ignition fails on four cylinders

[meedel]

I have installed a 4.0 HO engine from a Grand Cherokee in my Wrangler Y(R) in combination with a AX15 transmission and all the wiring. It's a 4.0 HO from '94 with 40.000 miles and injection.
What I can see now is that the ignition only fires at cylinder 3 and 4 ( 180 degrees )
I have allready changed the distributer, coil. What could be wrong ?

[fredjacksonsan]

94? It has cap and rotor. To start I'd replace those as well as check the plugs. And the wires.

[meedel]

Originally Posted by fredjacksonsan

94? It has cap and rotor. To start I'd replace those as well as check the plugs. And the wires.

Fred,
Thanks for your reaction.
I have allready changed the cap and rotor as wel as the coil.
If I connect a good wire and spark plug directly to the coil, I see the plug firing three (fast) times, rotor turning 180 degrees, and firing another three (fast) times, turning 180 degrees, firing three (fast) times, and so on.

I've checked the timing. This seemes to be good.

Is there any way to check the computer, besides the professional way ??

Regards,

Bert

[fredjacksonsan]

Originally Posted by meedel

Fred,
Thanks for your reaction.
I have allready changed the cap and rotor as wel as the coil.
If I connect a good wire and spark plug directly to the coil, I see the plug firing three (fast) times, rotor turning 180 degrees, and firing another three (fast) times, turning 180 degrees, firing three (fast) times, and so on.

I've checked the timing. This seemes to be good.

Is there any way to check the computer, besides the professional way ??

Regards,

Bert

Bert, you said you connected a good wire to the coil? Ok so you have the coil firing.

Have you made sure your plug wires are in good condition, and that they are secure on the cap and plugs? If the coil is firing, then I'd think there is a problem from there to the plugs.

Don't know about the computer thing for sure, but don't think it would cause the problem you're talking about (of course I could be wrong....)

[meedel]

Originally Posted by fredjacksonsan

Bert, you said you connected a good wire to the coil? Ok so you have the coil firing.

Have you made sure your plug wires are in good condition, and that they are secure on the cap and plugs? If the coil is firing, then I'd think there is a problem from there to the plugs.

Don't know about the computer thing for sure, but don't think it would cause the problem you're talking about (of course I could be wrong....)

Fred,

I don't think the problem is the cap or rotor. I have changed them both, and even the coil, but got the same results.
I get firing from the coil, but with a strange interval. As I sayd, it's an interval of 180 degrees.
So just after point 'zero' it fires three times very quickly ( at position cylinder 4), then it 'waits' till the rotor has moved for 180 degrees, and fires again three times very quickly ( at position cylinder 3 ).

So I think it must be something before the coil. The coil reacts on a signal from ?????

I tried to 'fake' the sensor, when removing it from it's position at the flywheel, and 'swinging' a metal peace in front of it, but I didn't get any signal from the sensor. So this test option doesn't work.

I have rebuild my whole Wrangler, so it's frustrating not to find what's wrong this time.

I wil send you my website link, when it's ready. There I explain all the things I've changed on my Jeep.

Regards,

Bert

[fredjacksonsan]

Your post reminded me....have you checked/replaced the camshaft position sensor and/or the crankshat position sensor? Those may be causing your problem and are worth a check.

You've already probably checked or swapped your plug wires to make sure they're goo.