KPLAFIN

iTrader: (1)

so since my laptop killed itself yesterday and i havent really gotten my MSPNP dialed in...i decided to remove it and go back to the stock ecu for a couple weeks until the new computer is ready and i have time to really mess with it..

I replaced the st sign fuse, removed and plugged the map line going to the megasquirt..plugged the stock ecu in, starts right up, idles for about a second, dies, just like not having a maf sensor plugged up. Then i checked the MAF..hooked up, give it another shot, same thing. Try my other maf..same..try my other stock ecu..same thing..any ideas?

Thanks, Brian

KPLAFIN

iTrader: (1)

reversed proces....runs fine (as well as it did) with megasquirt...any thought...anybody?

Arkmage

iTrader: (3)

sounds like the FP switch in the MAF maybe... I believe the 1.6L starts the pump for X amount of time during crank and after start. If it dies after X amount of time expires then it would probably be the FP switch in the MAF.

Quick test would be to jump the fuel pump switch at the diagnostics connector.

KPLAFIN

iTrader: (1)

tried two mafs and two ecus and it runs fine with the megasquirt (with maf in place)

KPLAFIN

iTrader: (1)

anybody...and yes i searched

FoundSoul

iTrader: (5)

I honestly can't think of any reason it wouldn't crank right back up on your stocker KPLAFIN, we've swapped back and forth on our test car several times, and never had a problem. There's no reason I can imagine that you'd have any trouble going back to the stock ECU- that said let's figure it out...

Are you running stock injectors?

Did you try jumpering on the FP as suggested above? That wasn't a bad suggestion...

You said you tried two separate stock ECUs, and two separate stock AFMs.... so in theory that should rule those out. Let us know on the above and we'll go from there...

richyvrlimited

iTrader: (1)

is it not something as simpe as the idle screw requires adjustment? if the car starts then dies, it could be because the idle is just far too low...

KPLAFIN

iTrader: (1)

ill give that a shot this evening...shouldn't be the problem b/c that hasn't been messed with since the stock ecu was in place.

Which pins are for the fuel pump? I didn't try it b/c he said something about the switch in the AFM being messed up and i assumed since the AFM is 99.9% likely to not be messed up since i've tried two....it'd be pointless, guess i shouldn't have overlooked any suggestions now that i think back..

92MX5

iTrader: (1)

Jumper F/P to GND in the diagnostics box.

Cheers!

Jeff

Matt Cramer

Check the fuel pump relay if the jumper doesn't work out - it has two coils, and the one the MSPNP doesn't use could possibly have burned out.

Also, did you make any adjustments to the CAS when installing the MSPNP to set the timing? Make sure you haven't turned it so far your timing is now way off on the stock ECU.

KPLAFIN

iTrader: (1)

thanks, i didnt realize there was anything along those lines that could've gone bad but still be able to use the squirt. i never touched the CAS..so the timing SHOULD be the same as it was when i took the stock ECU out...right?

FoundSoul

iTrader: (5)

Excellent thought on the dual coil FP relay Matt-- that could certainly be it... The stock ECU primes on the same coil we use, which would likely allow the car to start. But then it uses the other coil to keep it running, which would allow it to die if it was burnt out.

And yes-- the timing 'should' be right where it was... but it's always a good idea to check your base timing anytime you're messing with your ECU. Even if the risk is low of it changing, the consequences can be high if it did for some unforseen reason.

KPLAFIN

iTrader: (1)

checkin the relay and trying to jump it here in a few....i was planning on checking the timing before i drove it, but thats kinda hard to do if it wont start...but the odds of it being far enough off that it wont run are VERY slim. thanks for the replies..

...and foundsoul, i gotta say that DIYAutotune has hands down the best customer support of anywhere i've ever purchased anything from, car related or not...you search miataturbo looking for people with problems so you can help them, that's pretty damn impressive if you ask me.

KPLAFIN

iTrader: (1)

anyone think it could possibyl be ignitor related? the tach doesn't work, but other than that it runs fine with the squirt...

FoundSoul

iTrader: (5)

Wait-- the tach doesn't work?

It definitely could be the ignitor.

KPLAFIN

iTrader: (1)

part of me thinks it could be the ignitor...being replaced ASAP...but then wouldn't that make it do the same thing with the MS?..or does it have some different kind of communication with the stock ecu?

cjernigan

iTrader: (13)

Did you disconnect the coils/ignitor when you flashed megasquirt? That will fry it.

FoundSoul

iTrader: (5)

They're different devices, and with a standalone we remove alot of the 'diagnostic loops' that might cause the Stock ECU to freak out if say, a component didn't report back like it was supposed to. Just a thought.

Without a known good ignitor we won't know.

I'm thinking you need a known good ignitor, and Matt's FP relay theory is another good one.

shuiend

iTrader: (24)

Does the tach work with MS installed and not with the stock ecu or does it not work for either? The tach not wroking usually means the ignitors are fried. Ask me how I know and I can send you all my dead ones. I would check and make sure you are running inverted spark because that could also fry them.

cjernigan

iTrader: (13)

I thought with the DIYautotune mods you wanted to run non-inverted spark. Inverted spark using the diy mods fried one of my coils.