Best Ignition 12 volt Source ?

[ajkolar]

I have a 1988 VIP w/ 5.7 litre OMC cobra engine and drive. I installed the pertronix eletronic ignition kit and a flame thrower coil. Just wandering what/where the best 12 volt source is. It seems like sometimes when I hit my trim switch I can hear a brief stutter / miss from the engine and am wandering if possibly the voltage is dropping or the trim is creating a draw and causing a quick ignition blip.... Btw, it is currently hooked up to the a 12 volt switched source/terminal on the starter/solenoid.

 

[ajkolar]

Re: Best Ignition 12 volt Source ?

anyone?

 

[Fishermark]

Re: Best Ignition 12 volt Source ?

If you have an electric choke, you can usually tap in there. (I don't have a wiring diagram for your engine).

Another possibility is to simply splice into the main ignition wire at the main engine harness.

 

[bruceb58]

Re: Best Ignition 12 volt Source ?

Btw, it is currently hooked up to the a 12 volt switched source/terminal on the starter/solenoid.

There should be no switched source on the solenoid. On the solenoid there can be 4 terminals, one is the battery connection, one feeds the starter, one is from the start position of the ignition switch, and one(optional) goes to the coil to allow full voltage while cranking.

 

[Limited-Time]

Re: Best Ignition 12 volt Source ?

You mat have charging system or battery issues. I'd put a meter on the battery and watch the voltage as some one toggles the trim motor.

 

[ajkolar]

Re: Best Ignition 12 volt Source ?

Bruceb58, Your were right! The reason I thought I had a 12 volt switched source at a terminal on the solenoid is because the there was a purple / black wire still on the terminal which was spliced into the original resistor wire for the old ignition coil hookup.... So what I was really getting was the switched resistor wire power (through the purple and blakc wire) accidently when testing the cranking bypass terminal on the solenoid.

SO, now that I have that figured out, I am back to my original question where is the best place to get a true 12 volt switched source to connect to the positive ignition coil terminal. I don't have a problem running a wire from my ignition switch to the coil if in deed that is the best source... But if there is something better and or closer I would like to know about it (hard to tell from the wiring diagram). My electric choke is connected to the AC tap on the alternator so I don't believe that is a feasible option (plus I don't think having the eletric choke directly connected to the ignition positive terminal / source is a good idea).

Please advise!! Thanks in advance.

 

[gentner8]

Re: Best Ignition 12 volt Source ?

You may want to consider a relay if your ignition has a high draw. That way it can run direct off the battery, but still be switched on and off by the ignition. It would be a cheap and permanent fix, and your ignition box will have all the juice it would need.

 

[ricksl1]

Re: Best Ignition 12 volt Source ? HERE IT IS

Re: Best Ignition 12 volt Source ? HERE IT IS

OK , called a perteronix tech myself today , If you are using your old wire to + side ,don't !!! . Run a "new " wire from your ign switch to coil.The coil needs to see 12 volts , the coil needs to be (on v8) at least 1.5 to no more than 3.5 ohm internal resistor type or it (the coil) will get HOT and mis-fire. If your wire to coil now is a non-resistor type (most have a built in and read around 7.5 volts) it should give 12volts ,here again check voltage from your origonal +side wire ...if less than 12 , run a new wire from switch to coil+ that will or should give the 12 volts to coil (you might be able to pick it up somewhere else ,but I came right straight from switch, where ever you pick it up , make sure it goes off when key is turned off, leaving key on without running, will damage coil and or the module..in other words don't go straight to battery)...if your wire already reads 12v , then it's a non resisted (no in-line resistor). however the flame thrower should be no less than a 1.5 internal resistor type coil (V-8 ..4 & 6 cylinders need more (3.5) ...using a regular coil will fry sooner or later....also the gap on your new module and pick-up sencor (going back to the distributor) should be .030 you can shim if necessary but shouldn't have to ... it should be pre-set. check only if the coil thing still leaves you missing. These steps will elliminate the electrical issues...the miss could be in the fuel system

ps. lets let the FED's up the ethonal to 20% ....shops will stay super busy then !!!!
not sure where you are at but here in MD it's a Fed thing to have 10% ethonal in ALL gas now !! bet thier pumps are ethonal free !!
my 2 cents

 

[TBB]

Re: Best Ignition 12 volt Source ?

I had the same problem when I recently replaced the breaker points and coil on my 1986 Mercruiser 170 with a Pertronix Ignitor and Flamethrower coil.

I disabled the ballast resistor wire by connecting the (+) side of the coil upstream of the resistor wire, but only got 9 volts at the coil. Then I tried a wire straight from the ignition switch, and still only 9 volts. After some digging, I discovered that when the electric carburetor choke was connected to the (+) 12V side of the ignition switch, it would suck so much juice that both my handheld and dashboard voltmeters showed only 9 volts. However, if I remove the ignition wire connection to the electric choke, the voltage pops right up to 12 volts.

I haven't yet hit upon a good fix, but if anyone knows of one, I'd like to hear it.

 

[thunderroad]

Re: Best Ignition 12 volt Source ?

I'm considering going to a pertronix unit myself. So far all I've done is some preliminary reading. The module inside the dist cap has two wires, right? One to the - side of the coil and one to a switched 12V? So are you saying if you go to the flame thrower coil you need another full 12v to the + side of the coil?
Also...do you need to change the plug gap when you switch to this unit?

 

[Fishermark]

Re: Best Ignition 12 volt Source ?

The module inside the dist cap has two wires, right?

Correct.

One to the - side of the coil and one to a switched 12V?

Incorrect.

The two wires on the module are black and red. The black goes to the negative side of the coil. The red goes to the positive side of the coil. Simple.

You also need to have a full, switched 12v to the positive side of the coil.

It's that simple. Where you get the switched 12v is entirely up to you. TBB had a problem with the choke drawing the power down to 9v... I wonder if he is taking that reading with the engine running. Regardless, you need to get rid of the resistor wire and give the coil a full 12 volts. As mentioned, I spliced into the wire leading from the ignition switch back by the main engine harness.

 

[bruceb58]

Re: Best Ignition 12 volt Source ?

TBB had a problem with the choke drawing the power down to 9v... I wonder if he is taking that reading with the engine running.

Doesn't matter...you should have a full 12V at the coil without the engine running. 3V is way too much drop.

 

[thunderroad]

Re: Best Ignition 12 volt Source ?

Thank you, fishermark. I get it now. So....the dual porcelain (ceramic?) resistors that are in the circuit now would need to be bypassed so I could get a full 12V to the + side of the coil?

sorry for the semi-hijack.

 

[Fishermark]

Re: Best Ignition 12 volt Source ?

So....the dual porcelain (ceramic?) resistors that are in the circuit now would need to be bypassed so I could get a full 12V to the + side of the coil?

Correct.

 

[ricksl1]

Re: Best Ignition 12 volt Source ?

I'm considering going to a pertronix unit myself. So far all I've done is some preliminary reading. The module inside the dist cap has two wires, right? One to the - side of the coil and one to a switched 12V? So are you saying if you go to the flame thrower coil you need another full 12v to the + side of the coil?
Also...do you need to change the plug gap when you switch to this unit?

I have read you can gap from .035 t .040 (more fire @ plug ) supposed to increase spark/burn all incomming fuel/and better mpg's ???

 

[bruceb58]

Re: Best Ignition 12 volt Source ?

burn all incomming fuel/and better mpg's ???

You won't notice any better economy assuming the previous system was properly working.

 

[ricksl1]

Re: Best Ignition 12 volt Source ?

You won't notice any better economy assuming the previous system was properly working.

Bruce ,this came straight out pertonix mouth..honestly i wouldn't know ,I can't even get the one i've got workin right..keeps heating coils even with the internally resisted coil ...coils heating up and start misfiring after about 20 mins of running I keep byin coils and the keep over heating ...So i'm blank on this one ...just relaying what pertronix told me going to do the balast resistor w/12v + pertronix red on incomming and out going to coil+ get that voltage down at the coil..the only fish left to fry...she'll seemto run all day @ 2800rpm but once i throw the hammer to er , butin up time coil hot as firecracker...timing light test on all 8 wires shows intermitting fire on some and none on #6 ...so really the igniter wants to see 12v whre coil can run 7.5?? he_ _ maybe my moduel has picked up a problem with everything else going on

 

[bruceb58]

Re: Best Ignition 12 volt Source ?

Rick,

You need to absolutely be sure that all your sparkplugs are good, all your plug wires are good, cap is good, and rotor are good. If the coil has a bad path so that it can't discharge its energy when the field collapses, its going to heat up.

What is the condition of the distributor that you mounted the pertronox unit in? It is possible that at higher RPMs, the distributor shaft is moving and changing the airgap of the pick up. This is just a guess but you need to look at it just in case.

Have you ever run the positive wire of the ignitor straight to the battery...just as a test?

When you instaleed the pertronix module did you make sure that the distributor baseplate was clean...wipe it down with a solvent before mounting?

By the way, coils can get pretty darn hot.

 

[gdombroski]

Re: Best Ignition 12 volt Source ?

If you go to a flamethower that is less ohms then a 1.5 stock and go 12V to the coil you will damage or burn up your ESA. I know this is true as I burnt up two of them and had overheating coil issues to.

Accoding to new info from CDI who makes the Pertronix ignitor compatible ESA's "OMC Cobra Stock coils should be @ 1.4. Some aftermarket HOT coils are as low as 0.6, which causes a doubling (or more) of the coil current. Then coil current doubles.
The coil overheats and the electronic distributor is driving twice as hard."
That might be the cause of previous posts problems. If you go to 12V there needs to be a resistor between positive side and ESA."

I know this is true as I burnt up two.

Can't seem to copy off the PDF file which goes into detail on this. So, if you want it email me.

 

[ricksl1]

Re: Best Ignition 12 volt Source ?

Hi if u have the newest pdf ,would love to se it ..
ps Bruce ,dist tight and module was cleaned ,put in in accordance to the instructions ...ran great first yr and 1/2 the second ...that was before i knew a thing about the coil having to be intern 1.5 ohm deal ,i just hooked it up to the ole stock merc coil never looked back ran like a charm....crazy as it seems .i'm half tempted to throw the ole points back in and se what happens