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changed motor - nutter bypass - problems

535 views 1 reply 2 participants last post by  Geer_hed 
#1 ·
put an 83 4.2 in my 88 wrangler. the motor was in a 79
cj-7 with an older carb (not computer controlled). prior to taking motor out it ran fine. i installed the motor in my 88 wrangler. i clipped the orange and purple wires coming out of the ignition box and ran them over to my distributor. hooked the vacuum from distributor to the side of carb (choke side) and was ready to go. yeah , right.

backfiring through the carb!! cranked motor around until piston #1 was at top dead center. took dist cap off and rotor lined up with # 1 on cap. checked firing order and all cylinders hooked up properly on cap. has anyone had this problem or any tech advce for me. what about running the ignition box from my 88, is that the problem. would putting the ignition box from the 79 remedy this. do i need to play with the distributor. with backfiring out of the carb which way would i turn the distributor?
 
#2 ·
ASSuming everything you checked is great and wonderful, how do you know you got the #1 cylinder TDC on the compression stroke? could it be 180 out? Also, when I swapped mine just recently, I set it at 8 degrees BTDC on #1 compression, but it was way too retarded. This sounds like a timing/firing order issue.

The thought on the ignition modules is interesting. I'll see if the part numbers are different.
 
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