engine starting Questions

[Jeeper guy]

   So I got my rebuilt motor all hooked up and in and have a few questions. I went to start it and it cranks but no start. Ive got spark from my main coil wire, i can smell fuel from the throttle body and it wont start on ether. I beleive i have all sensors and wiring all hooked up. I think it could be the timing is off or the timing of the spark from the distributor cap. This is in a 90 yj with throttle body injection, if you have any suggestions or tips that would be helpful...

Also does anybody know the bolt size for the throttle body to the intake manifold? the old motor/intake had just studs.


Thanks Alex

[OJTV8CJ]

Have you checked the CPS? (Does it have one?)  If it is bad then sometimes it will think that TDC is wrong and throw the timing off.

Pull the plugs out of the motor and see if they are wet with gas.  That is a better indication of fuel than smelling the throttle body.  Checking it with a gauge is the best option.

Is the distributor off?  On the newer motor's the distributor will only go in one position and the computer adjusts from there.  Set the motor on TDC and then reset your distributor to the correct orientation.  Even if the distributor only goes in one way it - if the motor isn't on TDC when you stab it, you will be off.

You didn't say what you have done, but I am just spit balling here.

[Jeeper guy]

Yea i believe it a has a cps, but i haven't checked that yet, ill pull the plugs when i get home and see if they are wet. I am going to set the distributor to correct orientation and adjust. the Chilton's Manuel said you can not adjust timing on the motor because it is controlled through the ecm...

as far as what i have done, it is a rebuilt 4 banger that i swapped out for my old 4 banger. i really haven't done much to it yet to figure out what the issue is(not enough time in the day)... ill post back up tonight with what i find.

Alex

[Jeeper guy]

Ive got spark at the plug wires and tried to adjust the distributor/ spark timing and had no luck? im not sure if i did it correctly though...

[CRAZY LARRY]

bring the timing mark on the crank to tdc. pull the distributor cap to se where the rotor is pointing. it should point to the #1 wire. but it can be 180 out and still point to tdc. hope this help.also did you change out the whole distributor or just parts.the lifters  might need to get pumped up so they can open the valves all the way.

[Jeeper guy]

I brought the motor to tdc and made sure the rotor pointed to the #1 plug wire, and that didnt work. The parts that I swapped from my old motor was the just the cap and rotor, when that didnt work i tried my whole distributer assembly, that didnt work. So i just put the one that came with the old motor back on.

[CRAZY LARRY]

did you prime the oil pump cause the lifter won't be pumped up so the valves won't open

[Jeeper guy]

Larry that might just be the issue, do i just hook up a special tool to the oil pump and use a drill to spin it and that will prime it?

Thanks for all the suggestions guys

Alex

[OJTV8CJ]

Larry that might just be the issue, do i just hook up a special tool to the oil pump and use a drill to spin it and that will prime it?

Thanks for all the suggestions guys

Alex

Yes, but you will have to do it for like a minimum of 5 min.  "Normally" the lifters are soaked in oil before installation to alleviate a lifter problem like this.  If this is what it is.  I would suspect that "if" it is a lifter problem and you are trying to start it - it "could" have bent a pushrod.  I don't think this would be the case, but if some are up and some aren't it can happen.  I really don't think this is why it isn't starting but a compression check will tell you.

Have you tried starting fluid in the intake?  You have spark but do you have enough fuel? 

I still suspect a timing issue.  Everytime that I have had a problem with a Jeep not starting it is a timing issue.  They are so finicky about the distributor/ignition/CPS problems.

Do you have a timing light? (I imagine that you do as I can't imagine you talking something on like this without one)  Put your timing light on the number one wire and have someone else crank on the motor.  Make sure that the light is going off when the rotor bug is pointed to the correct orientation.  Then do the same thing and look at your timing mark on the front of the motor.  If you can't see it on the 0 degree - either the CPS is bad or the distributor/ECM is moving the timing advanced/retarded too much to fire.

It isn't barking or hitting on any cylinders at all?

[Jeeper guy]

yes, I have tried starting fluid in the intake and that didnt do anything. One time it acted like it kinda fired but i didnt do anything after that. No I do not own a timing light. If sombody has some free time one night to help me sort this out and hook up a timing light that would be greatly appreciated. Ill prolly hook up to the oil pump and prime it also.

Thanks, Alex

[OJTV8CJ]

I am like everybody else - I am going to be out of town until Sunday.

If you don't have it done by next week, I could probably find a little while in the evening to come see if I can help.

One other thing to do is move the plug wires 1 position at a time to see if that changes anything. Just a thought. It will cheat the ECM timing a little bit.

Good Luck!

[Jeeper guy]

well tonight i primed the oil pump wich seemed to help, I primed it until i had oil pressure, i did that twice tonight. then i set #1 to tdc and pointed the rotor bug to the first plug wire, this helped. I thought it was gunna start once, it back firing now and alot of "barking". so hopfully im getting closer to getting it started.

Alex

[OJTV8CJ]

If you have it that close you are probably 180 degrees out on your timing.

[Jeeper guy]

Well i tried it again last night and today and it just wants to backfire out of the intake, turned it 180* 0r 90* and still about the same outcome. It feels like it is so close to starting it is driving me crazy cant quite get it on the right timing....
     I also pulled the valve cover and hooked up my drill to my oil pump and pumped it for 10-15 minutes and made sure the oil flowed through all rods good. 
     Maybe a valve isnt opening?

Alex

[OJTV8CJ]

Nah, if it is firing you are close on the timing.  Can you move the distributor by one tooth on the drive gear?  With the preset or non-adjustable distro's - I can't remember.  If it is firing and barking you are "close".  Are you sure that you are at TDC on the intake stroke and not the exhaust stroke?

Try moving the plug wires by one position, if it gets worse move them the other way.