Ignition problem

[Dire Straits]

I have a 172 Ford and the only way I can get it to run is to tie the coil wire about 1/2 -3/4 in above the coil. It just started running crappy so normally I just throw a set of points and condenser in it and its fine. But this time not the case. I changed to electronic igniyion and still the same problem. Please help!

 

[Bern]

Sounds like a poor connection inside the coil wire to me. Time to replace it.

 

[Dire Straits]

(reply to post at 14:34:20 06/14/20) [/q

uote] Thanks for the reply. I have all new components. coil, wires , plugs and it did this before i converted it to EI and now it does the same thing.

 

[Bern]

So are you saying that TWO different coil wires act the exact same way? Meaning, you have to tie them up in order for the engine to run
properly?

 

[Dire Straits]

Yes that is correct. I have a video of it but I don't know how to upload it. lol

 

[Dire Straits]

 

[Bern]

I'm out of ideas. Hopefully someone else can help you out, otherwise you could be in Dire Straits!

 

[showcrop]

When you have money for nothing and the chicks for free you don't need a running 172

 

[MarkB_MI]

I put my hand upon the lever said let it rock and let it roll
I had the one arm bandit fever there was an arrow through my heart and my soul

I think your plugs are fouled. You can clean them up with a propane or acetylene torch. Or even a gas kitchen range. If you use acetylene, use an oxidizing flame and be very careful not to melt the electrodes.

 

[Dire Straits]

(quoted from post at 03:28:26 06/15/20) I put my hand upon the lever said let it rock and let it roll
I had the one arm bandit fever there was an arrow through my heart and my soul

I think your plugs are fouled. You can clean them up with a propane or acetylene torch. Or even a gas kitchen range. If you use acetylene, use an oxidizing flame and be very careful not to melt the electrodes.

Thanks so much! I never thought of that since they are brand new. But I will check the plugs!

 

[sotxbill]

if your pulling the coil wire out and tying it,,, your increasing the spark voltage significantly.... to make the tractor run...


suspect... defective plugs... some plugs,, no,, many plugs are now made in china and are plain junk. they simply will NOT fire under compression till you raise the spark voltage. BUt they will fire fine when out of engine under no compression.

suspect wrong/def coil or resistor added to coil....


suspect lousy plug wires that might be arcing to ground.. carbon tracks in the dist cap...


very low compression,,

 

[Dire Straits]

(quoted from post at 05:22:30 06/15/20)
if your pulling the coil wire out and tying it,,, your increasing the spark voltage significantly.... to make the tractor run...


suspect... defective plugs... some plugs,, no,, many plugs are now made in china and are plain junk. they simply will NOT fire under compression till you raise the spark voltage. BUt they will fire fine when out of engine under no compression.

suspect wrong/def coil or resistor added to coil....


suspect lousy plug wires that might be arcing to ground.. carbon tracks in the dist cap... so when I converted it over to EI should I have gone to a different plug?


very low compression,,

 

[Dire Straits]

Thanks for the reply. So when I converted to electronic ignition, I ordered everything that was recommended, matching resistor matching coil for the pertronix unit. Should I have went to a different plug? I'm running Autolite 216's.

 

[Dire Straits]

Also I ordered the recommended wires so everything was changed except the plugs.

 

[JMOR]

(quoted from post at 08:48:48 06/15/20) Thanks for the reply. So when I converted to electronic ignition, I ordered everything that was recommended, matching resistor matching coil for the pertronix unit. Should I have went to a different plug? I'm running Autolite 216's.

hen you are done fussing with everything else, verify correct resistor. Those are often not what their number would state them to be, therefore primary current too low & resulting HV spark too low. Best measurement approach is to connect coil primary in series with resistor and a DC ammeter, the connect the 3 series items across a well charged battery and measure current. It should be around 3 to 4 amperes. If under 3 amperes, resistor is too large (>Ohms).

 

[ErnieD]

Had the exact same problem. Replaced the plugs as last resort and it fired off. Thought the problem was fixed. Ran real rich when it would fire off and gradually cleared up. Pulled the air tube to the carb and found the float valve was leaking by and collecting in the base of the carb. Starts hard, runs rich new plugs will fix for awhile.

 

[sotxbill]

(quoted from post at 09:23:37 06/15/20) Had the exact same problem. Replaced the plugs as last resort and it fired off. Thought the problem was fixed. Ran real rich when it would fire off and gradually cleared up. Pulled the air tube to the carb and found the float valve was leaking by and collecting in the base of the carb. Starts hard, runs rich new plugs will fix for awhile.

yes running rich/ flooding can/will cause the plugs to be very wet, and shorted to ground.... ie no spark across the air gap if it can go to ground via the other "wet" low resistance path.

( lets not get into discussion about which way the spark ((electrons)) truly jump)

if it runs by moving the coil wire away from the coil a bit,, raising the voltage... again,,, fould plugs, defective plugs, wrong plugs, low compression are prime candidates...

 

[JMOR]

(quoted from post at 11:06:55 06/15/20)

(quoted from post at 09:23:37 06/15/20) Had the exact same problem. Replaced the plugs as last resort and it fired off. Thought the problem was fixed. Ran real rich when it would fire off and gradually cleared up. Pulled the air tube to the carb and found the float valve was leaking by and collecting in the base of the carb. Starts hard, runs rich new plugs will fix for awhile.

yes running rich/ flooding can/will cause the plugs to be very wet, and shorted to ground.... ie no spark across the air gap if it can go to ground via the other "wet" low resistance path.

( lets not get into discussion about which way the spark ((electrons)) truly jump)

if it runs by moving the coil wire away from the coil a bit,, raising the voltage... again,,, fould plugs, defective plugs, wrong plugs, low compression are prime candidates...

agree with what you say, and add that in this case, where he has changed every component in the ignition system, the possible culprits list opens up.

 

[Dire Straits]

Well I switched from AL 216's to AL437's and solved the problem. The 216 plugs were junk. Thanks everyone for all the help. We are deinitely "Brothers in Arms"