I'm wondering if testing the voltage to the coil might be in order? Is is AC or DC? And yes, I'll be extremely careful.

Easier and safer to pull a plug and crank the engine while putting the tip near near a ground to check for spark. Big fat and blue is a good thing....

You can certainly do that but first simply measure the resistance from pin A inside the 6-pin connector to a grounded point in the engine bay. You need to see the primary coil resistance. If not there is your problem.

Measuring the coil voltage needs to be done with the coil connected and you really need an oscilloscope with a 1:10 or 1:100 test lead to make useful measurements. Better yet, you'd have access to a current probe to see the charge curve of the internal capacitor.

Without the coil connected to the CDI there is no useful information coming out of pin A. The coil's primary is an integral part of the circuit. If for some reason the wire from pin A to the coil is interrupted or the wire from the coil to GND then you will see erratic measurements that don't help (leakage of the internal capacitor)

Ingo

Maybe this block diagram helps you understanding CDI and what to measure:

If you measure OHM from pin A to GND you need to see the coil primary resistance ~ 1 Ohm.
If you measure OHM from pin A to the center lead of the coil you need to see the coil secondary resistance (+ the very small primary) ~ 1kOhm.

With the box whistling both primary connectors of the coil need to show 0 volts. If not you have a harness or coil issue. Once a spark is generated (SCR triggered) the A output will show a sharp 400V spike of very short duration. With nothing connected to the box output A is ideally floating when the box whistles but due to the age of the internal capacitor there can be some significant voltage present all the way up to 400V. BE CAREFUL.

http://forums.pelicanparts.com/uploa...1478401543.jpg

When the same thing happened to me, it was because I had replaced my old black coil with a new silver one (bad idea). I put a 30 year-old black coil back on and haven't had trouble since. Borrow a coil and try it.

Thanks, that diagram helps a lot! The only thing that's not checking out from all the testing is the coil, and the Bentley manual says it's either the coil or the CDI. The coil's resistance is too high at the primary. I suspect that's the problem. Since the primary resistance is too high, it would make sense that there's not enough voltage coming out of the secondary coil to make a spark. I'll hold off on trying to measure any voltage at the coil while cranking, I have a new coil on order. Just have to wait a few days (unfortunately I'll be traveling at the end of the week, so hopefully it arrives before Wednesday). I'll report back.

It really isn't necessary to wait for an original coil to continue testing. Just find basically any old coil,
e.g. an old VW coil. Make sure that the test coil has a primary resistance greater than 1-2 ohms and
less than 5 ohms.

Your coil measurements appear spot-on and don't suggest there is anything wrong. Most meters don't measure very accurately down in the lower Ohm region and it takes some skills to differentiate between 0.5 Ohm and 1.0Ohm. What does your meter show when you touch both leads together. Anywhere from 0.0 - 0.6 Ohm is pretty normal depending on the quality of the meter and test leads and cleanliness.

Measure from connector A to GND and verify you see a very similar reading of ~ 1 Ohm.

The resistance values you've measured are basically right-on the actual values of the original black
Bosch CDI coil. The accuracy on the lowest scale where you measure 1.0 ohms is not much better
than +/- .5 ohms, so most likely your reading for that value is good.

Avoid wasting money on a new coil, which given the poor reliability of Bosch coils lately, as the new
coil will possibly introduce a new problem now or long term.

So if it's not the coil, not the cdi, not the dizzy, then what???

I think the measurement from terminal A inside the 6-pin connector to GND is still outstanding so you can rule out a harness issue.

I measured that, I have voltage.

Hi groovydude,

I think you have one of our CDI+ units. There is an green LED indicator on the top of the unit. Firstly it will light up briefly as a voltage test for 1 second when the ignition is switched on. So have someone switch the igntion on while you watch and check that.

Then, the LED will flash everytime it sees a trigger signal. Have someone crank the car over and see if it is flashing.

If it isn't flashing , the problem is most likely to be the green trigger wire on the distributor.

If it is flashing, the problem is the coil, or the connections to it.

Hey Jonny,

Firstly, I think I propped the wrong company a few posts back, sorry!

Secondly, that's brilliant. The LED worked as it should, so it's pretty clearly either the coil or the wiring. I'll work on the wiring while I wait for the new coil.

THANKS!

A few posts back it was suggested to try just a 'regular' Bosch Coil from a VW, etc. This is a simple, temporary substitution that will rule-out whether you have a coil problem or not. Even though this coil is not optimal in terms of spark energy delivered, it is perfectly fine for "go/no-go" test purposes. Even though you have made successful resistance measurements on the coil primary and secondary, that does not rule out whether the coil is arcing internally, a problem I have seen numerous times, especially with the silver-can replacement coils.

Great, so after 50+ posts it's determined that it's not a Bosch CDI, i.e. what all the troubleshooting
was focused on. Hopefully for you, if the CDI is bad, it can be rebuilt, e.g. unlike PermaTunes and
other aftermarket units.

Troubleshooting technique for dummies.......
 

I find it convenient and easier to use known good parts for CIS troubleshooting. My lack of technical knowledge in electronic is overcomed by having good working spare parts like these:

http://forums.pelicanparts.com/uploa...1478455059.jpg

While the black ignition coil could be bench tested, having a half dozen good coils is an advantage in determining the culprit. I have yet to find a bad ECU or CDI to send to Ingo. He has been giving everyone excellent advises for so many years and time for us to reciprocate by doing business.

Tony

???

Re-read the thread. The CDI is an aftermarket unit from the U.K., which might still be under warranty.
Furthermore, the problem is not fuel related, so no need for any of your 7 CIS Lambda units for troubleshooting.
You might consider sending the OP one of your 5 Bosch CDIs for ignition troubleshooting, though.

But if the CDI hard been a Bosch unit, the OP could have sent it to Pelican Parts for rebuilding, as they provide
that service. Isn't it interesting that few Pelican Parts forum members rarely if ever promote Pelican Parts for the
rebuilding services they provide?

Your missing the point.......
 

Dave,

I have very limited electronic knowledge but I could test and evaluate a CDI or ECU in question under 5 mins. using a certain set up. All these CIS components were tested and proven to be in good working condition. How long this thread been going on? And everyone was still quessing up to yesterday. And CDI is not even the culprit.

Tony

OP has original Bosch CDI unit and the aftermarket CDI+. With his original in the car died and swapping to the aftermarket seems to confirm it's coil or downstream.