Tweety's ea81 build

Tweety · Post by **Tweety** » Thu Dec 11, 2014 10:25 pm

Thanks Doug,

I'll try that in the morning. This dizzy was out of the engine prior to the supercharger (that one was recalibrated for the SC) and the SPFI had its own special dizzy. So its been a while since use but was working.

Nevertheless that test you gave is easy to do. I'll raise the current dizzy and I know the timing position of it etc. I like to eliminate things form the equation so that test is ideal.

And thanks for the confirmation of the test lamp on either coil point.

Tony

Subydoug · Post by **Subydoug** » Fri Dec 12, 2014 12:17 am

Forgot to mention, if you pull the distributor all the way out, it will still need to be grounded. A jumper leed does the trick.

Regards

Doug

Tweety · Post by **Tweety** » Fri Dec 12, 2014 9:41 am

Doug,

Did the test as instructed. no spark. am hunting for another module. will advise. Tony

Proton mouse · Post by **Proton mouse** » Fri Dec 12, 2014 11:12 am

Two other things come to mind Tony.....
1)The coil could be dead (and also is it one suited to electronic ignition?)
2) Is the engine earthed properly? Having just fitted motor and maybe forgetting earth strap?
John (#2)

Subydoug · Post by **Subydoug** » Fri Dec 12, 2014 12:11 pm

Both the spare and the current one in the car? Surely one module is ok. Stupid question, did you replace the blown fuse? When I get home tonight I will have a mess around with mine, see if there is any way of testing the module with a dmm.

Doug

tambox · Post by **tambox** » Fri Dec 12, 2014 12:48 pm

May be able to test it if the DMM has duty cycle.

Tweety · Post by **Tweety** » Fri Dec 12, 2014 6:10 pm

coil tested - not good. Thanks greg (Tambox for the procedure). no spark when negative side to coil is brushed up against neg of battery.

Fuse was replaced.

Seems the coil might be the culprit. Scott (El Freddo) is due here tomorrow with a spare coil.

All makes sense to me. Although I've never had a bad coil in my 80-85 cars I've owned.

Scott suggested kill switch on the bars. had that issue before. but no change.

Tony

Subydoug · Post by **Subydoug** » Fri Dec 12, 2014 6:30 pm

Yeah it seemed unlikely that both your ignition modules were cactus.

I expect a full report tomorrow :P.

Regards

Doug

Tweety · Post by **Tweety** » Fri Dec 12, 2014 7:09 pm

Just for curiosity I tested the coil ohms.

between the two connectors was 0.75 to 0.9 varying. (within spec)

between one connector and the high tension lead connector was 4750 ohms. According to google should be around 10,000 to 11,000 ohms.

This coil is a master blaster about 3 years old.

tambox · Post by **tambox** » Fri Dec 12, 2014 7:34 pm

Lower resistance readings can indicate the windings are shorted.
Shorted windings kill the induction field.
Then it no work, as proven by our coil induction specialist, Tony:)

Subydoug · Post by **Subydoug** » Fri Dec 12, 2014 7:51 pm

Also, ohms isn't the best reading to take, you really want to measure its inductance.

Regards

Doug

Tweety · Post by **Tweety** » Fri Dec 12, 2014 8:33 pm

and thanks to Dr google

Tweety · Post by **Tweety** » Fri Dec 12, 2014 10:40 pm

Google is amazing
This site

http://www.ultimatesubaru.org/forum/top ... coil-ea81/

Sows the following two posts on the master blaster 2 coil that I have

BLASTER 2 AND 3 SPECIFICATIONS
Output Voltage: 45,000 Volts Maximum
Operating Voltage: 12VDC
Primary Resistance: 0.7 Ohms
Secondary Resistance: 4.7K Ohms
Turns Ratio: 100:1

which is about what mine is in readings. Then the very next post

slideshow86 said

If the primary and seconary doesnt match my oem coil. How could this be the right coil? Will it hurt anything? Even the specs for the accel's dont match. Im confused.

It can hurt, yes. The resistance of the MSD/Accel are lower in order to facilitate a larger, hotter spark. While this may be good/useful for ignition (which is still debatable, and highly depends on application, mixture, ect), it is causing more voltage to reach the ignition module inside the distributor. This will degrade the module faster - often pushing an older module over the edge. Nothing lasts forever, but as with all electronics, the hotter you run them, the shorter their lifespan.

So there is always risk involved. Just as there is with running a ND distributor on a Hitachi coil - same situation if you reference the above specs I gave. The ND module was not designed to trigger the larger voltage that the Hitachi coil runs.

GD

So consider not buying a master blaster coil. Stick to stock. This also means my coil is good but not ideal. I'm confused as to if it is the problem. Scott will be here tomorrow. fingers crossed.

Subydoug · Post by **Subydoug** » Fri Dec 12, 2014 11:33 pm

If you scratched the neg terminal of the coil on a GND and got no spark, then the coil is fried, regardless of what resistance you measure. Like I said, you need to measure its inductance.

One thing that bugs me, few days ago when the fuse blew, did you have the brown wire connected to the coil when you probed it with your lamp? You should be able to hold your lamp on that terminal all day long and not pop fuses, just like you can put the lamp across the battery........I thought maybe it was something to do with the ign module but I cant picture how.

Doug

steptoe · Post by **steptoe** » Sat Dec 13, 2014 6:58 am

that is now second time I seen Dougy mention need to be measure its inductance - maybe not a bamboozling term to some ! I reckon a helpful comment such as that needs to come with a link to an explanation as to what it means and how - each time

I once used a new Bosch coil MEC 717 recommended by rising sun steve for EA82T - lasted less than a year before started to give odd poor performance symptoms. Slapped in new genuine coil - BINGO ! no more problems

tambox · Post by **tambox** » Sat Dec 13, 2014 9:32 am

Doug is correct, the true way to read a coil (pretty well any coil) is to measure its inductance. From that you can work out what you really should be seeing from it.
Unless you understand inductance and have equipment to measure it, it can be hard to make any sense of it.
Nice to do in the "ideal world", but Tony lives off a back road away from civilisation, so he's doing well.

YouTube · Post by **El_Freddo** » Sat Dec 13, 2014 1:17 pm

Ok, so we've swapped out the coil for a known good one (although, it was a "known good one" about a year ago); re-wired the coil as the power wire seemed to be on the wrong side - ignition power now on the positive side of the coil.

Hopefully the ignition around the wrong way hasn't flogged out the coils.

At the moment things are pointing towards the ignition module in the dizzy again... I've got two on order that should arrive Monday. Looking at posting one up to Tony asap to see if that resolves the problem...

Might try shorting the pos and neg of the coil to induce a spark - ok to do this?

Cheers

Bennie

tambox · Post by **tambox** » Sat Dec 13, 2014 3:22 pm

Yes, just briefly, on/off, do it a few times, ie imitate a set of points.
Do not short the coil +ve -ve, just on/off the -ve to ground, whilst the +12v is on.

tambox · Post by **tambox** » Sat Dec 13, 2014 4:04 pm

:)Did I hear a rumour that Tweety is chirping!!!!!!:)

steptoe · Post by **steptoe** » Sat Dec 13, 2014 8:17 pm

Can't wait 'til he sees a puddy tat then :po