How does my fuel pressure look?

[dmharvey79]

I am running the LMS 93 / 4+ tune on my 2013 SHO w/PP and I logged the following fuel pressure readings on my way to work this morning.

0-60 WOT with TC on (turning onto highway just prior to going WOT)


0-60 WOT with TC off


I've noticed some hesitation at high RPMs in the past, like others have mentioned, and I'm trying to decide if I should load the updated tune LMS sent me after I contacted them about this. I haven't noticed the hesitation since the weather here warmed up a little.

If I should go with the updated tune is it a good idea to go back to stock and then load the new tune or is it alright to load the current tune with the old tune installed? Thanks in advance!

[68_GT]

I have no idea but I'm interested in exactly this too. I have felt like fuel pressure is a problem my LMS 93 tuned 13 has. I get a hesitation more prevelant with a big downshift at high rpms. That's my biggest complaint with my tune at this point. Is there a LMS tune correction for this ? I have the V7 or what ever the last tune was in Nov. 13 and I still get it randomly. Sometimes my rpms wont even climb past a certain rpm like a rev limiter at 5-5.5K rpms. Then when it finally makes it to the shift point and hits the next gear up it pulls like a raped ape. Annoying and kinda the reason I gave up messing with my SHO lately it seems like there just not enough support for these cars. I lost all the wind out of my sails modding my SHO when LMS scrapped the XV1 tune. That's all I want is smooth acceleration to redline and boost to redline then I'd be 100% happy with mine. Doesn't seem like too much to ask from a tune on a factory boosted car.......

[EcoPowerParts]

Can you plot RPM as well? I'm going to assume you're seeing the pressure drop around 4500 RPM.

[BiGMaC]

dmharvey...
You may want to clarify what the tune adjustment was.  LMS has stated that the problem you describe seemed to be a cold weather problem and has an amended tune to remedy that specifically. So you might want to verify what you have with them so you don't load a cold weather tune if you don't need it.... or I guess you could just load it and log again to see.  I believe it may be posted here in their vendor section.

[68_GT]

Can you plot RPM as well? I'm going to assume you're seeing the pressure drop around 4500 RPM.

how is that fixed ?

[EcoPowerParts]

The fuel system I developed will fix it.

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[68_GT]

modified intake with aux injectors / pump etc... ??

[dmharvey79]

Thanks all!

I will look at plotting the RPMs along with fuel pressure, if possible. I'm new to the app, so I still need to learn it's full capabilities, but I only recall seeing the option to measure one item at a time. Both of those charts show a WOT pull from zero to 60-65MPH if that helps you estimate the RPMs.

The updated tune LMS sent is supposed to address 'fuel system limitations', and they pointed out that they observed a demand for 30-40% greater fuel above 4-4500 rpm, as a result of cold weather and differences in fuel (I assume they mean winter blend).

My goal here is to have a tune that utilizes, but does not exceed, the car's stock turbos, fuel system, etc. That said, if the hesitation returns with my original tune I guess I'll just switch to the updated tune they sent me (very fast response from Livernois BTW) and go from there. Given the reliability issues I've had with this car to date I'm pretty sure my upgrades will be limited to just the tune.

[Needmoreboost]

Can you on road log it and send it back to LMS to make revisions if need be?  Probably a pretty smart thing to do on any new tune loaded into your car.     I hope you get it sorted out.

[CrazyRacingMan]

What are you using to data log?

[dmharvey79]

Those quick logs/charts were done with the Torque app

[EcoPowerParts]

modified intake with aux injectors / pump etc... ??

Dual in tank fuel pump, new fuel line to fuel pressure regulator using stock line as a return line.

[IHeartGroceries]

modified intake with aux injectors / pump etc... ??

Dual in tank fuel pump, new fuel line to fuel pressure regulator using stock line as a return line.

Wait, so you found the supply problem to be between the fuel tank pump and the HPFP? Meaning, the OE HPFP could handle the fuel load you desired, but it was the in-tank pump that couldn't deliver?

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[EcoPowerParts]

modified intake with aux injectors / pump etc... ??

Dual in tank fuel pump, new fuel line to fuel pressure regulator using stock line as a return line.

Wait, so you found the supply problem to be between the fuel tank pump and the HPFP? Meaning, the OE HPFP could handle the fuel load you desired, but it was the in-tank pump that couldn't deliver?

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Yes I've been saying this for months

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[SwampRat]

modified intake with aux injectors / pump etc... ??

Dual in tank fuel pump, new fuel line to fuel pressure regulator using stock line as a return line.

Wait, so you found the supply problem to be between the fuel tank pump and the HPFP? Meaning, the OE HPFP could handle the fuel load you desired, but it was the in-tank pump that couldn't deliver?

Sent from my SM-N900V using Tapatalk

Yes I've been saying this for months

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YES You have been Mike , aka  4DRHTRD