350/th350 combo need some advice on troubleshooting a bad idle . What happens is when the vehicle is put into drive the engine shakes and wants to die out imeadiatley? Changed out the plugs , wires, fuel filter, distrubuitor, and retimed everything but still seems to want to die out. Even changed out the th350 shift module. Maybe a a leak somewhere, wrong plugs(autolites 68)? Any suggestions would be helpful. The Carb is a 650 cfm eldebrock and this is a fenderless white truck in my avatar. I aint no stranger to the hamb and i would appreciate positive feedback please. And i know this subject has been brought up about a million on times on this forum, please just looking for help. Thanks.
Back-up. Has this combo been fine 'till now, or is this a recent build? Carb new, rebuilt or never tested 'till now?
Sounds like you need a carb rebuild. Thats a best case scenario. Worst case is you have a burnt valve. Had that happen before. Has the same feel in a way. Hope this helps. Does it idle in park and neutral fine?
When you set the timing did you disconnect the vacuum? If not, when you put it in gear vacuum drops, timing retards, and a stall.
yes we did disconnect the vac*** when doing the timming, but it still has a drop in idle when shifting from park to drive
combo was fine 2months ago then recently took it to the machine shop for new seals due to some oil leaks, anyhow replaced the rear main oil seals and head gaskets and put a new double roller timing chain with and new oil pump , after we got it back to the shop we also got new plugs and wires but kept the same carb (elbrock 650 cfm) after getting all timed and ready to go the engine started running ruff with higher rpms and low idle or shutting off at stops. The machine shop did not notice any major signs of wear to anything upon or after replacing seals either. So could something have come loose like deposits? Bad rings? or Did we miss something?
It sounds like mayb one of yr vac***e ports on yr carb is not plugged and should be. On my 302 same thing happen to me after steam washing it and ended up being I cracked a rubber plug on the carb that covers the port
we sprayed carb cleaner at the base too and around the intake and heads to check for leaks and thus so far we did not see or hear any?
well since the heads were off id look at valve adj., vacuum leaks, timing off carb needs work or adjustment.and seems you already have most covered but id check it all again.and where unkledaddy said.
Could the torque converter be engaged? I had a trans start to go out and the torque converter wouldn't shut off, causing the motor to idle too low in drive and coming to a stop
They almost all have a drop in idle from park to drive. No one else has mentioned it yet so you may look for a va***m leak. They happen.
The same thing happened to me with a Pontiac Slim Jim. The fluid coupler wouldn't disengage when I came to a stop and it killed the motor.
yea the valves and torque converter are also gonna be checked as well, gonna try to adjust the rocker arms first and go from there.
If your getting a pop out of exhaust . Valve adjustment sounds too tight. Remember loose is always better than too tight.
I'd go along with ajmopar. Start with the simple fixes. Make sure you have the dizzy in right. Could be off a tooth. Readjust the valves. Not the plugs.
If all the other advice dont work, take your air cleaner off and try again. Sometimes when an air cleaner has not been changed out it can impede air flow so badly that exactly what you are describing can occur. Just a shot in the dark if you have run out of options...
Thanx for all helpful advice, I really appreciate all the help. Guys! Hope to get it running right for my friends wedding next week.
you probably did it first thing, but has the carb been tuned since you got the car back from the shop? idle speed set high enough? i'd eliminate that before i even started hunting for vacuum leaks.
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