Have gas and spark but will not fire???

[jeepinandy]

(EDIT) I'm no pro mechanic by any means. Just trying to help ya out here. If any of this is wrong someone please correct me...

Since the dist is mechanical, it has to be either timing chain/gears, or the dist gear, and/or cam shaft problems, since the dist gear runs off the cam shaft.
Would probably be easier to check the dist gears first. See how they look when you pull it out, if there is any gear problems with the dist gears or cam gears you should be able to tell, look for unusual looking marks on the outside of the gears where they could be slipping and check for chipped teeth, because if they're chipped, more than likely it was caused by some peice of metal from broken teeth.. Then check the timing chain and gears and see how they look, chain tension etc.
If that all checks out, or you replace parts as needed.
Put it all back together (in time firing on 1 on TDC on compression stroke, that is VERY important..)

Hope that helps..
:cheers:

 

[langer1]

Thing is you need to index the engine first before you yank the distributer.
Once you do that you will know if you need to pull it.
Once the engine is properly indexed if the rotor is on number one, no need to pull it out and look at anything.

My only point is there are much easer and safer things to do first.

 

[nate438]

That is what I said in a earler post if you read it. I put the enigne at top dead center and checked the position of the rotor "indexed it" and it was way off. That is why I'm pulling the dist.

 

[langer1]

That is what I said in a earlier post if you read it. I put the engine at top dead center and checked the position of the rotor "indexed it" and it was way off. That is why I'm pulling the dist.

I did read and I think you were TDC on the exhaust stroke not the compression stroke. that would better explain the rotor pointing in the wrong direction.

 

[nate438]

Yes but I also said in the same post I turned the engine again to the next top dead center which if I was on the exhaust stroke the first time this ment I was on the compresion stroke this time and it was still off. I found out how to tell which stroke it is on for sure and I can garantee you it's not pointing at the #1 plug wire.

 

[langer1]

Where is #1 Nate?

 

[nate438]

Still here wokring on it as we speek.

 

[nate438]

Well I pulled the dist. and everthing checked out fine. Teeth on the gear were fine and evething looks lormal, checked and the oil pump spins freeley. I put it back together and re-indexed the dist. put a new set up plugs in it and it fired right up! :eeks1: I took it out and drove it hard for a bit to clean the cylinders out of any extra fuel that had been pumped into them. I checked the plugs and it's running on all cyl, no wet or dry pugs all nice and tan, but it seems to run just a little rough still. Not back to 100% normal like it used to be. It has been sitting during this whole process for 2 weeks now and I'm just wondering if my gas is not helping the issue at all here? I went through the manual on cause I thought maybe I could adjust the timing a bit but no where in my chiltons does it even mention using a time lite on a 1990 4.0, it says once you get the dist in the correct position that the power train contol module will take care of it from there. Not sure if this matters but I also found one of the 3 wires to my O2 sensor on the exhaust was broke so I fixed that as well.

What do you guys think? Timming still, bad gas maybe or could a bad O2 sensor casue this since it apparently had had a wire broke for while? Or if the timing chain did jump a tooth and threw it out of time. Now that I re-timed it wouldn't the crank position in corilation to the cam still be off?

Of couse we still don't know what casued the timing to actually change either, that sucks.

 

[langer1]

The timing is done by the computer using the CPS and is not adjustable.

Yes the timing chain could have jumped but that would show up in the indexing
You would not be able to get TDC with both valves open.
Could you have water in the fuel, that would be hard to find with fuel injection.

 

[nate438]

Hmm, then maybe it didn't because I did have tdc with both valves open, I made sure of that! Strange. I did do some more looking and found a vacume line that was not sealing up very well, got that good and snug and changed the oil and to my suprise it runs great now! In fact it has never ran this good, kind of scarry but I will just ejoy it while it lasts.

Just wanted to say a big thanks to everyone who helped me on this, could not have done it without you!!!!

Nate

 

[langer1]

To bad we don't know what the problem was

 

[nate438]

Couldn't agree more.

 

[jeepinandy]

I agree on not knowing what the problem was, it may show it's ugly head again...
But anywho, glad you're up and running again!