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Old 09-12-2016, 02:50 PM   #1
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Default Very high RPM after start with ms3 & ms3x

Hey hairdressers,

Just finished building my MS3 with MS3x for my mk2 1.6 mx-5 with Frank's guide. It starts but runs on very high rpm and very lean (19 afr). I tried lowering the VE table to 35 in the idle zone, but it doesn't seem to help. I am new to this whole ecu tuning scene and I'm learning it pretty fast, but I don't know what to do at the moment. The idle valve works and I tried disconnecting it to see if it's the problem, but it didn't matter at all. I couldn't find a basetune for my car, so I just got myself a 1.8 basetune and changed the injector and engine size.

Wideband is connected as a narrowband at the moment because I'm switching the ecu every time cause I need to daily the car. Once the car will be idling normally, I will resolder it.

I included my log and tune, please point me in the right direction .
Attached Files
File Type: msq CurrentTune.msq (244.5 KB, 26 views)
File Type: msl wtf.msl (150.2 KB, 21 views)

Last edited by Alex Naoumov; 09-20-2016 at 10:56 AM.
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Old 09-12-2016, 03:00 PM   #2
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if youre lean, why would you reduce fuel?


what basetune? Im sure it's not a good one.



you certain you dont have a vacuum leak on your IM? I dont see how youre hit >4000RPM on the idle valve alone -- especially with those idle pwm% numbers (assuming you did the flyback mod to the expander card correctly).
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Old 09-12-2016, 03:19 PM   #3
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Thanks for your reply !

Quote:
Originally Posted by Braineack View Post
if youre lean, why would you reduce fuel?
That's stupid yeah, didn't really think about that...

Quote:
Originally Posted by Braineack View Post
What basetune? Im sure it's not a good one.
I can't upload the basetune right now cause I'm on the cellphone, you can see the tune I'm using in my first post.


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you certain you dont have a vacuum leak on your IM? I dont see how youre hit >4000RPM on the idle valve alone -- especially with those idle pwm% numbers (assuming you did the flyback mod to the expander card correctly).
Car runs fine on stock ecu with a bolt in the vacuum tube to block it, so I doubt there is a leak in the manifold. I didn't install the flyback diode because somebody told me that it is build in the Ms3x already.. Do you think I need to install iit
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Old 09-12-2016, 03:56 PM   #4
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did you do the wire from s12 on the pcb to d1 on the expander?
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Old 09-12-2016, 05:48 PM   #5
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did you do the wire from s12 on the pcb to d1 on the expander?
Yes, I did. I also tested all my outputs with a scope and they all work. Do you think I still need to install that flyback diode? Even if the expander has one built in?

Actually I had some trouble with this part:
Quote:
Step 2: fine adjustment of the VR circuits:
For the main board, measure the voltage on the upper leg of R54 while turning R56.
For the MS3X board, measure the voltage on the lower leg of R17 (close to U7) while turning R11.
In both cases, you want to see about 2.5 to 3 volts at that point, which puts you right in the middle of the actual output range of the sensors.
I measured around 2.3-2.4v at both points and turning the resistors didn't change much. Tbh I don't think this is the problem.

I didn't check for a vacuum leak, but I only removed the charcoal canister and put my vacuumline on that port that came free and the vacuumline is good and not leaking.
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Old 09-13-2016, 07:59 AM   #6
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no you do not still need the diode.

VR pots would only matter if your issue was losing cam sync.


use output test mode and fool with the idle duty % and see where the range of operation is.
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Old 09-13-2016, 07:59 AM   #7
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no you do not still need the diode.

VR pots would only matter if your issue was losing cam sync.


use output test mode and fool with the idle duty % and see where the range of operation is.
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Old 09-14-2016, 01:10 PM   #8
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Quote:
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no you do not still need the diode.

VR pots would only matter if your issue was losing cam sync.


use output test mode and fool with the idle duty % and see where the range of operation is.
Is it safe to run my car that long on 19-20 afr and 4k?
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Old 09-14-2016, 03:08 PM   #9
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Quote:
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Is it safe to run my car that long on 19-20 afr and 4k?
I would try adjust Req_Fuel to add fuel to the entire map. If the car is idling at 19:1, multiplying your Req_Fuel number by 1.3 would theoretically get you close to 14.7:1. At least the motor will be a little happier while you try to diagnose the issue.
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Old 09-21-2016, 06:09 PM   #10
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Thanks for the help guys! Finally fixed it, I accidentaly soldered the idle output to vics, and vics to idle lol.. After playing a bit with the tune I got it idling at 850rpm and did a small testrun
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Old 09-21-2016, 06:11 PM   #11
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whoops.
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