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AQ311 Hot CoilBad Tach

M

marshawk

New member
I am one a job that others hav

I am one a job that others have started. The problem began with a coil that got too hot to even touch and the engine quit. Tachometer was observed jumping around at that time. I am going to replace coil (3ohm) and run to test for spark with the tach diconnected. My question is how do you test to see if the tach is bad and could the coil burn up the module in the distributer as well?
 
"Bill, if the ignition module

"Bill, if the ignition module is toasted, the engine won't start as you won't get any spark. As far as I know, the most common cause for a toasted module (other than using the wrong type of coil) is to leave the ignition on for a long period after the engine has stopped. New Pertronix modules (Ignitor II I believe) are immnune to that problem.

The tach works with pulses from the coil, and more often than not they "jump" due to a faulty connection. After you replace the coil, you will find soon enough if the tach is bad or not.

BTW, I suggest that the coil you need is a 1.5 ohm for a regular Pertronix Ignitor or points, as your engine is a V-8. A 3 ohm coil is not the right one for your engine.

http://www.pertronix.com/catalogs/pdf/ptx/2007/ptx07_coil.pdf"
 
"El, generally speaking, how l

"El, generally speaking, how long is too long to leave the ignition on with a standard Pertronix Ignitor before you risk damaging the ignition module?"
 
"Bob, I'm afraid I don&#39

"Bob, I'm afraid I don't have an answer; you would have to ask the Pertronix folks about that. As far as I am concerned, and just to be on the safe side, I always turn the key off to stop the engine and leave it that way until it is time to start again."
 
"El, do you mean to say that y

"El, do you mean to say that you don't know something!?!? And here I thought you knew everything!
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Seriously, I too always turn the key off, but sometimes my girlfriend will put the key in the "on" position without starting the engine after she has put the key in the "accessory" position for one reason or another thinking that it is in the "Off" position. I have told her many, many times to watch for the red lights that display in the instrument panel when the key is in the "on" position, but she does not seem to listen to me for some reason.
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"Bob, Pertronix states the fol

"Bob, Pertronix states the following in the "troubleshooting tips" section in their site:

<font color=""0000ff"">What will happen if I leave the ignition switch on when the engine is not running?</font>

<font color=""ff0000"">Leaving the ignition switch on when the engine is not running, can cause permanent damage to the ignition system, and related components. This does not apply to the accessory position of the ignition switch.</font>

http://www.pertronix.com/support/tips/default.aspx

So, if they don't give a figure, I guess it is because they don't want any liability.

Now, if your better half does not seem to listen to you, I suggest that you print the Pertronix page in the above link and let her read what can happen if she leaves the ignition key in the "on" position. I have heard many times that women are much better at reading and following instructions than we are, so it won't hurt giving it a try (let's call it "psychological warfare").
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"Not only will I have her read

"Not only will I have her read the Pertronix warning, but I have also considered attaching some small color coded arrows to the instrument panel which are aligned with the 3 different key positions...maybe red for the "on" position, green for the "accessory", and white for "off"."
 
"Finally got back on the job t

"Finally got back on the job today and put the replacment batteries in to do some checks. Again this job was already started,,, Resistance check on existing coil that was replaced; primary circuit + to - 3.9 ohms. It has a hot spark from coil. Got spark to spark plugs. I was told that same problem (coil got hot) was found with the tach wire removed with this coil. I am unable to test run due to a heat exchanger that was not winterized this winter. Wires to coil on positive side all purple: 1)to french starter with resister to prevent back feed 2)to electric choke 3) to instrument panel light switch. This provided only 9V On negative side 1)Black to module 2) grey to tack. When I get it back together and run her I am going to elimate the tach first. If that is not it what else the choke? Is only 9V to the coil OK?"
 
I am rereading my own post and

I am rereading my own post and see that El advised useing a 1.5 ohm coil. With the 9V supplied from the instrument panel a coil marked for "use with external resistor" Should be the right one. Am I still on track?
 
"Bill, on my engine (same

"Bill, on my engine (same as yours) I have the 1.5 ohm coil (12V), no ballast or resistor wire, and electronic ignition. However, I get 12V to the ignition, not 9V. The external resistor was used with points and 9V coils, but you should not need that arrangement if you are running electronic ignition and a 12V coil."
 
"El, I was suspect to the &#34

"El, I was suspect to the "only 9V". I will move on to finding the missing 3 volts. Do you think that low voltage was/is the cause for the origional hot coil problem?"
 
"Hi Guys,

I am having a sim

"Hi Guys,

I am having a similar problem not sure if it is relyted. Just installed a new to me/used distributor, new pertronix, new Coil, and new plug wires. I get 12 Volts on the entrire system until I hook up the Pertronix ignitor Red + wire then it drops just below 9 volts on the poistive side of the coil. The voltage gauge on the dash also drops below 10 v. Have not tried to start it yet.

Any ideas on this?

Thanks

Dave"
 
"Bill, that wire may be there

"Bill, that wire may be there to install a 9-volt coil; that is, a 12 V coil that requires an external resistor to work. In that case, you will have a ballast resistor installed. I don't have such arrangement, but I rewired my boat and did not follow Volvo Penta's vision of the original ignition wiring (which is designed more for distributors with points than for electronic ignition).

David, I am not sure why you are experiencing such a drop in voltage. Is your battery fully charged? Also, have you installed the Pertronix module correctly? That is, red to (+) of the coil and black to (-) of the coil?"
 
"Evening El; I am positive on

"Evening El; I am positive on the wiring to the coil, Pertronix Red to +, Pertronix Black to -, Purple ignition to +, grey tach to -. Battery seemed fully charged but I will double check in the morning.

This evening I found that the wire between the alternator and resistor had been pulled out of the resistor, was just hanging there. Fixed this but did not seem to help maybe the resistor is shot. :-( Would this effect the voltage at the coil?

Thanks again!!!"
 
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