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-   -   1990 Miata DIYPNP hard to start cold. (https://www.miataturbo.net/megasquirt-18/1990-miata-diypnp-hard-start-cold-61845/)

MustangMike 11-23-2011 06:02 PM

1990 Miata DIYPNP hard to start cold.
Hey guys first I'll tell you what im working with. Its a turbo'd 1990 1.6l with a MS DIYPNP, Map daddy 4 bar map sensor, BMW tps, runs great. The problem is when the engine is cold i have to crank for around 10 seconds and pedal the gas for it to start. When its warm it fires right up. I feel like it may be related to my IAC... thats also just my guess... i dont have a clue. If anyone could help it would be great! Let me know if i should post anything to help out. Thanks,

jnshk 11-23-2011 07:06 PM

Does it seem to run just fine with good AFRs once you finally get it started, or does it run rough until it warms up?

miatauser884 11-23-2011 11:09 PM

Trying increasing the cranking PW% at the temps you are having trouble with.

MustangMike 11-24-2011 12:48 PM

you have to hold the throttle at about 2,500rpm for a few seconds then its fine. If you dont it will stall. Runs great with great AFR's. Ill try increasing the PW either tonight or tomorrow and and see if it changes anything.

miatauser884 11-24-2011 01:20 PM

sounds like the IAC max range may be set too low if you are using closed loop. check your idle valve control. Shit, send me your email and i will send you a tune form my diypnp, you can use it to compare.

MustangMike 11-24-2011 06:08 PM

That would be awesome! [email protected]. As for the afr's im actually not 100 percent positive. My wideband sensor is at the end of my downpipe and I don't have an exhaust on the car yet so its not accurate in its current location. When tuning on the dyno I welded a bung further up stream and used an external wideband. My problem seems very similar to the thread that just got posted after mine "cold starts will end me" hopefully one of us figures this out lol.

MartinezA92 11-24-2011 06:26 PM

Hmm our problems seem to be a little different actually. You have trouble getting the car to start, mine fires right up but immediately falls on its face, and if I touch the gas it'll stall.

You also use your IAC, I don't.
+1 to taking a second look at your cranking PW's.

MustangMike 11-24-2011 07:03 PM

Ahh I see, miss read your thread :p, mine has a nasty hesitation also that I didn't mention that's like you described, when you touch the gas after starting it will hesitate and stall if you hold the gas. Problem gets better when the engine is warm. Maybe I can learn something from your thread also!

miatauser884 11-24-2011 10:36 PM

also make sure your 4bar map sensor is calibrated in tunerstudio

Edit: check your email

MustangMike 11-25-2011 06:01 PM

Yup just double checked the map sensor, everything looked correct. Got your email im going to do some compairing tomorrow! Thanks a lot!

giblets 11-28-2011 09:04 PM

Have you checked the cranking rpm threshold? I found that mine had been reset to 200rpm after a firmware update which obviously made it hard to start.

Braineack 11-29-2011 07:48 AM

yeah cranking rpm needs to be closer to 350rpm.

if the throttle needs to be held, it's obvious you have fueling issues.

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