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ECMlink Help needed understanding strange results when trying to tune car. Logs attached

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TurboSpider

Proven Member
223
16
Nov 2, 2015
York, Pennsylvania
So just had my engine rebuilt, got about 70 miles on the rebuild. I am trying to get my a/f dialed in. Here is a list of the mods I have so everyone knows. 97 spyder gst. Bottom end is a 6 bolt, stock crank wiseco pistons .20 over, stock 6 bolt rods. Top end is 2g head running green top CAS. 1200cc injectors, walboro fuel pump, rewired fuel pump. Aftermarket FPR. BC heavy springs and retainers and 272 cams. LC2 wideband mounted after flex pipe and before downstream factory o2 and hard wired to factory downstream o2 sensor input on ecu. Front o2 is the stock sensor that came on the car, not sure how old and possibly maybe bad? I am letting ecu get readings off front o2 and am not simulating narrowband as my wideband is further away from turbo where instructions said to mount it. Car is running Speed density with no boost leaks at throttle body, throttle plate ect.

I had to bump idle up to 900 because sometimes car was dying out when I pulled up to lights or stop signs and would definitely stall if I turned the a/c on. I did fix this somewhat by getting ISC position to around 30 It was originally at like 70 at idle. It now hovers around 30 range but does go up when a/c is kicked on. I changed the open loop thresholds to make the car run in closed loop more like ECM link wiki suggested to do and drove car around 30 minutes or so trying to get the throttle over a complete range. Keep in mind this is still a new engine on its break in so I didn't want to take the rpms up too much. Car should of been running on waste gate pressure but seems the boost is getting pretty high for waste gate pressure according to 4 bar map sensor.

The main issue I have is car seems to idle ok when first started and warmed up and seems to idle around 14.7. Once car has been on for a long time or if car has been shut off and restarted hot it idles rich around 12:1. This is in closed loop mode.

When I started the cruise a/f seemed to be around stoich at idle like it should and car seemed to be running overall really good. Possibly the best it has. I went out on lots of hills trying to put engine under different load factors like I should have. Somewhere around the 2,171 seconds into the log, the car started to seem to have more rich a/f at idle and fuel trims where increasing much higher then they did earlier on when first started. Around 2291 seconds in the log, the car seemed to be back to idling better around 14.7. No changes where made at all in ecm link at all during this cruise. I was strictly trying to gather data to do the combined fuel trim adjust for SD.

Closer to the end of my drive, I started increasing my rev range to try and get the higher rpm cells of the VE table to be activated. Around 2857 seconds into the log, I reved the car up to about 5,000 using 1/4 throttle and then gave it about 1/2 throttle for a short time. Boost spiked to 22 psi according to baro and CEL flashed as I recorded 8 degrees of knock. I didn't dare do that anymore and drove the car home pretty conservatively after that. When I got back I right clicked and did the combined ft adjust sd ve and applied the recommendations into the chart. I noticed the car was back to idling around 12:1. I shut the car off and reflashed the stock open loop threshold numbers back in and restarted the car.

It seemed car still wanted to idle in closed loop around 12:1 and was not idling as good as it did in the beginning of the drive. I locked it in open loop and took it for a short cruise and got a log. Locked in open loop I was able to idle closer to 14.7 at idle but my a/f seemed to jump around a little with rpm variation, possibly because my VE table still needs more work? Also when locked in open loop when I come to a light or stop sign the cars idle seems to go lower then it should almost stalling. Actually at the very end of this log I turned on the ac which stalled the car.

So the main issue I seem to be having is the car starts up cold and idles around 14.7 once warmed up. After driving it for awhile it seems to go back and forth between wanting to idle around 12:1 and around 14.7:1. I cannot figure out why the variation in closed loop a/f. In open loop it appears to be closer to stoich like it should so am I looking at a possibly bad o2 sensor that is going from working ok to not working right? What is your thoughts on that?

Another thing I did notice is that during my entire first cruise in which i was gathering data for the combined ft adjustment I had lock manifold different pressure checked. No sure that was supposed to be checked or not but I do have the stock MDP on stock intake.
 
1st cruise open loop thresholds increased to keep it in closed loop as much as possible. Ignore title of log which says open loop cruise it should be closed loop cruise
 

Attachments

  • long open loop cruise.elg
    2 MB · Views: 31
Log when I locked it in open loop.
 

Attachments

  • locked in open loop ac turned on and stalled engine at end of log.elg
    686.9 KB · Views: 25
Drove car to work this morning and got a log. It ran and idled good. I bumped the idle up to 950 but that was all the changes I made.
 
I see a few little things. You need to manually adjust your TPS. It can work using offsets but it is best to set it correctly. .63v at idle. I see at idle, the TPS is reading 1%.
Your ECU is adding fuel in the log so I suspect it is too lean globally. Try -61% global. See if fuel trims come in to within + - 5%.
In your antilag settings, you have it enabled but you are not enrichening fuel??? Put 10% in at least or disable it.
Under MafComp, you could disable MAF compensation when using Speed Density.
Lastly, and this is up to you, under the DASH tab, a lot of us change the stock (worthless) boost gauge to "knock"
There is probably more but those are the little things I saw.
 
Ok I set my TPS with key on car off, I will change it to when the car is idling. Thanks for the suggestions. I will give them a shot. Were you going off the 1st log when I was running in closed loop or the 2nd log where I had it locked in open loop? Just curious because I may have screwed around a little with global fuel after the first log trying to get the fuel down
 
It was labeled long open loop cruise but it was going into closed loop occasionally, which is what I was seeing.
 
So I tried what you said and changed the TPS to .63V at idle. The problem is, it seems to change back after the throttle is reved a few times. Seems like it always goes up to .65 or .67 after the throttle is moved a few times. I even tried changing it slightly below .63 to see if it would come up to .63 after I hit the pedal a few times but it always goes higher. Any ideas why this might be?

Also I put a new denso o2 sensor in o2 housing. That seemed to help somewhat and o2 is cycling more. Seems like when car is running in closed loop it is closer to 14.7 at idle and idles a little better than what it does in open loop. Does tuning only change the open loop a/f or does it change both open and closed loop? If it only changes open loop, then maybe I just need to tune it. Seems like when its in open loop it goes kinda rich around 10.0 when I am around 3k rpms and on partial throttle slowly building boost.

Still has an issue when it gets hotter or when restarted when hot where the idle and A/F is all over the place. I got some more logs. I can post if it helps. I did change the global like you suggested.
 
.65 is ok, mine vary a little also. Go in and adjust it in Link now that it is close.
The car runs in open loop (following your settings) at WOT or when you lock it in open loop. When in closed loop, the ECU fuels and times the car with feedback from all of the sensors. Sometimes you need to check the box that is in Misc, I think, for Hot Start Enrichment.
 
So if my car is running rich every time I go into open loop, I need to use the VE table and lower those numbers to get the fuel down correct?

Also I need to use TPS adjust correct to get the TPS zeroed out again, right? I am going to do that and drive the car some more when I have a chance and take a log. I am going to readjust the open loop thresholds so it stays in closed loop more like it says to in the wiki and drive the car some more and then run SDVEadjust tool, apply those changes, reset the fuel trims after the adjustments are made to the VE table, set it back to stock open/closed loop thresholds, and get a log of normal driving and post the results.
 
Last edited by a moderator:
Yes you go in and adjust the TPS now for full range and yes, go drive in varying conditions, and then see what the VE table suggests. Apply it if you want. I ALWAYS save the log prior to changing stuff that way if it doesn't do what I want or like, I just load the previous log back in.
 
Here is a log i got from this weekend. Drove about and hour. I will upload the photos of the ve table both before and after making changes
 

Attachments

  • long cruise with matt open loop thresh holds adjusted.elg
    2.4 MB · Views: 19
You are still a bit lean. The ECU is adding some fuel but it is close. Open up your log, and right click on the log and do the SDAdjust CombFT. Open up the same log again and look at your VE table before you did an SDAdjust and you will be able to compare the differences in what you are running and what Link is "suggesting".
 
I thought my voltage seems to be a little lower then I think it should be. Sometimes it bounces up to 13.7 but seems to idle around 13.0 Probably my alternator is on it's way out
 
The ve graph on the right represents what it was set at when I took the above log. The table on the left with the bold numbers represents what ecm link suggests after running the sdadjust on the above log

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I tried smoothing the table out from what sdadjust suggested. Not sure I am doing it right. I highlighted all the cells from top to bottom that were changed. So going off the table in the post prior, I highlighted the 1000 rpm column starting at 5.5 and selected all the cells between 5.5-12.9 as they are all in bold from being changed. I right clicked and hit interpolate rows top to bottom and it adjusted these cells.

I went through the same way only highlighting cells that were bold. Once I got done going top to bottom, I highlighted left to right and hit interpolate left to right and it smoothed it out. This is what it looks like after doing that. Does this seem ok to you? If so, I will save this to ecu.

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Should I drive the car more and get another log at this point? Should I keep the open loop thresholds to what I changed them to? Right now, it is set to keep it in closed loop longer. Or should I change the thresholds back to stock and get a log that way?
 
Reset fuel trims to let Link learn from your NEW adjustments. Its at the top menu under ECU.
 
Ok yes I always forget about resetting them. I will reset fuel trims and take it on a short drive and see where it is at then and post a log
 
Yes if you check my first log I got a CEL for having more than 2* of knock so I am trying to stay out of it until I can get that straightened out. Not sure if is false knock though because it seems like I am not lean when it happens and I have read somewhere if you don't torque the knock sensor to a certain spec it can cause false knock if its over tight
 
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