ECMlink Idle surge fuel trim issue?

[Purple_T63]

I am having issues with my idle. Basically when cruising if I coast the car idles at 2200rpm. When in gear and NO BOOST the air/fuel fluxuates up and down between 13-15 steadily. And when ever I come to a stop my idle starts to surge. Sometimes it surges quickly sometimes slowly.

I don't have any vacuum leaks I already went through the whole process to verify if my idle works correctly and it should all be good. I have 2 logs here. 1st one is me cruising and the 2nd short one is the idle surge I was talking about.

Timing is a 5 degrees. I am new to this so let me know if you need more info. I will be updating my mods list soon also since I see people using this to figure out issues.

 

[Vegas Smith]

This webpage has everything you need to know about setting your idle:

Dsm Idle Control | Six Sigma Dyno Tuning | United States

DSM Idle control by Six Sigma Tuning

www.sixsigmatuning.com

 

[Purple_T63]

I will be checking for leaks again tonight. But before hand I was trying to understand how ecmlink works last night. We noticed that the fuel trims were very off when the idle started to surge. I know that you can adjust them in the STFTandO2feedback tab but I don't understand what the numbers actually do. Id like to understand them before I touch anything that could make anything worse. Also when I am in boost you can see in the logs that all the data becomes normal again (air fuel,etc) So this is why I am pretty positive that this is caused by the tune and it looks to be the fuel trims that are off. I will check the link sent above tonight and report back tomorow.

 

[dwb]

I'd start with your TPS and Idle Switch controls.
First, fix (adjust) your TPS manually so you do not need to use TPS adjustment.
Second, what do you want for idle switch operation? Since it seems your TPS is not adjusted correctly, I'd go with the idle switch. So uncheck 'disable idle switch while moving' and uncheck 'simulate idle switch from TPS.' See screen snip below for your current settings:

You must be logged in to view this image or video.

Furthermore, your ISC steps seem to be off. Zero steps at idle doesn't seem right to me. So you will want to properly adjust your curb idle.
Use the controls to ground timing and diagnostics connectors, then adjust the BISS until your reach your 850rpm target idle. Don't forget to uncheck the two when done.

You must be logged in to view this image or video.

 

[Purple_T63]

I'm not sure what you mean by what I want for the idle switch operation.

If you are talking about if I want to use the idle switch or not doesn't matter to me as long as the car idles correctly.

I tried to ground the timing yesterday and the car would surge and timing wouldn't stay at 5 degrees. All the issues stayed the same while driving and at idle. So maybe I still have leaks but it doesn't seem to point that way anymore. I fixed a lot of vacuum leaks that I thought I did not have, and my idle still fluxuates.

I will try to reset the fuel trims tonight with the fixed vacuum leaks to see if maybe it fixes it.

It also seems that I am running very lean at idle so maybe I need to add fuel between 500 and 1500 rpm.

 

[dwb]

I'm not sure what you mean by what I want for the idle switch operation.

You have both 'enable idle switch operation' and 'simulate idle switch from TPS' enabled. Pick one or the other, not both.

Also you need to uncheck 'disable idle switch while moving' if you want it to idle properly when coasting in neutral or clutch disengaged.

I tried to ground the timing yesterday and the car would surge and timing wouldn't stay at 5 degrees.

Only use the two grounding options while you are setting your curb idle, fully up to temp. Disable them when done.

From the help file:

• Enable idle switch operation
  Disabling idle switch operation by unchecking this checkbox will make the ECU believe that the throttle is open even when it's not, disabling closed-loop idle rpm control and coasting fuel cut.
  
• Disable idle switch while moving
  Checking this checkbox will make the ECU believe that the throttle is open whenever the car is moving, disabling closed-loop idle rpm control and coasting fuel cut when the car is moving.
  
• Simulate idle switch from TPS
  Checking this checkbox causes the ECU to ignore the physical idle switch and to simulate the idle switch state from throttle position. RawThrotPos values of 34 and below will result in the ECU seeing a closed idle switch while values of 35 or above will result in the ECU seeing an open idle switch.
  
• Ground timing connector to ECU
  Certain diagnostic procedures in the shop manual require that you ground the timing connector going to the ECU. You can either go out under the hood and do this manually or you can just check this box which simulates the grounding of this pin inside the ECU.
  
• Ground diagnostic pin to ECU
  Certain diagnostic procedures in the shop manual require that you ground the diagnostic pin on the diagnostic connector. You can either crawl under the dash and do this manually or you can just check this box which simulates the grounding of this pin inside the ECU.

 

[dwb]

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[Purple_T63]

I checked the coils of the tps yesterday. All seemed good the resistance seemed a bit low (1350 ohms) when closed but it was at 900ohms before. I also unchecked the Idle switch while moving. Now when ever I let go of the throttle while driving it cuts fuel. Not sure if I like it since it jerks a bit. When I put it in neutral it still idles high (towards the 1800rpm range) .

Next , I grounded the diagnostic pin and timing at 5degrees and it wouldnt keep the timing at 5 with both activated at the same time. I had to uncheck the diagnostic pin for it to work. Not sure if thats normal or not... The idle seemed good sometimes but it still surges. I can get it to surge slower by messing the the "STFTandO2feedback" I also added some fuel at lower rpms and it seems to have helped a lot. When ever the idle seemed to be stable the fuel trims look good and dont spike up above 8% rarely.

Again I am no expert on this but this is really starting to look like a tune issue more and more since when ever I changed things with the idle it fixed but started to surge when coasting in neutral. It always one or the other.
Here are the logs.

Sidenotes : Can adjusting my manual boost controller affect how my car idles?

The 2nd datalog is where the car started to throw some heavy knock at low rpms in 3rd and 4th gear while building boost. Figured Id throw it in maybe it will show something.

 

[dwb]

MBC should not affect idle. However, I just looked at your mod list and realize you are not using a stock MAF. All my experience is based on a stock MAF...so I'll stop my ramblings.

One thing I noticed in your logs, your coolant temp sensor seems to be misbehaving. I see it regularly dropping 50 degrees F and back in less than half a second. At one point over a full 100 degree swing (206* -> 104* @ 11.2 seconds on your fatknockers log). I have no idea what issues that might cause but it should be looked at. Maybe it needs a new sensor?

Also, on your pulls, were you trying to hold WOT or were you feathering the throttle? I see lots of TPS fluctuation which could be your foot, or could be an issue with the TPS. Either way, you should try to recalibrate your TPS manually.

 

[steve]

I forget which, it might be both, but there is an RPM limit to the diagnostic modes. 1200RPM sticks in my mind, above which the ECU no longer holds conditions for the diagnostic. Setting base timing would be the strongest case for doing that.

 

[Vegas Smith]

There's something wrong with your TPS or the wiring of the TPS because it goes haywire up to 89% and the rpm don't move indicating it's not real. It's possible the power is grounding out somehow. Save your wideband under pin assignments and capture it during logging.