Hello, so I've had my 88 d100 for 4 years. Just discovered it was running 40 degrees out of time which I thought explained the lack of power. When it was put back in time it would cut off when put in gear. I replaced the timing chain but when I stab the distributor with the button facing center it will just keep spinning and not fire but when the button is facing the firewall at tdc it fires but won't stay running. Also the the wires 6 and 1 are reversed but following correct firing order. Any idea on what's going on, thx

 

Assuming this a small block from your description.

If you have a timing light start it and add some advanced timing.

If you don't, turn distributor counter clockwise to advance timing.

This should work if firing order is correct and in correct rotation.

 

Yes, sorry it's a small block 318. I have tried advancing and retarting the timing but I can't find that sweet spot. Also if it idles below 1200 rpm it will not stay running.

 

I would stop take a breath and go back to basics.

High idle could be carb/manifold leak. Are you starting with vacuum advance hose off and plugged?

Do TDC ON COMPRESSION STROKE! Set oil pump drive slot pointing at drivers side first front manifold bolt, drop in distributor pointing forward, start #1 wire there, then looking down going clockwise #8 next then #4 and so on. Turn distributor counter clockwise so rotor "button" is before #1 (between 1+2). Remove vacuum hose from distributor and plug with golf tee or screw.

Engine should fire right up first time if you do this.

 

some people are confused that when the cam gear timming marks are lined up that the dist rotor is pointing to #1 plug wire BUT it is not it will be pointing to #6 plug wire. and what my friends just said is right. here is a saying my dad cam up with to keep straight the plug wiring.
Mopar single fire V8 dist cap wiring
My dad made this saying about small and big block dist cap wireing. To reduce wiring confuseion. “the small block has the dist in the wrong place, in the back of the engine. BUT the shaft rotates the right way clockwise. The big block has the dist in the right place, in the front of the engine BUT the shaft rotates the wrong direction counterclockwise. Both wire #5 and #7 on both ALL ways have #5 before #7 on the cap AND block. And most / some stock V8s have the fireing order cast in to the intake manifold. And more info: if the cap has a vent hole next to the center tower. Plug it with JB-weld.

 

If your motor was actually 40* out of time ? IT WOULD NOT RUN !!!