I'm running a ported 12a turbo, all wired up and tuned- it runs fine at idle and high RPMs when its hooked into the computer but after about 3 min of being unplugged to go for a test drive it starts to just turn off and reset constantly- its getting progressively worse now its hard to start at all
any ideas of what to check ?

I was going to post up a video of what its doing but now it won't even start-
any ideas?


I'm running my tach signal wire from the negative side of the leading coil-
running my power wire through the ignition-
several grounds in good shape are hooked in

 

I have two units that I use in my race car (One Spare) which are rubber mounted and the cable and DB connector that plugs in to the unit is supported on the same aluminum base as the Megasquirt only 3” away. Same with the vacuum hose. 6” from there I installed weather tight push together electrical connectors for each circuit going off to all of the individual sensors injectors coils ECT. It is located in a dry cool place with lots of air flow and very accessible to remove the cover and access the plug in connectors. My car has been in on some major crashes, once at over 100 mph in the air twice over a distance of 100s of yards. After the car was written off I transferred the Megasquirt to my next back up car and with a flick of a few switches it fired right up no issues.

In saying this I think if your car ran fine then died your problem is out side the Megasquirt it self. Now that it does not have power be very careful not to disturb the wiring on the car when making your tests.

In all cases of electrical problems the best problem is complete failure. The reason for this is intermittent on off problems are related to heat (Expansion and contraction of parts, movement) or movement (vibration) open and closed circuits or dead shorts.

Dead shorts are the easiest to find. A burnt fuse or wire related to that circuit stands out like a sore thumb.

Start at the DB connector and work back through your wiring, fuses, switches,battery,grounds. Note in a lot of case people automatically assume that a lack of power is related to the positive side of things. Check the grounds the atoms have to travel in a complete loop to do there job. Also do not assume that only one spot is your problem you may have several.

If after all your checking and you are 100% sure it is in the Megasquirt (Power circuit) check with the proper testing equipment and go off electrical schematics off the web site. I found the schematics to be invaluable resource of information.

I hope this helps take your time and do each section one at a time with a tester. Do not just look at each connection, test and wiggle each one ever so gently. In some case at my work on the equipment I repair I have spent as much as 14 hours to find a bad connection in one circuit. But it never Fu#@ up again.

Best Regards
SCCA RX7 RACER