Strange Idle, please help! - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to   Members

ECUs and Tuning Discuss Engine Management, Tuning, & Programming

LinkBack Thread Tools Search this Thread
Old 04-09-2010, 07:19 AM   #1
Junior Member
Thread Starter
iTrader: (2)
Join Date: Sep 2008
Posts: 89
Total Cats: 0
Default Strange Idle, please help!

Well, its been 2 weeks, I've given the OBDII enough time to re-learn... and I wonder if anyone here can help

1) upon start-up, whether it is in the morning or the second/third start of the day, the a/f floats well into 18+ (where my LC1 stops reading), and idles very poorly, yoyoing up and down, its getting worse too because it died 2-3 times in the last week just from the start-up

2) After 5-10 minutes drive, then everything is normal, idle reads about 16-13 a/f, which is fine, stable and everything, this is a common thing no matter if its after the 2nd or third start, the difference is, tonight for example, i had fog lights on the first trip and it was idling fine, i did notice a few days ago though, that on first trip, turning the fog lights on and off at idle have a direct effect to the A/F, it'd usually rise to 15, to even 16 at times with the fogs on

On the 2nd start, after 5-10 minute drive, with fog lights on, the idle is into 18s again, I found out when I got home my fan had kicked on, does this show symtoms of an electrical fault? or possibly? my light weight braille or my alternator is not producing the power needed to run my gauges, lights, etc.

3) and just to tip the scale to the electrical fault, whenever I try to move the windows up or down, it always brings the idle to around 400-500 and want to stall, and it usually stalls if i don't let go of the window switch,

So, I ask the experts on the turbo tuning, is this a related issue to the tune? or it is related to all electrical connections, possibly a bad ground somewhere? or worse, my battery or alternator?

I am running a GT2560 FM hardware
460cc injectors
AEM FI/C with MAF to the OEM computer

I am going to take a snap of the map today

Thanks for reading! I'd like to get this fixed ASAP, I hate to start the car in the middle of a parking lot and making alot of noise... or causing some damage
kyriian is offline   Reply With Quote
Old 04-09-2010, 03:28 PM   #2
Senior Member
Join Date: Jul 2008
Location: Phoenix
Posts: 657
Total Cats: 12

Loose / disconnected ground perhaps?

Do a search for where each big grounding point is and make sure they are all clean and functional.
oilstain is offline   Reply With Quote
Old 04-09-2010, 04:08 PM   #3
Junior Member
Thread Starter
iTrader: (2)
Join Date: Sep 2008
Posts: 89
Total Cats: 0

the one thing I almost forgot, and only realize is that the PCM light has been on since the middle of last summer, we cleared it twice and when read, the data was not making any sense, so we left it because it caused no problem

Can a bad/failed PCM cause any problems like bringing voltage right down?

BTW, we tried adding some fuel back in idle and it did help, but it did not help any with the voltage drop problem, the fan for example, when it switches on, the rpm drops right down to 400-500 before it takes it up, the A/F runs slightly leaner when the fan is running, and runs back to rich when its off
kyriian is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Need help - Stock Balancer and Fastforward overlay pulleys Frank_and_Beans Supercharger Discussion 13 09-12-2016 09:17 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM
why is my car running like pewp? (tune/datalog) itsMikey MSPNP 3 09-28-2015 07:40 AM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -4. The time now is 07:31 AM.