86' LXi Ignition System Power Loss

[firefighterwhite89]

Occasionally, my a20a3 starts, but at times, when revved up it loses power to the ignition coil. We replaced the coil, yesterday, but then narrowed it down to the power to the coil itself was shorting after revving beyond 2.5k. What could be causing this? We couldn't find any shorted wires. Could it be my ignition switch?

Also, the engine was just rebuilt. All New Rod And Crank Bearings, All New Triple Layer Steel Gaskets, All New Seals, New Oil Pump, 160* Thermostat, New Alternator, New Piston Rings, Polished All The Head And Bottom Block, New Ignition Coil, All New Fuses, 2Gauge Battery Wires, Got Rid Of The EGR and A/C Compressor And Components, Shop Cleaned And Inspected Injectors, New Belts, Everything Just About, And I Can't Figure This Out. Drove It 1300 Miles To SC And It Drove Perfectly Fine.

[lostforawhile]

it sounds like the ignition module for the dizzy is failing.

[Dr_Snooz]

Welcome to the board! I wonder how you are diagnosing this. Do you have a voltmeter wired up to the coil that shows you this? The wiring to that passes through both fuse boxes, so check your fuses first.

The shop manual is here. There is a good wiring diagram on p. 24-3 that you can start tracing. The diagram is for an '89, but it will be very similar for yours.

[lostforawhile]

you should have constant power at the positive side of the coil with the engine running it's the ground that is switched. normally when you have rpm specific problems it's the module failing. you need to verify the spark is dropping off at rpms though. maby one of those spark plug testers that go inline in place of the plug, then you set a gap on it, and watch to see if the spark gets weaker when the car is revved.

[firefighterwhite89]

We Replaced The Ignition Switch, And Ignition Coil, And Still, I Can Turn The Key On And Off and Occassionally, Get Power To The Coil. IDK What It Is. Maybe A Main Relay??