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MX5 Turbo 1990 MS1 Lean AFR (Air leak???)

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Old 07-25-2014, 08:15 AM
  #81  
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Originally Posted by xXxKillDogxXx
Also my idle AFRS are extremely lean 15-17s... when cold its about 13-14 though. and in boost I do hit 10s but it flucates between 10-11- sometimes 12 but that might be be coming off the throttle when it hits 12s in boost.

Anyways ill update tomorrow guys, and hopefully adjust me idle settings.
you should tune your fuel settings while you are at it.
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Old 07-25-2014, 11:31 AM
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Okay so a update and some sorta good news...

The car passed its MOT finally after adjusting the handbrake numerious times but I think september all the brakes can be renewed and the fronts upgraded for 4 pots, as for the backs maybe 1.8 calipers if I can get my hands on some.

I got the car plugged in today and started to fiddle with the idle settings and noticed that i couldnt test the IAC valve because the box for warm temp was greyed out...

Then i noticed the car was set on PWM + Warmup only and after all my research i keep hearing always use closed loop so I tried it out of interest and low and behold the car idles a lot better I also let the tuner studio autotune the idle for the sheer fact it was miles out on the AFR and scary lean.

My only issues now is the idle still fluctuates about +-100rpm where its trying to get it to 900rpm, now from what i have read i may need to adjust the PID settings but i couldnt find them could anyone direct me ? Its a MS1 btw.

And lastly I took the car around the block to see if the idle was actually gonna stay where it should and a couple times I thought the car had turned off cause I was not used to having the car idle so low haha however every now and then the idle will stick/hang at 1500 possible sticky IAC valve?

Either way good news I think and it means I am one step closer to making it run perfect.

PS: Thank you, and im sorry for being a stubborn idiot before.

Edit: just done some more reading and I could adjust the deadband range which from what i can remeber is set to 100 which conincides with what i was seeing with the flucuation on the RPM, good idea or no?
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Old 07-25-2014, 12:11 PM
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Setting the dead band too tightly can make the idle oscillate worse but I don't recall what my settings are. When I get to my laptop next, I'll show you all of my settings.

You could try tightening it up by 25 and then 50 and see what it does. You can always change it back.
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Old 07-25-2014, 12:43 PM
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Originally Posted by sixshooter
Setting the dead band too tightly can make the idle oscillate worse but I don't recall what my settings are. When I get to my laptop next, I'll show you all of my settings.

You could try tightening it up by 25 and then 50 and see what it does. You can always change it back.
Well I read some docs on the ms1 and it said trying between 25 and 50 was a good choice so I'll give it a go and see what happens.

Also I'm gonna autotune the car later in the night soon when the roads are clear so I can get the best tune.
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Old 07-25-2014, 12:45 PM
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The idle hanging at 1500 is more likely a result of your idle not being tuned properly. Too much spark advance in the idle cells was causing a similar condition on my car, but before you go start pulling timing you should finish tuning your idle.

When you autotune the rest of the VE table make sure it doesn't try to change the idle cells or it will screw them up.
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Old 07-25-2014, 05:46 PM
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Originally Posted by thenuge26
The idle hanging at 1500 is more likely a result of your idle not being tuned properly. Too much spark advance in the idle cells was causing a similar condition on my car, but before you go start pulling timing you should finish tuning your idle.

When you autotune the rest of the VE table make sure it doesn't try to change the idle cells or it will screw them up.
Ill set it so it dont affect anything under 1.5k RPM like advised above, what would be the best way to learn how to adjust the spark advanced if all else fails?


Anyways on to tonights antics I took it for a drive tonight and while warming up the idle was awesome it started without throttle it also idled straight away on 800 then the ecu kinda went okay the car needs to warm up and bumped the idle up to 1100 even though its set to 1400 for warm up.

Once warmed up though the idle didnt really wanna settle, it would stick about 1500 and sometimes a tad higher, the interesting thing was the AFR were low to high 14s which shouldn't really cause a problem right?

One thing I am thinking though is maybe the idle may need adjusting on the throttle body its self since surely if that is way out the IAC valve can only do so much? as any got any sort of default settings I could try on the idle screw like maybe 2 and half turns or something.

Also I tested the IAC valve earlier which I did forget to mention, I set the warm idle to 2000 which it did make the idle change however it went higher than 2000 rpm and also took about 10 seconds after pressing burn to actually change anything is that normal?
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Old 07-25-2014, 06:14 PM
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Stop blindly changing settings and read one of the many guides here on tuning closed loop idle. If you set your idle to 1400 on warm up and it only hits 1100, that means your idle is not tuned. Try tuning it COMPLETELY first, as that may show you have no mechanical issues.

And based on what you've posted so far, I'm going to recommend that you don't even look up how to adjust the ignition timing. That way there is less chance of you accidentally blowing up your engine.
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Old 07-26-2014, 09:13 AM
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Originally Posted by thenuge26
Stop blindly changing settings and read one of the many guides here on tuning closed loop idle. If you set your idle to 1400 on warm up and it only hits 1100, that means your idle is not tuned. Try tuning it COMPLETELY first, as that may show you have no mechanical issues.

And based on what you've posted so far, I'm going to recommend that you don't even look up how to adjust the ignition timing. That way there is less chance of you accidentally blowing up your engine.
Im not blindly changing settings I know the difference between warm up and closed loop, going to give tuning the idle another go set time setting it to warm up only and once up to temperture setting the idle with the idle screw and adjusting the fuel till its low 14s so I can get a more stable idle.

Once thats done ill swap it over to closed loop again which should be fine if fuel i set it good enough.

from what i found on here my map settings around idle is pretty normal and I should just have to adjust the fuel thats it. Fingers crossed everything goes well!
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Old 07-26-2014, 09:17 AM
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Mine is set this way currently:



Until this week the minimum DC and closed DC were 10 and the idle was set at 1050rpm. My new radiator fan has a high draw and when the A/C came on it stalled occasionally so I started raising the settings to try to mediate the problem.
You won't likely need to do that.
Attached Thumbnails MX5 Turbo 1990 MS1 Lean AFR (Air leak???)-idle_zpsedb4da0b.jpg  
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Old 07-26-2014, 12:05 PM
  #90  
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Default Hmm not sure what to so here

Okay so I made idle a bit more rich just to eliminate that being a problem plus there is no harm in it really and I can fine tune it later. I also set it to warn up mode and dropped the idle to 900 off the throttle body which means the iac should be doing nothing and then I put it back in closed loop mode.

This seemed to help a bit however I still have a wierd idle every min or so and I videod it just to show you.

I can't see of being anything major but I can't put my finger on it tbh.

What so you guys think

Last edited by xXxKillDogxXx; 07-28-2014 at 02:58 PM.
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Old 07-28-2014, 12:07 PM
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So I took the car for another drive yesterday and the idle is just so unstable, every now and then when i stop at the lights the car will try and idle at 400-500 rpm...

And i really cannot put my finger on what the issue is.
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Old 07-28-2014, 02:47 PM
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Originally Posted by xXxKillDogxXx
So I took the car for another drive yesterday and the idle is just so unstable, every now and then when i stop at the lights the car will try and idle at 400-500 rpm...

And i really cannot put my finger on what the issue is.
Take off the IAC if you havent already and clean it with some electronic cleaner.

Carbon build up might be gummed up on it.
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Old 07-28-2014, 04:53 PM
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Originally Posted by Girz0r
Take off the IAC if you havent already and clean it with some electronic cleaner.

Carbon build up might be gummed up on it.
It seems to be that the IAC valve is a bit of bitch to take off seperate from the throttle body so I might just take it off as a hole unit and clean it.
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Old 07-28-2014, 05:14 PM
  #94  
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Double post.
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