New 304 Won't Start

I just finished rebuilding my 304. I can get it to turn over and run for a few seconds, but then it dies. I timed it per jeephammers directions, then put it back about 5* btdc. I know it has fuel, cause I can see it spraying in the carb. I don't know what else to do. I don't want to hurt the motor before break-in. Any help is appreciated.

 

What year/model?

If it runs more than a second or two, then it has to be running out of fuel, or losing spark. You won't damage the motor if it has oil pressure. A few seconds should be enough time to build up oil pressure.

 

75 cj-5, although I think the motor is from a 78. I'll change the fuel filter, although is appears pretty clean. Could it be the idle set or something like that?

 

I presume you still have the original Prestolite ignition system.

A typical problem with a '75 is a bad ignition module. I certainly sounds like that, if it really runs a few seconds (really a few seconds, like 5-10 seconds, more than just catching and then not running). Take the top off of the carburetor and see if the float bowl is full.

It could be the idle setting, but I presume you did not change anything, and it idled before your rebuild. You can adjust the idle mixture screws and the idle stop (idle speed) screw. Adjust the idle speed so that the throttle plates are obviously open. Set the idle mixture screws to, say, 2 turns from the bottom.

 

I haven't tried starting it again but I did put a new filter on. So Timgr, are you saying that if it runs for like 5-10 sec and could be the ignition module? It does only run for about 10 secs, them chugs down and dies. It almost souns more like a gas problem. I'll take off the carb top and take a look. Also, are there supposed to be 2 gaskets (one above and below the plate) for the carb?

 

Fuel seems intuitively more likely, but a bad ignition module could be the problem.

There's only one gasket under the carb top. You can remove the carb top with the carb on the car (that's what I would do). Take the center bolt out and the screws around the edge and you can peak under the top; it will still be held on by the choke plate rod - I don't recall if you can wiggle that out or not. The engine will run with the carb top off, but I don't advise it. The carb base needs a gasket of some type between the insulator and the carb, and the manifold and insulator... assuming you have an insulator.

 

have you checked for any vacum leaks?

 

I haven't checked for vacuum leaks yet. But while we're talking about that, I have the egr valve going to the top port of the egr cto and the second port is hooked up to the port coming off the front of the mc 2100. Is this correct? BTW, I have put on a new fuel filter and fuel pump but have notice that the filter is only filling up about half way. Shouldn't the whole thing fill up?

 

ok I fixed one problem and got 2 more. the timing was alittle off. got that fixed and she fires up. now, my new oil gauge doesn't work. I ground the send unit wire and it goes up to around forty. so now I guess my sender is bad? its brand new as well. I was reading somewhere about there being two senders, but I don't know how to tell which one I need. Does anyone know? The other problem is the temp seemed a bit high to me. After about 5 mins the temp got to about 205. This was with the jeep in the garage with the door open (obviously). I shut it down for fear of causing more problems. Is this temp ok. BTW, I haven't hook up a mechanical oil gauge, but there is oil in the heads so I assume I have got goo pressure.

 

I forgot to mention, I have a mechanical gauge with the probe in the thermo housing and I also have the stock gauge hooked to the stock sender. The mech gauge was reading 205, while the stock gauge was just coming up in the green, like a quarter way.

 

Ther sender for a guage looks like this:


The listings I looked at are a mess. This is a picture of a Standard PS219, which I presume is right. The proper way to test your gauge is to substitute a fixed resistance for the sender. There should be a resistance spec in the FSM.

I would expect the gauge to peg at the top or bottom when you short the wire, so that puzzles me.

JMO - the factory electric gauge isn't your best option. I have a full-sweep mechanical gauge in my CJ-6.


You can test your temp gauge with a pan of hot water on the stove. Compare the readings to a thermometer.

205 is high if you have a 195 thermostat and no load.

 

hmmm, had to turn the idle up??
I'd say it's a vacum leak somewhere, (hopefully not the intake gaskets)
or your EGR might be stuck ON. Might be your idle circuit is clogged, (was the carb "tossed @ a bit when it was off)???
When it "stalls" does a pile of gas vapor leak outta the top of the carb??? (like the float was stuck and flooding-hence the chugg a lug when it's running).
How's the plugs?? wet fouled???

As for you oil pressure.
Put a ohm meter on the sending unit, It should have contunuity with ground when OFF, (light on), and lose it when you fire.
Here's hoping you have a bad sender and not 0 oil psi!
Joe
Aren't rebuild problems a blast??chainsawguy
"Did I do this or was it somehting wrong BEFORE"?????
Jeeps you gotta love 'em

 

Replaced the electric oil pressure gauge with a mechanical one. Works great...60 psi of pressure. Now I gotta work on the temp issue.

 

Is the water pump new? Are you sure water is circulating ? The reason I ask is I just had this problem on a 258, Bought a new water pump from Auto Zone, told parts guy standard rotation . Thought no more of it, put it on, Wrong rotation! Parts guy says standard is now reverse . ?? Went to napa and bought correct pump. Fixed problem. I should of checked.

 

I'll go check that out...good point.