Stalls when put in gear

[panteramatt 1]

I have a 69 with an fmx. My buddy came over to check the car out and messed with the carb and it doesnt run right now. It will start fine when in park but as soon as I put iit in reverse, it dies. It has an edelbrock barb so I turned th emixture screws out 2 turns and turned up the idle to around 1000 rpm just to see if it still stalls and it does. I also noticed when I turn the left screw out the idle will raise but when I turn the right one, nothing happens. What could cause this? Ran fine before.

[StephenC 10]

I have this same problem with my car not sure if its your case or not but basically my car will stall when I put it in gear if its not warmed up yet and if the chokes closed

[panteramatt 1]

No choke and the car is warmed up.

[foothilltom 33]

Your idle-mixture screw settings will have nothing to do with how your car behaves with an open throttle. Think of that as a totally separate fuel delivery system that is only relevant with a closed throttle.

 

I would get back to equilibrium before I do anything else by turning both idle-mixture screws all the way in, turning them back out 1.5 turns and leaving them be (for now). Set you idle screw to proper idle (800 rpms or so). Then tackle the real problem of stalling with an open throttle.

 

Start by telling us what else your pal did. Any changed gaskets? Did he take the carb off? New spacer? Did he disconnect or reroute any hoses? Did he remove a vacuum cap and forget to replace it? Vacuum leaks can cause all kinds of funky behavior including stalling.

 

Did he change the timing? Make sure you're at 6-8B with the vac advanced removed.

 

Did he adjust the floats or needle seats? You could be running super lean and ouila, stalled. Did he adjust the accelerator pump? If that's not giving you a positive squirt on initial throttle, you'd stall.

 

Again, tell us exactly what changed and we'll be more helpful.

 

Tom

Edited April 28, 2010 by foothilltom

[panteramatt 1]

All he adjusted was the mixture screws and the idle, thats it. Thats what makes me think its something else. It doesnt have to do with open throttle cause it stalls as soon as I put it in gear.

[Fordrevhead 29]

I would guess he knocked off a vacuum line by accident. When you put an auto in gear the vacuum will drop... if it's already low via a leak it will be such a drop it will just stall. If you have power assist brakes you are probably dropping it more by pressing the brake pedal just before you put it in gear. So check lines and put a vacuum gauge on it.

 

Also, check the timing. Your initial timing might be too low... or the vacuum advance line might be the one that came off!

Edited April 28, 2010 by Fordrevhead

[panteramatt 1]

Where sbould my timing be at? And to check timing; i need to pull the vacline off of the dizzy and plug it right?

[bigperm2 10]

Your timing should be 10-12 (sea level.) You should check it with the distributor vacuum disconected and pluged. After your timing is set, you can plug the vacuum line back in and recheck. The vacuum should be ported vacuum, and your timing should still read 10-12 degrees. When you tip the throttle open, you should see a faster advance in the timing (vs. disconnected and capped.) The problems you are having could have been caused if your buddy set the idle speed to high and dropped the idle by leaning out the mixture.

[panteramatt 1]

I dont thinks it the carb as i turned the idle.up pretty high and even turned the screws out and as soon as i put it in reverse; it instantly dies. This only started after he messed with the idle.though and i never touched the timing. I did put a new coil and pertronix3 in though

[foothilltom 33]

If you swapped out your old points for a EI module, you have changed your timing and possibly dramatically. Get a timing light, pull the vac adv from the dist, plug it, and get it out of the way of the fan blades. My shop manual says 6B for a 302, but folks generally go more like 8 (or even 10B) if you're reading the advice (I'm not sure you're reading all of mine).

 

Vacuum is still a top suspect here. It's important to rule out a leak and set your idle-mixture and idle to achieve maximum vacuum. To do this, you really need a vacuum gauge and a tach but you can just use your ear in place of a tach. Unplug a port on the manifold (the one to the power booster works) and plug in your vac gauge. Your engine should run noticeably bad with an open vac port. Note the reading on the gauge. It should be about 18" of vacuum give or take depending on your setup. If it's substantially lower than this, you probably have a leak. That needs to be found and corrected before any of the rest of this will matter. Assuming no leak...

 

Turn your idle mixture screws (quarter turns at a time on both sides is good) while noting the change in the vac reading. Continue adjusting until you get the highest vac reading. Then simply set the idle screw until you have a good 800rpms or so.

 

Keep in mind that your engine's behavior is an interplay of many variables. When you change one thing, you need to go back and check/change other things. I would set your timing first considering your EI swap, but your timing will change if you have a vac leak, so it's kind of a circular path. Be ready to double-check everything when you change something else.

 

Good luck.

Edited April 28, 2010 by foothilltom

[buening 63]

Go to Autozone and buy a $20 vacuum gauge. Let us know what vacuum you have at idle. I've had this problem in the past and it was a big vacuum leak.

[panteramatt 1]

Thanx Tom. That helps a LOT. Didnt think that the timing would have changed as it did run terrible before when I put it in gear after he messed with the carb but it did run. Now it just instantly stalls out. Timing make sense. I think the carb ir idle was bad before and when I replaced the points, it got worse. I dont think its vacuum as this all started after my buddy messed with the carb but I am borrowing a Vac gauge this weekend. Tried to check the timing the other day but the balancer was too rusted to see the #'s so Im going to sand it down and mark 0 and use the advance on my timing light to get it at 10. Would sticking a screw in the vac line be a sufficient plug?

[panteramatt 1]

Where exactly should I hook the vac gauge into? In the back of the manifold is a T with one end going to the tranny and the other capped off. I imagine I can stick it in the capped part?

[DRASTiK 22]

That capped port should be fine for the vacuum gauge.

[panteramatt 1]

Just ordered one and will put it on tomorrow. Should I have it hooked up before I start it or after its warmed up and idling?

[foothilltom 33]

You can connect your vacuum gauge at any time, but I usually wait until the motor is fully warmed up and the choke is wide open. When you pull the cap off that T, your engine should run much worse. It's interesting to observe this so you can appreciate how vacuum affects things. You can put your finger over the open port while you're getting the vacuum gauge on there. Once the gauge is attached, the motor should get happy again and a reading should be obvious.

 

You should have a relatively steady reading (an inch or two of fluctuation is OK) at idle. If you don't have a good vacuum reading (18 in or so), you may have a leak and it's best to research that before wasting your time setting the mixture. A tell-tale sign of a vacuum leak is the inability to stall out the motor by dialing the screws all the way in.

 

To answer your question about capping the vac advance...a golf tee works great, but anything that will plug is fine. That port is "in front of the throttle" and pulls little vacuum relatively, but it's good to plug it.

 

Keep us posted. It will be interesting to see how it runs by just setting the timing correctly based on everything you've said.

 

Tom

[buening 63]

another quick way, but not always failproof, is to cup your hand and put it a few inches above the carb (with air cleaner off). The idle should level out or RPMs increase if you do have a vacuum leak. The principle behind this is you are slightly restricting the amount of air coming into the carb, thus making the fuel/air mixture richer. A vacuum leak is the engine sucking air elsewhere, so slightly restricting the airflow will make it go somewhat back to normal.

[panteramatt 1]

Great info. One quick question: when I screw the left screw in it will stall the motor but when I screw the right one in, nothing happens. It also doesnt raise the idle like the left one does.

[foothilltom 33]

That is interesting. This is getting over my head pretty quick now, but it could mean there are some dirty/clogged passages in the idle circuit in your carb. Remove the needle entirely and make sure it isn't broken. If it's a Holley, it should have a pointed end. You could compare it with your other one (but just remember the setting of the good one) and see if they match.

 

I'm sure the other guys will have some advice there.

[Fordrevhead 29]

crap I forgot all about the Pertronix from your other thread. Sometimes I reply to too many people I cant keep it all straight in my head, lol.

 

OK, so definately suspect that timing now! You need to run a LOT more initial timing. I am sure the Pertronix directions talk about this. Double check that you're ignition is getting full 12v+ and then go to the timing as indicated.

[panteramatt 1]

Interesting. Never heard that you need more timing with the pertronix. Anyone know how much? I would think if the timing was off it wouldnt even start. Its an edelbrock carb by the way.

[buening 63]

Great info. One quick question: when I screw the left screw in it will stall the motor but when I screw the right one in, nothing happens. It also doesnt raise the idle like the left one does.

 

Been there done that and got the Tshirt :cool2: You have a blocked passage in your idle circuit on the right side of the carb. If possible, remove the carb and empty it of fuel. Remove the idle mixture screws and blow some compressed air through your mixture screw holes. Install the carb again, set the mixture screws both out 1.5 or 2 turns, then crank the motor to fill the fuel bowls and it should fire up. If you still have problems, you may have to remove the carb, remove the metering rods from the top plate, and then remove the top plate to inspect the jets. You may have to blow air through those passages as well. This is cause be rust particles or something that makes it past the fuel filter and plugs the carb up. Your mixture screw on the right side isn't responding because it's plugged up. Hope this helps!

[foothilltom 33]

Interesting. Never heard that you need more timing with the pertronix. Anyone know how much? I would think if the timing was off it wouldnt even start. Its an edelbrock carb by the way.

 

Can somebody clarify this? I wasn't under the impression that an EI module changed the timing specifications for the motor. Matt, for sure you need to SET the timing after the installation of the Pertronix, but when you said "you need more timing", it made me wonder what you meant. I'd set it to 8B unless folks here think otherwise.

[buening 63]

I've never heard that Pertronix requires more timing. Timing is timing regardless of the ignition used. I typically recommend 32-34° total timing all in by 3000rpms. It may come in sooner or later depending on the springs you have, and mechanical timing is dependent on the weights in the distributor.

 

Follow my instructions above about blowing air through the carb passages, then stick a timing light on the car and set the timing.

[Pakrat 1,043]

FWIW I'm of the school that all cars are different and timing is not something that should just be set to a specific pre determined number, you should give your car as much timing as it likes (within reason of course) and to do that you need to time it by ear. Just about any of these cars will run at Ford's ridiculously enemic setting of 6* BTDC and that may give you the most fuel efficiency but it sacrafices performance and responsiveness greatly.

 

To time by ear simply advance it until you start to hear the car ping then back off a little until it smoothes out. A test drive will tell you if you need to dial it in a little more one way or the other, then you can put a light on it and see where you are at for a reference and check the total timing, my guess is you'll be at 10* BTDC at least. I have a mildly modded 302 and it likes 13* BTDC best.