Page 2 of 2 FirstFirst 12
Results 21 to 40 of 40

Thread: Erratic Idle on 2018 Mustang GT

  1. #21
    Tuner in Training
    Join Date
    Oct 2016
    Posts
    28
    Quote Originally Posted by kris5597 View Post
    I PM'd you.
    replied.

  2. #22
    Tuner in Training
    Join Date
    Oct 2016
    Posts
    28
    Ok so here is a log with the car acting up on stock tune and then after some mapped point changes.
    Attached Files Attached Files

  3. #23
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    531
    I ran into an issue with 2018 and CAI that was causing erratic idle plus it would die occasionally if you tap the gas pedal ever so slightly. Ended raising the spark @ idle.

  4. #24
    Advanced Tuner
    Join Date
    May 2015
    Posts
    406
    It's very confusing as to why this issue is present. It's like the vehicle cannot figure out how to idle properly. Follows MP VCT and adjusts timing to figure it out, but still struggles. In factory form, I consistently have the issue. My tune actually makes the car driveable, even though it's not perfect. I know if I bring into the dealership they will sit and scratch their head as I, but not make any progress and I will be out of a vehicle.

    Kris

  5. #25
    Senior Tuner
    Join Date
    Jan 2013
    Location
    Hawaii
    Posts
    1,415
    At idle your MAF being at like .6-.7 lb/min seems low, MAP is high, inffered or not on a stock tune its usually pretty close. STFT trending lean, Id say you have a possible vacuum leak somewhere.

    Throttle blade is moving erratic, MAF sensor is directly picking up on the changes of air flow. Could just be a throttle body motor issue or it trying to fight a vacuum leak to target an airflow to achieve its torque goal.

    From one log to another the HPFP is high, and differ from each other by 500psi. I would have expected to see only like 550PSI at idle not 2K+. More indication of a higher than normal fuel demand for idle caused by a vacuum leak.
    "We can never be right, we can only be sure that we are wrong"- feynman

  6. #26
    Tuner in Training
    Join Date
    Oct 2016
    Posts
    28
    Even after my changes I still have the same issue. Car just seems to bounce around mapped points which causes the cam timing to change obviously even though it should not be. It should be going to only the mapped points commanded. Just going to keep trying more changes. I have even checked for vacuum leaks via smoke test, compression test, spark plugs, cleaned maf, everything else I can think of. Whats crazy is car never throws any codes other than random misfire and only occasionally if at all.

  7. #27
    Advanced Tuner
    Join Date
    May 2015
    Posts
    406
    Quote Originally Posted by murfie View Post
    At idle your MAF being at like .6-.7 lb/min seems low, MAP is high, inffered or not on a stock tune its usually pretty close. STFT trending lean, Id say you have a possible vacuum leak somewhere.

    Throttle blade is moving erratic, MAF sensor is directly picking up on the changes of air flow. Could just be a throttle body motor issue or it trying to fight a vacuum leak to target an airflow to achieve its torque goal.

    From one log to another the HPFP is high, and differ from each other by 500psi. I would have expected to see only like 550PSI at idle not 2K+. More indication of a higher than normal fuel demand for idle caused by a vacuum leak.
    I will investigate a vacuum leak as well. Check out this log from the other day. Coming to a stop, and this is the result.

    Kris
    Attached Files Attached Files

  8. #28
    Senior Tuner
    Join Date
    Jan 2013
    Location
    Hawaii
    Posts
    1,415
    In that log, it looks like some unexpected friction. Looking at TCC slip, some how while in park, It looks like the input shaft has some load and gets more on it like a clutch is being applied. Spark goes up very near MBT to over come this before the engine starts to stall. neutral or park disconnect the input from the wheels so TCC slip should be 0 as the input shaft can free spin. In gear as you can see input shaft is connected to tires at 0, so TCC slip is very near = to Engine RPM.
    "We can never be right, we can only be sure that we are wrong"- feynman

  9. #29
    Advanced Tuner
    Join Date
    May 2015
    Posts
    406
    Unfortunately it also does this in park/ neutral as well. The vacuum leak seems plausible as well. I will remove the intake manifold and throttle body today to inspect o-rings. I wonder if it could be a defective throttle body as well...

    Kris

  10. #30
    Advanced Tuner
    Join Date
    May 2015
    Posts
    406
    I took everything apart, intake manifold, throttle body, injectors, intake and inspected all o-rings and seals. Aside from some dirt and grime on the injector o-rings, I didn't find anything. Hoping there was a dirt or sand particle under the injector creating a small leak. I guess we will see over the next day, will keep you guys posted.

    I have tried a bunch of different combinations in the calibration trying to resolve the issue. The car doesn't die anymore, but sometimes it certainly seems like it wants to. I'll collect some more data.

    Kris

  11. #31
    Advanced Tuner
    Join Date
    Feb 2017
    Location
    TX
    Posts
    389
    Is there a tune file to correspond with any of the datalogs?

  12. #32
    Advanced Tuner
    Join Date
    Feb 2017
    Location
    TX
    Posts
    389
    Well, I found a possible problem, maybe, maybe not. Are the 18's missing a table?
    If ya'll haven't tried the following, maybe give it a shot if you haven't tried the distance table below.

    no-optimal-stability.JPG
    newdistances.JPG

  13. #33
    Advanced Tuner
    Join Date
    May 2015
    Posts
    406
    That's correct, it does not exist in my calibration, or any other 18 I've tuned. That would be useful to prevent the optimal stability from hunting around. Because even with a one commanded MP, it still moves around quite a bit. Needs to be at 0...

    Kris

  14. #34

  15. #35
    Advanced Tuner
    Join Date
    May 2015
    Posts
    406
    That is the VCT mapped point table for optimal stability, not the distance table previously mentioned. The distance is the table that lets it deviate from selected mapped points. Which doesn't appear to exist on the 18s at all. I emailed support.

  16. #36
    Advanced Tuner veeefour's Avatar
    Join Date
    Oct 2016
    Location
    Poland
    Posts
    531
    Oh I see - you can force OS to stay in 1 MP using just this table. You don't need a distance table for that.

  17. #37
    Advanced Tuner
    Join Date
    May 2015
    Posts
    406
    Quote Originally Posted by veeefour View Post
    Oh I see - you can force OS to stay in 1 MP using just this table. You don't need a distance table for that.
    I tried, it doesn't listen. Reconfigured the load table a load over what it idles at and commanded only MP1, it refuses to listen. Whatever is wrong I feel is a more in depth issue than the calibration can control or fix.

    Kris

  18. #38
    Advanced Tuner
    Join Date
    Feb 2017
    Location
    TX
    Posts
    389
    The stock calibration will be searching in between 0, 1, 2.

    There's good use for the Optimal Stability Distance Table. I like setting Optimal Stability to hold cam angles during a shift. If I have a 7800 RPM shift and the RPMs fall to 5800 in the next gear. I use Optimal Stability to hold Optimum Power cam angles. During a shift, instead of the cams retarding IVO 35, EVC 45, Optimal Stability will hold IVO 8, EVC 18 and be ready for the throttle in the next gear.

    They do ignore certain tables. Optimal Stability Max Load does not have very much effect.
    Same thing for Best Drivability, set max load to 4.0 and it will show the source before you go into Optimum Power.

  19. #39
    Advanced Tuner
    Join Date
    May 2015
    Posts
    406
    More idle nonsense. I can't seem to get it resolved. Waiting for the Optimal Stability Distance tables to be added, but that won't fix it. IT SHOULDN'T HAVE TO BE THE FIX. About to bring it in, at a loss...

    Kris
    Attached Files Attached Files

  20. #40
    Tuner in Training
    Join Date
    Oct 2016
    Posts
    28
    Ok so I have some findings to report on my car......I could not get anything tune related to help with the issue so nothing there but I came up due for an oil change and decided to try a thicker higher quality full synthetic oil(5w30), not the ford motorcraft synthetic blend(5w20) I used previously. I also used a k&n oil filter instead of the motorcraft one as well. Pretty much immediately the car idled better. After the oil change I decided to go get some food and wait in the drivethru window to test if anything got better, cause that was the time the issue would be the worst on my car(sustained idle stopped in gear). The car never bobbled once or even dipped in rpm! Granted I still have my idle set higher than stock(currently 750) but for the last past week car has not acted up at all! So now I am going to put the idle settings back to stock and see what it does. Also my mpg on hwy increased 3mpg since the oil change. So maybe a fix or worth a try from others using the ford oil.