Fellow Comencheros help!

[rics87]

I hope this post will not go on too long, here goes.1987 4.0 5-speed 185,000mi on clock still orig engine. Broke down 2mos. ago found the dist gear broken,replaced re set dist. by placing at TDC moved oil pump to 11:00 pos. as per how to reset timing once engine turned.Popped in and pointed to #1. Start engine idles,But stumbles and spits thru pipe @2000rpm.Replaced evry known sensor on truck! evn new injectors.No plugged cat. Still no resolution.At my wits end,but not giving up.

[Geonovast]

With #1 at TDC, the rotor should be pointing just past #1 post, not directly at it.

[rics87]

okay, so the rotor should be just past #1? do you mean its' whole witdh? i'll try it thanks

[mvusse]

Yup, sounds like your timing is off. By more than one tooth too.

[Eagle]

You could also be 180 degrees out of time. Remember, the crankshaft goes around twice for every one revolution of the distributor, with each cylinder coming up twice -- once for compression (which is when it fires) and again for exhaust. Let's just say that I know how easy it is to forget that, and set the distributor so it's firing on the exhaust stroke.

[Geonovast]

You could also be 180 degrees out of time. Remember, the crankshaft goes around twice for every one revolution of the distributor, with each cylinder coming up twice -- once for compression (which is when it fires) and again for exhaust. Let's just say that I know how easy it is to forget that, and set the distributor so it's firing on the exhaust stroke.

 

I don't think that's it, since he says it runs. But his dizzy is definitely off.

[airspeed]

I had a similar situation with my 2.5 when I was putting it together. The distributor post is a 4:00 and the rotor needs to be set at 6:00. I kept looking at that and thinking this can’t be right, I had two different manuals and they both said the same thing. You stop and think the engine actually fires ~ 10-15 BTDC, that rotor is probably in the right place.