Electronic Ignition Problems

[AlfaGreg]

About a year ago, my friend installed a new ignition system in my Spider similar to the one they use in their Alfa racecar. It has worked faultlessly for them over the years and has for me until about a month ago.

As we all love intermittant problems, I thought I would throw this out there for discussion.

Optical Unit: Crane XR700
MSD Unit: MSD 6AL
Coil: Bosch Red, c/w external ballast.

Problem: Immediate ignition cutoff while driving for 1/2 hour or more or a non- start condition when stopping for gas etc (i.e. heat soak condition). Strong crank over, no firing. Restarts after 1/2-1 hour of cooling down. Works perfectly both before and after ignition cutout or non start condition. Optical trigger LED does not flash during non start period. All components in engine bay on passenger's wheelwell area near carb filters.

Fuel System: Excellent. New filters. Fuel present Twin DCOE 40's
Battery: Excellent.
Plug wires: New
Wiring, Fuses etc: All functional, terminals clean and Stabilant22 treated.
Optical Trigger: Set as per manuf. reccomend. No visible probs.


This seems to be a heat related problem and has recently shown up. If the ballast were bad, the car would start, then not run. I believe ballast resistors are either go or no go. The coil is new at the time of ignition upgrade. The race car application has not encountered any problems, so incompatability should not be an issue. Popular speculation points to a faulty or failing coil. I have to go on the assumption that the Crane and MSD units are functional for now as i do not have a replacement.

Weather permitting, I will try to duplicate this fault this weekend with someone to help with diagnostics. I will bring along a spare coil and ballast.

Interested in any comments or similar experiences with XR700/6AL setups, coil selection etc.

Thanks in advance.

[John M]

Hey Greg:

I am a little confused as to what you currently have in your car. You mentioned you have a Crane XR700 and a MSD 6AL. Those are both ignition "brain boxes" for lack of better words and its either one or the other. Also, the MSD does not have a flashing light to indicate the pickup. That is only the Crane so I am not really sure which you have in there. Also you mentioned an optical unit and referenced the Crane box. I am assuming you are meaning the optical pickup conversion for the distributor, but you also mention failing points. And again its either one or the other.

I can say that the bosch red coil is most likely not compatible with the MSD 6AL. They list their cannister coils (i.e. MSD Blaster 2) that are compatible with the demands of the high energy multispark MSD 6AL. Crane offers a compatible cannister coil for their multispark Hi6 series box and it is the PS 60 I believe.

An optical sensor replaces the points as the pickup in the distributor and is more accurate. Both the Crane and MSD box will work with the optical sensor. Only the MSD will work with points as the pickup.

On the MSD you do not have to use a ballast resistor as the ignition power is hooked to the box as a relay trigger and not the coil. I know on a Crane Hi6 you don't need the ballast resistor, but I am not sure on the Crane XR700

A final note on these systems. Be sure to not use solid core plug wires. Performance wires are required if you want the boxes to last and the solid core wires will probably burn them out in short notice.

No matter what you have in there here are some suggestions.

1. I would first check or replace the coil next time it fails to fire. This would allow you to rule it out quickly.

2. If you currently have an optical trigger in place in the distributor, with the MSD you can actually hook into the points for an alternate timing pickup. That would allow you to rule out the box. If it never happens again, its a bad optical trigger.

3. If it occurs, and the coil checks out, and you have ruled out the optical sensor, then its the box itself.

Best of luck on getting her back up. I had a Crane Hi6 fail and it was that it failed to pickup the timing signal from the distributor. So I switched to MSD. But they have been known to bite the dust too. They are wonderful when they work right.

Best Regards,
John M

[AlfaGreg]

Hi John

My Crane XR700 is an optical trigger points replacement module using a shutter wheel and pickup in the distributor. I do not have points. This unit has a green LED that illuminates when the trigger is activated or "fired" so to speak. Used on its own to fire a coil, it requires a ballast resistor when the engine is running.

However, in my application, it is used to trigger the MSD 6AL. This in turn sends the optimal voltage to the coil and I tell you, the results are great.

This combo has been used sucessfully with a Bosch Red coil with an external ballast resistor in a racing application for many years.
I think you are right to do a coil replacement as the first step in eliminating the problem. MSD are not too fussy about coils and say it will work with any stock unit, but note that an oil filled coil must be mounted upright.

So I'll try that and go from there.

Thanks for the help.

[emr5503]

Are the OE red Bosch coils with external ballast "oil filled"?

[AlfaGreg]

I have been trying to find that out. My coil is mounted horizontally in the usual stock position. I have been told that this
may be a problem and may have to be mounted vertically to avoid
any oil not immersing the coils.

I also will note that my MSD is a 6A, not a 6AL as I believe I previously posted.

[emr5503]

Mine is mounted the same "stock" (horozontal) way. I'm also using a Crane type optical shutter (no points), but no "brain box".

[Mr. C.]

First, you should if you haven't already determine if the problem is a no ignition problem. After trying to start the car for a while and getting no start - what do the plugs look like? wet, very wet,
or dry?
Pull a plug and ground it while cranking the engine do you get a spark or no spark or weak spark?
Seems funny that the LED is lighting but we are going after the electronic ignition.
I always hook my timing light up to the coil secondary wire while cranking if the timing light flashes rapidly, you almost always have spark at one or more plugs or your rotor is bad.
These are a few basic tests that can help you establish the type of problem.

[John M]

Hey Mr. C.

On this system, the Crane XR700 has a LED that flashes to note that it is picking up the timing input from the optical wheel in the distributor. So steady light is a bad thing when it should be firing. It should be flashing.

Hey Greg:

I think I am finally clued in but very curious. I understand that you are using the crane setup as strictly a pickup for the MSD. Turns out the MSD has a magnetic trigger they market. Crane has the optical trigger. So in order to use your optical setup in the distributor, the signal has to run through the crane box and then to the MSD. Have I got it?

Just for curiousity's sake, how do you have the MSD receiving the signal from the Crane? Are you going through the points pickup or the magnetic trigger pickup? Very interesting setup.

Again, my first thought on heat soak failure is the coil. And you are correct, it should be mounted vertical. But, if the light is not flashing on the crane when you get this no fire, heat soak situation, that would seem to limit it for me to the optical LED inside the distributor being fouled with debris, inoperative, or out of alignment (if that is possible). I have read that particular type of pickup will deteriorate over time and may be adversely affected from heat.

You have to tell me Greg how you like that system setup. I have not dealt with the LED optical stuff as I just hook my MSD directly into the points for the timing pickup. Have you been able to incorporate a custom distributor and advance curve?

Best Regards,
John M

[Mr. C.]

Sorry all ! I read but didn't hear or something. I missed the part that the LED was not flashing.

[John M]

Hey Mr C:

Have you ever seen that setup before that Greg is describing? Seems a pretty unique solution to use that optical sensor. I personally have never seen that in action.

Best Regards,
John M

[Mr. C.]

John,

No I have not seen this setup. It does sound interesting. I guess I had sort of dismissed optical sensing when the use of hall effect triggering was introduced. I worked a bit on hall effect in the computer business and am still intriqued by how small the components can be made and how very reliable they are.

But optical works well in automotive applications doesn't it. And I guess that any electronic setup is a few hundred times better than contacts. I think I may have mentioned that I have installed a bunch of Pertonix units in Model A Fords and early Ford V8s.
Any one who has had to struggle with the old beehive distributor on an early V8 just has to love electronic never change points ignition.

[Roadtrip]

On the other hand, the good 'ol points and condenser systems usually just don't stop working and require a component change. A maintained points and condenser system is extremely reliable . . but the key words are maintain. Most car owners these days couldn't tell a fuel injector from lug nut. I've never had a points and condenser system fail me, but I've had TWO electronic systems on two different cars have their ignition modules fail . . . and that means the car is D E A D in its tracks until the module is replaced.

That said, electronic systems are fairly reliable and provide much better performance . . . . but my 74 stock Alfa is keeping the points nevertheless.

[evilgidget]

I don't have an answer for everyone else, but i do have a question on the MSD 6A's.
I bit the bullet & fitted one up with a blaster coil (and stock points) this afternoon, and i now have no tacho...
Any suggestions, other than ignoring it?
Cheers.

[AlfaGreg]

I would like to thank everyone for their assistance and suggestions on this thread. Today, I was finally able to repeat the no-start condition in my garage (wonders never cease!!) with my neighbour present, who is a very experienced mechanic.

To review, I have a Crane Fireball Optical Trigger, an MSD 6A spark box and a Bosch Red coil. When things heat up, I would experience either ignition cutout while driving, or a non start condition when stoppped for gas etc.

We were able to determine that all systems were receiving power during the fault condition, but the Fireball was not sending a trigger pulse back to the MSD. So I am going to firstly pull the distributor and examine the optical sensor and shutter wheel for possible problems. Being virtually solid state, it may be difficult to see anything. Then, probably order a new optical pickup and begin from there.

It is encouraging to know all other components seem to be working as they should. Hopefully it will be a cheap fix!!

[John M]

Hey Greg:

After our initial discussion, I finally went out and invested in a optical trigger bosch distributor from RML with custom advance curve. Setup at 6-7 degrees BTDC and then 36 degrees total advance all in by 3500 rpms. You will be interested to know that RML now offers a 12 volt optical trigger to send the correct type of signal directly to the MSD 6AL or Crane Hi6 without the need of the XR700 unit. Hope it all works out well.

Hey Evilgidget:

Did you plug the tach wire into the side of the box? If you did and still not working, you will need a tach adaptor that is available from MSD.

Best Regards,
John M