Acceleration Issue

[Anonymous]

I wanted to create a new post in the hopes of getting all advice or help possible in working to correct the acceleration problems with my 200 Falcon Six.

I'll briefly recap what has been going on with the car:

-Quickly starts and revs to high RPMs with ease in neutral and park.

-However, once put into gear the car has a very difficult time accelerating. Moderate to hard acceleration causes the car to miss, and often stall. With very slow steady acceleration it is possible to gain speed.

-When the engine is cold and the choke is engaged, the car will run fine, however, once the choke kicks down and the car is put into gear the problems begin. I want to make clear, though, that when warm the car will start without an issue and will rev to high RPMs in neutral and park.

-This is the third remanufactured carb I have had put on the car. I have had the car into two different shops and they have not come up with any solutions except that the carb could be the problem. I don't believe that the current carb is the cause of these problems.

-I have pretty much replaced all of the ignition components, (plugs, points, condenser, rotor, distributor cap), except the distributor and coil. I have also replaced the fuel pump and the fuel filter.

-recently it was suggested that I check the vacuum advance on the distributor through a method described by drpepper. According to this simple check, the vacuum advance appears to be functioning without any leaks in the vacuum line.

-it was also suggested that I might possibly have the wrong carb matched to the wrong distributor. I however to not know if this is the case, the distributor on the car is original, and I can attest that my remanufactured carb looks identical to the original carb on the car. It would be very helpful if anyone could tell me how to tell if they are mismatched. If it is helpful, I have posted pictures of both the carb, and the distributor below.


I really do appreciate all the help that anyone has to offer. I do not wish to be an annoyance to this board, but I almost feel that this is my last place to turn to. I haven't been able to find someone or a shop that has been able to diagnose the problem, and what makes matters worse, is that I feel that the solution should be fairly simple.

Thank you for your time and suggestions.

Matt

 

[Anonymous]

Hey, this might not help at all, but i installed a new engine in my car, same distibutor, and same carb as you. I had the exact same problems, as soon as the choke opend and the engne was warm it would have no power, and most of the time would die, I have rebuilt many carbs and decided that this one needed rebuilt. I took it off and rebuilt it......same problem, I was rather ticked.
Luckly I had a 170 with a holley single barrel on it, I had just recently rebuilt it so after screwing with float levels on the autolite 1100 (i think that is the name of the carb that was giving us so much trouble) and still no luck i decided to put the holley on to see if it was my engine or the carb. Sure enough it was the carb, I have had no ambition to mess with the carb any more so i left it off and have been running the holley. I am not current with the replys you have got from preveous posts on this subject but have you checked initial timing and if it checks out (mine is at 12 deg) check to see that the harmonic balancer has not slipped and you are setting the timing to a completely wrong initial. I know there is some problems with carbs that dont have a spark controll valve working with the distributor but from what i understand (dont have the book in front of me right now) but youre dis, and carb should be fine. What year engine do you have? and what size?


Ill be thinking of other reasons why it wont work and will probally post again, Hope we can figure this out. Cody

 

[Anonymous]

Thank you for the advice. The engine is a '66 200. I recently timed the car to either 10 or 12 degrees. I'd have to go check what it is set to. That is an interesting notion that the harmonic balancer might be off, but I do not believe that it is, or that this is an ignition problem

Thanks for the help, I really appreciate it.

Matt

 

[cfmustang]

I can attest to the slipped balancer problem. I was having all sorts of issues last year (not exactly the same) but all efforts to resolve them failed.

Many people told me to double-check the TDC of the balancer and for the longest time I put it off thinking that could not be it. Well, I finally checked it and sure enough it had slipped 10 degrees. When I thought I was set at 12 degrees, I was at 2!

It did not solve all my issues, but it got the ball rolling and once the ignition was set straight, I could get the carburation to where it needed to be.

 

[johnnyzoom]

Has anyone ever pulled that dizzy out? You said your vehicle has always run like this, right?

 

[Anonymous]

no, the distributor has never been pulled out.

 

[cfmustang]

Personally, here is what I would do:

1) Verify TDC. If your timing is way off (and you don't know it), you'll never get anything else set. Take away one more variable from the equation.

2) Once that is straight (and it may well be fine right now) and if it is still having problems, set the carb back to factory base settings.

3) Start from scratch. Is the carb running rich or lean and when? Test when cold when it is running fine and test once it is warmed up. If it is lean, partially covering up the top of the carb will smooth it out. If it is rich, introducing a vacuum leak under the carb (disconnect a vac line like the pcv) will smooth it out.

What you describe with it running better choked sounds like a lean condition. I am by no means an expert, maybe someone else can chime in and describe the symptoms of an overly lean condition.

 

[Anonymous]

Once had a problem that sort of sounds like what your confronted with. A number of years ago I was in the process of restoring a 67 Mustang. I had done a whole bunch of things at once, new points, sparkplugs, cables, distributor cap, vacuum advance, rebuilt the carb, etc. Car started right up, checked the dwell, set the timing, and verified the vacuum advanced adjusted the carb - the usual stuff. It was running great in the garage, however out on the road it was a real dog! Like yours it would miss and bog down on acceleration, the only way it would get to highway speed was if you very gradually applied the gas. Something was obviously wrong. Took the car back to the garage and, in neutral, both at idle and when you popped the throttle it would run great. Double check everything and couldn’t find anything wrong. Took car back out on the road and the same thing, once it was under load it wouldn’t run for crap! I must have spent a week trying to trouble shoot this thing before I found the problem and you’ll never believe what it was! The arm of the new set of points, I had installed, had a crack in it! The crack, apparently, cause a sufficient amount of flex in the arm that it would affect the timing when there was a rapid rpm change. Put in another set of points and the problem went away.

 

[CobraSix]

Couple of things.

Definitely verify a few things:

1) TDC is the same on balance and the #1 cylinder. Fairly easy way to do this is to buy one of those telescoping wands with a magnet on the end. Pull the number one spark plug. slowly rotate the engine in the direction of normal rotation (clockwise IIRC). Biggest thing is to make sure your on the compression cycle, not the exhaust cycle. Put the wand into the #1 plug hole (extend the handle) and let it rest on the stop of the piston. Slowly continue rotating the engine by hand (wrench or socket) until you see the wand end stop moving down. Now slowly rotate the engine by hand making note of when it first stopped moving and when it first starts moving back up. Now split that difference and it should put you close to TDC. make a mark on your balance to correspond with the braket on the engine.

2) Second part to see if you are having timing belt slip, if you can get the engine to 2600-2800 RPM, check timing there and see what the total timing is. This will tell us if you have possible timing belt issues, vacuum advance issues, or if the timing system is pretty much set.

3) Gut instinct (not caught up on other post) is a vacuum leak somewhere. Try when the engine is warmed up and choke is off, to take a flat piece of cardboard and slowly cover up the carb venturi. If the RPMs go up or the engine smooths out, you are running lean. Other symptons of lean is overheating engine, exhaust, etc.

Slade

 

[Anonymous]

i was thinking vaccuuum leak too

to me, it sounds carb/vacuum related...I had problems with my choke for a while. it could be you a running to lean....like it was tuned while car was still warming up...now on WOT its lean

do you hear any pinging when accelerating?

chaz

 

[Anonymous]

no, there is no pinging durring accelartion. I checked today and I do not believe that the car is running too rich or lean.

I am begining to believe that there is a vacuum leak, but I cannot find it. I was wondering if anyone had suggestions as to where I should concentrate my efforts, and what was the most effective way to find a leak.

If I cannot find one, I am going to go on and check the harmonic balancer. Hopefully it is an easily correctable vacuum leak.

 

[Anonymous]

dont know what tranny you have but on my c4 there is a vacume kick down on the lower left, my car was missing and stumbling badly and come to find out that vacume line had come unpluged and it took me for ever to find it. i felt like an idiot after that...... fixed the running rough problem.

 

[mugsy]

1) What is the dwell? verify that. Personally I would use a dwell meter and not gap the points.

2) Disconnect the vac advance to the dizzy, put on a vac meter ont he tube and rev the engine. What does the vac do? what level does it go to?

3) To find a vac leak, spray the joint with carb cleaner. When the "leak" is filled with the cleaner fluid the engine should run smoother or RPM pick up. If there isn't any changes then there is no leak. Typically sray at the base of the carb.

4) What is the voltage at the (+) terminal of the coil while running?

tanx,
Mugsy 8)

 

[Anonymous]

I want to thank all of you for your help and suggestions. Today I think I finally found the problem. The car has a c4 trans on it which has a vacuum line that runs from under the carb to the back of the trans. I had checked this line before for leaks and didn't find any. So today out of desperation I went back over and rechecked anything that might a cause of this problem. I think my problem was coming from a crack in the metal line near the point where it wraps around the bell housing to the back of the trans. Tomorrow I am going to remove the line and replace it.

I hope this will do the trick. If not, I'll post again. Thank you all so much for your help.

Matt