Hesitation in boost and high rpm

[BoostedSho2010]

Timing has nothing to do with fuel pressure

I know but it has something to do with hesitation. My car hesitates a lot when it does not have enough timing. Compared to when it's dialed in.


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[ajpturbo]

Timing has nothing to do with fuel pressure

I know but it has something to do with hesitation. My car hesitates a lot when it does not have enough timing. Compared to when it's dialed in.


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Your car hesitates because of something else...Timing follows load...The ECU is always trying to run the max amount of spark allowed.....It wants to tickle the knock sensor.

Basically the knock logic is running the max allowed spark at all times.

 

[polskifacet]

Is there a way to see what voltage the HPFP solenoid is getting with the SCT? I wonder if the solenoid is getting incorrect voltage once it starts going higher than stock fuel demand.

 

[polskifacet]

Not sure if it helps or not, but here is a log of my XSport in cold(er) temps. I'm not certain, but I assume the fuel system is the same as the SHO?

I also had the AJP boost regulator installed, so it would have helped minimize pressure drops during shifts.

Ambient: 8.6 F
IAT2: mid 50s at start of runs
Target Boost: 14.5 PSI

Note, since this log was taken, I've changed the regulator boost reference and moved down to 15.95 PSI springs, which helps with the pressure drops. We've not had any bitter cold since making these changes, but if it gets back down close to 0, I will log again for comparison.

My log looks very similar to MiWiAu even though he is running more boost(1.5 psi more), the curve, frp recovery and variation is oddly similar.

 

[ajpturbo]

Not sure if it helps or not, but here is a log of my XSport in cold(er) temps. I'm not certain, but I assume the fuel system is the same as the SHO?

I also had the AJP boost regulator installed, so it would have helped minimize pressure drops during shifts.

Ambient: 8.6 F
IAT2: mid 50s at start of runs
Target Boost: 14.5 PSI

Note, since this log was taken, I've changed the regulator boost reference and moved down to 15.95 PSI springs, which helps with the pressure drops. We've not had any bitter cold since making these changes, but if it gets back down close to 0, I will log again for comparison.

My log looks very similar to MiWiAu even though he is running more boost(1.5 psi more), the curve, frp recovery and variation is oddly similar.

I'm not sure there were that similar...I'd have to see exactly which 2 you are looking at....But his boost was higher AND the temps were super frigid and his recovery was much better if I remember...Your log show a clear lack of fueling for the boost level

 

[BoostedSho2010]

Is there a way to see what voltage the HPFP solenoid is getting with the SCT? I wonder if the solenoid is getting incorrect voltage once it starts going higher than stock fuel demand.

You can plug the X4 into the car once you plug the lap top in you can see much more.
Only fuel pump % current config

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[polskifacet]

Quick update, I emailed LMS and Anthony sent the logs of the runs after the LPFP change to their head calibrator. I also sent them the picture of the HPFP to show that it is also new. Fingers crossed!

 

[ajpturbo]

You sent them logs that you did via livelink sct?...that's interesting since they dont use sct and they said the data provided is not reliable....it makes it easy to use that program if you dont have one of your own...may as well lower overhead

 

[StealBlueSHO]

You sent them logs that you did via livelink sct?...that's interesting since they dont use sct and they said the data provided is not reliable....it makes it easy to use that program if you dont have one of your own...may as well lower overhead

I asked this question earlier... the OP said their stance hasn't changed but they are willing to entertain them for this issue...


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[polskifacet]

There is no other option unless they send me a device of their own to log. Also hopefully a sign that they are serious about finding out WTF is going on.

 

[Livernois Motorsports]

We have offered to have the customer bring the vehicle to us for a diagnostic test. At this point we are still believing this to be a mechanical issue but cannot confirm until we can go hands on with the vehicle. As it has been stated above, this is a rare instance, we have many of these vehicles out there without this issue with the same tunes. Both us and the customer are quite baffled by the instance but we are working diligently to not only pinpoint the issue but solve it as well.

 

[ZSHO]

We have offered to have the customer bring the vehicle to us for a diagnostic test. At this point we are still believing this to be a mechanical issue but cannot confirm until we can go hands on with the vehicle. As it has been stated above, this is a rare instance, we have many of these vehicles out there without this issue with the same tunes. Both us and the customer are quite baffled by the instance but we are working diligently to not only pinpoint the issue but solve it as well.

Thanks and due appreciate LMS taking there time and resources in resolving the OP issues once and for all.  Z  :thumb: :thumb:

 

[SHOdded]

Would love to see this resolved.  Internet opinions can only do so much LOL.

 

[derfdog15]

We have offered to have the customer bring the vehicle to us for a diagnostic test. At this point we are still believing this to be a mechanical issue but cannot confirm until we can go hands on with the vehicle. As it has been stated above, this is a rare instance, we have many of these vehicles out there without this issue with the same tunes. Both us and the customer are quite baffled by the instance but we are working diligently to not only pinpoint the issue but solve it as well.

Good on you LME, glad to see this, hopefully it gets resolved favorably!

 

[ZSHO]

Thanks to everyone who has offered there support on the Topic on hand but for the time being further discussions will continue as soon as we hear back from the OP,Thanks in advance.  Z

 

[ZSHO]

I would remind everyone to please keep your discussions grounded and straight to the point,and thanks for your cooperation. Z

 

[polskifacet]

Hey guys,
Huge shout out to AJP (*1000) for helping me out (dozens of emails back and forth) with a different tune(s) as well as FoMoCoSHO for sending me his SCT X3 to test with. How could I forget ZSHO!! For continued sanity checks.
The logs are available on my hosting site http://polskifacet.dynu.com:55698/uploader/uploads/Pictures/Logs/

AJP did end up alleviating the FRP with tuning magic but he is still convinced there is some other underlying issue. I feel like at this point I am at the mercy of LMS in finding this gremlin. I have done everything I could from my end that made sense, I don't feel any more part swapping will be efficient without fully understanding what is happening and I have obviously tried a different tune/tuner.

On the bright side, it was fun working with you guys, logging, trying different things. Thank you. Stay "tuned" for progress with LMS.

 

[MiWiAu]

AJP did end up alleviating the FRP with tuning magic but he is still convinced there is some other underlying issue. I feel like at this point I am at the mercy of LMS in finding this gremlin. I have done everything I could from my end that made sense, I don't feel any more part swapping will be efficient without fully understanding what is happening and I have obviously tried a different tune/tuner.

Thanks for the update! Some other underlying issue with hardware? The LMS tune? Did the AJP tune magic completely resolve the fuel pressure issue via "normal" adjustments, or was some sort of unique compensation required to resolve?

I guess what I'm getting at: were you able to completely rule out hardware and isolate the FRP issue to the tune?

Thanks again for updating!!


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[polskifacet]

From my understanding he did have to compensate. I will let him give facts.

 

[polskifacet]

Logged after R&R rear turbo boost side pipe and changing waste gate hose.

0to100
3rdGear

When looking at 0-100 and both LPFP and HPFP, they look to go up and down together. A drop of 20 psi on the lpfp equals something like 400 psi on the hpfp. Seems like the whole system is having trouble keeping up vs just the HPFP after the above mentioned repairs.