94 XJ weird no start

[Kejtar]

It's my dad's rig. What it does is this:
It turns but doesn't fire up. Looks like no fuel pressure. Cleaned the grounds, swapped the relays. Fuel pump relay is clicking like a machine gun sometimes (during the no start) and gets hot. I'm thinking I need to get yet another relay and try again. Or is there some other thing that I should look at ?

[Matthew Currie]

It's my dad's rig. What it does is this:
It turns but doesn't fire up. Looks like no fuel pressure. Cleaned the grounds, swapped the relays. Fuel pump relay is clicking like a machine gun sometimes (during the no start) and gets hot. I'm thinking I need to get yet another relay and try again. Or is there some other thing that I should look at ?

You can just swap in one of the other relays, like the one for AC clutch, and see if it makes a difference. After that, if no change, I'd look for shorts in wiring, and perhaps a quick check for a shorted/seized pump motor, by simply unplugging it at the tank end and seeing it if makes a difference in relay behavior.

[Kejtar]

You can just swap in one of the other relays, like the one for AC clutch, and see if it makes a difference. After that, if no change, I'd look for shorts in wiring, and perhaps a quick check for a shorted/seized pump motor, by simply unplugging it at the tank end and seeing it if makes a difference in relay behavior.
Pump is on the list. Swapping out relays doesn't seem to do it though (did that last night) so unless there is more then one bad relay it's gotta be something else. Shorts is next on the list (tracing some of those wires is going to be a PITA).

[Hazardous]

I am having the same problem. I can bypass the relay with a test light and turn on the fuel pump. So I know that it is not a relay problem. I am thinking more and more of it being a security sys. issue. But I'm with you any help would be great.

[Kejtar]

I am having the same problem. I can bypass the relay with a test light and turn on the fuel pump. So I know that it is not a relay problem. I am thinking more and more of it being a security sys. issue. But I'm with you any help would be great.
Shouldn't be a security system as it would not be intermittent. The problem still persists. Oh well, now that I"m back in town I'm hoping to catch it in the act.

[Hazardous]

I must have worked on mine this weekend for about 4 hours. Its not a security thing or an ignition switch thing. I've got it down to the Green with orange stripe wire that comes from the ecm. I beleive the problem is there. With the voltage meter hooked up to it I get 6.4 volts while the relay is clicking. Now mine will click getting louder and louder until it all finally kicks on, then I can start it fine. I checked that wire after it was running and it had full power(13 or so volts). I belive it to be eather a bad connection at the coil, a bad coil, or the ecm? Hope this helps.

[Kejtar]

I must have worked on mine this weekend for about 4 hours. Its not a security thing or an ignition switch thing. I've got it down to the Green with orange stripe wire that comes from the ecm. I beleive the problem is there. With the voltage meter hooked up to it I get 6.4 volts while the relay is clicking. Now mine will click getting louder and louder until it all finally kicks on, then I can start it fine. I checked that wire after it was running and it had full power(13 or so volts). I belive it to be eather a bad connection at the coil, a bad coil, or the ecm? Hope this helps.
what year is yours?

[Hazardous]

1992 Limited 4.0 automatic. Tonight I'm thinking about putting 12 volts to the wire and seeing if it fixes it.

[Okee420]

check your crank sensor ,driver side atop of bellhousing behind the manifold follow wire and disconnect plug above manifold next to valve cover clean connections and try again it happens to my 90' about once a year I just have to wiggle connection sand starts every time, I also keep a spare one in the glove.

[Okee420]

This is a very common problem and can drive you nuts the first time it happens,cost me 600$ at jeep dealer first time after they burnt out ign. and the computer.New sensor is about 50-60$.good luck

[Hazardous]

The problem is that the system is not even turning on the fuel pump right away. The cps does not have anything to do with that does it?

[denver_dave]

I also think it is the crank sensor, the same thing happened to my jeep, thats what it was, .. also happened to my dads jeep down in texas, same problem- crank sensor

[SteveT]

Do you have spark at the plug? Are the plugs wet with fuel? Try to see if you have fuel , or spark issues.

[Hazardous]

I may be speeking on behalf of both Kejtar and myself. But the problem that we are having is more of a power issue to the relay?(multi function) In my case until the relay stops clicking the fuel pump is not even turning on. That wire that I was talking about earlier powers the coil and the fuel pump through that relay. I have not read and cannot find where this system is wired at all through the cps. The cps picks up the signal as the engine is turning over right? Judging by reading post from the past(no start), all the cps problems have begun with fuel pump turning on upon ignition. We don't even have that. Also once the relay kicks on the Jeep starts up just fine. If the power does go through the cps before it turns over, Cool, I will try to clean off that connector tonight. I guess I'm still sceptical. Kejtar are you still there dude, is any of this helping you. Nice to get some responses on this topic. Hopefully we can help out a lot of people.

[Hazardous]

Put a new computer in mine and it fixed it!!!!!!!!!!!!!!!!!!!!!!!!