Engine Stall in Drive or Reverse

[7212Mopar]

Thanks to CP, I got the engine start problem fixed earlier in the week by changing the ballast resistor. On Thursday night after dinner, I took the car out and drove to my buddy's house about 12 miles away. Car started and ran fine all the way. I took my buddy out for a short cruise around his town and made a few stab at the gas pedal on the HWY (very light traffic). On the way back to his house, car died when I made a stop at the stop sign  . Engine can be restarted right away and can stay running normal in netural or in park. But when I put it in drive, the engine will stall unless I raise the RPM and brake at the same time. That was pretty much what I had to do to get home. There is no backfire and car runs great on the freeway.

So I spent some time this weekend looking through related old threads. This is what I have done so far:

1. Check for loose connections in the engine bay and under steering column. Everything seems ok.
2. Check and adjusted reluctor gap to 0.008.
3. Test ignition coil resistance, result is 2.2 ohms at +/- terminals and 6.6k ohms at - to coil tower. Seems to check out per some old threads.
4. Clean battery terminals. Battery tested 14.8v at idle and 13.1 v when engine is off.
5. Adjusted RPM, timing and mixture. Engine runs smooth at 800 RPM, 17.1 in-hg vac and 8 degree BTDC initial timing. Electric choke operates normal.

Engine will stall when AT is in reverse or in drive. Runs normal in P or in N. If I add more initial advance, RPM goes up a bit, engine seems stay alive a bit in D or R but runs rough. As soon as I turn on the light or turn on my ventialtion, engine will stall.

I am thinking my battery might be weak from all the cranking earlier in the week so I bought a battery tender/charger from Costco today, just to make sure. My MSD Blaster ignition coil, engine wiring harness, carb/intake and all the vacuum hoses are essentially new, less than four months. Also no vacuum leak that I could find. At this point, I am thinking to replace the voltage regulator and then the ECU in order, probably get the Rev_N_Nator. Do you guys think I am on the right track? Any suggestions?

[GranCuda1970]

Sounds like your on the right track I was thinking voltage regulator, or ECU, bulkhead connections. Dont think the netral safety switch for the AT would cause that. But all your checks were good may be the carb. If it is not spark it is fuel. Is the wiring harness the origional Old crusty.

[Bullitt-]

my problem was the idle screw was turned in to far exposing to much idle transfer slot
http://www.chevyhiperformance.com/howto/45638/photo_10.html
advanced timing, backed off idle screw, readjust idle mixture.
Time engine per CP's instruction  http://www.cuda-challenger.com/cc/index.php?topic=4430.msg33565#msg33565

[Chryco Psycho]

 
This is a carb problem , could be as simple as dirt in the air bleeds or some tuning as suggested above

[7212Mopar]

Ok, Thanks for the info. I will check and adjust the carb and timing again this weekend. The carb, fuel filter and fuel pressure regulator are new, installed less than 6 months. I don't understand that why would the carb cause the engine to stall when I turn on the lights or turn on the ventilation fan? It does that in P or N as well.

[Chryco Psycho]

extra load on the alternator from the fan or lights dropping the idle slightly

[7212Mopar]

I got my new Mopar voltage regulator installed last night. Now, the engine will not stall when in D or R with the lights or blower turned on. However, RPM drops and it idle kind of rough and RPM is low. Feels like it can die any second. I will do as Bullitt CP suggested and try to adjust the carb and timing this weekend. Crossing my fingers that this will take care of it and that I can take it out again for a weekend cruise.

[7212Mopar]

On Saturday, I watched the Eldelbrock troubleshooting videos, removed the mixture screws and cleaned the passages with compressed air. Let the engine warmed up, checked timing, set idle and adjusted the carb mixtures. Engine seems to idle better when put in gear and will not stall. Big change was after I removed the Mopar orange electronic ignition box and replaced it with a Rev_N_Nator unit. Turn key and engine won't start. Read the instruction again, checked voltage at the ballast resistor, everything was fine. After unplugging the electric choke, turn key and engine instantly fired up. The new Rev box needs minimum 5 volt to start and the electric choke voltage drop was excessive. So I added a switch to turn off the electric choke during start and then turn it on after. Checked timing again and engine idle and runs very smooth, vacuum at idle was raised from 17 in-hg to 19 in-hg and no more stutter. I then took the car out for a drive and I must say the Rev_N_Nator is amazing. Car is so responsive to the throttle now and seems to pull harder than ever before since I had the car (10 months). On the road, I think I had the engine rev up to slightly under 5000 RPM, very smooth. I will try to take it to higher RPM next week to see how it runs. The unit has a built-in rev limiter and I set it at 6000 RPM. I must say I am very please with the Rev_N_Nator.

[Chryco Psycho]

I have also heard a lot of good things about the Rev-n-Ator boxes

[Bullitt-]

Great news.. ..
What is your voltage to the ballast resistor?  I wonder if this was the issue all along..

[7212Mopar]

Ballast resistor was new that fixed the no start problem. I think the engine stalling is a carb tuning thing like what guys said. It must be the gas gummed up the idle circuit. Just glad it is ok now. Thanks for the pointers.