On the hook, again

[Bill]

The Great Pumpkin was, for the second time under my extended ownership, brought home on the hook today  . Sure I was in stop and go traffic in the 79% humid , 80 degree temps for almost 30 minutes, but I've been stuck in worse. What I found strange was that out of gear the car idled and revved just fine, but as soon as I dropped it in to drive, it sputtered and stalled out. Almost sounded like a run on situation of sorts. Would immediately restart, but again, under load, it died. Tank, pickup, lines, filter are all fresh. Thanks to AAA Platinum (don't leave home without it  ), the trip home was an uneventful one, although due to Covid concerns (I understand completely), we had to grab an uber for the ride home. Took uber longer to get to us than AAA. Car fired right up after the 40+ mile tow, drove it into the garage and tucked it in for now. Not certain if their was dirt in the needle seats, fuel pump going bad, or the carb is due for a trip to "Drew" for a complete going through, which is what I am leaning towards at the moment. SWMBO chalked it up as just another adventure for us, she has always been good like that over the years.

So, with that bit of ramble out of the way, what say you? Am I on the right track?

Bill

[A-Snake]

FWIW, I would first check all vacuum lines for leaks. Disconnect and plug all of them. See if it will run in drive, then reconnect one at a time to hopefully find the one with the leak.

[Side-Oilers]

Given all you said is fresh on the car, my guess is a fuel pump problem.  Of course, the carb is also a possibility.

How was the coolant temp at the time?   Fuel percolation?

[Bill]

Given all you said is fresh on the car, my guess is a fuel pump problem.  Of course, the carb is also a possibility.

How was the coolant temp at the time?   Fuel percolation?

Cooling system was not an issue, as best as the temp gauge can be used as a litmus test, just shy of the 6 o'clock position, surprisingly a hair towards the 7 o'clock position. I have a set of the smaller Mr Gasket 3710 heat shields under the carb, have been using them on all my cars for years with wonderful results. I'll be checking the basics today, multimeter check of the coil, cracked vacuum lines, and squirter volume. Thanks to all for the posts/ideas here as well as in PM's. We will get to the bottom of this one way or the other.

Bill

[shelbydoug]

Transmission. Converter maybe.

[Bill]

Transmission. Converter maybe.

Rebuilt 5,000 miles ago, but will check fluid levels (flushed and changed less than 900 miles ago).

Thanks

Bill

[Greg]

If the engine runs well in park then the problem has to be related to the transmission torque converter.  It's locking up and stalling the engine.

[shelbydoug]

Transmission. Converter maybe.

Rebuilt 5,000 miles ago, but will check fluid levels (flushed and changed less than 900 miles ago).

Thanks

Bill

Well you asked and those could be symptoms of a locked up or failing transmission converter.

[69 GT350 Vert]

I had that problem in the past of stalling when putting car in drive.  It turned out to be an improper air/fuel ratio when car was in drive under hot operating conditions.  If you are using fuel with ethanol in it, that contributes to the problem since it is being baked in your fuel bowls on top of your heat-sink engine. 

I installed a wideband Oxygen sensor to see what my a/f ratios actually were.  They were 22:1 right off idle, which is very lean.  The fact that your car started up and was not stalling when you got it home after the tow says it was likely some type of temporary fuel issue, not a permanent mechanical issue. 

Ultimately, I installed a Holley Sniper throttle body fuel injection system and have never been happier with my classic car.  Cold starting, throttle response, elimination of fuel percolation, etc.  No more fuel storage on top of a hot engine.  It was a lot of work to install it without modifying or drilling holes in my car, but worth it if you want to drive your car using today's ethanol fuels.  The sniper maintains 13:7 to air/fuel ratio, and your target idle rpm regardless of whether you are in drive or park.  No more stalling in stop and go traffic in hot weather.  It is almost impossible to tune a carb for that scenario using ethanol fuels of today. 

I'm sure several will disagree with this approach, but it has worked for me quite well for over 2 years now.  I could put the carb back on my car over a weekend if I wanted to, and nobody would know the difference. 

[corbins]

Transmission. Converter maybe.

+1...chased that problem for 2 seasons, changing all sorts of stuff . Finally discovered the converter had gone bad . Several tows home during those 2 summers.

[shelbydoug]

Transmission. Converter maybe.

+1...chased that problem for 2 seasons, changing all sorts of stuff . Finally discovered the converter had gone bad . Several tows home during those 2 summers.

That is only one possibility of the symptoms but something rarely considered. It was just offered in hopes of limiting chasing his tail with no solutions arrived at.

PARTICULARLY on a recently serviced transmission. Sometimes you can't change the fluid. On some if the regular service calls for a fluid change at 50 and  you are at 85, you can no longer do it. You leave the fluid alone.


I'm having hot starting issues also just this year. I'm wondering now if the fuel was re-formulated recently in favor of EFI?

[Bill]

Coil checked out with the multimeter
N0 broken, cracked, or leaking vacuum lines
All rubber type fuel lines are ethanol compatible when I put the new hard-lines in.
stainless steel line from pump to carb
New fuel filter installed
Did compression check to play it safe, all is good
Checked carb nuts to make certain they were not loose, also base for signs of leakage, none found.
No drips, no leaks for the fuel system, no vacuum leaks detected
Squirters looked strong (no Jon, I did not use a match  ), although bowls were drained and I had to crank for 15-20 seconds to get it to fire
No fuel in oil thank god

No joy rides yet to check the transmission, but I'll get to that as I have time.

Thanks for all of the ideas, keep them coming.

Bill

[Side-Oilers]

When did you change the fuel filter?  Maybe is already partially blocked? 

Sounds most like a fuel delivery problem to me. Fuel pump, filter, or heat-related fuel vaporization are among the possibilities that come to mind.

But I have no experience with torque converter problems.  My vintage cars are all manuals.   

[shelby67]

i had the same problem about 30 years ago on my boss.  change your condenser as it got heat soaked in the traffic and opened up.  when it cooled down you were fine again
Bill P.

[rhjanes]

Hate to state the obvious, but what is the Idle RPM? 
If it's an automatic.... Use some BIG chocks on the tires, set up your RPM tester.  Have the hood up so you can get to the carb.  Set the RPM gauge so you can see it while sitting in the car with the hood up and wheels chocked.  DO NOT "GOOSE" IT!!!  Start it in Park.  Check the RPM.  Remember to NOT touch that gas peddle!  put it in gear and watch what the RPM drops to.  My 302 sometimes (Usually when it is still warming up) tries to stumble.  I've watched the RPM and noticed it dropped below factory spec.  Like 75-100 below.  I just turned the screw to up the RPM by 100 RPM and the issue vanished.