Annoying misfire
 

well i had been trying to work around these random misfires in higher boost with fuel and timing. i was about to start looking into my ignition system. Went to get gas at my usual mobil station....misfire seems to be gone. Two weeks ago when doing some road tuning i needed gas so i stopped and got gas a sunoco instead of my usual mobil. I guess the car didn't like that gas. so much time wasted:vash:

i do need to someone to make a pnp cop solution for my megasquirt system.

I'll build a PNP harness for you. $40, soldered and heatshrunk, you supply the cops and a 1.6 ignitor.
I am building them for a couple other members already. Just waiting on my valve cover to show up (been waiting for a few weeks now) so I can get started.

sign me up and i'll find the coils, i already have a 1.6 ignitor running in my car, do i need anther one?

on a sidenote, how dangerous is a misfire in heavy boost, it doesn't seem to knock or ping, just quick hitch with a fast small backfire in the exhaust and then back on it's merry way.

Well what I do is gut the ignitor and scavenge it for a connector. It makes the COPs trully PNP and look factory installed. IMO, it's a better, more stable connection than just pushing spades into the car's harness (which was my original plan).

oh ok i gotcha, i'll try to find another one, sucks i think it threw out my blown one.

i have one that i blew the tach signal out of ;)

if i get mine wokring tomorrow and mail up some pins for ben ill send that up as well.

Cool!
Thx

dude that would rock if you're willing to do that for me. i really need to finish up this car but this misfire is holding me back. I really hope a nice set of cops fix it. my setup now at 15 psi feels really good when it doesn't skip a beat. I killed a newer gti with at least an exhaust yesterday. from about 30-70 pulled about 6 cars on him

I know you guys are going to kill me for digging this up, but I assume the COP setup cured your random missfire issues? I'm getting very random missfires with no knock or ping. It feels like someone hammers the brakes halfway through a pull at 14-15psi and it ONLY does it while deep into boost.

$10 says it's your overboost. post log and msq and ill prove it.

I'm using this great 10 year old Link ECU that came pretuned with the car but without software for it, which makes things a real PITA. To check about overboost, could I turn boost down to say 10-12psi and see if the problem still persists?

FYI, I spoke a couple days ago with a guy who bought a car with a "pretuned" ECU. He's about to put his 3rd motor in. Get the software ASAP.

Thanks for the heads up you two. I will go ahead and look around for the link software and information about how to tune it.

Go to FM website and see link for dataloglab. Great app, buy it. Do you have the serial cable to plug into the laptop? If not, you'll need it. FM will also provide support, Jeremy is very good with this ECU. I run one also.

I should still have the serial port cable and adapter around here somewhere. I'll find it then look at buying the software

Went to 16psi just to verify your suspicion about overboost..... misfire galore. Dropped it back down to 12-13psi and didn't have a single misfire.

i have the same problem and always had it. It does not do it all the time just once in a while when boosting in 3 or 4 gear all the way. I had my car dyno tuned and the tunner said it for sure a missfire but has no idea where is coming from. I bet its and ignition problem.

I just turn the boost down. Its as boring at 12psi as it is at 15-16 psi

any miata with a LINK is boring. You down at least 20hp at every boost level because of the weak basemap no one tunes. You could like others have stated have an ignition related issue, ie, blowout.

I tune