Engine Cj7 304 crank won’t start

[Agreenlee]

I have a 1976 CJ7 304 auto trans. A month ago while driving the water pump went out. I drove it onto my trailer and towed it back home. When I got back home it wouldn’t start. I pushed it off the trailer into the garage and I started looking into it before I started on the water pump and it was a bad ignition module. I replaced with a new module and started right up. After replacing the water pump I tried to start it to bleed the system and it just turns over and shakes while cranking. I checked for fuel and spark and I have both. It started once for maybe 5 seconds and it was rough as if the timing was off. But I did nothing to mess with timing. During one of the start ups it backfire through the carb. Is there any suggestions on what it might be? Everything is stock on it. Carb was rebuilt this year along with new fuel system, plugs, wires, coil and starter solenoid, i haven’t touch the distributor but it ran perfect before the water pump going out.

 

[Manic Mechanic]

I'd double check the firing order after setting it to tdc (top dead center) just to rule out. To me it sounds like it's 180⁰ out. Dunno how sense you were driving it but stranger things have happened with Jeeps before

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[Armyvet25]

I have a 1976 CJ7 304 auto trans. A month ago while driving the water pump went out. I drove it onto my trailer and towed it back home. When I got back home it wouldn’t start. I pushed it off the trailer into the garage and I started looking into it before I started on the water pump and it was a bad ignition module. I replaced with a new module and started right up. After replacing the water pump I tried to start it to bleed the system and it just turns over and shakes while cranking. I checked for fuel and spark and I have both. It started once for maybe 5 seconds and it was rough as if the timing was off. But I did nothing to mess with timing. During one of the start ups it backfire through the carb. Is there any suggestions on what it might be? Everything is stock on it. Carb was rebuilt this year along with new fuel system, plugs, wires, coil and starter solenoid, i haven’t touch the distributor but it ran perfect before the water pump going out.

A bad module can fail by triggering continuously even a new one if defective, but usually they work or don't. I'd double check firing order like mentioned, pull the dist cap and crank looking for jumpy rotor turn like a bad timing gear, set at top dead center see where rotor is aligned. I have a couple spare modules one Ford one AMC I believe, have no idea if both are good but were removed from running engines. Free to anyone who needs them, if you don't want a used one or think you need it, up for grabs by anyone else. Pay postage and yours, also a new mechanical fuel pump for the 4.2.

 

[Agreenlee]

All the wires are in correct firing order and I removed the distributor cap and set the number one piston at TDC on compression and the rotor was aligned with number one piston.

 

[Manic Mechanic]

All the wires are in correct firing order and I removed the distributor cap and set the number one piston at TDC on compression and the rotor was aligned with number one piston.

Pour a little gas in the carb (air cleaner off) and try and start it. If it fires and runs for a few seconds then you have a fuel delivery issue

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[Agreenlee]

I’ve tried both gas and starting fluid and no luck.

 

[Manic Mechanic]

I’ve tried both gas and starting fluid and no luck.

And your sure you're getting spark

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[Agreenlee]

Yes I’ve put a test light on each plug wire and pulled all the spark plugs and grounded them and they all had a bright blue spark

 

[Armyvet25]

back to basics, pull the plugs and see if fuel or oil fouled, may also have to check compression to see if cam wiped

 

[Agreenlee]

I figured it out but don't understand it. After trying everything with fuel, spark, and timing I put the old ignition module back in to check compression since it wasn’t giving spark and it fired right up and ran perfect. I plugged the new one in that was working and still gives it spark and it won’t start. I’m replacing the new module with a different new one to keep in the glove box. Thanks for all the help