Engine Misfire

[Dan]

My GW has recently developed a bad misfire. I just rebuilt the carb, knowing that it needed to be done anyway to correct some idling issues, and I had hoped that might fix the misfiring. I think it did help the idle issue, but the misfire is still bad. I'm thinking timing chain (145,000 miles and I'm unsure if the PO ever replaced it)?

Can anyone help me diagnose the cause? What is the easiest way to tell if the timing chain needs to be replaced? Ignition timing adjustment does not seem to help at all.

[64Trvlr]

When did the backfiring start, before or after you rebuilt the carb? Did you check for a vacuum leak? Is the carb together correctly? Have you done a compression check, checked the spark plugs and wires, the cap and rotor and coil?
:cool:

[Dan]

Thanks for the reply.

It's not backfiring, just misfiring. Happened before the carb rebuild. New cap, rotor, plugs, and wires. Coil checks out OK. Ignition module checks out too. I'm fairly confident that it isn't in the ignition system (but not 100% sure). Also replaced the fuel filter to eliminate that. I am going to do a compression check to check out rings and valves, but haven't done that yet. Any other ideas? What's the easiest way to check timing chain?

[Crazy_Jeepman]

I like useing a timing light for checking the timing chain. Hook it up, start it up, fire the light on the balancer find a mark any mark align it with something anything if the mark is dancing all over the place and will not hold steady it is most likely a sloppy chain. The other way is remove the dist. cap set balancer to TDC (don't really matter just as long as you have a referance point) and by hand turn the motor over till the rotor turns then mark balancer then rotate motor back in the other direction mark balancer again the distance between the two marks is the amount of slop the chain has. ;)

[ December 28, 2001: Message edited by: Crazy_Jeepman ]

[Dan]

Thanks Crazy_Jeepman. Has anyone heard about any decent kits to buy? Autozone has a standard timing set by Dynagear for around $30, and a "better" set for around $50. Also, how do you manually rotate the engine? Breaker bar on the balancer?

[Crazy_Jeepman]

Yes a socket on the balancer bolt with a breaker bar works well. I would be sure that it is a timing chain problem first, a lot of work for nothing if it does not correct your problem. Never bought a set from the ZONE so I could not tell you. I buy my parts from Summit Raceing. I would go with a double steel roller set though, but that is a personal choice. Good Luck ;)

[ December 28, 2001: Message edited by: Crazy_Jeepman ]

[Dan]

Thanks again. I'll check out the slop in the timing chain and check compression tonight.

[la mula pescadora]

I have used the method of turning the cranck shaft and whach the rotor it work pretty well