84' c10 stalls in gear

[DeltaP]

Don't forget them famous GM slipped dampers where the rubber deteriorates and throws all possible timing marks off. The vacuum source for the vac advance must be from a source below the venturi line of the carbuerator. HTH

[Schurkey]

Originally Posted by DeltaP

Don't forget them famous GM slipped dampers where the rubber deteriorates and throws all possible timing marks off.

Not just a GM problem. Happens with all makes and models that use that style of rubber-isolated torsional dampers.

Originally Posted by DeltaP

The vacuum source for the vac advance must be from a source below the venturi line of the carbuerator. HTH

No modern carburetor has a venturi-vacuum port that's accessible; so any manifold or ported (timed) vacuum port will work; some timed vacuum nipples intended for EGR would work, but would require more-than-typical throttle opening to advance the timing.

Try manifold vacuum and ported vacuum, use whichever one works best.

[777stickman]

This is just a real WAG on my part. If it's got a PCV valve, try pulling it out of the valve cover and plugging it with your thumb or pull the hose off the carb and cap that. See what happens.

Good luck.

[j cAT]

Originally Posted by 777stickman

This is just a real WAG on my part. If it's got a PCV valve, try pulling it out of the valve cover and plugging it with your thumb or pull the hose off the carb and cap that. See what happens.

Good luck.

too bad he is from OK. If he was from my area I could get that fixed in 15 min.

still have my 1984 Camaro.

[Bain]

Thanks for hanging in there with me guys. I'll re-check the vacuum at the rpm settings you suggested tomorrow weather permitting and look for a leak where you all suggested and let you know the result good or bad.

Off topic, I had an 84 camaro for about a week before it got stolen but I do still have my 81' z/28 I love that car I'll sell my house before I sell it lol

[Bain]

Ok so far today I've followed cats advice and adjusted the rpm to 1100 and set timing to 7deg which definitely seemed to help the most although I didn't have to adjust it much to get it there. Then I dropped rpm to 700 in neutral and started checking vacuum. At the manifold was a constant 15 in. The vac adv was 15 steady, but the port to the upper right of the PVC hose on carb was barely registering at all. Next I dropping it into drive and the rpm dropped to 500 just like you said it should although I don't it could go any lower with out dying from the sound of it. It didn't stall though finally so I drove it about 20 feet to the fence line, stopped, put it in reverse to back back up to the shop again and it stalled out as I gave it gas to go but seems to stay running before I give it gas. That part I wasn't expecting. I couldn't try drive again as I am out of room to move forward. I'm gonna let it sit for a bit then try again to see what happens. Also in an attempt to get the vacuum up I removed all the vacuum lines except the adv, PVC, and one manifold going to a sensor on the pass side firewall but it didn't seem to change anything especially.

[Bain]

ok I spoke a little too soon. I went back down after that last post and started it up and checked for leaks again with starter fluid then after fixing one possibility of a small vac leak at the brake booster line I decided to hook the vac gauge up and fine tune the timing a bit more and now I am getting a solid 17 in at around a 700-750 idle and it seems to be running fine now. I'm gonna let it cool down completely for a few hours then fire it back up cold and see how it acts. Hopefully it'll run good and I can get through a good test drive. If so this truck is going back to its owner tonight and out of my hair lol then it's on to my next project.

I'll post up again tonight to let everyone know if its done for good or not.

[j cAT]

Originally Posted by Bain

ok I spoke a little too soon. I went back down after that last post and started it up and checked for leaks again with starter fluid then after fixing one possibility of a small vac leak at the brake booster line I decided to hook the vac gauge up and fine tune the timing a bit more and now I am getting a solid 17 in at around a 700-750 idle and it seems to be running fine now. I'm gonna let it cool down completely for a few hours then fire it back up cold and see how it acts. Hopefully it'll run good and I can get through a good test drive. If so this truck is going back to its owner tonight and out of my hair lol then it's on to my next project.

I'll post up again tonight to let everyone know if its done for good or not.

with a carb vacuum is a very important test item. I have a chart which I use that has vacuum troubleshooting guide. with this you can see exactly how the engine is in condition and also any leak detections by using a T fitting to insert and check for vacuum loss. 17 inches in neutral is good. if it were a solid 19 inches no fluctuations that would be a very tight not worn engine.... engine should idle very smooth no shakes...

remember the engine vacuum is sucking the fuel out of the carb ..low vacuum no fuel for engine.. then you get people adjusting the mixture screws to TRY to compensate for the vacuum leaks....

the good old days ...

[Bain]

Alright well it just made a solid test drive around the neighborhood but then I pulled into the driveway then when I put it in reverse to back up it acted like it was chugging then died. Possibly running rich? I'm gonna tweek it a bit more tomorrow hopefully finish getting it lined out.

[j cAT]

Originally Posted by Bain

Alright well it just made a solid test drive around the neighborhood but then I pulled into the driveway then when I put it in reverse to back up it acted like it was chugging then died. Possibly running rich? I'm gonna tweek it a bit more tomorrow hopefully finish getting it lined out.

you did check the vapor purge line at the carb base for fuel .. sometimes the vapor system fails and raw fuel gets sucked into the intake thru this line..

[DeltaP]

Did this carb come off the original 305? Also get rid of that charcoal canister if its got one and clean out the jets.

[Bain]

I did actually disconnect the purge canister and everything that went with it yesterday while I was trying to get up to 17 in of vacuum so I hooked it back up this afternoon but it didn't seem to change anything so then I decided to try and tune the mixture screws again but until they are screwed all the way in it doesn't seem to affect the idle at all so I can't really tell if I'm helping or hurting the mixture with each quarter turn or full turn for that matter but after backing them back out to 2 1/2 turns from full in I tried reverse again and now it seems to back up fine although it still sounds like its chugging a bit to me. Either way those adjustment screws don't seem to be having near the effect they should. This is the carb that originally came on the 350 btw I left it on.

[j cAT]

Originally Posted by Bain

I did actually disconnect the purge canister and everything that went with it yesterday while I was trying to get up to 17 in of vacuum so I hooked it back up this afternoon but it didn't seem to change anything so then I decided to try and tune the mixture screws again but until they are screwed all the way in it doesn't seem to affect the idle at all so I can't really tell if I'm helping or hurting the mixture with each quarter turn or full turn for that matter but after backing them back out to 2 1/2 turns from full in I tried reverse again and now it seems to back up fine although it still sounds like its chugging a bit to me. Either way those adjustment screws don't seem to be having near the effect they should. This is the carb that originally came on the 350 btw I left it on.

disconnect the fuel vapor line at the carb base . then use a plug on the carb base port for this line... then adjust the mixture ..

[Bain]

Thanks for the suggestion jcat I'll try that the next chance I get. Is that something I should always do while adjusting them or is that a test that will tell us something about what's wrong?

[j cAT]

Originally Posted by Bain

Thanks for the suggestion jcat I'll try that the next chance I get. Is that something I should always do while adjusting them or is that a test that will tell us something about what's wrong?

with that line removed from the carb and now you can adjust the mixture then this is the problem of too much fuel bypassing the carb jets..

if this does make the vehicle run good then leave as is until you can get a new vapor system for the fuel if you must have this working. I had an issue with this system twice and both times it was the vacuum valve that had a split in the valve rubber internal.. this is used to direct fuel vapors to the carb/intake port. if that valve messes up then raw liquid fuel gets sucked into the engine and it runs too rich.