Engine stalls when put in gear...stumped
Thread Starter
2nd Gear
Joined: Oct 2020
Posts: 2
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Engine stalls when put in gear...stumped
I've been helping a buddy try to get his c3 76 vette mobile so he can move. The issue is that when he puts the car in gear, the engine stalls. I have searched up and down the forums looking for the answer and have tried tons of stuff but no dice, so here we are. Also, the car was at a shop for a holley 600 install that they never finished to try to remedy the same issue, they botched the job and probably were the ones that blew a head gasket.
There is a long laundry list of items done to the car, so I will try to write them all down.
Headgasket and head job.
holley 600
waterpump
alternator
timed the car
new plugs(gapped to spec)
verified no vacuum leaks( even blocked off brake booster at one point)
tried a hot to the coil to take electrical out of the loop
The car will start and idle, but as soon as its put in gear it stalls... I have looked in wiring diagrams, but cannot find where a black/green wire goes, its hanging loose on the passenger side of the trans... what else could cause the car to stall?
There is a long laundry list of items done to the car, so I will try to write them all down.
Headgasket and head job.
holley 600
waterpump
alternator
timed the car
new plugs(gapped to spec)
verified no vacuum leaks( even blocked off brake booster at one point)
tried a hot to the coil to take electrical out of the loop
The car will start and idle, but as soon as its put in gear it stalls... I have looked in wiring diagrams, but cannot find where a black/green wire goes, its hanging loose on the passenger side of the trans... what else could cause the car to stall?
Is my vette stock?? HAHA
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2020 C3 of the Year Finalist - Modified
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vacuum pump and take off the distributor, put the pump on the vacuum advance nipple and pump. you will see the mechanism move.
Burning Brakes
Joined: Apr 2012
Posts: 1,084
Likes: 96
From: Bowmanville Ontario
This happened to me when I put my Holley 650 double pumper on.
Here's the bad news. The Carb is too big for your engine.
I had to go back to my Quadrajet.
I put the Holley back in the box and put it on the shelf until I upgrade my engine with new heads, etc.
Sorry for the bad news, but a stock engine can't handle that much fuel.
Here's the bad news. The Carb is too big for your engine.
I had to go back to my Quadrajet.
I put the Holley back in the box and put it on the shelf until I upgrade my engine with new heads, etc.
Sorry for the bad news, but a stock engine can't handle that much fuel.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
What he (R.R.) means is, remove the dizzy cap so can you can monitor the Vac Adv canister. Using a hand vacuum tool which can be found on EBay ($20), remove the vac line from the carb to the dizzy canister. Then hook up your vac tool. A few pumps should move the canisters arm and rotate the Adv plate.
Start the engine and see if it idles in gear while the canister is holding Vac. Plug any open hoses.
But all that does is prove the canister is ok. You still don't know if its getting proper Vac from the carb. Put your finger over the hose end to verify.
There should be two ports on the front of the carb or one in the back. You want full manifold Vac and not "timed" or ported.
Start the engine and see if it idles in gear while the canister is holding Vac. Plug any open hoses.
But all that does is prove the canister is ok. You still don't know if its getting proper Vac from the carb. Put your finger over the hose end to verify.
There should be two ports on the front of the carb or one in the back. You want full manifold Vac and not "timed" or ported.
Last edited by HeadsU.P.; Oct 29, 2020 at 12:29 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
This happened to me when I put my Holley 650 double pumper on.
Here's the bad news. The Carb is too big for your engine.
I had to go back to my Quadrajet.
I put the Holley back in the box and put it on the shelf until I upgrade my engine with new heads, etc.
Sorry for the bad news, but a stock engine can't handle that much fuel.
Here's the bad news. The Carb is too big for your engine.
I had to go back to my Quadrajet.
I put the Holley back in the box and put it on the shelf until I upgrade my engine with new heads, etc.
Sorry for the bad news, but a stock engine can't handle that much fuel.
Last edited by HeadsU.P.; Oct 29, 2020 at 09:36 AM.
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Racer
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Assuming no vacuum leak, the motor can't hold an idle because the ign timing retards when there's that 200-300 rpm drop that occurs when the trans is dropped into drive. The park/neutral degrees of timing advance should be maintained when it's dropped into drive. Try bumping up the timing a couple of degrees,reset the curb idle see if it improves the stall-out problem. If it does not, the mechanical advance may have to be recurved.
Had a 1976 L-82, 4-sp
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From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
This happened to me when I put my Holley 650 double pumper on.
Here's the bad news. The Carb is too big for your engine.
I had to go back to my Quadrajet.
I put the Holley back in the box and put it on the shelf until I upgrade my engine with new heads, etc.
Sorry for the bad news, but a stock engine can't handle that much fuel.
Here's the bad news. The Carb is too big for your engine.
I had to go back to my Quadrajet.
I put the Holley back in the box and put it on the shelf until I upgrade my engine with new heads, etc.
Sorry for the bad news, but a stock engine can't handle that much fuel.
Melting Slicks
Joined: Oct 2012
Posts: 2,156
Likes: 273
From: Dunedin NZ.
If the engine will run and idle I doubt that the carb is at fault but you don't say what the idle speed is and have you tried increasing it as a temporary measure to see if the engine will keep running? Has the idle mixture setting been done? A 600 Holley will work even on an old 350 pick up truck motor. Does it do the same thing when started in park then shifted to reverse as starting in neutral then shifting to drive?
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
Is your vacuum advance connected to manifold vacuum or is it still connected to ported vacuum. If ported, connect it to manifold vacuum, reset your idle speed and try again. The drop in rpm wheN you put it in gear may be causing vacuum to the advance canister to be lost and causing the engine to die.
And a 650 com carb is definitely not too big for a 350. In fact it’s probably ideal. Anything in the 600-780 range works well.
And a 650 com carb is definitely not too big for a 350. In fact it’s probably ideal. Anything in the 600-780 range works well.
Burning Brakes
Joined: Apr 2012
Posts: 1,084
Likes: 96
From: Bowmanville Ontario
I had the car on a Dyno and with the carb, I was getting 120hp.
We tried to swap out the jets but they were already the smallest he had in his kit.
Last edited by 74Ken; Oct 30, 2020 at 07:25 PM.