No spark and no power to the fuel pump

[Jeepfanatic89]

Alright so I have a project comanche that I haven't been able to get to run in months I've replaced many parts including the distributor cap and rotor many new wires, ignition coil all of the relays and fuses and I still have no spark or power to the fuel pump is there something I'm missing that could cause this 

[Ωhm]

Try cruiser tip 7:  Crank Position Sensor (CPS)

[Jeepfanatic89]

I replaced the cps last year could it fowl out that quick 

[Ωhm]

CPS is common to both of your problems. Take the voltage (ac) measurement.

[carnuck]

On the fuel pump, does it pressurize the system for 3 seconds when you turn the key on? If not, check the ground behind the left tail light and the harness plug on the frame under there.

 

 

My Comanches:

2nd Louey 1987 SB

First Louey 1988 SB

90 MJ LB parting out.

[Marine1Texas]

you need to work on the fuel side 1st then go to the firing side. like ^ both above said cruiser tips. Grounds, for fuel pump are behind the driver side rear stop lamp. Can be one issue there. After you make sue that is good, you need to start at the pump and see if you getting power. like above said, are you getting power for the 3 seconds when you move key in to run mode. If not you need to check that ballast on the driver side of the bonnet/engine bay. see if broke, disconnect and if working. You can temporarily bypass it if needed. If all working there then you need to trace wiring back to fuse box.

 

The cps is know to get dirty and have a real weak signal. they have some mods in cruisers tips to drill it out and get the thing closer to your fly wheel. Cruisers tips will probably solve your problem.

 However there has been bad ecu's on some and dripping master clutch's that eat away the inside of your fuse box, causing a load of gremlins.

Steps, cruiser tips, then fuel and fuel wiring, then cps and other wiring

 

[Jeepfanatic89]

I did replace the clutch master cylinder that was dripping fluid on the fuse panel. the ballast resistor was the first thing I checked it blows those frequently and it was running then just died. As far as the fuel pump normally you can hear it kick on when you turn the key but it's not doing that but I haven't checked the relief valve on the fuel rail to see if it's built any pressure. I'll have to check the grounds I've replaced many of them already.

[jdwillys]

This is a stretch, but did you possibly unplug the wiring harness that goes from driver side tail light to the passenger side tail light (the plug closer to the passenger side). That must be plugged in, to complete the ground.

[Jeepfanatic89]

Hey guys I know it's been a while but I finally broke down and bought a new ecm for the Jeep. I have fuel pressure when I turn the key on but I still don't have any spark and can't figure out why 

[Marine1Texas]

check your crank position sensor. could be dirty, bad connection, fried wire or just bad.

[Jeepfanatic89]

I put a brand new one in it less than a month ago 

[DirtyComanche]

First I would check the cranking voltage output from the CPS.  Lots of the aftermarket ones are junk, there is no saying you didn't get one that's bad out of the box, or that it isn't too far from the flywheel.

 

After that, the ICM is kinda the only big component left in the ignition system.  Since I have a spare, I'd try swapping it first.  If I didn't, I'd probably chase some wires.  You should be able to get a FSM with decent wiring diagrams off Cruiser's site.

[cruiser54]

TEST the CPS. Most replacements are JUNK.

 

http://cruiser54.com/?p=50

[Ωhm]

Also, make sure your IGN Module is powered up (I1 feed) and module is grounded. C213_A (I1):C213_B (GND). From 88 electrical manual.

[Jeepfanatic89]

I ohm tested the cps I'm getting about 205 and I did a voltage test on it. It's running anywhere from     . 7-.9 and the icm is pretty much the only thing that I haven't replaced 

[ComancheKid45]

Check wiring above the parking brake assembly for wear/shorting. 

[Pete M]

and don't forget the CAMshaft position sensor too. it can also cause a no-spark.   

[carnuck]

On Renix? Mine ran with dist (with Cam sensor) unplugged


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