no spark no spark NO SPARK!!!!!!!!!!

[javatrooper]

Just swapped in a 4.0 ho from a 92 Larado into a 93 Sport. Both engines ran before the swap. At first, I didn't get spark from plugs but I did get spark from the coil. After two days I go back out and no spark from the coil now. Bench test both coils I have and just a little off spec but I know they are good.

So, bought and installed new cap, rotor, wires, coil, and crank position sensor. Nothing. Swapped back my old distributor for the 2nd time to change the cam position sensor. Nothing. Dist not 180 degrees off, like that matters.

Tomorrow I will try to borrow an analogue volt meter and test the cam position sensor. Will also try and swap computers. After that, I have no idea where to look.

Any ideas?

[Airjer_]

Do you have power to the coil?

When you initial turn on the key you should have power for a couple of seconds and then none until you crank the engine over.

[javatrooper]

Checked it this morning. One line has 11.6 volts and the other had 3.4 or something like that. This is with the ignition on. Does that sound right?

Also, can anyone tell me the color of the pos and neg for the cam position sensor? I have a light brownish or off-white, an light blue in the center (which I think is ground) and a red wire. My diagram is for a grand cherokee and is different colors. I want to confirm it is working.

I also confirmed my home-made block ground was good. It is

And I ohm tested every fuse in the car, all good.

[javatrooper]

I just went out to recheck and here is what happened.

1st-- I busted the tab on the connector after taking it off about 100 times. shit

2nd--I get a reading of 11.06 volts from one side of the connector. the other side had a reading of 2.6--2.7. It would fluctuate as my fuel pump relay clicked on and off. (this is another problem that I thought was unrelated that began after the swap) when I unplugged the relay the reading went to 3.0 volts and held steady. The voltage never goes away.

I'm trying not to buy a new fuel pump until I at least get a spark.

How can a clicking fuel pump relay and clicking fuel pump prevent spark?

[Airjer_]

If there is voltage on both sides than there is a ground problem and voltage is feeding back through the ground. The PCM grounds the coil so there should be no voltage. If you have a test light hooked to the positive side of the battery and probed the ground side of the coil you should see the test light flicker when you crank it over.

[javatrooper]

Thanks for the advice. I think you've pointed me to the right direction. I think that the clicking rely for the fuel pump and the voltage at both coil connections are related. Maybe the wiring harness got pinched installing the engine. I was doing this solo... so maybe a power wire running to the fuel pump is shorting over to the ground of the coil.

Also, I think the auto shut down relay powers both the coil and the fuel pump so something in that section of the harness may be something shorting out.

Thanks again. I was getting close to giving up and selling my tools. About to go insane here.

[javatrooper]

Problem solved. Only took me a month. I feel real stupid here. Found 3 ground wires not connected to the block on the passenger side close to firewall. Thanks to everyone who tried to help.

[wrightz28]

K.I.S.S.

I used to have this posted in my garage to remind myself.

[ASE AMD]

Bad pcm grounds are always fun. I lost spark on a Honda civic once. 3 days later I found a loose ground on steering column caused by a stripped loose bolt.. it was the ground the pcm uses to ground the coil. Fun times.