Car stalls when shifted into Reverse or Drive

Cougar Community Classic Cougar Maintenance Restoration and Repair
1

Hello,
I put a Holley 4 barrel carb on my 68 302 and sometimes when the car is shifted into gear the car sputters
(engine violently shakes) and stalls. It doesn’t happen every time I drive it as it ran fine when I went to have new tires installed. But the trip home was a mess, the drive home it had to be shifted into Neutral to stop it from stalling. I found one vacuum leak and plugged it, the car ran fine in the driveway and ran fine for a trip around the block. I parked in the driveway and went back out to cruise around the block again, I had trouble starting it and when it started and I shifted into Reverse it stalled. It finally allowed me to drive around the block, but when I had to stop at the stop signs to lights the car would stall unless I put it in Neutral.

Now a little more info/background on the car, I don’t have the vacuum lines connected for the headlights as the lines were removed by the PO. Also, the PO hacked up the AC/Heater components, so no vacuum connections there either. (This line was the leak I found as the plug fell off during one of the trips) I checked the line to the Automatic Transmission and it appears to be good as well as the one to the Power Brakes. The PCV line is connected too.

The car previously wouldn’t start without using starting fluid, but ran fine once started. I replaced the carb with the new Holley and had a local Hot Rod mechanic install a Petronix II setup because the points setup was and not working correctly. (It ran fine from their shop to get the tires)

Sorry for the long post, but I am at a loss and the mechanic is confused as well. Also, my wife isn’t please spending all this money on a car I and the family cannot enjoy. Any and all help/suggestions is greatly appreciated.

Thank you,
Paul

2

Hi Paul,

It sounds like a fuel issue to me.

What RPM does your car idle at in park?
Have you checked / adjusted the fuel float levels on the carburetor?
Have you checked, or replaced the fuel filter recently? If it is clogged it could be restricting fuel flow and “starving” the carb.

3

Hello Mike,
Thank you for the reply.

The RPM’s in park are around 1100. The mechanic checked the float levels and made some adjustments. The fuel filter is new, along with the fuel lines and gas tank. Fuel pump is the oldest part in this system, but it was new about a year ago.

Paul

4

Did this start after the Pertronix was installed? I had a similar problem that turned out to be the Petronix. It turned out that it wasn’t shifting into gear that caused the stall, but the nearly simultaneous pressing of brake pedal (which drew electrical current that apparently was enough to upset a bad pertronix unit). Try turning on everything electrical while in park or neutral, press brakes, and see if it causes the stumble.

5

I am interested in this as it sounds like my original 302 headed 289, ran at idle but wouldn’t make power. It was all modded on the top end with the typical single plane Edelbrock, Holley, Electronic ignition. I was going to a different motor, so I never gave it a go.

Tough way to go doing 2 things at once, especially spark and fuel. It might help to go backwards on one.

So for the sake of curiosity, what is the vacuum at idle and at 2-3000 rpm? Has the mech blocked off all the manifold feeds and checked?

It is a stock manifold and what is the cfm on the carb?

6

How is the Pertronix hooked up? “+” terminal should not be connected to the original coil “+” wire. Because of the resistance in this wire there is a voltage drop as the wire heats up and resistance increases. There is an additional voltage drop when the idle speed decreases as the trans is put in Drive or Reverse. The Pertronix will shut off if the voltage drops below a certain value.

Pertronix should be connected to the pink (RUN) wire off the ignition switch between the ignition switch and the resistor wire. Putting a fuse in the line is a good thing too.

7

MrEos,
The car was doing this before the problem started, the points were not working correctly, so the Pertronix was installed to see if the stalling was due to the faulty points. I ran the car with the all of the electrical things powered on, but it made no real difference.

Thanks,
Paul

8

Devildog,
I don’t have a vacuum gauge and I don’t know if the mechanic used one and no I don’t think they removed any of the vacuum lines yet. I will check with him tomorrow.

As for the manifold, it is the stock one and the carb is a Holley 600.

Thanks,
Paul

9

sfhess,
The Pertronix doesn’t appear to be connected to the original coil wire. But while I drove it tonight, the car seemed to shift late and kind of hard. When I had the transmission rebuilt I don’t know if they replaced the modulator (The guy who installed it had a massive stroke and can no longer communicate) so I am wondering if that could be causing an issue, does that sound reasonable?

Paul

10

My first guess was a vacuum leak.
Could be a vacuum leak in the line going to the modulator, or maybe the line fell off.

11

The rubber hose connecting the steel vacuum line to the modulator could be split or fell off. Best to replace with a new piece of hose.

12

I had the same issue when I installed a pertronix kit in the original distributor, I installed a Proform HEI dsitributor on the car when I reassembled the motor during the restoration of my car. The car ran great with the HEI distributor but I wanted to go back to the smaller stock unit to allow the install of a larger air cleaner and also just because it would look a little cleaner under the hood with the stock distributor and cap.
I went through the stock distributor and verified that it was in good working condition, installed the Pertronix kit then removed the Proform , installed the Pertronix equiped stock distributor/new cap and proper wires, when I tried to start the car it acted like I screwed up the firing order, I went through this several times (it was correct), so I decided to mess with the intial advance, I finally got the car to start with this at 20 degrees BTDC (Proform was at 10-12 but would start at TDC on up).
Once I had the car running I warmed it up and tried to move it out of the garage, as soon as I put it in gear it stalled, I was able to get it to move by advancing the initial advance to 26 -28 degrees but the car ran poorly (quite a bit of detonation) and was difficult to restart when it was at running temperature.
After going through this I reinstalled the Proform and the car has ran perfect (again) ever since.
Both distributors were connected to ported vaccum.

Side Note:
I have a 1969 F100 with a 360/C6 that has a Pertronix kit (Same one as I put in the Cougar) and it runs great… It was one of those things that makes no sense to me

13

Legendary, I suspect that the problem you were having was that the braided ground wire was either missing or not installed properly. The plate the points or Pertronix sit on moves on a pivot for vacuum advance. IT must be grounded to the body of the distributor. The braided wire needs to run from the plate, where it is secured by a straight bladed screw, to one of the Phillips headed screws that go to the body of the distributor. The hold down clamp should also be clean and tight.

14

I will take a look at that when I get back in town this weekend, the distributor is in a bag on a shelf in the garage , I will let you know what I find.

15

Here’s how you can find out if your pertronix is acting up.

Use a timing light. Put the clamp on the coil wire. Zip-tie the trigger so the light always flashes. Rest the timing light on your windsheild wiper, or on the fender…just somewhere you can see the light flashing. Get in, start the engine, put it in gear and see if the light stops flashing to indicate the ignition cutting out.

That idle is way too high. Sounds like the carb and ignition both need adjustments.

You may need to use a piston stop to find “true” top dead center to see if your balancer is reading correctly. Mark the zero position and use a dial-back timing light to chart your timing without the vacuum hooked up.

Unplug your vacuum advance and check the initial timing. If your throttle is open enough at idle to actually have vacuum in the ported vacuum line and your distributor is adjusted to have perceived correct initial timing, then perhaps when you put it in gear, the vacuum might drop off enough to let the vac advance retard to way less timing than there should be at idle.

Here are the round abouts I like to use for timing.

Initial somewhere between 12-18. My initial setting is based on how much I can get away with when running it at full temperature, shutting it off for a 5-10 minute hot soak and re-starting it on a hot day. If it has a push back sensation during starting, then I back it off a couple degrees to make starting smooth. That is my initial setting.

It seems the engines in our Cougars like 34-38 degrees of TOTAL timing. Initial + curve range equals total timing. So, if you have 14 degrees initial and want 36 total, you’d need a 22 degree range in the curve. The curve should max out around 2400 to 3200.

Vacuum advance. I find 8-12 degrees is all I like in the vacuum advance when the initial and mechanical timing are set properly. The vacuum cans that pull 20-25 degrees are for the low compression, EGR equipped, emission ridden slugs from the late 70’s. Most vacuum advances are adjustable. Some of the adjustable ones will not go low enough to get 8-12. Advance Auto parts used to carry a brand called GP Sorneson, their part number was VCF-408. That one you could adjust down to 0 vacuum advance. This is the one I use, or cross reference to another brand.
Vacuum advance is for part throttle efficiency. With the throttle is open only a little during cruising, the air/fuel density is very light and the engine can stand and optimally needs more advanced timing for better combustion. This is why I hate to see street cars with no vacuum advance.

Here is what I’d do, find true top dead center and get the timing with 14 initial, 34 total and 10 in the vacuum advance, then you can adjust the carb and futher fine tune if you desire.

16

i just installed the Pertronix II. Before, car was idling at 1100, and sometimes higher when cruising (no gas to coast at 30mph). i did install it straight at the coil. I did wash the plate in the distributor with acetone as mentioned in the instructions. The idle is now at 500 (need to neutral and tickle the pedal at stops). Didn’t bother me overmuch before as i ride it on the highway most of the time. The performance is way better at all speeds. Original points problem was a sloppy plate (the base where the points are screwed in). That sure isn’t an issue anymore.

Since Pertronix mentions to run it at 12 volts, i got myself a Pedapter From the Rktmn, and it does have a 12 volt source.

i now have an appointment monday morning for timing and carb/choke adjustment at a local garage.

17

OK, I think I have it fixed. I replaced the carb when the same model, but it didn’t solve the problem. I adjusted the new carb and everything was going well, I shifted, the car ran put it park and the idle went to 2000 RPM’s hit the gas peddle and the idle dropped to 1100. I was feeling pretty good at this moment and decided to take it for a spin. Put the air cleaner on, got in put it in reverse and the car stalled right away. Good feelings left and anger swelled. Started the car, tried again another failure. Removed the air cleaner check the carb to make sure gas was still getting into the carb that’s good. So I start the car again, put it in reverse it stays running so I put the air cleaner back on, and it stalls again. So I look down the snorkel portion of the cleaner and notice the “flapper” is closed, so I open it start the car and put it in gear and it stalls. I check the flapper and it’s closed again. grab a chrome air cleaner throw it on and start the car put it in gear and it stays running. After five minutes it’s still running so time for a drive. Drive it around for 30 minutes, car stalls once but starts right back up and I’m cruising again. I continued to drive the car the rest of the evening and all goes well. So yesterday, get the whole family in the car for a Father’s day ride (Which is special since my wife doesn’t like the Cougar) we drove the car father than it’s been in a year and it felt GREAT! I was smiling from ear to ear, my neighbors were screaming and clapping as the car finally left the garage. Took a couple of them for a rides as well.

So I have a question, does it sound reasonable that the car was stalling, because it had no oxygen?

Thanks for all of the advice, I really appreciate it.
Paul

18

after installing the Pertronix, i had my appointment at the garage this morning.

1st, all my idle problems were:

19

after installing the Pertronix, i had my appointment at the garage this morning.

1st, all my idle problems were:

  • the cougar idled at -7 degrees (Pertronix might have had that effect)
  • the carburetor’s electric choke was plugged in the wrong place. IT needs 12 volts when car is ON. He swapped the connector from the rear of the solenoid to the Alternator wire that was switched 12V.
    one vacuum port at the base of the carb has a little rubber cap on it, and it was split on the side. he Macgyvered me another cap with a piece of hose and a screw

everything settles to a nice smooth 600 rpm, and got adjusted to 1350 at cold start.

all i have left is change the return spring for the throttle. You might want to have a looksee, in case the throttle doesn’t ease back as far as it should.

Couldn’t it be vacuum also? Big difference between smooth idle and rough/stall

20

Someone who is familiar with the flapper should chime in, I do not have the original unit, so I am curious when and how it is opened. My Barracuda had a warm air shroud from the exhaust mani into a bottom inlet for warm air, and the flapper would switch to the main snorkel inlet when warm, I think it was bi-metal spring operated.

Even with the flapper closed, can’t it pull air from the shroud inlet? Could it be blocked or something?

You should see if it opens at idle when it warms…

Well congrats on getting her running well!