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Suddenly running lean

 
Old 08-16-2018, 02:04 PM
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Default Suddenly running lean

My megasquirt is MS3 Basic from Rev and everything else in my car is stock.

I got my '99 1.8l 10ae running with megasquirt few days ago and I've been autotuning it a bit.

First day it suddenly started running lean with like 17-19 afr but problem went off after a few engine restarts.
Now it happened again when I was idling at parking lot, afr suddenly went to 17-19 and car stalled and after I restarted engine problem persisted and I couldn't keep car running without giving it gas.
Also started to be a strong fuel smell.

My log is from starting the car after it stalled when idling.

E:

Also I noticed burning smell and faint smoke coming out from two gauge holes next to my afr gauge in my center console.


Also the car maybe feels like its running on 3 cylinders, im not sure but the car is a bit shakier than usual and the exhaust note is different and feels like car has lost like 70 horsepower.

If I go wot the afr is ~14.5, normally it would be 12.5
​​​
Could the problem be a bad ground/wiring or something?
Attached Files
File Type: msq
CurrentTune.msq (275.1 KB, 14 views)
File Type: msl
2018-08-16_20.48.482.msl (173.5 KB, 11 views)

Last edited by topsu; 08-19-2018 at 07:37 PM.
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Old 08-18-2018, 11:24 PM
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You're likely suffering from injector heat-soak and I guess (just a guess) your injector dead-times are off. Probably too short. Check the forum for injector heat soak and take it from t here.
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Old 08-19-2018, 04:11 PM
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Originally Posted by stefanst View Post
You're likely suffering from injector heat-soak and I guess (just a guess) your injector dead-times are off. Probably too short. Check the forum for injector heat soak and take it from t here.
Thanks, I'll look into this.


Also today when I started the car the same problem started instantly. I also noticed some kind of burning smell and gray smoke coming from the two gauge holes next to my afr sensor on my center console.
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Old 08-19-2018, 04:42 PM
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Originally Posted by stefanst View Post
You're likely suffering from injector heat-soak and I guess (just a guess) your injector dead-times are off. Probably too short. Check the forum for injector heat soak and take it from t here.
Thanks, I will look into this.

Today car ran fine first but ~2h after first drive I started the car again and the problem was back.

Here is a log of me driving with this problem on:
https://www.dropbox.com/s/4qo1iwvcxx...04.37.msl?dl=0

Also today I noticed burning smell and faint smoke coming out from two gauge holes next to my afr gauge in my center console.


Also the car maybe feels like its running on 3 cylinders, im not sure but the car is a bit shakier than usual and the exhaust note is different.
Could the problem be a bad ground/wiring or something?

Last edited by topsu; 08-19-2018 at 05:01 PM.
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Old 08-19-2018, 11:34 PM
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Originally Posted by topsu View Post
Thanks, I will look into this.

Today car ran fine first but ~2h after first drive I started the car again and the problem was back.

Here is a log of me driving with this problem on:
https://www.dropbox.com/s/4qo1iwvcxx...04.37.msl?dl=0

Also today I noticed burning smell and faint smoke coming out from two gauge holes next to my afr gauge in my center console.


Also the car maybe feels like its running on 3 cylinders, im not sure but the car is a bit shakier than usual and the exhaust note is different.
Could the problem be a bad ground/wiring or something?
Injector heat soak is worst at a hot re-start. It's also worse the cheaper the injectors are. I used to run five-Os and the car was essentially undriveable when hot.
The easiest way to deal with it is to lower target AFRs in the lower kpa cells and enable PID AFR control in idle.
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Old 08-20-2018, 01:25 PM
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I think I found my problem.

When my car was running badly I pulled 2nd spark plug wire out and cars behavior did not change, when I put it back it started to run normally again. Had to do it again when after a while car started to run badly again.
Could the problem be in my ms3 settings because these problems started same day as I installed my megasquirt.

I'm using '99 1.8 NB stock coils.


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Old 08-20-2018, 01:41 PM
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Intermittent problems with spark cutting out are not caused by Megasquirt install. Your coils may be on the way out, running only marginally. Were cylinders 2&3 affected, or just #2? They are both running off the same coil.
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Old 08-20-2018, 02:11 PM
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Not sure about other times but those two times it was cylinder 2.

I'll start looking for toyota cops from local junk yards.
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Old 08-20-2018, 04:51 PM
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Why not fully diagnose the problem before you start buying parts? It's not my money of course.
Also: Why buy Toyota COPs? Miata ignition works just fine and is easier to install. Or are you going for 400+hp?
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Old 09-06-2018, 10:04 AM
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Installed aftermarket coilpack and now it's running perfect again.
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Old 09-07-2018, 02:28 AM
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All you did was bandaid the issues by throwing more powerful coils at it, did not fix the root cause
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Old 09-11-2018, 04:36 AM
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Originally Posted by Dlaitini View Post
All you did was bandaid the issues by throwing more powerful coils at it, did not fix the root cause
Bad ignition coils when cylinders 2&3 not firing wouldn't be a root cause? I cant what else could be the reason especially when the problem was fixed by new coils.
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