Ignition voltages

(jskv12@aol.com) #1

I am looking for anyone who has a crane 700 fireball ignition module on their series 3 e type. I would like to know if any of you have measured the voltage at 1) The positive side of the coil ignition switch in the on position
2) The positive side of the coil while ignition switch is in the cranking position. 3) Voltage on the 12 volt side of the ballast resistor white wire input from ignition switch when in the on position. 4) Voltage at the 12 volt side of the BR white wire input from ignition during cranking. 5) Voltage on the 12 volt side of the BR white/green wire ignition in the on position. 6) Voltage on the 12 volt side of the BR white/green wire while cranking. Ed Sorrel are you out there? My car is shutting down when warm. You can see my post previously from last week for description.

Jeff Kahler 74 etype ots, 84 XJS, 96 XJ12

(jskv12@aol.com) #2

Ed Sowell…sorry for the misspelling Ed!


(Ed Sowell) #3

I started a thread on my most recent ignition problems in January. You might glean something from that. I did do a lot of measurements, and one thing still leaps to mind: The cranking voltage was low (perhaps 10.8 or something like that) and I thought it was OK. Much time and work later, I learned that was NOT ok. My battery was in it’s last days. Have your battery tested under load. Also check the point to point resistance from all aft contacts to all forward contacts. If you don’t have the schematic showing the correct values, let me know. I had a failure in which it would start, then die as the key dropped back to Run. There was an open resistor in the path in the Run position!

I have the Crane XR700 installation guide which has some diagnostic procedures. I can send a copy to you if necessary, but it might be on the Web somewhere.

(jskv12@aol.com) #4

Morning Ed

I would appreciate the Crane info. I did read your thread from January with great interest and do have the wiring diagram in the shop manual however did not find the voltages I was looking for. My battery is fully charged as it cranks the starter well.

Where was the open resister in the run position on your car? Mine will sometimes crank but not start until the key drops back into the run position.?..?

I posted a description of my car’s issues I think on your January thread few days back let me know what you think, any info is appreciated!,

And thanks in advance for the Crane info


(Ed Sowell) #5

Here’s the XR700 Installation Instructions:

I found some brief notes from my December/January failure diagnostic efforts. I got only 7-8 voltage at coil + while cranking. Beside the not I wrote “Ok,” which I later learned was NOT Ok. I did many other tests that led me to believe I had a bad optical trigger, which might not have been correct. I replaced it and it still didn’t start.

My battery was fully charged and cranked well also. After an immense amount of work, replacing the battery was on the path of getting back on the road. Take it somewhere and have it tested under load.

I’ll dig out a ballast resister pack diagram and proper values after breakfast :wink:

(Ed Sowell) #6

ballastResistorPackTesting.pdf (64.5 KB)

My readings were, from the top: 102 Ohms, 9.6 Ohms, 1.0 Ohms, 1.2 Ohms.

As you can see, in the SW (Run) key position the path to the bottom forward pin has two resistors (0.72-0.80 and 0.9-1.0) , whereas in the Start position it has only one (0.9-1.0 Ohms). When mine failed in 2002 the 0.72-0.8 Ohm resistor was open.

Hope this helps.

BTW, I now notice the XR700 diagnostics don’t show a coil + test. There’s one in the ROP book though

(jskv12@aol.com) #7

Thanks so much for the info! I have a new ballast resistor as I suspect it is the culprit. I am also going to perform the freeze spray test as suggested by others when I get the car into failure mode at my next opportunity.