Help interpreting Sct log

[ridered74]

Hopefully I did this right.

I just emailed you the original csv file as well SBS.

 

[tech10002]

I mean, when your fuel pressure drops below 1500psi the combustion pressure inside the cylinder can exceed what the injectors are pushing. LMS themselves wrote a hole post about it.

At 800psi in his log, the injectors are not firing to keep from getting stuck or damaged. Again, this is from LMS...

I bet if you look at his throttle position is closing to protect the engine from having problems.

That fuel pressure is UNSAFE plus he is getting high knock retard, which means it’s really not safe.

I say he loads the stock calibration back with the 2bar map sensor as opposed to running that tune.

It’s SIMPLY NOT SAFE..


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Yeah, I don’t know dick about direct injected engines, though I’m learning a lot lately, and it really concerned me. When fuel pressure is a third of commanded, it gets your attention.

I wish there was more info like this out there about v11 before I spent 600 bucks with LMS. There seemed to be nothing but glowing reviews before I purchased. Now people with the same issue seem to be coming out of the woodwork, and it seems the only fix LMS is willing to do is pull power way back or sell you a $1600 pump.

Fuel pressure is about 1400 or higher up to about 5800 RPM. Above 5900, it really crashes. Just to be fair though, knock retard is running 2.5 to 3 where it’s running out of fuel, so I don’t think I’m at risk of a hole through a piston. Though I am going back to stock for now. I’m not sure where the 7.4 max was because I logged for over 10 minutes and I haven’t found where it went that high yet. That might just be intermittent false knock.

I need to do a stock log to get a feel for where everything is supposed to be.

 

[tech10002]

What is the load parameter where fuel pressure starts to decline?

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Looks like it's about 1.62 as it starts to crash and peaks at 1.75 as fuel pressure starts to climb back up.

 

[MHW100]

Are there really only a handful of people experiencing a problem and the 'many' other v11 users blissfully destroying their engines because they aren't experiencing any overt adverse effects?

 

[Raging Bull]

My thought process as well !!! ^^^^^^^

 

[StealBlueSho]

ridered74 sent me his datalog.. here is a screen shot from the 1st through 2nd gear pull.

Notes: Fuel pressure drops down to 954psi at the top of second but stays below 1160psi through most of the run. Additionally the throttle is closing to keep AFR's from climbing due to lack of pressure and to protect the motor. He has a high KR event of 7.5+ at the end fo the run, the rpms are not clean either, maybe he was in manual mode? but it didn't shift out of second at the top end which might be due to the manual mode or something else..

Eitherway.. this is a another example of dangerous fuel pressure drops. Most tuners don't like seeing ANYTHING below 1500psi.. LMS claims they don't like seeing anything below 2100psi+.. This datalog is showing WELL below both of those numbers. Its pretty much the same as the OP as well as my experience before the upgraded pump. Ambient outside temp is 69F according to the datalog

 

[brucelinc]

Are there really only a handful of people experiencing a problem and the 'many' other v11 users blissfully destroying their engines because they aren't experiencing any overt adverse effects?

I don't have a dog in this fight but that is a good question! I realize that there is some production variation between vehicles but if some are experiencing enough dangerously low fuel pressure to cause drivability issues, how many are JUST ON THE EDGE of safety....and could fall over at any time?

 

[mybigsho]

This is some good info.. I would like to invest in a sct device to do some data log. What one should i get? I too get the miss fire when I get into it on the hwy. At the track it runs good thru all the gears. I would like to try different tuners and see who runs the best.. I will say I was impressed with the v11 93 from lms.. But if there are better,safer,and faster tunes I'm all for it..

 

[luigisho]

Are boost-a -pumps enough to help stabilize fuel delivery? You might be able to make do with a $300 setup vs 1200?

 

[StealBlueSho]

Are boost-a -pumps enough to help stabilize fuel delivery? You might be able to make do with a $300 setup vs 1200?

From what I have read, the BAP helps some... iirc the testing showed a couple hundred psi increase at the rail. The issues isn’t the LPFP, it’s the HPFP not able to keep up with the load vs demanded AFRs.


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[ridered74]

ridered74 sent me his datalog.. here is a screen shot from the 1st through 2nd gear pull.

Notes: Fuel pressure drops down to 954psi at the top of second but stays below 1160psi through most of the run. Additionally the throttle is closing to keep AFR's from climbing due to lack of pressure and to protect the motor. He has a high KR event of 7.5+ at the end fo the run, the rpms are not clean either, maybe he was in manual mode? but it didn't shift out of second at the top end which might be due to the manual mode or something else..

Eitherway.. this is a another example of dangerous fuel pressure drops. Most tuners don't like seeing ANYTHING below 1500psi.. LMS claims they don't like seeing anything below 2100psi+.. This datalog is showing WELL below both of those numbers. Its pretty much the same as the OP as well as my experience before the upgraded pump. Ambient outside temp is 69F according to the datalog View attachment 7949

Yes, I forgot about that but they were having me shift using the paddles to see if manually shifting earlier in rpm's would resolve the issue.

Funny thing is, I sent that exact datalog to them and the response was "did not see anything out of the ordinary on logs".

 

[SHOdded]

If fueling is a restriction, wouldnt the proper mod be to remove that restriction? Tuning can work around it, but longterm, upgrading the HPFP seems a sturdier solution.

 

[ridered74]

If fueling is a restriction, wouldnt the proper mod be to remove that restriction? Tuning can work around it, but longterm, upgrading the HPFP seems a sturdier solution.

That is one way to solve the issue. I ended up going the route of an AJPTurbo tune. No unsafe fuel pressure drops and about $1400 less than an upgraded HPFP.

As a customer that has spent a good bit of money at LMS over the last four years, I'm extremely disappointed that I was told that log showed nothing out of the ordinary, and if I ever did spend the money on the upgraded pump, it certainly would not be with them.

 

[SaveMelMac]

If fueling is a restriction, wouldnt the proper mod be to remove that restriction? Tuning can work around it, but longterm, upgrading the HPFP seems a sturdier solution.

Coming from other platforms that are GDI and turbo pretty much the first mod before you do before anything was HPFP. Coming to the SHO I was quite surprised that it was not even brought up. Time to start saving up...

 

[MHW100]

I still think LMS needs to chime in or simply mod their v11 tune. These graphs appear to provide sufficient for evidence to suggest that their tune is systemically dangerous. Surely it can't be written off to vehicle variation.

Also, was this always a problem with their tunes? They've been the safe bet for years given engines aren't exploding on them or the net would be rife with examples . Logic would suggest it's maybe a just a v11 phenomenon.

 

[StealBlueSho]

If fueling is a restriction, wouldnt the proper mod be to remove that restriction? Tuning can work around it, but longterm, upgrading the HPFP seems a sturdier solution.

Sure, but they should at least offer an OTS tune that doesn’t require a $1600 part to be safe...

They have been tuning these for almost a decade without it with no issues.... why all of a sudden now?


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[SaveMelMac]

Sure, but they should at least offer an OTS tune that doesn’t require a $1600 part to be safe...

They have been tuning these for almost a decade without it with no issues.... why all of a sudden now?


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Agreed, but does anyone have logs from the older versions? Do we in fact know they were safe? I think I might just uninstall my tune and wait till this gets all sorted out.
Also I think it would be best on LMS part to fourmulate a response from their tuner not the sales guy. If they were sent the logs and said it should be no concern I would like to hear why.

 

[Raging Bull]

That’s a great question ! Yes why now and why are these other tuners having better results ? I don’t even want a tune on mine anymore. Can’t be comfortable driving. And I know once u tune it’s in u these tuners aren’t here for the life of your car they provided u with there service now it’s in us. They can ALL say they are safe but are they really. Man stock is looking real good to me. Besides I thought my SHO was pretty quick before I even knew about a tune , as did many of u probably.Is that not why we like them? So it may not be the faster than all but definetly quicker than most So that’s where I’m at. I haven’t had any issues it’s parked with the tune still on it. Just don’t know. When I bought it I said I was gonna keep it stock. And maybe I should have !

 

[StealBlueSho]

Agreed, but does anyone have logs from the older versions? Do we in fact know they were safe? I think I might just uninstall my tune and wait till this gets all sorted out.
Also I think it would be best on LMS part to fourmulate a response from their tuner not the sales guy. If they were sent the logs and said it should be no concern I would like to hear why.

The logs from 2010 SHO are great. Fuel pressure holds well even with their race tune.

They don’t offer anything BUT the V11 now on the 2013+ so unless someone has old logs, it’s not gonna happen.


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[Raging Bull]

For the record I’m not bad mouthing any of the tuners here. Like I said I have no issues with my tune 93 v11. Just want everyone’s car to be right how we all like them