First time starting 280zxt with MS

[bherd]

Hi all,

 

Figured I would share what it took to get my 83 280zxt started on a Megasquirt II Extra.

 

Coming back from a couple year restore where the engine had been torn down, bored, stroked, new turbo, I.E. everything was different. I installed a weatherpack connector between the stock ECU and the injectors (6 wires to 2), I then installed a similar connector on the MS II built from a DIYAutotune kit. I plan on doing Fuel pump speed control, boost control and detonation detection eventually as well as logging fuel pressure but may leave teh spark on stock for a while until I am more confident about detonation detection.

 

In spite of the fact that the Megastim stimulator showed both injector banks firing, I was suspecting that something was wrong with with one bank and pulled the MSII and tested on the bench with a spare injector, sure enough one bank would fire, one wouldn't. I traced it to a cold/missing solder joint on the current sensor resistor in the current limit circuitry, so it would turn on an LED but not an injector.

 

Still didn't fire but I would only crank it about 6 seconds at a time, after which I would then switch the plug back to stock ecu and let it "clear it's throat". I pretty much spent the winter with a fouled/flooded engine due to sporadic work in the cold, and I wasn't about to revisit that place. I scoped the injector times which on stock and found them running at 1.6ms but about 3 times as often as my 4.6ms pulses from the MS. At the end of the day I relied on the Required Fuel Calculation and didnt muck with the ECU firing configuration further.

 

I assumed it was not starting due to being too rich but had no proof since it would either start or not (it didn't). I then started the Z with the stock ECU and jumpers between the connectors, once running I moved one bank of injectors to the MS, it coughed but kept running and I started tuning for minimum MAP. Sure enough it had been rich and within a minute or two I moved the second second bank and was even able to start the Z on the MSII. It all came down to the cell for 0kPa and 500 rpm (duh!) had been mid-thirties,and liked mid-twenties a lot better.

 

A few minutes later I turned on auto learn for TunerStudio and witnessed a noisy AFR reading overwrite my hand tweaked idling cells... I assume you have to do this once to learn to lock the cells.

 

So figured I would pass on the crawl then walk approach to getting an MS running, in my case at least I could run one bank from stock and one from MS until I could get tuned well enough to switch completely over without spending 20 minutes wondering how bad I flooded the engine.

 

Bil

[twofouroh]

Thanks! These hands-on troubleshooting testimonials are great. My truck is running MSII/3.0/EDIS4 - spark only while I fab a port injection manifold for my engine, since it never came with port injection ('84 720 with a z24). The spark side went about 10 times easier than I thought, I sure hope the fuel does too, because it looks pretty tricky so far . . .