[Danny K]

I hope I'm posting in the write section... kinda new here.

I have a '69 Mark III that starting running like dog turd all of a sudden. Pulled it out of the garage, it was fine. Started it up to back it back into the garage and with the accelerator pedal halfway down, the car was barely moving and rpm's were very low, almost as if it were flooding, but the exhaust smelled just fine.

I just parked the car and came back to it another day. So first thing I did was pull the plugs. They were all fouled out. The motor is still breaking in so I assume this may be the issue. Replaced all the plugs and fired it up. It started, but still running like crap. Terrible idle. Seems to smooth out a little bit when I give it gas but when it comes back down it idles rough and will eventually stall if I don't feather it a little to keep it running. Exhaust does not smell rich. I even isolated the vacuum system (minus distributor)

So I'm thinking it has to be something ignition-wise. I start at the coil:

Mallory Aftermarket (for breaker-points ignition) Coil: 1.8 ohm primary and 10,800 ohm secondary. Seems to be ok although stock coil is 7,800-8,800 secondary. Most aftermarket coils seem to be on the higher side.

Wires look good, they are basically brand new... 4 years old but less than 1,000 miles on them and were replaced with engine rebuild.

I took the cap off and inspected the points. I can't really tell and don't have much experience with them other than adjusting but the surface looked kind of pitted and also, the contact on the bracket part of the points has a hole in it so I can see through it. Is that normal?? Anyways, I lightly filed them and reset the gap. Started right up but still running like crap.

I'm out of ideas. I'm willing to bet it isn't fuel related but could be wrong.

Any ideas??

 

[redtail]

I hope I'm posting in the write section... kinda new here.

I have a '69 Mark III that starting running like dog turd all of a sudden. Pulled it out of the garage, it was fine. Started it up to back it back into the garage and with the accelerator pedal halfway down, the car was barely moving and rpm's were very low, almost as if it were flooding, but the exhaust smelled just fine.

I just parked the car and came back to it another day. So first thing I did was pull the plugs. They were all fouled out. The motor is still breaking in so I assume this may be the issue. Replaced all the plugs and fired it up. It started, but still running like crap. Terrible idle. Seems to smooth out a little bit when I give it gas but when it comes back down it idles rough and will eventually stall if I don't feather it a little to keep it running. Exhaust does not smell rich. I even isolated the vacuum system (minus distributor)

So I'm thinking it has to be something ignition-wise. I start at the coil:

Mallory Aftermarket (for breaker-points ignition) Coil: 1.8 ohm primary and 10,800 ohm secondary. Seems to be ok although stock coil is 7,800-8,800 secondary. Most aftermarket coils seem to be on the higher side.

Wires look good, they are basically brand new... 4 years old but less than 1,000 miles on them and were replaced with engine rebuild.

I took the cap off and inspected the points. I can't really tell and don't have much experience with them other than adjusting but the surface looked kind of pitted and also, the contact on the bracket part of the points has a hole in it so I can see through it. Is that normal?? Anyways, I lightly filed them and reset the gap. Started right up but still running like crap.

I'm out of ideas. I'm willing to bet it isn't fuel related but could be wrong.

Any ideas??

replace the burnt points, and if should run better. Sounds like that's all it is. points used to burn out all the time. New points are like $10, so if they look burnt, throw a new set in.

 

[FEandGoingBroke]

OK to have hollow points, some are like that some are solid.

 

[colkerr]

Could also be a vacuum leak.

 

[Danny K]

I isolated the vacuum system from the engine to determine if it was a vacuum leak. Still runs the same. I did however discover that the vacuum advance was bad! So I replaced it and now it runs/idles great! However when I accelerate, the engine bogs down and wants to go nowhere. If I accelerate lightly, I finally get past the dead spot and the car takes off like a rocket. I have a feeling this is carb related, but it didn't do it before I starting having the running issue.

I checked dwell angle and it is at 26.4 (on the factory spec of 26-31 +/- 6) so I assume the point gap is dead on. It seems to be running a little rich but not terrible (where exhaust is unbearable in a garage). I am currently using a Holley 0-80783c with a 5.5 Power Valve. My engine idles in drive at 14". I have a hard time believing it's running rich on acceleration because the power valve opens later than sooner so it shouldn't be flooding out while accelerating.

Might it still be an ignition issue? (to note, I am running a little advanced on full manifold vacuum).

 

[PSIG]

I isolated the vacuum system from the engine to determine if it was a vacuum leak. Still runs the same.

Danny, colkerr isn't just meaning a leak in the vacuum system, but a leak into the intake system anywhere, such as past carb, base, or intake gaskets, torn PB booster, etc. Do a full leak check.

I did however discover that the vacuum advance was bad! So I replaced it and now it runs/idles great!

Few folks realize how important the ignition timing is. While you replaced the canister, was it of the correct vacuum and advance rating? Sometimes parts stores just throw out one that fits a "Ford", and there are several varieties. Beyond that, you now have working vac advance, and so your increased base timing may be affecting it differently. Perhaps try re-setting your base timing jsut to make sure it's not an issue. Then likely on to carb stuff, such as your PV which sounds a bit too low at 5.5, float levels, etc.

David

 

[DanH]

replace the burnt points, and if should run better. Sounds like that's all it is. points used to burn out all the time. New points are like $10, so if they look burnt, throw a new set in.

idel's great now with a vacuum advance changed . he got the dwell info to the 1/10 degree ..

someone thats building a custom emgine/fuel system should come up with the Correct answer .
WASN'T THE POINTS .tell him what and why the suggestion you'll give will fix it

 

[Danny K]

David,

While you replaced the canister, was it of the correct vacuum and advance rating? Sometimes parts stores just throw out one that fits a "Ford", and there are several varieties.

How do I know I have the right advance? This one came on a spare reman distributor I had for this car just laying around. I do not have a distributor tag to reference.

Beyond that, you now have working vac advance, and so your increased base timing may be affecting it differently. Perhaps try re-setting your base timing jsut to make sure it's not an issue.

By base timing, do you mean with vacuum line disconnected? Since I have my distributor connected to a full manifold vacuum source and not a timed port, whenever I try and disconnect the vacuum line it either A) won't restart or B) I can finally get it running and so I time it to correct spec, but then once I reconnect the vacuum line, the RPM shoots WAY up. Would it be wise of me to get the distributor back on a timed port? I've heard either works, but a full vacuum port actually allows the engine to run a little cooler but you have to "advance" the timing a bit to compensate.

 

[PSIG]

How do I know I have the right advance?

Check your service manual. I should have it if you don't, but it will have to wait until tonight or tomorrow. If you don't have the Ford manual set, get it. A wise investment for any classic Ford owner.

I've heard either works, but a full vacuum port actually allows the engine to run a little cooler but you have to "advance" the timing a bit to compensate.

I don't follow the little timing advance. Normally (stock distributor), set stock base timing (no vac), attach vac, reset idle rpms and mixture, and go. Or, set max advance at "all-in" rpm (no vac), attach vac, set idle mix and rpms and go. No 'little advance to compensate' as that throws your total off - if I'm following you. What are you doing differently?

David

 

[arnoldtx]

You haven't said if you set or checked the timing?

 

[70XL]

David,
By base timing, do you mean with vacuum line disconnected? Since I have my distributor connected to a full manifold vacuum source and not a timed port, whenever I try and disconnect the vacuum line it either A) won't restart or B) I can finally get it running and so I time it to correct spec, but then once I reconnect the vacuum line, the RPM shoots WAY up. Would it be wise of me to get the distributor back on a timed port? I've heard either works, but a full vacuum port actually allows the engine to run a little cooler but you have to "advance" the timing a bit to compensate.

I believe you should plug the vacuum line when you pull it from the advance canister. If you don't plug the vac line you have a vac leak. Do all your set up, initial timing, fuel mixture and idle speed with the vac. adv. disconnected, and line plugged.

 

[Danny K]

The way the car (distributor) was originally set up was with a ported vacuum switch. Right now it's just on full manifold vacuum. It's been running fine all along until the advance diaphragm blew out. Now that I've replaced it, it idles fine but won't accelerate until it gets past a certain point. I didn't touch anything, timing or carb-wise. So my question is: does it have something to do with it being on full vacuum right now and maybe the advance was "bad" all along and the way it was timed was compensating for the faulty advance, and... should I switch it back to a timed vacuum port with ported switch the way it was originally.

The issue I am having seems to be timing related. It isn't running rich, but I have no way of telling if it is starving for fuel either.

 

[DanH]

The way the car (distributor) was originally set up was with a ported vacuum switch. Right now it's just on full manifold vacuum. It's been running fine all along until the advance diaphragm blew out. Now that I've replaced it, it idles fine but won't accelerate until it gets past a certain point. I didn't touch anything, timing or carb-wise. So my question is: does it have something to do with it being on full vacuum right now and maybe the advance was "bad" all along and the way it was timed was compensating for the faulty advance, and... should I switch it back to a timed vacuum port with ported switch the way it was originally.

The issue I am having seems to be timing related. It isn't running rich, but I have no way of telling if it is starving for fuel either.

I see dwell and vacuum numbers . No timing numbers .

put the timing light on , get the numbers .with and without vacuum to the can .

check the carb pump shoother setting . 5.5 p/v doesnt belong in a stock engine for normal driving

 

[Danny K]

So should I be using timed vacuum port or am I ok with full vacuum and why one over the other?

 

[DanH]

So should I be using timed vacuum port or am I ok with full vacuum and why one over the other?

only you know why its the way it is .

 

[70XL]

So should I be using timed vacuum port or am I ok with full vacuum and why one over the other?

I'd say go back to ported vacuum. Set the base timing with the vac advance disconnected, plug the vac line. What is the vacuum reading idling in park? Base timing 10 - 12* for a start. Tweak the idle fuel screws on the carb to tune the mixture and then set idel RPM to around 800. I would think a stock engine should have more than 14"Hg at idle.

I believe your previous experience with RPM's increasing after plugging the vac line back onto the advance canister is the strong vacuum advancing the timing a bunch at idle. The base mechanical, or centrifugal, timing was being advanced too much at idle by the addition of the vac adv.

 

[Ford/IHman]

So should I be using timed vacuum port or am I ok with full vacuum and why one over the other?

Not arguing with anyone here but why can't you just time it by ear til it sounds smooth and healthy and then tune your carb to match it? Unless we are spraying the kids drag truck it gets timed by ear. The engine will tell you what it wants by how it runs. We are dealing with old technology in a points style ignition. As far as points go I have seen the new points made today corrode twice to three times as fast as points made some years ago. Why not go electronic? We have two tractors from 1947 and 1953 we tractor pull with and both have electronic ignition conversions. Much easier to tune,start and they make more power than their point ignition counter parts. Just a thought!

Tony