MX-3.com

So far my diagnosis.. two fried ECUs... but I need help here!

I even memorized the freaking pin out from going over it over and over again..

I decided to revert the failed megasquirt installation. I just want stock for now. ECU has reference volt out 5 volts. Has keep alive power and pcm power. pin 3G for disty (orange wire) has 5 volts which leads me to believe thats normal. I checked cylinder indentification pins, and wires. Checked crank sensor wires. I checked all wires having to do with disty and traced them out. I checked all fuses. Wiring loom now is back to stock form. I triple checked wires as per pcm diagram on the manual and still no spark.


I replaced the HEI , replaced whole distributor with one that my friend had running.


My next step is to replace the disty set up with an external coil (coil has been replaced).

And then replace ecu.

I know one ecu is bad because the fuel pump fails to come on at start and the kl36 ecu.. no spark. Both ecus no spark. Any tips?

No spark, no pump, -> disty signals.

Check the wiring between the pins on page G21, I believe.

Ok so I tried a different crank sensor and same thing no spark. I checked wires in disty, signal wire has voltage, 5 volts to be exact which is what the ecu puts out? Hei has been replaced and all wires have been tested for continuity and voltage. The next thing on my sights is the camshaft position sensor. IF that doesnt work ill test using a k8 ecu. If that doesnt work im screwed.

Unless its a fuse, the only thing that sets the timing for the spark (and tells pump when to run) is the signals from the hall effect sensors in the distributor.

I don't know where this crap about the crank sensor causing a no-start came from, but its crap. crank sensor is a performance thing for spark resolution up high, good for a HP or two.

Ryan wrote:Unless its a fuse, the only thing that sets the timing for the spark (and tells pump when to run) is the signals from the hall effect sensors in the distributor.

I don't know where this crap about the crank sensor causing a no-start came from, but its crap. crank sensor is a performance thing for spark resolution up high, good for a HP or two.

True... There are 2 sensors in the distributor... A cylinder 1 identification sensor and a tdc sensor... With out the TDC sensor signal you'll have no spark... The crank sensor on the side of the engine you can disconnect and the car will still start and run...

Check make sure you have a good battery, also check to make sure your cranking speed is high enough... While you are at all this have you removed the cap and verified that the rotor is turning while you are cranking?

Hector built Goldmember and successfully bent all 6 rods in a 300 HP KL. He's gonna have the basic bases covered...this is gonna be something small and iritating, not something glaringly obviously... until you figure it out, then it will be glaring

I replaced the whole distributor and sensors inside, coil crankshaft and no go. There is 5 volts going into the disty signal wire. I can hear the i jectors click when I turn the disty by hand (and grounded) No spark at all. Hmmmm My next step is to trace all the disty wires and check them each one by one. Ill also try another ecu next week.

I do have a fairly new optima battery and it cranks pretty fast. I do connect it to the charger after a few cranks to avoid battery damage.

If the injectors go when you do it by hand, then your signals are fine.

IF the pump does not run, try just jumping F/P and GND and starting it... but if you still have no spark don't bother.

If the injectors fire, disty is giving signal, its either wiring between ignitor signal and ECM, or coil itself, or wiring between years of disties being a bit off (if you're using a different-than-stock T0T57x71(2) )