lean area around 2500ish rpms-2014 ctsv

[sgod1100]

Ok, had a quick look at log. Definitely the same spike as me.

In the log, your hitting 28g/s fuel flow around 2850rpm. You're switching to normal flow around the 25-26g/s I suggested, but that's still too soon in this log.

Try setting low flow upper to 29g/s in 2800rpm and all the cells below make say 34g/s, above 2800rpm can stay stock. Change the low flow lower to match the 5g/s drop as mentioned before. Takes a bit of fine tuning to pick your spot when you want it to switch. If you make the cells below 2800rpm a high number, in winter/summer/all conditions the change to normal flow won't happen until 2800rpm or more. Same goes for cells above 2800rpm, if they're a lower number (like stock values), then as you pass 2800rpm the fuel requirement for the switch becomes less. Helpful in summer, and keeps everything centered around the 2800-2900rpm.

If want to switch even later, just look at your logs and work out how high you need the values before the switch, and how low you need the values after the rpm you want to switch. Basically choose an rpm, check multiple logs for fuel flow at that rpm, make numbers high before the rpm you want, and numbers low after rpm you want.

Also, majority of my tests are done in 4th gear, and WOT anywhere from 1200-2000rpm. Feel sorry for the clutch and engine, but really helps to see the lean spots and switching when they're unaffected by transient.

Unsure if 3rd gear WOT would have vastly different fuel flow, but just check your logs and choose a fuel flow and rpm above 2800.

Forgot to mention as well, I changed my Hot Fuel Soak and Hot Fuel Pressure to match the lower pressure.

Screenshots of all that's needed for the fuel switching and pressure, and also my openloop DC.
Attachment 136487

Yeah, I did notice that I was at a higher flow than the 25 g/s that I put in. Im just stumped at why my fuel pressure didn't go down to 45 psi. If you look at "requested" and "desired" in the channels they both say 45 psi, but the pressure is still at 50 psi. I'll try matching the hot tables as well. And yeah, I was in 3rd gear...i HATE flooring my car at low rpm while in 4th..

[sgod1100]

Attachment 136489Attachment 136488Attachment 136490

ok, I feel like an idiot...i cannot get the FP down to 45 psi even though that's is what is being requested. WTF am I missing?? lol. Current tune with a log STILL showing FP at 50 psi. I didn't do any WOT on this log as I wanted to figure out why my fp is not dropping to 45 psi.

FP still at 50 psi.hpl2.35 pulley, ID1050Xs, CURRENT TUNE-FLEX FUEL.hpt

[JayRolla]

So I went through all my old logs. I did my headers, xpipe, removed rear o2s and wbo2 all at the same time. Was still on stock injectors. I started the car before disabling the rear o2s and got the permanent rear o2 code that I have read can cause issues. I cut one of my rear o2s so couldnt install them to get rid of that code. This is when I noticed the hesitation at 2500rpms. Then since I had a wbo2 I noticed it was a lean spike. I am positive the issue started as soon as I did the headers/xpipe/rear o2 removal.

Sgod I wonder if we get a set of rear o2s connected, enable them in the ecu, and see if that helps the test that might be causing our issue. I don't think it's an IDC issue since it happens in e85, pump gas, your 850s, now 1050s and even on my stock injectors. Unfortunately I think for the code to pass it needs good cats installed or a way for us to trick them with maybe a resistor of some sort.

[PGA2B]

Nope, I have mine installed and ran with and without them turned on and still have it.

[sgod1100]

ok, I feel like an idiot...i cannot get the FP down to 45 psi even though that's is what is being requested. WTF am I missing?? lol. Current tune with a log STILL showing FP at 50 psi. I didn't do any WOT on this log as I wanted to figure out why my fp is not dropping to 45 psi.

FP still at 50 psi.hpl2.35 pulley, ID1050Xs, CURRENT TUNE-FLEX FUEL.hpt

please dis-regard my fuel pressure issue...i'm definitely an idiot as I wasn't flashing the fscm when i flashed the new tune...smh. I am now able to get the fuel pressure down to 45 psi

[sgod1100]

So I went through all my old logs. I did my headers, xpipe, removed rear o2s and wbo2 all at the same time. Was still on stock injectors. I started the car before disabling the rear o2s and got the permanent rear o2 code that I have read can cause issues. I cut one of my rear o2s so couldnt install them to get rid of that code. This is when I noticed the hesitation at 2500rpms. Then since I had a wbo2 I noticed it was a lean spike. I am positive the issue started as soon as I did the headers/xpipe/rear o2 removal.

Sgod I wonder if we get a set of rear o2s connected, enable them in the ecu, and see if that helps the test that might be causing our issue. I don't think it's an IDC issue since it happens in e85, pump gas, your 850s, now 1050s and even on my stock injectors. Unfortunately I think for the code to pass it needs good cats installed or a way for us to trick them with maybe a resistor of some sort.

that's initially what I thought but PGA2B burst my bubble on that one (real nice pal...lol). Like he stated above he has them connected and tried both ways (enabled and disabled) and still has it. I do think it definitely has something to do with it though because, like you, mine started right after I removed my cats and installed the I.D 850s. I even disabled them BEFORE I started my car. I didn't realize you noticed it on the STOCK injectors....hmmm....I never drove mine on the stock injectors after I removed my cats..it was straight to the ID850s

[sgod1100]

Interesting how, for me at least, just a few extra % IDC can shrink the lean spot down.

On a few logs, I?ve seen the surrounding areas go a tad rich. I think I pulled a bit out of the VVE peaks and smoothed the transition into and after the peaks.

Did another log tonight at 45psi, and 2000-3000rpm WOT nice and smooth, maintaining commanded PE.

No help for the part-throttle 2000-3000, still lean as before. I think I?d have to be running pretty low fuel pressure to clean up the part-throttle PE EQ error, and no chance in closed loop (although I don?t notice this much).

GHuggins, I?m sure you?d be knowledgeable on this. 45psi with 10-15psi boost leaves a pretty poor 35-30psi delta pressure. Have you run them this low, or gone lower?

What I found is when I lowered the pressure down to 45 psi and did a part throttle PE pull the lean spot actually got WORSE due to the lower fuel pressure (that's what it looks like to me anyway). Go to 2:13 sec.....I've never seen the lean spot over 20% before. Now I'm wondering if I should go the opposite direction and increase the low flow pressure

FP 45 psi and part throttle PE.hpl

[L1FTD]

What I found is when I lowered the pressure down to 45 psi and did a part throttle PE pull the lean spot actually got WORSE due to the lower fuel pressure (that's what it looks like to me anyway). Go to 2:13 sec.....I've never seen the lean spot over 20% before. Now I'm wondering if I should go the opposite direction and increase the low flow pressure

FP 45 psi and part throttle PE.hpl

Very interesting stuff. I?ll post some good logs of mine in different states of tune.

Not sure why yours wouldn?t take the fuel pressure changes straight away, majority of tables are in the ECM. Anyway got there now and it didn?t help, sorry about that. I?ll compare your log to mine and see if we?re doing the same thing.

I?ve tried engaging high flow 65psi at 90kPa when I enter PE. Did make the car feel a bit smoother (maybe in my head) but the lean was still the same for me. Might work for you.

Did think how some of you guys must be running E85, and sgod1100 having the problem with ID850s. IDC would already be up with that. No idea why mine is behaving differently the more I get any IDC up.

1600 & 2600rpm feature heavily in the factory LSA tunes. Constantly popping up with different requirements to the rest of rev range. VVE humps from factory, torque model drops, etc. Is the only common thing we all have, the factory LSA cam? LS9 is a reasonably similar engine but doesn?t seem to have this issue either

[L1FTD]

Here are a couple of short pulls from last night, and one from the other day with pressure higher.

You can see how part-throttle the lower fuel pressure does nothing, WOT the AFR is pulled back inline.

Maybe I'm just masking the problem via more IDC. Majority of other things tried, the lean spike has still been there, either a bit better or worse. Changing the pressure it appears it doesn't even try to spike anymore.

The AFR does spike a bit when I change to normal flow and the pressure overshoots. I've noticed switching to normal flow even later (2900-3200), the pressure overshoot reduces the higher I go. That being said, I don't like running low flow anyway, would much rather run 55-65psi any time in boost.

I tried zeroing the VE reversion stuff one time. Funny that those tables, in LSA form, have a value of 1600 (is it 1600rpm? the first of the lean spikes), and then LS9 has those tables zeroed. When I zeroed them, the lean spikes were completely gone and I was running richer. Tried again the next day and the spikes were back.

Same thing for misfire detection, those values start (aren't maxed) from 1600rpm. Disabled misfire detection, and I had no lean spikes and I was a bit richer. Tried again the next day and spikes returned.

Be nice to see someone with an LS3 with LSA blower, and someone with an LS9, both running no cats, stock cam, ID1050's.

Short WOT and part-throttle PE + 45psi + PE 11.5.hpl
WOT and part-throttle PE + 45psi + PE 11.5.hpl
WOT running hot fuel condition 55-60psi.hpl

[L1FTD]

Another couple of logs from today.

Played with pressure more. This time setting low flow 40psi, normal flow 45psi, high flow 65psi. Low > normal switch around 1800rpm WOT, normal > high switch around 3000rpm WOT.

Trying to get a higher IDC for the 1600rpm lean spot, and staying in 40psi for the part-throttle 2600rpm. Seems to have helped 1600rpm WOT slightly, and part-throttle 2600rpm improved as long can stay in 40psi. Downside is a leaner heavy tip-in, would need to make the switch from low > normal happen quicker above 1800rpm. For reference, the earliest LSA tunes had 36psi low flow pressure. Obviously revised their thinking and bumped it 50psi.

Again, none of this will help with the closed loop or light part-throttle. The heaver the part-throttle, the more this has helped me. Very light part-throttle into PE isn't changing the lean spike much.

In the 30min. log, I had changed Injector Off-Time (Fuel>General>ECM 45524), down to Min. Pulse for ID1050x. Have set this to zero before, same result.

Result is richer everywhere, would be interesting to see if re-tune airflow for the injector off-time would make any difference. A post from DSteck I found, from many years ago, has ID recommending a minimum of 0.75 for this parameter.

https://forum.hptuners.com/showthrea...se-width-table

Short log is with the same tune, only thing changed is Inj. off-time back to stock.

30min. 40psi-45psi-65psi + Inj. off-time 0.297.hpl

40psi-45psi-65psi + Inj. off-time stock.hpl

[sgod1100]

Very interesting stuff. I?ll post some good logs of mine in different states of tune.

Not sure why yours wouldn?t take the fuel pressure changes straight away, majority of tables are in the ECM. Anyway got there now and it didn?t help, sorry about that. I?ll compare your log to mine and see if we?re doing the same thing.

I?ve tried engaging high flow 65psi at 90kPa when I enter PE. Did make the car feel a bit smoother (maybe in my head) but the lean was still the same for me. Might work for you.

Did think how some of you guys must be running E85, and sgod1100 having the problem with ID850s. IDC would already be up with that. No idea why mine is behaving differently the more I get any IDC up.

1600 & 2600rpm feature heavily in the factory LSA tunes. Constantly popping up with different requirements to the rest of rev range. VVE humps from factory, torque model drops, etc. Is the only common thing we all have, the factory LSA cam? LS9 is a reasonably similar engine but doesn?t seem to have this issue either

No need to apologize, as I appreciate you brining this to the table. Reviewing your logs it definitely got rid of the lean spot during WOT. Just wish there would be some way to get rid of it at part throttle as well

[sgod1100]

Here are a couple of short pulls from last night, and one from the other day with pressure higher.

You can see how part-throttle the lower fuel pressure does nothing, WOT the AFR is pulled back inline.

Maybe I'm just masking the problem via more IDC. Majority of other things tried, the lean spike has still been there, either a bit better or worse. Changing the pressure it appears it doesn't even try to spike anymore.

The AFR does spike a bit when I change to normal flow and the pressure overshoots. I've noticed switching to normal flow even later (2900-3200), the pressure overshoot reduces the higher I go. That being said, I don't like running low flow anyway, would much rather run 55-65psi any time in boost.

I tried zeroing the VE reversion stuff one time. Funny that those tables, in LSA form, have a value of 1600 (is it 1600rpm? the first of the lean spikes), and then LS9 has those tables zeroed. When I zeroed them, the lean spikes were completely gone and I was running richer. Tried again the next day and the spikes were back.

Same thing for misfire detection, those values start (aren't maxed) from 1600rpm. Disabled misfire detection, and I had no lean spikes and I was a bit richer. Tried again the next day and spikes returned.

Be nice to see someone with an LS3 with LSA blower, and someone with an LS9, both running no cats, stock cam, ID1050's.

Short WOT and part-throttle PE + 45psi + PE 11.5.hpl
WOT and part-throttle PE + 45psi + PE 11.5.hpl
WOT running hot fuel condition 55-60psi.hpl

Regarding the reversion table, in stock form I'm pretty sure those tables are zero'd out. I did try using ZL1 values for those along with zl1 prediction coefficients and lean spot was still there. I noticed that too regarding the misfire detection, but I didn't change them as I didn't think they were connected in anyway to the fueling, but ya never know..

[sgod1100]

So I went through all my old logs. I did my headers, xpipe, removed rear o2s and wbo2 all at the same time. Was still on stock injectors. I started the car before disabling the rear o2s and got the permanent rear o2 code that I have read can cause issues. I cut one of my rear o2s so couldnt install them to get rid of that code. This is when I noticed the hesitation at 2500rpms. Then since I had a wbo2 I noticed it was a lean spike. I am positive the issue started as soon as I did the headers/xpipe/rear o2 removal.

Sgod I wonder if we get a set of rear o2s connected, enable them in the ecu, and see if that helps the test that might be causing our issue. I don't think it's an IDC issue since it happens in e85, pump gas, your 850s, now 1050s and even on my stock injectors. Unfortunately I think for the code to pass it needs good cats installed or a way for us to trick them with maybe a resistor of some sort.

fyi, I decided to try and re-enabled COT protection, but just set the temp thresholds high and no dice, lean spot is still there

[sgod1100]

Guys I have a question, so I was wanting to test low flow pressure at 60 psi, however when i change the low flow to 60 it defaults to basically 80psi with the DC of the pump stuck at 100%. I was able to increase it to 55psi with no issue, but the minute i try 60 it gets stuck at 80psi. It normally would come back down to commanded but it never did. Do I have to mess with the "regulation pressure" table or something to get the pressure down to 60?

Also..one thing to note is looking at this log if you go to 8:14 notice i'm in partial PE and the lean spot is NOT there at 2600 rpms....

FP stuck at 80psi with a commanded of 60 psi.hpl

[L1FTD]

Guys I have a question, so I was wanting to test low flow pressure at 60 psi, however when i change the low flow to 60 it defaults to basically 80psi with the DC of the pump stuck at 100%. I was able to increase it to 55psi with no issue, but the minute i try 60 it gets stuck at 80psi. It normally would come back down to commanded but it never did. Do I have to mess with the "regulation pressure" table or something to get the pressure down to 60?

Also..one thing to note is looking at this log if you go to 8:14 notice i'm in partial PE and the lean spot is NOT there at 2600 rpms....

FP stuck at 80psi with a commanded of 60 psi.hpl

That's strange, never seen my pressure that high.

I'm guessing if you've set low flow to 60psi, and left normal flow at 60psi, it doesn't like it and has gone into a default max. pump/max. pressure mode.

When I've increased pressure, I've just set normal flow to come in early. You shouldn't have to touch or flash any tables in the FSCM for the pressure changes. Maybe only when lowering it down a lot, think there's a minimum desired pressure table in there but not sure if it even gets used.

If you want to try, just set the low flow upper to like 4g/s in every cell, and low flow lower to 3g/s every cell. This will force you into normal flow (60psi) whenever you're above 4g/s. Won't take much throttle to do that.

Same for if you want to go into 65psi very early. Set low flow upper down to like 2g/s every cell, high flow upper down to 5g/s every cell (go 1g/s low flow lower, 4g/s high flow lower). The pump will be ramping up and down constantly, but you'll be able to see if more pressure helps straight away.

I looked at your log, to my eye, seems the issue is still there. You're richer everywhere with such high pressure, but the spike still comes in, just doesn't go above commanded EQ because of the overly rich condition. Have a look at 1:42 & 2:51.

[L1FTD]

Just for comparison, here are a couple from today.

Tried low flow down to '09 CTSV 36psi, 45psi normal, 65psi high.

Running a bit richer due to mucking around with those reversion and misfire settings again. Tried many combinations, does nothing for the spike, waste of time again

The 36psi seems to have smoothed the 1600rpm spike, just as the 45psi smoothed the 2600rpm.

One log shows me running around 50psi, spikes present. Other log shows when pressures are down lower, spikes smoothed.

Again, sorry, nothing for the part-throttle. I know that's what you're really chasing

Try setting your Manifold Volume 10% less than stock. I went lower than stock today, trying to help the lean tip-in with lower pressures at low rpm. Helped quite a bit, going to muck around more with the low pressures and transients.

Hot fuel 50psi WOT + Part-throttlle + PE 12.hpl

36psi-45psi-65psi WOT + Tip-in.hpl

[sgod1100]

That's strange, never seen my pressure that high.

I'm guessing if you've set low flow to 60psi, and left normal flow at 60psi, it doesn't like it and has gone into a default max. pump/max. pressure mode.

When I've increased pressure, I've just set normal flow to come in early. You shouldn't have to touch or flash any tables in the FSCM for the pressure changes. Maybe only when lowering it down a lot, think there's a minimum desired pressure table in there but not sure if it even gets used.

If you want to try, just set the low flow upper to like 4g/s in every cell, and low flow lower to 3g/s every cell. This will force you into normal flow (60psi) whenever you're above 4g/s. Won't take much throttle to do that.

Same for if you want to go into 65psi very early. Set low flow upper down to like 2g/s every cell, high flow upper down to 5g/s every cell (go 1g/s low flow lower, 4g/s high flow lower). The pump will be ramping up and down constantly, but you'll be able to see if more pressure helps straight away.

I looked at your log, to my eye, seems the issue is still there. You're richer everywhere with such high pressure, but the spike still comes in, just doesn't go above commanded EQ because of the overly rich condition. Have a look at 1:42 & 2:51.

Yeah you are right , I didn't catch that. I did notice that having the pressure at 55 psi the lean condition was less pronounced as far as feeling goes. When I couldn't get the pressure to drop down to 45 psi it was because I had my min desired in the fscm set at 50 so that wasn't allow me to drop the low flow pressure below that. Gotta love trying so many things and NOTHING seems to completely fix the problem...lol.

[sgod1100]

Just for comparison, here are a couple from today.

Tried low flow down to '09 CTSV 36psi, 45psi normal, 65psi high.

Running a bit richer due to mucking around with those reversion and misfire settings again. Tried many combinations, does nothing for the spike, waste of time again

The 36psi seems to have smoothed the 1600rpm spike, just as the 45psi smoothed the 2600rpm.

One log shows me running around 50psi, spikes present. Other log shows when pressures are down lower, spikes smoothed.

Again, sorry, nothing for the part-throttle. I know that's what you're really chasing

Try setting your Manifold Volume 10% less than stock. I went lower than stock today, trying to help the lean tip-in with lower pressures at low rpm. Helped quite a bit, going to muck around more with the low pressures and transients.

Hot fuel 50psi WOT + Part-throttlle + PE 12.hpl

36psi-45psi-65psi WOT + Tip-in.hpl

So did you max out all of your mis-fire tables and it fixed the lean spot initially? I thought that's what you mentioned before. I've never messed with any of the mis-fire tables before

[sgod1100]

Just for comparison, here are a couple from today.

Tried low flow down to '09 CTSV 36psi, 45psi normal, 65psi high.

Running a bit richer due to mucking around with those reversion and misfire settings again. Tried many combinations, does nothing for the spike, waste of time again

The 36psi seems to have smoothed the 1600rpm spike, just as the 45psi smoothed the 2600rpm.

One log shows me running around 50psi, spikes present. Other log shows when pressures are down lower, spikes smoothed.

Again, sorry, nothing for the part-throttle. I know that's what you're really chasing

Try setting your Manifold Volume 10% less than stock. I went lower than stock today, trying to help the lean tip-in with lower pressures at low rpm. Helped quite a bit, going to muck around more with the low pressures and transients.

Hot fuel 50psi WOT + Part-throttlle + PE 12.hpl

36psi-45psi-65psi WOT + Tip-in.hpl

From what I've been experiencing we need high pressure during part throttle conditions and lower pressure during wot conditions...lol

[L1FTD]

Yeah you are right , I didn't catch that. I did notice that having the pressure at 55 psi the lean condition was less pronounced as far as feeling goes. When I couldn't get the pressure to drop down to 45 psi it was because I had my min desired in the fscm set at 50 so that wasn't allow me to drop the low flow pressure below that. Gotta love trying so many things and NOTHING seems to completely fix the problem...lol.

Ok yeah that?s the one. Should be only one you need to touch in FSCM if you?re changing pressure.

I?ve lowered mine to 200kPa, was 300kPa stock, and changed my Openloop DC for BAP. Only two things touched in FSCM, the rest ECM.