Bad or slack timing chain??
#1
Bad or slack timing chain??
I'm having issues getting the 307 to run right in my '83. If I stab the gas it'll stall out as if it's flooding, occasionally shooting fuel up through the carb (once in a while it'll backfire through there). Even a gentle tap of the gas will upset things and come close to stalling it or it will stall it out. It used to do this while driving and I thought it was a carb issue but now it isn't drivable since you can't touch the gas without a problem.
There are no vacuum leaks and it's throwing no codes. The car has 143k on it and the only thing I can come up with is the timing chain is slack. Everything else is in tune, carb, dist cap, wires, etc. The plugs fouled once but I cleaned them best I could and it doesn't miss. Timing issue or did I miss something?
There are no vacuum leaks and it's throwing no codes. The car has 143k on it and the only thing I can come up with is the timing chain is slack. Everything else is in tune, carb, dist cap, wires, etc. The plugs fouled once but I cleaned them best I could and it doesn't miss. Timing issue or did I miss something?
#3
I did some reading and did the test of turning the crank while watching the distrib rotor. I was able to turn the crank some 2-3" each way before the distributor rotor began to move! That can't be right. It must've jumped time from starting it up to move it around the driveway..
#4
See my post here; https://classicoldsmobile.com/forums...tml#post559706
#8
I did some reading and did the test of turning the crank while watching the distrib rotor. I was able to turn the crank some 2-3" each way before the distributor rotor began to move! That can't be right. It must've jumped time from starting it up to move it around the driveway..
#9
The crossover being off is part of another failing project I started (the broken studs are impossible to deal with), it did this before then with no change. It definitely has that much slack in it, I double checked since I read your post and it's definitely close to 3" as I pull the belts and watch the pulley and rotor. That's got to be the problem.
#12
Whether it's the cause of your problem or not, 143K miles on the original timing set is living on borrowed time (pun not intended ).
Once the chain is replaced (hint: you MIGHTASWELL put a new water pump on while it's apart), then you can see if the CCC system is adjusted properly. Also, having the exhaust disconnected will cause the O2 sensor to read falsely, compounding any other problems.
Once the chain is replaced (hint: you MIGHTASWELL put a new water pump on while it's apart), then you can see if the CCC system is adjusted properly. Also, having the exhaust disconnected will cause the O2 sensor to read falsely, compounding any other problems.
#13
Since rotation is measured in degrees and not in linear units, and since a long wrench handle will move farther than a short handle through the same number of degrees, exactly where are you measuring these 2-3"?
Are you measuring at the balancer / timing scale, at the end of your wrench, or somewhere else? And if it's at the end of your wrench, how long is the wrench?
- Eric
#15
Joe: Strangely it appears it was replaced once before but nothing else was touched, go figure. That o2 sensor appears to be original and is stuck in place, I often wonder if it's even working right. Never got a code but it's old. If I had my way I'd yank the whole mess and drop in an emissions free Olds 350, even a 330.
Great point Eric. I know it isn't the correct way, but I was watching how far the alternator pulley moved each way, marking it and the housing as a reference point. I wanted to turn at the crank but I don't have the adapter for it (three bolt harmonic). Truth be told I'm still learning about these things..
Great point Eric. I know it isn't the correct way, but I was watching how far the alternator pulley moved each way, marking it and the housing as a reference point. I wanted to turn at the crank but I don't have the adapter for it (three bolt harmonic). Truth be told I'm still learning about these things..
Last edited by at3reg98; June 29th, 2013 at 01:45 AM.
#16
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