Hello all, long time lurker first time poster. I've got a '89 4.2, terrible miss fire when cold, only getting eight mpg, throwing black chunks out of the tail pipe. I put the timing light on it and it is no where near the timing marks, it would be something like 30-40 before tdc. Now I know this cannot be possible. A previous owner replaced the chain and I'm thinking the cam is off by one tooth. If my assumption is right, when I fix it will I have the adjust the carb a lot ? I have no experience with carbs and I'm apprehensive about touching it. Thanks for any help!
Wow that timing is way off mine is at 10* you may not need to adjust the carb you may need to. Are you running the stock or after market. ? My timing was all over the place on my YJ cause I had a worn out distributor so I upgraded to a CRT distributor it solved my timing issue
Everything is stock and original as far as I can tell other than the usual tune up things. 145,xxx miles, runs well enough for summer cruising on the weekends but it is hard to start when cold and warm.
check the end play in your distributor, it will thro the timing off. max is 20 thousands.
also, when you checked the timing did you have the vac advance capped?
adjust the timing back to 10 at about 800 rpm's with the vac advance capped, how does it run?
check the end play in your distributor, it will thro the timing off. max is 20 thousands. also, when you checked the timing did you have the vac advance capped? adjust the timing back to 10 at about 800 rpm's with the vac advance capped, how does it run?
I didn't think to cap the vacuum since I was checking at idle, I will add this to the list when I check everything again this weekend hopefully.
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