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Old 10-17-2012, 09:46 PM   #1
OC_Nooby
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Default Cold start idle issues with new o2, No cold start idle issue without o2.

I put this in the tuning section but guess its more appropriate here.

Issue:

During a cold start with no o2 sensor plugged in the car fires up at 1500rpm then makes its way down to 900rpm. Perfect, no issues!

Now we do it again but this time install the o2 sensor. Fires up at 1500rpm then makes it way lower then jumps up, goes down, jumps up, rinse and repeat. When the rpms go up the car leans out, when the rpms drop the car richens. It does this until the car is warm.

Once the car is warm you can start her up and it idles perfectly.

o2 sensor is brand new. I was running without an o2 for 2 weeks until I received it today. Once I put it in/cleaned the codes the car would idle as described above. Also to note, this happened with the previous o2 until it crapped out on me.

Can this be pointing to the MAF?
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Last edited by OC_Nooby; 10-18-2012 at 06:01 PM.
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Old 10-18-2012, 10:51 AM   #2
sidewayz
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maf leak or air leak of some way.
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Old 10-18-2012, 12:32 PM   #3
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If it was you would see it in both situations would you not? After all a leak is a leak.

Last edited by OC_Nooby; 10-18-2012 at 12:41 PM.
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Old 10-18-2012, 04:04 PM   #4
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Holy crap, you pointed out my cold start issue to a T. Only problem is that I have ID 1000cc injectors and I seem like i'm the only person who's having this issue with them. AFR/Idle swings when it's cold until the temperature needle starts to move then they both settle where they should be.
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Old 10-18-2012, 06:02 PM   #5
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Quote:
Originally Posted by Subian View Post
Holy crap, you pointed out my cold start issue to a T. Only problem is that I have ID 1000cc injectors and I seem like i'm the only person who's having this issue with them. AFR/Idle swings when it's cold until the temperature needle starts to move then they both settle where they should be.
Well, at least now there are 2 people thinking about it
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Old 10-18-2012, 11:48 PM   #6
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3 people.

I think few people notice because they touch the throttle shortly after starting, and the ECU only does this until you touch the throttle or until the engine is warm.
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Old 10-19-2012, 01:08 AM   #7
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Quote:
Originally Posted by NSFW View Post
3 people.

I think few people notice because they touch the throttle shortly after starting, and the ECU only does this until you touch the throttle or until the engine is warm.
Truth, I was so happy when I didn't have the o2 plugged in. Well with the cold starts
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Old 10-19-2012, 03:04 AM   #8
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Try adjusting your closed loop target compensation (ECT) table to target richer when cold.
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Old 10-19-2012, 11:22 AM   #9
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Quote:
Originally Posted by Carbibbles View Post
Try adjusting your closed loop target compensation (ECT) table to target richer when cold.
I'll try this, also pulled some fuel out of the cranking enrichment table as well.
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Old 10-19-2012, 11:35 AM   #10
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Quote:
Originally Posted by Subian View Post
I'll try this, also pulled some fuel out of the cranking enrichment table as well.
Report back
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Old 10-19-2012, 12:28 PM   #11
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Quote:
Originally Posted by OC_Nooby View Post
Report back
Are you using the same injectors?
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Old 10-19-2012, 02:14 PM   #12
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Quote:
Originally Posted by Subian View Post
Are you using the same injectors?
FIC 1100cc
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Old 10-23-2012, 04:17 PM   #13
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Quote:
Originally Posted by NSFW View Post
3 people.

I think few people notice because they touch the throttle shortly after starting, and the ECU only does this until you touch the throttle or until the engine is warm.
I leave the throttle alone for a few minutes. Only until the temp needle starts to move when the idle/afr settles.
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Old 10-24-2012, 12:13 PM   #14
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Quote:
Originally Posted by Subian View Post
I leave the throttle alone for a few minutes. Only until the temp needle starts to move when the idle/afr settles.
Same.


Its the little things that bother me ahah
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Old 10-25-2012, 09:15 AM   #15
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Quote:
Originally Posted by OC_Nooby View Post
Same.


Its the little things that bother me ahah
Are the values in your tune "half maf'd"? If so, do you mind posting your injector latencies?
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Old 10-25-2012, 02:04 PM   #16
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Injector latency stay the same. I'll post them later on when I have my netbook.
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Old 11-10-2012, 11:09 PM   #17
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I changed my MAF as I had a spare. I can definitely say it doesn't swing as madly as it did before. My old MAF was dirty. Still swings but its a little more acceptable. Just an update.
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Old 11-12-2012, 09:02 PM   #18
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Quote:
Originally Posted by Subian View Post
Are the values in your tune "half maf'd"? If so, do you mind posting your injector latencies?
6.5v = 3.32
9v = 2.00
11.5v = 1.35
14v = 1.00
16.5v = 0.72

Injectors scaled to 550 (FIC 1100)
MAF values are halfed.
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Old 11-14-2012, 08:22 PM   #19
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if your unplugging your front 02 and this issue goes away then its a tuning issue.... FIC 1100 CC injectors idle like a stock motor when you get it right... MAF adjustments are not taken into consideration when you unplug the front O2... kinda like when you just unplug the MAF... I would be interested in seeing some logs with your front 02 and your rom... Maybe its something i can help with remotely... PM me.
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Old 11-15-2012, 01:23 AM   #20
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The car idles very nicely if its warm. It fires up quickly but after say 10 seconds it will run lean/rich until about 40-50c. Then it stabilizes. I'll take a video tomorrow and post it up. I'm sure its a tuning issue.

I had my system smoked today. No leaks. o2 Is new and MAF is cleaned.

BTW, you have a PM thanks!
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Old 11-29-2012, 09:16 AM   #21
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Quote:
Originally Posted by OC_Nooby View Post
The car idles very nicely if its warm. It fires up quickly but after say 10 seconds it will run lean/rich until about 40-50c. Then it stabilizes. I'll take a video tomorrow and post it up. I'm sure its a tuning issue.

I had my system smoked today. No leaks. o2 Is new and MAF is cleaned.

BTW, you have a PM thanks!
https://www.youtube.com/watch?v=xfG_S5GjrXI

This is the exact thing that happened when I tried a set of Bosch 1kcc injectors before switching to ID's. Didn't really change much after taking out 30% of cranking fueling.
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Old 11-29-2012, 11:40 AM   #22
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All the warmup fueling is based on static compensations so if your injectors are big the numbers are off. After a min or so fueling correction begins so I usually find that it gets into a loop of overcorrecting because the initial starting point is off. The cranking is not the problem if the car turns over, it is the warmup fueling/decay tables.

Try bumping up your latency by 5-10% across the board I have found that helps out significantly on most cars.
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Old 11-29-2012, 12:01 PM   #23
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Quote:
Originally Posted by lukeskywrx View Post
All the warmup fueling is based on static compensations so if your injectors are big the numbers are off. After a min or so fueling correction begins so I usually find that it gets into a loop of overcorrecting because the initial starting point is off. The cranking is not the problem if the car turns over, it is the warmup fueling/decay tables.

Try bumping up your latency by 5-10% across the board I have found that helps out significantly on most cars.
Can you give me an example with the warm-up/decay tables in ECUflash/Romraider?
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Old 11-29-2012, 01:39 PM   #24
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It is a complex mix of offsets and decays, It takes some trial and error to figure it out. Getting good E85 cold starts takes a bit of work on these tables in addition to cranking.

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Old 12-02-2012, 12:03 AM   #25
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I have messed with cranking and warm up enrichment as well as latency. I might not have played with decay (can't recall). Would you add or remove? I don't mind trying.
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