camo31_10.50

ok..soo...a few weeks ago i posted about my '86 shooting compression back out through the carb...i only have about 3/4 throttle, anymore foot than that and it seems to cut out..and the Tach starts jumping around..we thought it was an exhaust leak (because it had one) so we replaced the gasket and fixed the leak..but the problem was still there (the new gasket HELPED the problem..but did not fix it) so we thought fuel next..so we put 2 cans of this stuff called B12 in the tank..to clean the lines (thought they might be clogged, therefore not giving the engine enough gas) hasnt helped yea only been in the tank for 2 days (could take up to a week to work fully) so i went ahead and put a new fuel pump on it (a manual pump, just like stock.) once again..helped the problem but didnt fix it...so im STUMPED!

The problem started one day when i was gettin on the interstate, i was in 2nd gear doin about 30, rpms at about 3800 or so..(didnt have a tach back then) when i pushed in on the clutch to grab 3rd gear..i heard a loud pop..(kinda like a backfire out the tailpipe) and when i let out on the clutch and gave it some gas i could hear the exhaust leak..so im kinda thinking it has somethin to do with the valves in #4 cylinder (because thats where the exhaust leak was at..at the bottom of the manifold at the backside of the motor, closest to the firewall) if anybody has any input then please help..been dealing with this for a while..and its VERY annoying to only be able to do 65 on the interstate (yes thats my top speed with this problem)..

abecedarian

the tach jumping around suggests to me that either the distributor pick up coil or ignitor are acting up.
are you hearing any detonation / pinging when the tach starts jumping?

camo31_10.50

actually yes..everytime the tach starts to jump (while driving) it shoots the compression out the carb.. in the form of a loud POP...would the ignitor off of my 20R work..just temporary (like hours at most) just to see if thats the problem..see i was thinking it COULD be timing..but idk..im just guessing..tryin to steer clear of having to pull the head AGAIN! already replaced the headgasket...

camo31_10.50

bump!! anyone

Yodaforce

Aside from the tach jumping around, it sounds like a carb problem I had once. I priced a rebuild for the carb, thaught it was way overpriced, and considering I had no propr knowledge that someone had not been into it before I baught it, I opted to go with a New Weber 36 DGEV. Did the swap in under an hour, and ever since, I have not any problems. I had discovered through it all that my #4 was low on compression, my ignitor was fading out (which had never happened before, usually they just quit all together), but even after replacing my timing chain, distributor, ignitor, coil, head gasket, intake and exhaust gaskets, I never could shake the problem until I replaced the carb.