I'll be doing megasquirt coding, etc... tonight, I'll be able to take a look at that msq and verify that nothing is wrong with it.

 

Second trigger active edge should be rising, although that shouldn't cause you not to get spark.

Other than that I don't see anything wrong with the ignition settings assuming the CAS was stabbed as stock, so there must be some kind of wiring or power problem on that coil, or the plugs or plug wires are bad.

Ken

 

As posted we've tested the coils. Thanks for the input on the settings. So you think it may be power related(to the ecu?) even though it triggers the spark once when you turn the key? I think it has to do with the voltage drop on start up but it shouldn't matter since the drop is identical to my car which starts and runs fine with stock electronics. Plugs and wires are all new. It doesn't show any spark even with the tester hooked up and grounded except once when turning the key to the run position. The cas was stabbed in stock location.

Brent

 

im not sure it has to do with a voltage drop on startup, but to rule that out you could use a nice big beefy car battery (if you're using something like a dry-cell or smaller battery) hooked up to a batt charger. You shouldnt see much of a drain that way. One other thing to check would be for corrosion or junk on the battery terminals or leads. Just take some degreaser and/or sandpaper to them (depending on what they need) to make sure that they're nice and clean. This can cause a significant resistance otherwise, which may cause an extra-large voltage drop. Also, corrosion on any other connectors can cause weirdness,

You said that it fires the coils once when you turn the car on? or it fires once when cranking, but no more after that.

 

Everything is brand new, harness,battery,terminals,grounds(that are daisy chained to tranny, eng,firewall,frame etc...) Even tried a different battery with 800cranking amps. Also as mentioned before we tried (and left in) a coil that's been running in my car. It's 100% not to do with the coil,wires,plugs or battery.


Brent

 

Well, if nothing else works, would it be possible to hook up another transistor in line with the signal to boost output? Kinda like this:



This is just a rough guess at values, and if the coils can use/withstand a 12V signal it may be better to use that from the main relay instead of 5v from the MS.

On a different note, what condition are your plugs and plug wires in? Did you confirm that the pull-down resistors are 4k7's?

 

Resistors are 4.7k and the plugs and wires are new along with every other wire in the car that's related to engine and ecu. Besides it fires once when you turn the key on. No idea on the transistor, I doubt the ignitors would handle 12v. Certainly wouldn't try it.

Brent

 

Yeah, I've never heard of this issue you're having. The only thing I can come up with is to change the pullup resistors from 4.7k to 2.2k and see if it works, although I'm doubtful that it will.

Where is the MS grounded? Maybe there's a ground difference between where the coil is grounded and where the MS is grounded that's large enough to keep the +5v going to the ignitor from ever reaching zero.

I *have* seen that happen.

Ken

 

Thanks, I'll try it and let you know.

Brent

 

All the grounds for the ecu are bolted to the uim and the main ground harness that we built is bolted to the uim about 2" from them. Tried added a ground strap directly to the coil bracket and no change. We've been considering an msd box for about 2wks now, it should amplify the signal enough. What do you think?

 

OK, but where is the battery? where is it grounded? where is the engine grounded to the chassis?

Ken

 

Battery is in the storage bin behind the passenger seat and is grounded to the seat belt bolt. The engine is grounded to the frame where the tranny/starter ground is located. We then ran grounds from there to the coils,transmission and uim where the grounds for the ecu are. Everything has a ground that leads back to the main ground.

It looks like we're going to just send the ecu to someone and get them to test it. Or just try a new one.

 

Brent,

I took a look at that MS box. On power up, the two right led's lit, the left one did not. Leading spark did not work, but trailing did. Some further checking indicated the transistor driving the left led was faulty. I replaced it, and the board now works properly, firing the leading coil on my test bench just fine.

On another note, when wiring up to the stock S4 cas on my test bench, I could not get a tach reading until 1500 rpm or so. I did try swinging the VR pickups in the cas tighter to the wheel, but that didn't solve the problem. The 2nd trigger additions to this board are all potted in some black plastic material, so I couldn't investigate further. I did not touch the settings of the blue VR pots. Given you said you had a good rpm reading when cranking I'll assume it's something odd with my test bench.

Please contact me ASAP to arrange shipping of this unit back to you.

 

That's great news! Glad you found something, I was pulling my hair out over this thing.LOL. Can't tell you how much we appreciate the help. Did you let rxfreak know? I'll call him today and he'll arrange shipping asap. Thanks again renns. Hopefully we'll get to meet at the motm.

Brent

 

No, I didn't let him know, as i wasn't sure who the primary contact was. I'll drop him a line now. I'm heading up to Algonquin for a canoe trip later next week, and won't make motm. Summer is too short!

 

Thanks Roger, I think we can all say that we are happy you found the problem. I realy appreciate your help. Anyway, I PM'd you with my shipping info and everything else.

Thanks again!!!
Marc Brien

 

Huge thanks to Renns! Helped us out large, the car is running now and we're hoping to have it tuned by the end of the week.