Post propane install issues, help!

[Tallz]

I recently installed a Gotpropane kit on my 78 CJ5 304. I filled the tank and checked everything for leaks. The first time I cranked the motor it did not start and after I cranked it for a few seconds it backfired through the exhaust. This happened more than once. So I bought all new distributed cap, rotor, wires and plugs. then again tried cranking the motor it no longer backfires but still won't start. I then tested the coil and it tested good. I also checked all the fitting on the propane kit and everything was good. I also tried leaning out the mixture on the propane body before the plug change, but put it back where it was after the plug change.

I've heard the got propane kits run better with a little more advance in timing. Should I try to advance the timing? I've also heard or seen on other forums it's a good idea to increase the plug gaps to .25"?

A couple background items, I installed a new Painless wiring kit and the motor sat for two years before the propane kit and wiring kit were installed, I don't know if this will matter, but there it is.

Does anyone have any ideas on the subject? Any info would be greatly appreciated as I am stumped.

 

[driver920]

we installed one of those kits on a 350 not long ago and had no problems with it but if everything appears right in the install i would say maybe put a carb back on it to see if it fires that way other than that i would have to see the system to trouble shoot it

 

[Tallz]

we installed one of those kits on a 350 not long ago and had no problems with it but if everything appears right in the install i would say maybe put a carb back on it to see if it fires that way other than that i would have to see the system to trouble shoot it

Up until last night I was figuring there was something wrong with the propane system, but after a good nights sleep I am starting to think something in the ignition system is wrong. Everything I have heard about the gotpropane system is it's good to go right out of the box for my V8. Other than a little tuning, it should just fire right up.

 

[kawzx10]

I installed my gotpropane kit about a year ago. I could not get it running good for the life of me. It was backfiring and wouldn't run. I had just rebuilt the motor and had some vacuum leaks on the intake. apparently these kits depend on vacuum to pull the pane. Once i got the intake sealed up it ran like a champ.

 

[blznnp]

havn't had any problems with my kit, engine runs way better than my old carb but then again, my carb needed to be rebuilt. Like kawzx10 said, you don't want any vacuum leaks with a propane set up. The only other thing other than vacuum that I would check is make sure your distributor isn't 180 out.

 

[Tallz]

Today I spent a fair amount of time checking, again, my wiring and again the ignition system. I found the (resistor?) on the coil, the wire was pulled out and probably part of the problem. It looks to be broken off inside so i cant splice on a new one. I also checked points and dwell, but that seems ok. When I went online to check prices for a coil I came across a link for an HEI replacement distributer with plug wires for under $200. I went ahead and ordered one, from what I read it's a worth while investment at minimal maintenance and hotter spark? Hopefully that will solve it.

On the topic of vacuum leaks, how do I test for a vacuum leak on the intake?

 

[Tallz]

havn't had any problems with my kit, engine runs way better than my old carb but then again, my carb needed to be rebuilt. Like kawzx10 said, you don't want any vacuum leaks with a propane set up. The only other thing other than vacuum that I would check is make sure your distributor isn't 180 out.

One more note, the jeep ran great before I parked it 2 years ago. So I figure the distributer is the the right location. I also checked today for a possible stuck valve and all is working well.

 

[kawzx10]

Are you cranking it with out pushing on the gas? If not have you tried it while giving it gas? I had to give it half throttle to get it to start when it had a vacuum leak.

 

[Tallz]

Are you cranking it with out pushing on the gas? If not have you tried it while giving it gas? I had to give it half throttle to get it to start when it had a vacuum leak.

Nope, 1/2, 3/4 throttle. At first that's when I was getting the backfiring. Now I give it a couple pumps while starting but nothing, not even a stutter.

 

[kawzx10]

I used the starting fluid trick to check for vacuum leaks. You spray starting fluid on possible vacuum leak spots and it messes with the idle. Mine was kinda running though. I can't remember how much throttle I was giving it but it was atleast half maybe even full. It was running really crapy and wouldn't stay running without staying on the gas.

 

[kawzx10]

Have you checked for spark how does it look?

 

[UFAB]

First off check your timing and spark after all of your past adustments, check all the intake fittings to include brake booster and vaccum lines. Vaccum is the most important feature with getting the propane to prime from the regulator. There is a primer button on the vaporizer you can push to give more fuel to the regulator. Perhaps a shot of starting fluid will help fire and create a bigger vaccum to pull.

I have installed several got propane kits from Cary, had a few not work out of the box. Problems included a bad diaphram in the regulator, no spring inside the vaporizor, missing set screw.

One 22RE setup I had was so bad at start up every time that I made a bypass vaccum storage system with an electric solenoid hooked to the ignition switch.

Also check your supply line, making sure no blockage in your hoses to the vaporizer, electric solenoid charged and open? Unhook the hose from the vaporizer to the regulator, push prime button, should blow really cold vapor.

Good luck

 

[mighty midjet]

Choke it! when i installed a propane system on my bug i could not get the propane to flow until i manually choked it and the vacuum from the engine pulled enough to open the diaphragm in the regulator. put your hand over the mixer/carb while somebody else turns it over and wiggle the throttle back and forth

 

[Tallz]

Thanks for the great suggestions. I am going to install the HEI distributer, check the timing again and the try some of the suggestions above. If nothing changes, I will update this thread and go from there.

I think the got propane system is a really good one, but unfortunately the instructions that come with the kit are really, really vague. I wish they had a little more detail included, better organization and a trouble shooting section. I hope some day they will realize that not all the installers of the system are experienced mechanics and when problems do arise any level of installer can get tips and tricks directly from the source.