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mfg

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Posts posted by mfg

  1. dapy,.....Avantis of the early 80's era used GM's 'Computer Command Control' emissions related system. It's a good system, but complicated, and can be problematic.....as these parts really don't 'age' well. The good news is that if this '81 should develop problems with this system, parts are still available to fix it ...OR...the carb and distributor can be swapped out for readily available non computer controled earlier parts (say 1979 Chevy V8 carb and dist). I went this route on my '83 and never looked back!

  2. The hesitation on hard acceleration is probably related to the choke pull off problem, because the hose you fixed probably never did allow the choke pull off to open the choke completley, which it is doing now. That would have given you a slightly richer mixture.....which Quadrajets are known to like. Hesitation, or stumble on acceleration, is a common Quadrajet problem... fixable if you bring the carb back into proper adjustment. Suggest you look on the internet under 'Quadrajet carb problems...hesitation'. You'll find plenty of info and tips there.

  3. sort of....floating in the piston, clamped in the rod......unless it is an R3 and up then it's shrunk in the rod. I like bushed rods with full floating , however you need pin locks in the pistons to run these. It's a good idea to use them on R3, or R4 engines too as I have seen where the pin worked loose from the rods and score the cylinder walls.

    Great explanation!

  4. Filling the tank to at least half full isn't a bad idea....the fuel gauge itself could be a bit 'off'. Next time you're under the car inspect the entire fuel line including the flex hoses for seeping fuel indicating a pinhole leak...these can drive you crazy, even if you don't see a puddle of gas on your garage floor.

  5. I go along with a choke problem. The 'low idle' after a cold start would indeed indicate a choke plate that is not being activated to close...and a fast idle cam staying in the low idle (hot engine) position. The real question is why isn't the choke closing on a cold engine?....Something blocking the linkage? Thermostatic cover slipped to choke off position? As kboyd said, observe the choke for smooth operation and full shut when engine is cold (not running). ON THE OTHER SIDE OF THE COIN.....The choke may be operating just fine, but the choke 'vacuum pull off' may have failed (very common) causing the choke plate to remain closed too much...and your engine is actually running 'over rich' and 'choking' until it runs a few minutes and warms up thereby opening the choke plate.

  6. Your water pump is probably OK, but I think I'd change to a 165' thermostat. My '85 came with twin electric fans that work alright but definitely do not move air like the full size engine driven fan in My '83. My '83 will run 140-160' in the hot summer if I do not run a 180-195' thermostat. Does your '85 have an engine driven fan with a healthy thermostatic clutch?

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