got the ignition switch dropped down off the column, and moving it with a screwdriver I can read 12v by probing everything, but Ive got nothing else as far as functions.

Am I way off base or missing something here? Any guidance would be appreciated.

[Johnny6guns]

Forgot to add - I also swapped in another ECM I had around from a planned upgrade. It didnt change anything either.

Its actually cranking stronger than it was before after all this, but still not firing. Im lost.

[Rob Dimel]

I’m having a similar issue with my boy’s Jeep. Been trying to figure it out since just after Christmas. It cranks, but won’t start. Definitely has no spark.

We’ve fired the parts cannon at it. Replaced the ignition switch, the crank position sensor, the ignition control module, the coil, used Cruiser 54’s guide to refresh all the grounds. Nothing.

The other odd thing is the fuel pump does not prime when the key is turned on. However i created a separate ground and hooked it to the fuel pump relay. The pump kicks on and stays on.

I’ve been convinced it’s been a ground issue, but I’m not sure since we’ve upgraded and refreshed them. I’m baffled.

Hoping you get an answer that can help us out too.

[cruiser54]

The pump could be bad or the hose inside the tank split.
What happens if you use starting fluid in the throttle body?

Have you tested the CPS? New doesn't mean anything any more.

[Saudade]

There are fusible links on the starter relay that power various areas. Check the realy and look for any signs of burning.

Also double check your ignition switch and fuses.

[Johnny6guns]

Originally Posted by Saudade

There are fusible links on the starter relay that power various areas. Check the realy and look for any signs of burning.

Also double check your ignition switch and fuses.

Ive tripled checked ignition switch and tried 2 different ones with the same result.

Im definitely considering the starter relay. Is there a way i can go about checking the fusible links?

[Saudade]

Since it's easy to do, take the nut off the starter relay and make sure all of the eye terminals are clean. Put them back on. Be careful not to overtighten the nut.

At the ignition switch, the red wire comes from the post on the starter relay. With the key turned to RUN (on), you should have power at the orange and yellow wire.

Do any of the accessories work when you turn the ley to accessory?

[Johnny6guns]

Originally Posted by Saudade

Since it's easy to do, take the nut off the starter relay and make sure all of the eye terminals are clean. Put them back on. Be careful not to overtighten the nut.

At the ignition switch, the red wire comes from the post on the starter relay. With the key turned to RUN (on), you should have power at the orange and yellow wire.

Do any of the accessories work when you turn the ley to accessory?

Just saw this so Ill have to do it tomorrow.

So i tested each side of the fusible links with my DVM and had continuity, so im assuming they are good. I also pulled out a spark plug and set it on the valve cover, and had no spark while cranking.

So no spark.. does that leave the ICM and Starter Relay Solenoid?

And to add - I had gone probing around the ignition switch the other day, and I want to say that in the "On" position, I did NOT have power. But I will have to double check.

What are the two directions Id be headed in either case? If there is power, what is my next step? If there isnt power, where should I look?

I appreciate the advice so far greatly!

[Johnny6guns]

Originally Posted by Saudade

Since it's easy to do, take the nut off the starter relay and make sure all of the eye terminals are clean. Put them back on. Be careful not to overtighten the nut.

At the ignition switch, the red wire comes from the post on the starter relay. With the key turned to RUN (on), you should have power at the orange and yellow wire.

Do any of the accessories work when you turn the ley to accessory?

Ok, so assuming I did this correctly, and assuming you mean a yellow wire and an orange wire (I do not have an orange/yellow striped wire)...

I ran a some jumpers to the known good ground at the firewall. Probing the ignition switch, I get 12v at the red wire, but I get 0.0v at both the orange wire and the yellow wire in the Run/On position. And I have no accessories in the position at all.

[RCP Phx]

If you checked for voltage at the ignition switch, then it sounds like a bad switch.

[Johnny6guns]

Originally Posted by RCP Phx

If you checked for voltage at the ignition switch, then it sounds like a bad switch.

I have tried 2 different ignition switches, 1 brand new and 1 less than 2 weeks old. Both give the same result.

[Saudade]

Yes, a yellow wire and orange wire.

Does sound like the switch is bad or something wrong with the connector. Check the connector for any burn marks (common failure).

If you slide the slider to the first detent (towards the steering wheel), that's the accessory position. Next is Off-lock (steering wheel locked). Then Off-unlock (middle detent). Then On. Finally Start (closest to the firewall). If you use a rod or screwdriver to move the slider, it should spring back to On from the Start position.

When you insert the rod from the column, the key should be in the off-unlock position and the switch in the off-unlock (middle) detent. Don't tighten the switch mounting screws until you have the rod back in place.

[Johnny6guns]

Originally Posted by Saudade

Yes, a yellow wire and orange wire.

Does sound like the switch is bad or something wrong with the connector. Check the connector for any burn marks (common failure).

If you slide the slider to the first detent (towards the steering wheel), that's the accessory position. Next is Off-lock (steering wheel locked). Then Off-unlock (middle detent). Then On. Finally Start (closest to the firewall). If you use a rod or screwdriver to move the slider, it should spring back to On from the Start position.

When you insert the rod from the column, the key should be in the off-unlock position and the switch in the off-unlock (middle) detent. Don't tighten the switch mounting screws until you have the rod back in place.

Ok, then after seeing this, I can tell you that it will begin cranking in the "On" position. If i leave it there, it will just crank and crank. Moving it to Start, it will keep cranking and spring back to "On", but continue cranking. I have to physically move it back to one of the other 3 positions to make it stop cranking, and I have no power to any accessories in any of those positions.

[Johnny6guns]

Originally Posted by Saudade

Yes, a yellow wire and orange wire.

Does sound like the switch is bad or something wrong with the connector. Check the connector for any burn marks (common failure).

If you slide the slider to the first detent (towards the steering wheel), that's the accessory position. Next is Off-lock (steering wheel locked). Then Off-unlock (middle detent). Then On. Finally Start (closest to the firewall). If you use a rod or screwdriver to move the slider, it should spring back to On from the Start position.

When you insert the rod from the column, the key should be in the off-unlock position and the switch in the off-unlock (middle) detent. Don't tighten the switch mounting screws until you have the rod back in place.

I figured out why it cranks in On and corrected that.

Question- what is the brown wire? Where does it go? Whoever I bought this off of did some of their own wiring.

It looks like they tied the yellow wire and the brown wire together in the harness, and brought it down to where it plugs in where the yellow wire goes, across from the ground on the ignition switch.

I feel like i have a mess on my hands now.

[Saudade]

Originally Posted by Johnny6guns

I figured out why it cranks in On and corrected that.

Question- what is the brown wire? Where does it go? Whoever I bought this off of did some of their own wiring.

It looks like they tied the yellow wire and the brown wire together in the harness, and brought it down to where it plugs in where the yellow wire goes, across from the ground on the ignition switch.

I feel like i have a mess on my hands now.

Oy! Sounds like the previous owner (or someone earlier) had the issue and simply spliced the 2 wires together.

In theory, it should work since the Yellow connects in the ON position, but not in Accessory.