JohnW8

94 ITA Miata 1.8L
Freshly built engine

I'm having a startup issue. I get a violent misfire, with only #2 cylinder
sparking until temps come up then it smooths out with the other cylinders sparking. The car started and idled great (13.5afr at startup). I went to the dyno for tuning and it performed pretty good other than losing a wideband o2. Finished up and loaded it onto the trailer drove it home and it barely was able to start to get off the trailer. (8.5:1 afr at startup)

MSPnP reflashed firmware
.20 over pistons
RC engineering cleaned and flowed factory tan injectors (250cc)

Cam Angle Sensor has been replaced as well as the coils with the ISC racing MSD coils. All harness connections have been cleaned and checked then double checked. Ignitor has been checked compared to a known good one
New NGK plugs gapped at .40

Please look at the attached datalogs and MSQ and give me some more ideas to check.

Thanks!

FoundSoul

iTrader: (5)

What firmware was loaded on the unit? Was it the firmware we have in the MSPNP download package specifically for the MM9495 with or without MAF? Or a different version?

Ben

iTrader: (33)

When were the coils replaced, before the dyno tune, or after the problem started occurring?
When you reflashed firmware, did you disconnect the ignitor first?

What tools do you have available to you--do you happen to have a scope?

JohnW8

I reflashed using the firmware from the DIY site specifically for the MM9495 with MAF.

JohnW8

Coils were replaced after the Dyno tune. The car was misfiring during the dyno session a wee bit. After the session was over I put the car on the trailer and by the time I got home the car was crap. Firing on one cylinder, too much fuel at start. I replaced the coils and CAS thinking the coils had failed. It didn't make any difference on a cold start. Once warmed up it runs pretty good.
I did disconnect the coils when I did the reflash. I don't have a scope.
This car doesn't have the IAC on it. The previous owner "modified" the IAC to flow air constantly (big-*** vacuum leak) so I took it off and blocked the area off with a plate. Prior to the dyno it would fire and idle nicely.

Ben

iTrader: (33)

John,
Your description makes me think cold solder joint somewhere. But can you send me a copy of your pre-dyno .msq as well as a copy of your post-dyno .msq? I'll compare the two and look for anything 'funny' but it doesn't sound like a settings issue from here...

JohnW8

Hey Ben,

Here are the msq files pre dyno (7-18) and post dyno. (7-23)

I've since added the GM open IAT sensor and started pulling fuel from the warmup enrichments. I'll do a cold start tonight after work to see if it did any good.

Thanks for looking.