I have a big block in my 74 crewcab and it starts fine but when it gets warmed up the truck just seems to sputter and stop. It will crank over but it seems like it is getting no spark. It has ford electronic ignition installed and a regular Ford coil. What is weird is you put snow on the coil and it will start up right away. the coil says on the outside of it, "use with resistor " but no one can tell me what is this resistor? I am wondering if this is my issue as if the coil is cold it works fine, but once it warms up it is dead. any ideas would help! Thanks.

 

Do you have a voltmeter. You will need to measure the voltage at coil positive to see if you have a resistor wire in the system. The resistor wire will drop the voltage to the coil so it won’t get hot.

Did this truck originally have points or a Ford DS2 electronic ignition system?

Does the coil have a push on horse shoe type connector?
Jim

 

Points or Dura spark makes no difference. All had a resistor wire leaving the ignition switch in run position. It is 1.4 ohms and voltage drop reading will not show it up unless circuit is complete. No current flow, no voltage drop.

 

Measure the voltage at the coil + terminal while the engine is running. That will give you the correct reading. If you find you have 12+ volts at the coil +, just go buy one of those large white resistors made for a Chrysler product, and install it inline with the coil. If you find you need this and get it installed, and it cures the problem, write back in, there are a few other details and a wire you need to add to top it all off(make it start better cold). Check the voltage first.

 

The truck is a 74 which I believe had points. but I dropped in a 460 (545 now) from a 1976 Lincon which has the stock ford electronic ignition. I will have to borrow a volt meter, that is one tool I don't have yet. The coil is the old style with the screws and nuts on the top. So the voltage coming out of the coil on the positive side should be 12V??

 

No, the coil voltage on the positive side of the coil should be something around 9v. We are suspecting you will find it is 12v when you put your meter on it. If it is, then that explains the coil overheating, I am surprised the module hasn't cooked itself if you find this is the case.

I can't tell you for sure, but I think you may need to change the coil style also. Do some research on the internet, or someone who knows may write in, but I believe the Ford Duraspark II system uses the different coil with the pins instead of the threaded posts for a reason. Maybe your coil will be ok, but I am not sure about it.

 

No wires attached. Stock coil should read .8-1.6 ohms across pos and neg. 7700-10.500 oms from center post to either pos or neg. Method of connection doesn't really matter if horseshoe clip or posts. This info is from the Ford shop manual. Yep, you need a meter. I try not to list exact voltage measurements as they are dependent on batt, charging system and condition of all connections, but values listed by Franklin2 should be close.

 

My buddy still isn't back with his volt meter but I did install a Mallory Resistor ( a white block with 2 plug in's) installed inline on the positive side of the coil. I didn't get it hot enough today to see if it quits again however over 3000 RPM it started missing and rumbling.. didn't sound good at all. I guess I need to wait for that volt meter! ****!

 

Agreed, there is no sense in moving forward with a solution until you've correctly identified the problem, hence the need for a multimeter.

 

Well I finally figured out this issue> the voltage regulator has the 4 pins to it, and one was completely rusted out which is funny as it is only 4 years old. go figure. Now it starts like a top and doesn't overheat one bit! Yahoo! TYhanks guys for the help!