False Knock Procharged S550

Just wondering if you have tried reloading stock tune and then rewriting tune. That def solved some of my issues, though false knock still a problem.

markmurfie said:

http://www.datazap.me/u/markmurfe/log-1503790620?log=0&data=4-5-8-10-11-12-14-19&solo=4-5-8-11-12-19

At idle you have a bank to bank difference of 4%. At idle you are seeing 10-15% correction for a lean condition. At cruise this difference reduces.

At cruise you are seeing 20%- 45% correction. When you were cruising at 3000rpms it started to effect your measured lambda over 45% correction. Thats not good.

http://www.datazap.me/u/markmurfe/l...o=2-3-4-5-6-7-8-9-11-12-14-19&zoom=9891-19482

Zoomed in and rescaled to the cruise part of the log.

Based on the different throttle angles(MAF follows them which is good), engine RPMs, and load. I would say this is a predictive fuel correction. MAF was changing very little with RPM change, but the more load dropped the more fuel it pulled. Load is based on air mass derived from RPM and MAF values and the airmass that fits the volume of the engine. Something like this would need to be corrected in the speed density, in which the math is very complex. Tuners can and usually disable the compare the ecu does with the MAF to the speed density. If its disabled or the air mass multiplier is maxed out then its unlikely to be fixed in an email tune.

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Thanks for the feedback...The saga continues. Will see what I can sort out with them tomorrow. The car will be parked until then.

venumous said:

Just wondering if you have tried reloading stock tune and then rewriting tune. That def solved some of my issues, though false knock still a problem.

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Yes, I did actually try this and it seemed to help quite a bit on the R5 tune, though I'm now throwing lean codes.

I've pretty much had enough of mine. I put my stock pump back in and hooked up BAP to see if problem is there on prior tune and it is. May be time for me to go GTR anyway.

venumous said:

I've pretty much had enough of mine. I put my stock pump back in and hooked up BAP to see if problem is there on prior tune and it is. May be time for me to go GTR anyway.

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Haha man, I've had the same internal struggle for a while, but figured I would boost and be happy. Have had quite a few bugs so far, all of which I'm hoping we can sort out, otherwise I too may be going that direction next season. Would just be tough to give up the S550.

So an update...Getting a bit frustrated. Received another tune rev today and it feels horrible. Bogged down, weird timing everywhere and an overall horrible driving experience. Tuner is now asking whether I have vacuum leaks. I'm 100% certain I'm not and they're basically saying it doesn't make any sense and that I likely have a leak somewhere. I have checked the car over 2x fully and cannot find anything. Hoses are tight and boost is holding fine at 5 track days I've monitored. I'm pulling 10psi at redline with no boost gauge fluttering on the revision that performed well.

It also doesn't make much sense to me that one revision out of at least 15 performs amazing, with no knock, great performance and every other tune revision pulls timing like crazy with tons of false knock. I would use that revision full time, however it's throwing lean codes P0171 & P0174 after around 1 hour of drive time, which tuner is saying is false codes, but I certainly don't want to be driving around with lean codes. The revision they sent today based on the rev that runs the best to get rid of lean codes feels horrible again. Only change they said was made was corrected fueling based off of the same revision that works well.

When sending this revision based on the lean codes I was getting, he had mentioned that he forgot to apply the latest MAF trims and that this should correct it. No more check engine light, but performs horribly.

Logs from today if someone can provide some feedback:

Cruise log sport mode:

https://www.dropbox.com/s/btxyl181ck7g6lm/datalog1 r5c cruise sport.csv?dl=0

WOT Sport mode 1:

https://www.dropbox.com/s/n4tn7ghlaeexinm/datalog1 wot sport 1.csv?dl=0

WOT Sport mode 2:

https://www.dropbox.com/s/dut14nhkp38x15u/datalog1 wot sport 2.csv?dl=0

Your MAF frequency shouldn't be jumping around like this. Still very lean while cruising.

I compared a similar section to a car with a good MAF. The Frequency is Khz vs hertz so just multiply or divide by 1000. The Lb/min are the same. It will move around but jumping up and down 200 hertz is bad.

Are all these cars that are seeing false knock tuned by Lund?

markmurfie said:

Your MAF frequency shouldn't be jumping around like this. Still very lean while cruising.

I compared a similar section to a car with a good MAF. The Frequency is Khz vs hertz so just multiply or divide by 1000. The Lb/min are the same. It will move around but jumping up and down 200 hertz is bad.

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What could be done to correct this? Trying to determine whether a tune issue, or potentially a mechanical issue?

If one tune works fine and the rest don't, I'd lean towards tune. But I'm not an expert like Mark!

Check for damage to the Plug and wire harness.

Clean the sensor with some CRC mass airflow sensor cleaner. Spray the hot wire and let dry for a while. No need to rub it with a Qtip or anything. See if the frequency improves. If not replace it.

The frequency is a direct representation of airflow. So unless your engine has something causing some very ruff airflow this sensor is dirty or bad.

How is the sensor oriented in the charge pipe?

They're adamant that something is loose on the car. Either vac line, or exhaust connections/something touching headers potentially. I'm going on 30 log sessions now.

Will have it up on a lift soon to rule everything else out. Will also pull the MAF sensor and check it.

Who installed the kit?

dubster99 said:

Are all these cars that are seeing false knock tuned by Lund?

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That seems to be a very common tuner but ive noticed a higher than average percentage