After Megasquirt, Very bad Idle issue
 

Hi guys,

Got the MSPNP 9093 installed. Went through the normal procedures and fired it up. The car was barely idling and would die after a few minutes. It wouldn't even idle long enough for me to try to lock the timing under Spark Settings. My car currently has the following mods:

93' LNC Motor w/ stock bottom end
Mild P&P, no backcuts, or valve grinds- just removed some casting marks and burrs
Integral Stage 2 Cams for hydraulic lifters (Spec: 254 degrees duration int/exh with 9.4mm of cam lift
Aftermarket 4-2-1 Header
Stock Airbox w/ AFM
Full RSR Exmag GTII exhaust
Stock Catalytic converter

I was told by some of the guys at DIY Autotune that the stock base map for the PNP unit was not giving enough fuel and possibly the cranking setting for pulse widths were not enough to idle the car with aftermarket cams.

Matt at DIY Autotune recommended that I use the ITA Race Base Map to start my tune. I was looking at the .msq found here:

MegaSquirtPNP by DIYAutoTune.com

under:

MSPNP_MM9093_ ITA_JT16_Base_Map_102908.msq

Do you think the added pulse widths value as well as the changed VE table get the idle back a bit? Or would it means there's something else I'm missing? I won't be doing anymore testing until I have the LC-1 connected to get valid AFRs, but I'd like some insight from possibly guys that have done a MSPNP install on a car with aftermarket camshafts.

I know this is the Miata turbo forum, but I am building an IRTB'd car lol. I just wanted to get the hang of tuning before I slap on the throttle bodies....which I also have waiting.

Any suggestions?

Thanks in advance,
Eddie

There's your answer.

Seriously, it's damn near impossible to properly tune a standalone ECU on a modified engine without one. Maybe you're way too lean, maybe you're too rich. Once you get the mixture in the mid 14s, you can play with idle timing a bit. I run about 17° at idle, but some folks prefer to haul it back to 10-12°.

Also, have you inspected your timing calibration by setting the Fixed Angle to 10 and then adjusting the trigger angle (in software) while watching the pulley with a timing light until it aligns at 10? That's something else that'll screw with your idle if it's off.

Only one - get your wideband installed.

+1

I don't understand how you would go about this without one.

Is your car a california car? If so it has different injector paths or somethin like that and it will run really erratic. I had the same problem. But if you ordered it and told them your car was a cali car and they sent you the right ECU then its another problem.

Easiest way to check if your car is a cali if open the hood and look on the bottom of the hood and check if anywhere says california.

I believe all of the MSPnP 9093 units are now being shipped with the correct pinout for CA '93s. They're identical to the '90-'92 cars, except for two additional fuel injector lines.

Late last year, I had a fellow Floridian's new MSPnP9093 open my my desk to do the TPS mod, and I noted that there were two jumper wires soldered across two pairs on pins on the underside of the main ECU connector. I compared these to the wiring diagram, and found that they were the mod to enable the other two injectors in the CA93 cars.

So unless the OP's MSPnP is fairly old, it should be equipped to handle both CA and non-CA '93s.

clean out the iac valve.

Don't worry too much about blowing up the motor...you basically must "try" to blow up a naturally aspirated motor.

I already asked him this; it's a model 1.3v, I'm not sure when DIY did the '93 sequential injection fix.

Easy enough to find out. Pop off the connectors and check for continuity between each set of pins. I don't have my CA93 wiring diagrams with me ATM, so I can't tell you which sets of pins for sure, but someone's gotta have the '93 docs handy.

If it's the same as '94 (and I think it is) then you should have continuity between 2U-2Y, and between 2V-2Z.

For that matter, if the OP does not have a green/white wire in 2Y and a green wire in 2Z, then it's not a CA car and it's a moot point.

LC-1 is already on its way.

I was just asking for some opinions on the difference between the regular base map included with the kit and the ITA Race base map - which was tuned for a ITA race car.

Also in response, I couldn't even get to the timing calibration portion (by setting fixed angle at 10 degrees) because the car wouldn't idle long enough. Also, since the car has had some cams and what not added.....it might require a significantly different tune versus the base map tune (which was modeled after a completely stock car)

I thought the base map would suffice to keep the car running (which many have done before installing a wideband anyways).....I wasn't going to drive on it in the condition, just wanted to fire it up and see if I can set timing and what not, per DIY Autotune's instructions.

The values that I saw for ITA maps had a signficantly different pulse width under cranking settings, had a much more richer VE Table setting, and also signficantly different Ignition Advance settings.

Would the difference in cranking settings likely be the answer to the poor idle mess at startup? I'll verify when I get the Wideband on....but just wanted to hear some insight on guys who are bit more familiar with the Megasquirt than I am.

Thanks,
Eddie

If it starts you go directly into After Start enrichments, then after that timer had decayed warm-up mode until you reach 160*F.

if you have a long timer set and are forcing a particular MAP value during ASEs, that could lead to stalling issues as the fuel requirements start to change.

I had the same problem when i loaded up a PNP map on the DIY. The car would idle for about 10 secs (if that) and sounded like shit. I took baro correction off under the fuel injection menu and it started and idle right after.