Troubleshooting procedure/decision tree for total failure

[Westfield 11]

I had a failure of my ignition this weekend after 1800 miles over two years. It is a MegaJolt Jr. on an Austin Healy Sprite engine. It first manifested itself as a miss or stutter at 3/4 throttle and above under hard acceleration. At that point it idled just fine, I was doing carb jetting changes and thought I was simply misjetted on the main circuit. I stopped, changed main jets while the car idled which one can do with a Weber and drove off. It was OK for about I min and then sputtered under the same conditions, after fired in the exhaust pipe and then died completely. I checked all the easy stuff: fuse good, no loose wires all connectors solid. The sensor had moved away from the trigger wheel due to a loose bolt. This was corrected, but there was no change, system was totally dead. I suspect the trigger wheel sensor was the cause of missing at RPMs above 5800 over the past week, but that is just a guess. I have not yet connected the system to the laptop, should I start there?

Where should I begin to troubleshoot? Any FAQs or published proceedures? Is there a list of electrical values at the various pins when the key is on or when cranking?

[brentp]

Hi,

At least you identified the loose sensor so far!

Here is a troubleshooting guide that should help verify signals to the megajolt:
http://www.autosportlabs.net/MJLJ_V4_ve ... tion_Steps

You should double check your sensor for any damage in case it came into contact with the trigger wheel. Also, check for spark while cranking.

Please keep us updated on what you find!

[Westfield 11]

Found it! One of the pigtail leads on the VR sensor had broken inside the connector. I disassembled it and soldered it back into place temporarily and it started right up. Now I just need to obtain another sensor plug for a permanent repair. Thanks for the help Brent.

BTW, I am totally satisfied in every sense with the system.

[brentp]

Glad you found the problem! And thank you for the kind words!

We have the sensor pigtails in our online store, here:
http://www.autosportlabs.com/ford-crank ... -p-73.html

[Westfield 11]

Thanks, I already got one from my local guy. Now I need to figure out why it breaks up at 5800 when the rev limiter is set to 6800. It feels like it just hits a wall and begins to spit and sputter and will not rev any higher.

Also will the SUV input be able to record the 5v output from an AFR meter. I would like to do this to aid tuning.

[brentp]

SUV input? Do you mean the Auxiliary input?

Yes, you will be able to log from your wideband meter using that input.

[Westfield 11]

SUV input? Do you mean the Auxiliary input?

Yes, you will be able to log from your wideband meter using that input.

Sorry, damned auto correct on iPad.....