Idle is jumping up and down
2 Attachment(s)
So i got my base timing set and my required fuel to a point where the car (1990 1.8 swap(1995) with MS3X and stock injectors) idles. The first time i started it today it idled very smooth, almost flawlessly. However it started to randomly jump up to 1800 or so RPM and then fall low around 500 RPM, it kept doing this until it would drop too low and stall out. I'm not sure what would cause it to be randomly start doing this but i have attached the logs i took.
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Your tps needs calibration for starters.
Post your tune also. |
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Originally Posted by Akina_Downhill
(Post 1437691)
Your tps needs calibration for starters.
Post your tune also. |
You might be experiencing a noisy tps signal, which is common. You could remedy this with a shielded signal wire and a better ground.
Perhaps the throttle itself might be the culprit, or your tps/tps mounting. It seems like you are running a required fuel value of 16.5ms, you need to adjust this, enter 1839cc and 265cc/min as your values if you are using stock injectors and click okay. You will be prompted to powercycle the unit for the changes to take effect. |
Originally Posted by Akina_Downhill
(Post 1437815)
You might be experiencing a noisy tps signal, which is common. You could remedy this with a shielded signal wire and a better ground.
Perhaps the throttle itself might be the culprit, or your tps/tps mounting. It seems like you are running a required fuel value of 16.5ms, you need to adjust this, enter 1839cc and 265cc/min as your values if you are using stock injectors and click okay. You will be prompted to powercycle the unit for the changes to take effect. |
Set reqfuel correctly and then tune idle VE
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Originally Posted by elior77
(Post 1437899)
Set reqfuel correctly and then tune idle VE
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Changing your reqfuel will change the whole ve map.
Set the reqfuel right and tune the table right - post log and msq of the problem. |
What year is the car?
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Originally Posted by vitamin j
(Post 1437980)
What year is the car?
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So i went ahead and adjusted req fuel to 11.6 according to the specs. I got it idling after messing with the idle ve and now i'm getting the same unsteady idle after it warms up for a bit. It seems to be fine and steady on cold start. I took two logs, the first was a steady idle and right near the end of the log is when the unsteady idle occured. During the second log the issue was happening the whole time. Also when i try to start it after the unsteady idle happens, it won't steady out again and will continue to jump until it drops too far and stalls out in about 5 seconds of run time.
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2 Attachment(s)
Forgot to attach logs
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Have you actually tuned your closed loop idle?
Is your initial value table dialed in correctly? This has been discussed a zilion times. |
You should start with open loop, you can check my blog.
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Overall your idle doesn't look bad in those logs, good enough to tune CL. I recommend going to your VE table and Spark table and making all the idle cells very close to one another. So that during the full range of idle the spark maybe changes 1 degree and fuel is steady. Then just tune the PIDs.
You just started the car for the first time, gotta tune it! |
Originally Posted by Akina_Downhill
(Post 1438214)
Have you actually tuned your closed loop idle?
Is your initial value table dialed in correctly? This has been discussed a zilion times. |
Originally Posted by vitamin j
(Post 1438231)
Overall your idle doesn't look bad in those logs, good enough to tune CL. I recommend going to your VE table and Spark table and making all the idle cells very close to one another. So that during the full range of idle the spark maybe changes 1 degree and fuel is steady. Then just tune the PIDs.
You just started the car for the first time, gotta tune it! |
Originally Posted by Carrera95
(Post 1438331)
I'm already in closed loop though, i didn't touch open loop. Also what does PID stand for, i can't find it for the life of me.
PIDs are the Proportional, Integral, and Derivative in your closed loop window... |
There is a somewhat standar procedure to tune idle and it has been discussed, step by step, a thousand times.
Use search function, or get someone to tune your car. |
I struggled with idle also and couldn't figure out what I was doing wrong. Then I discovered braineacks website and copied his closed loop settings from his base tunes and it was almost perfect immediately!
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