Technical 350 boggs out on drive

[LowMOJO]

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.

[dickster27]

You don't mention what cam you have. If it's a big en' you'll need a higher stall converter.

[LowMOJO]

It's a regular stall as far as I know. But that is wanna my suspects that's it's going out?

[slammed]

Back-up. Has this combo been fine 'till now, or is this a recent build? Carb new, rebuilt or never tested 'till now?

[garcoal]

what is your idle set at

[pinkynoegg]

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?

[terryr]

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.

[LowMOJO]

Originally Posted by pinkynoegg

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?

yes it does idle in park and neutral fine, but it has a slight pop/miss on the drivers side exhaust

[LowMOJO]

Originally Posted by terryr

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 vaccum when doing the timming, but it still has a drop in idle when shifting from park to drive

[One Finger John]

Originally Posted by LowMOJO

yes it does idle in park and neutral fine, but it has a slight pop/miss on the drivers side exhaust

Ahh.... and more will be revealed.

[LowMOJO]

Originally Posted by slammed

Back-up. Has this combo been fine 'till now, or is this a recent build? Carb new, rebuilt or never tested 'till now?

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?

[WILL's_50_SHU]

It sounds like mayb one of yr vaccume 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

[LowMOJO]

Originally Posted by WILL's_50_SHU

It sounds like mayb one of yr vaccume 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

yea so far all signs point toward a leak, but we checked that one already thanks

[brokenspoke]

vacum leak..how did you check it...I had the same symptions once and found a leak under base of carb

[LowMOJO]

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?

[unkledaddy]

Originally Posted by LowMOJO

Even changed out the th350 shift module.

Maybe this is where you have a vacuum leak.

[outlaw256]

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.

[ajmopar]

Valves ajusted too tight?

[flatheadz-forever]

adjust the idles speed up in drive

[Inked Monkey]

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

[porknbeaner]

Originally Posted by LowMOJO

yes we did disconnect the vaccum when doing the timming, but it still has a drop in idle when shifting from park to drive

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 vacumm leak. They happen.

[GassersGarage]

Originally Posted by Inked Monkey

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

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.

[LowMOJO]

Originally Posted by GassersGarage

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.

[Novadude55]

I agree w/ porknbeaner, sounds like a vacuum leak to me

[gerry miller]

If your getting a pop out of exhaust . Valve adjustment sounds too tight.
Remember loose is always better than too tight.

[Dave29]

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.

[fiftyv8]

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...

[LowMOJO]

Originally Posted by fiftyv8

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.
[B]Just a shot in the dark if you have run out of options...[/B]

Thanx for all helpful advice, I really appreciate all the help. Guys! Hope to get it running right for my friends wedding next week.

[unkledaddy]

Originally Posted by LowMOJO

Hope to get it running right for my friends wedding next week.

Let us know what the fix was.

[jazzbum]

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.

[LowMOJO]

Well guys bad news. Turned out to be a burnt valve
Back to the machine shop.

[pinkynoegg]

Originally Posted by LowMOJO

Well guys bad news. Turned out to be a burnt valve
Back to the machine shop.

Dang sorry to hear that. I know the feeling though. Just think of it this way, all the bad luck is getting out of your system now and not later

[unkledaddy]

Originally Posted by LowMOJO

Well guys bad news. Turned out to be a burnt valve
Back to the machine shop.

Sorry to hear it.
Thanks for getting back and good luck with it.

[31Vicky with a hemi]

How did the machine shop miss a burnt valve when doing head gaskets ext:

How was it running fine 2 months ago with a burnt valve but not now.

Or did you just burn it trying to dial it in ?

Does not compute .....

[gerry miller]

Quick valve job and your down the road.The "SHAKE" will be gone!!!!

[LowMOJO]

Originally Posted by 31Vicky with a hemi

How did the machine shop miss a burnt valve when doing head gaskets ext:

How was it running fine 2 months ago with a burnt valve but not now.

Or did you just burn it trying to dial it in ?

Does not compute .....

bad machine shop, will not disclose the details cuz im better than that but will use a more trusted ,recomnded shop in the near future!

[jazzbum]

weak. sorry to hear that. but it could always be worse, i guess.

[Motorhead Extraordinaire]

Get yourself access to a smoke machine and smoke it. I'll bet you got a vacuum leak.