LMS tune and low quality fuel

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tech10002

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I’ve searched trying to find an answer, but have come up empty. My question is what if I get lower octane fuel, either by mistake or not being able to find 93 while traveling. The car stock will retard timing and still run okay without anything bad happening. Does the same apply when you’re running the 93 octane LMS tune? Does it still adjust for varying quality of fuel?
 

StealBlueSho

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I’ve searched trying to find an answer, but have come up empty. My question is what if I get lower octane fuel, either by mistake or not being able to find 93 while traveling. The car stock will retard timing and still run okay without anything bad happening. Does the same apply when you’re running the 93 octane LMS tune? Does it still adjust for varying quality of fuel?

To a limited degree. LMS still utilizes the stock Octane Adjust Ratio parameters. Meaning it will scale back spark to keep knock within acceptable limits.

Ideally you should have your tuning device loaded with 91 and 89 octane tunes as well if you are in a bind.


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Lostneye

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I was passing through NJ where it is against the law to pump your own gas and the attendant put in 91 instead of 93. Let me tell you he was quiet annoyed with me getting out of the car and stopping the pump, but not as annoyed as me. I topped it off with 93 and babied the car for the ride home without issue.
 

SHOdded

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As tuners will admit :D. The most intense part of the tuning changes are reserved for heavy to fullon acceleration. People have accidentally filled up too much E85 when mixing, and have survived by either of the two methods mentioned above.
 

tech10002

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To a limited degree. LMS still utilizes the stock Octane Adjust Ratio parameters. Meaning it will scale back spark to keep knock within acceptable limits.

Ideally you should have your tuning device loaded with 91 and 89 octane tunes as well if you are in a bind.


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I have an 87 octane tune loaded on the tuner. I just hate flashing while on the road. I have had bad flashes with an SCT tuner on my truck in the past and don’t want to be stranded somewhere. I was mainly concerned with getting some gas that wasn’t what it was supposed to be or something like that. Just didn’t want to damage something because it would take a minute or two to notice the poor performance and back off till I could get some good gas.
 

tech10002

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I was passing through NJ where it is against the law to pump your own gas and the attendant put in 91 instead of 93. Let me tell you he was quiet annoyed with me getting out of the car and stopping the pump, but not as annoyed as me. I topped it off with 93 and babied the car for the ride home without issue.

You can’t pump your own gas there? I’ve never heard of something like that before. Must be like the cast iron plumbing and metal conduit building code requirements in NYC. The law exists just to make somebody more money.
 

StealBlueSho

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I have an 87 octane tune loaded on the tuner. I just hate flashing while on the road. I have had bad flashes with an SCT tuner on my truck in the past and don’t want to be stranded somewhere. I was mainly concerned with getting some gas that wasn’t what it was supposed to be or something like that. Just didn’t want to damage something because it would take a minute or two to notice the poor performance and back off till I could get some good gas.

I have never had a bad flash with the LMS device. As a matter of fact... I used it once to restore my stock tune after a failed SCT load that bricked my car.


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SHOdded

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No device is immune to failure. Yes, LME devices have failed in the past. But not frequently by any means.
 

tech10002

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I have never had a bad flash with the LMS device. As a matter of fact... I used it once to restore my stock tune after a failed SCT load that bricked my car.


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Yeah, that’s what I was concerned about. I had a bad flash in my truck that bricked it where the tuner itself corrupted and had to get the stock tune rebuilt for me so I lost the original stock tune. The instructions for the LMS tuner say to plug the car into a battery tender when you flash so it made me a little nervous not doing it in the garage. I’m assuming they flash fine on just battery voltage, and that’s just an extra precaution, then.
 

StealBlueSho

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I have never used a battery tender when flashing... guess I live on the edge... however... the new MyCalibrator Touch takes FOREVER to save off the stock tune and then load the new tune. After that it’s really fast to switch tunes...

Actually had me worried... but nah.. all good!


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Jeff2017

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You can’t pump your own gas there? I’ve never heard of something like that before. Must be like the cast iron plumbing and metal conduit building code requirements in NYC. The law exists just to make somebody more money.
It is the unions in NJ that make it impossible to pump your own gas. Too bad the politicians their don't have the guts to stand up for the consumer.
 

ridered74

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No device is immune to failure. Yes, LME devices have failed in the past. But not frequently by any means.

Mine failed once out of maybe 30-40 times. Took much longer than normal then at end it just said something like "file failed to load", tried again immediately after that and it worked fine.

My SCT4 on the other hand has failed a couple times and once had me thinking my ECU was bricked as it was completely unresponsive for a good 10 minutes. Couldn't turn on accessory power, couldn't lower the windows, nothing.

I won't hesitate to use the LMS tuner regardless of where I am. The SCT4 only gets used if my car is sitting in my driveway at home.
 

Lostneye

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I've never used a battery tender either, I don't even own one. I think that is just LME covering themselves. If the battery dies mid flash it can brick the ECU but unless the battery is bad or that car sat for a while that shouldn't happen. It's only takes a few minutes to flash and probably less than a minute to write the new file to the ECU.

I bought a travel case that fits my tuner, stock MAP, OBD scanner, etc and keep it in the car. Make sure you have a torx driver for the MAP screw as well.
 

tech10002

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I have never used a battery tender when flashing... guess I live on the edge... however... the new MyCalibrator Touch takes FOREVER to save off the stock tune and then load the new tune. After that it’s really fast to switch tunes...

Actually had me worried... but nah.. all good!


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I noticed that too. In fact, the first time I tried to save the stock file, it failed. The second time it worked but must have taken 20 minutes.
 

tech10002

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Mine failed once out of maybe 30-40 times. Took much longer than normal then at end it just said something like "file failed to load", tried again immediately after that and it worked fine.

My SCT4 on the other hand has failed a couple times and once had me thinking my ECU was bricked as it was completely unresponsive for a good 10 minutes. Couldn't turn on accessory power, couldn't lower the windows, nothing.

I won't hesitate to use the LMS tuner regardless of where I am. The SCT4 only gets used if my car is sitting in my driveway at home.

Yeah, I have an older SCT version 2 in my truck. It has failed many times over the years, but always worked on the second try except once when it totally took a crap on me. It sounds like the LMS tuners are much less prone to failure, though.
 

tech10002

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I've never used a battery tender either, I don't even own one. I think that is just LME covering themselves. If the battery dies mid flash it can brick the ECU but unless the battery is bad or that car sat for a while that shouldn't happen. It's only takes a few minutes to flash and probably less than a minute to write the new file to the ECU.

I bought a travel case that fits my tuner, stock MAP, OBD scanner, etc and keep it in the car. Make sure you have a torx driver for the MAP screw as well.
I keep mine in the oddly shaped leftover space the sub box doesn’t take up in the pass through. The tuner, original map, original tstat, and a torx fit nicely in the little nook.
 

OmaHahn

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I found this out the hard way! I have 93 in my city everywhere and I "assumed," it would be state-wide also. Drove 4 hours to the in-laws and then 3 days later to come home find out none of their gas stations had 93. I was in pure panic mode! So I fueled up with 91 and crossed my fingers. Well, nothing happened at all, I even floored it to find out, again nothing. I barely noticed maybe a little slower, not as peppy as the 93.
 
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