No spark-coil problem?

[seattle_Jerry]

Nothing like a subject thats been beat to death...and yet is still confusing.

I did the plug wire next to the block spark test- nothing
Coil wire next to the block - nothing

Voltage to coil - around 6 to 7 V
Resistance across +/- with coil disconnected from car - 12.5
Resistance between coil output socket and + terminal - 1.6

Its a 67 230SL with what appears to be the original coil. It is terracotta red on top.

My coil to dist. wire is 7.28
plug wires - 1.22 except for that stupid 5.22 on #1

So from what I gathered...it doesn't hurt to replace the coil with the red sticker and cooresponding resistor.

I looked around the site and tech manual and didn't see any values for what the coil should measure at for resistance. The voltage going in seems in range from what I read.

I guess I just want to make sure I order everything I need.

[Benz Dr.]

Are you saying the coil wire is over 7,000 ohms? You should have close to zero for best performance.
The later sets with screw on resistors are 1K each so that should be about 2.1 - 2.5 at the most.

Open and close the points with a screw driver ( points should be closed ). If you get a spark the points are bad and if the spark comes from the tip of the of the screw driver that's normal. If it comes from the shaft of the screw driver where it's rubbing against the points the condesnor is bad.
Coils rarely fail.

[seattle_Jerry]

Thanks! I'll try that out.

[seattle_Jerry]

yeah I just double checked the resistance on the coil wire. 7000 ohms. What really sucks is they are brand new, but have sat in the garage for 6 months , so its not like I can return them.

[Benz Dr.]

Is the coil wire one with resistor ends? You might be able to remove them and put regular ends on instead. If you have steel core it should go down to zero resistance.

[seattle_Jerry]

I did the test and got no spark from anything (points, screwdriver etc.) I also got no spark with the coil wire held just off the block.
New coil?
Sorry I haven't had the chance to call you back Dan.I get busy with work in the morning and then it is past 5 PM in your time zone.

[Benz Dr.]

Check to see if you have voltage at the coil coming from the main wiring harness. In this case, you would be looking at the wire going to the ballast resistor first. If you have voltage there but nothing going to the coil the ballast resistor is probably fried.
If voltage is going through the resistor then it looks a lot more like the coil is bad. Good time to put the red coil and ballast resistor in there.

[seattle_Jerry]

Yup I have voltage at the coil. So I guess add that to the order.
What is sad is that I took the PO's word that it was a bad ignition switch that was the reason for the car not running. So I have a new one of those too.

Who knows...maybe it was bad too or the coil was already on its way out. I guess what do I expect from a $10,000 car

[ja17]

Hello Jerry,

Make sure the points are opening.

[seattle_Jerry]

Finally got a chance to put in the parts I got ages ago. New red coil and resistor, condensor, points and correct wires.

Still no spark. I don't see anything when I pry the point apart with a screwdriver either.

I'm reading 4 volts at the coil.

On the resistor, where does the wire that connects next to the black dot connect on the coil? left (+) or right (-) as you look over the fender?

I am starting to suspect that something was wired wrong by the PO while troubleshooting his non-running car.

The wire on my resistor comes off the black dot terminal to the + on the coil.

On the "-" side there is a red wire of mystery coming out of the harness and a blackwire that goes to bolt on the side of the distributor. This is also where the condensor wire attaches.

[hands_aus]

Is the little isolating rubber grommet on the small bolt on the distributor that the condenser conencts to still there?
Maybe there is a short to earth.

[glennard]

Jumper 12v from the battery directly to the 12v(high) side of the coil(disconnect the existing wires-green/black?).   It's a short trip.  Bypasses everything.  Should then have(with the points open) 12volts at both other coil spots and 12v at the points contact-hot side.  Otherwise, you've a short to ground-and smoke!  There should be no other wires in that part of the circuit.  Car/engine should/will run with the jumper. Gotta disconnect to stop it.

[seattle_Jerry]

I was checking the bolt on the dist. per Bob's suggestion. That ended up not being the problem, although it looked like it..but it got me checking continuity.

It turns out that there is continuity from ground/earth to the power coming into the resistor. So I have to track that down.

[glennard]

That's the same point(high side of the resistor) as the high side of fuse 2, the 'Run' contact on the ignition s/w, and alternator light. (The Start/Run/Coil/Dist circuitry is unfused.) You've a short somewhere.  Did it run on the jumper to the coil?

[graphic66]

Could be the condenser, very easy to check, just put another one in. I shorted mine for just a second adjusting the points and it fried instantly.

[seattle_Jerry]

I haven't tried jumping yet per your instructions. I'm still trying to find out why that wire is grounded.

[seattle_Jerry]

I've traced the problem back to a short in the wire that goes to the ignition light. Its kinda funny that a light can keep your car from starting.

The short is somewhere between the wiring harness junction next to the hood release and the center gauge in the dashboard.

[hands_aus]

quote:Originally posted by seattle_Jerry

I've traced the problem back to a short in the wire that goes to the ignition light. Its kinda funny that a light can keep your car from starting.

The short is somewhere between the wiring harness junction next to the hood release and the center gauge in the dashboard.

I think the iignition light wire is in parallel with a wire to fuse #2, that connects to the ignition switch.