68 CJ5 buick 225 oddfire V6 not firing on cylinders 2,4,6

i just bought a 68 CJ5 ran good except under load or when you rlly got on the gas it would cut out and backfire i figured it just needed a carb cleaning but now its not firing on the passenger side bank of the engine only 6 fires everynow and then any ideas as to what it could be? i was told possibly the distributor but i checked it thoroughly and its all timed right so im lost as to what it could be id appereciate any input, thanks in advance

 

well i just cleaned the carb just now after my troubles started it helped the side that fires runs even better now but cylinders 2,4,6 still aint firin

 

So at this point, you don't know if it is ignition or fuel. correct? Put your timing light on nr 2 (while engine is running) and see if it will trigger the timing light. If it is triggering then move to nr 4 then 6. If all are triggering the light then you problem is most likely fuel.

 

well i dont think its fuel due to the fact i took apart the carb today but it could be and well i know the plugs are sparking i just dont think its at the right time

 

Are you sure it is an odd fire distributor?

 

whats the difference?

 

Check your points/dwell, it can cause this.

 

well its a prestolite distributor i dont know anything about them

 

well its a prestolite distributor and i dont know anything about them

 

I've never worked on a prestolite either, in the 39 years i've had v6's, i have only had Delcos.
It might be time to upgrade the distributor?
Still, check the points.

 

yea everyone i talked to is like whats prestolite so yea im thinkin dist upgrade and i checked the points they seem fine but know of anywhere to get a good cheap one for these engines? ive had a hard time findin any

 

Huge difference. But, did it fire on 2,4,6 before you worked on the carb? If you didn't change the dist and it ran before it probably isn't that. Did you put a new cap on the Dist.? I don't see how a carb problem could possibly cause mis-firing only on one bank of cylinders. Does it have a GM style HEI distributor (coil in the cap)? Here's something you can try. Move all the plug wires at the dist. cap one post clockwise. After you do that, does it only fire on 2,4,6 and not on 1,3,5?

 

Don't do what Posimoto said,yet.
Try replacing the points first, I hope you have access to a dwell meter, or set them with some feeler guages or try the match book method that is talked about on this site now.
Get the points from a good source, Napa, Carquest etc.. not O'Rileys, I've seen several point sets that were junk from O'Rileys due to improper assembly.

HEI distributors for your Jeep seem to be for sale on the internet fairley regularly.
Next best is to get a Delco dist and put a pertronix in it.

 

Napa carries parts for the Prestolite. I had one in my Jeep & it ran fine, it;s just harder to work on than the Delco.

 

it used to run pretty rough on 2,4,6 then it quit and just 6 fires sometimes but i worked on the carb after it quit runnin right and i put the carb back on and it still wont fire on 2,4,6 but it has the stock prestolite distributor in it with what looks like a newer prestolite cap but it looks to me like a even fire cap meaning all the points inside the cap are evenly spaced would that effect anything?

 

well i dont have a dwell meter i might have a buddy with one so ill ask and i guess make a trip to napa later i just dont wanna drop $200+ on a distributor unless im sure its the problem

 

then don't guess....figure it out.
fuel and electrical problems can give similar symptoms.
do the fuel check first..make sure the carb is operating correctly.
then check for spark, etc etc.
nothing wrong with using the Prestolite distibutor, they are dependable.
don't shotgun repair, or you'll never figure out the problem.

 

Carb doesn't know which cylinders are firing and which aren't, and has no control over which ones do. It might run rough because of a bad carb, but not only on one bank of cylinders. A compression test on that side of the engine might indicate if you have a totally trashed head gasket which could cause the whole bank not to run. I'll be amazed if it's a fuel problem.

 

I agree with Patrick - spark not fuel.

You mention the distibutor cap may be in question - I haven't seen the prestolite cap so I can't comment on what it should like. Could you take a picture and post? Then someone with the correct cap could maybe tell? Or maybe someone would be able to post a picture of the correct cap?

Or, maybe go to NAPA and look at a cap if they have one (or look at a picture book is they still have one).

Also - check plugs & wires, compression check.

Good Luck