turbo LQ4 rev limiter weird stall, help a brother!!

[kylefentz]

Newbie requesting some brains. Build in my signature. cold under light acceleration bogs badly but my main concern is any time I get into it roughly 40% throttle or more it will studder exactly like a rev limiter but im no where near my set rpm. Ive searched and either cant find one that fits or get flat sidetracked (whoa a squirrel). My wideband reads way ricbh at 8-9:1 but if I let off slightly and get back into sometimes it will come out of it. I haven't felt a WOT pull in almost a month due to trying to tackle this myself but ive had enough. 60 psi vacuum line disconnected 58psi connected. My fuel trims are super lean and I believe my injectors are becoming clogged due to this resin like substance (rubber deteriorating) on/inside my injectors. I have a gang of these injectors until I can get some FIC'S but refuse to order anything until I figured this out. Feel like I may be leaving out info but any help would be greatly appreciated.

[5FDP]

Post your tune.

I noticed that you are already at 140kpa and still in closed loop, that is not good at all.

[kylefentz]

I apologize, still learning but I added it. thanks

[5FDP]

Change the PE so that is works with your MAP readings and not your foot. Because you can be way into boost but because you are no where near your throttle enable, it won't dip into your PE or BE settings.

Lower the pedal enable way down to like 40% and raise the PE enable to 90kpa, leave the BE enable at 110kpa. Normally you'd want your PE to be leaner than your BE because you don't need (in AFR terms) 11.7 commanded AFR at when it's NA nor do you need that much fuel when you are at 1-4psi of boost. Aim for 1.180 for PE, then plug 1.180 into the 100kpa cell of the BE. Highlight the 100-130kpa cells and click interpolate. Now you have fueling that gets richer as boost rises and will be at 11.7 commanded at 5+ psi.


Use your wideband to tune the VE table. I'm not sure how you ended up with your current VE but it's not very good. It's pretty much just a ramp instead of a curve. If you reference a stock VE, that is kinda how it would want to look.

I would disable all your fuel trims and closed loop. Get the wideband into the logs, create a wideband error against the commanded AFR/Lambda and use that error to correct the VE. Open loop is the only way to stop the computer from fighting itself until you fix what needs to be done.

[kylefentz]

once again I appreciate your knowledge and on the subject of that VE table...…..the "tuner" returned my truck to me like that. 99% of that tune was paid for in 100 dollar bills, yeah, I know. thanks dude

[kylefentz]

whewwww……...I understand I still need some fueling work but holy s**t this bastard is a rocket ship now, thanks homie

[kylefentz]

alright so the morning after making 5FDP's suggested changes I swore it was fixed, but now it seems to happen as I previously described only sooner, As in sooner per TPS. From the logs ive saved it seems, keyword seems, to happen after it warms up, an exact ECT I cannot give. Since I am commanding more fuel sooner, is it possible that this rev limiter thing I am experiencing is actually just to much dam fuel? My AEM x series wideband 30-0300 reads 8-9 afr when this is happening and even going 40mph you can smell the e85 after I let off. Im finding conflicting info on tuning VE per a SD e85 tune so is there a thread or sticky that is recommended with good info to follow once I do get my wideband in my logs. I recently purchased the pro feature set and already have the pro link cable (a friends) but since this truck is not a can bus equipped truck, isn't there another pass-thru cable that I need? If someone can please attach a link to this cable thatd be awesome as I cannot find it separate. Attached is the tune with the changes I made and a log of issue (time stamp 8:43:18) thank you again.5fdp suggestions plus dynamic hi rpm change.hptmore bulllshit.hpl

[kevin87turbot]

alright so the morning after making 5FDP's suggested changes I swore it was fixed, but now it seems to happen as I previously described only sooner, As in sooner per TPS. From the logs ive saved it seems, keyword seems, to happen after it warms up, an exact ECT I cannot give. Since I am commanding more fuel sooner, is it possible that this rev limiter thing I am experiencing is actually just to much dam fuel? My AEM x series wideband 30-0300 reads 8-9 afr when this is happening and even going 40mph you can smell the e85 after I let off. Im finding conflicting info on tuning VE per a SD e85 tune so is there a thread or sticky that is recommended with good info to follow once I do get my wideband in my logs. I recently purchased the pro feature set and already have the pro link cable (a friends) but since this truck is not a can bus equipped truck, isn't there another pass-thru cable that I need? If someone can please attach a link to this cable thatd be awesome as I cannot find it separate. Attached is the tune with the changes I made and a log of issue (time stamp 8:43:18) thank you again.5fdp suggestions plus dynamic hi rpm change.hptmore bulllshit.hpl

The VE table is really high. Usually the PE and BE is disabled when the VE table is populated like yours is.
Your long term fuel trims are disabled in your tune, but haven't been cleared with your scanner. I'd start by resetting them with your scanner and then you can get to work on dialing in the VE.

[kylefentz]

Sorry for the ignorance but your saying disable both boost and power enrichments, turn ON ltft?s, clear fuel trims then start over and base my results off my physical readings from my wideband (in the truck) even tho my wideband isn?t in my logs?? Thank you for your help.

[5FDP]

No, don't do that.

Your VE is still unchanged from before, that is part of your problem. You still have to take the time to tune the VE with the wideband hooked up. Your fueling is basically a ramp and not a curve. So as soon as the MAP rises it's just smacking it with fuel no matter the rpm.

Like I said before, look at a stock VE table and how it's shaped. In the end your VE table will look somewhat similar. If it was me I'd be taking a stock VE and more or less pasting it into your VE right now and then working the tune over from there.

[kylefentz]

Thats the kind of answer i was looking for. Again thank you.

[murfie]

How confident are you in this decapped injector value? Did you send them off to be tested?

The narrow band voltages to me indicate its very rich, comparing VE says it should be lean, getting your wideband in the logs would be very telling.

I'm attaching a sheet with what I would start with for a 2 bar VE table.

6.0 3gen 2 bar VE.xlsx

[kevin87turbot]

Sorry for the ignorance but your saying disable both boost and power enrichments, turn ON ltft?s, clear fuel trims then start over and base my results off my physical readings from my wideband (in the truck) even tho my wideband isn?t in my logs?? Thank you for your help.

No, don't turn on LTFT's and don't disable boost and power enrichments.
I was simply saying to use your scanner to reset the Ltft's.

You really need to get the VE table dialed in. 5FDP has given you some solid advice on this one. Just follow his suggestions.

[kylefentz]

im not confident at all in the injector I have. they were not flow tested they came straight from the junk yard, to the Dremel tool, to the truck. I had some 903's that were flowed which is what im basing my values on but I removed them due to this sticky black resin shit that was on the end ( which these have it too). I need a new fuel system I get it but when people say build a VE table, okay sure, wheres the thread on that because I sure don't see it. I understand I need some FIC'S or something with actual data but I was hoping to learn how to tweak this thing before I spend a grand on injectors. Trust me this thread will end one day with a beautiful VE table and HP numbers specifically some new guys like myself can learn from threads instead of running into dead ends which this forum is filled with. I will load this tune and get back with all of you. thank you very much for your input, it is beyond respected. I also did get my prolink going and my signals will be boost (AEM x series) and wideband (AEM 30-0334). STAY TUNED

[murfie]

Yeah, if you're not confident in the injector data, start with a good guess based on the stock VE table, stay in the high side, but reasonable. modify the injector data(flow rate vs KPA) to get fuel where it should be. This will keep your load and cylinder air mass some what in the ball park. So many other table depend on those and if they are way off it can put things in a dangerous condition. you will need a user math of BAro minus MAP both in KPA to popluate the axis of a grph, and fuel trims in the graph to tell you where the flow rate needs to go.

You should be able to idle and drive the car staying in closed loop, it of boost and open loop conditions, and find your injector flow rate for nearly all the MAP pressures. This should show you a pattern that you can trend into the higher MAP pressures.

Once you have that you can then make small adjustments to the VE table based on injector data you are confident in.

No matter how much boost you add to an engine 105%VE+ is just not likely to be happening. Air flows only when there's a pressure difference and getting 5%+ more air that you expected from the pressure difference just isn't realistic. The only thing that causes this is the injector values being higher than they really are.

[5FDP]

In the giant ocean of the internet and youtube video's I'm sure there are things out there about creating a VE table.

Our main point was that the VE that was in the first tunes in this thread are the complete opposite of how they should be. When you look at VE table of a stock 5.3/6.0 engine for example, it does not just start at a value and take off like a ramp for a bike jump. There is a "curve" or a slope it takes as rpm and kpa rise.

Even when you add boost, the shape of the VE will be very similar. Use the 3D graphs in the editor to look at the shape it gives. Depending on injector size and fuel pressure will also determine what the values in the table will be. You can have different tunes where the VE will be much different in numbers but the same similar look will be the same.

I don't have the ability to alter peoples tunes because I only have the original MPVI and not the MPVI2, so I can't change it to show you that way. But it should look sorta like this.

2020-04-11.png



Here what I want you to do. Open a stock 5.3/6.0 tune, highlight the entire table. Right click and copy with axis. Go into your tune, highlight the whole table, right click and paste. Now it will have copied over the 15-100 matching rows. Then highlight the 100kpa row and paste that row into the 210 kpa row. With the 210 kpa row still highlighted, in the blank box at the top type in 10 and click the + icon.

Now highlight from 100-210kpa and click interpolate between vertical bounds. That will create the rest of the table for you with the same exact shape as what where there. It is completely possible that the values there are too rich for the size injectors you have. So you may have to highlight the entire table again and remove anywhere from 10-30% worth of fuel just to give you a good starting point. From there you will be using the wideband with a wideband error that will tell you where in that VE it is too lean or too rich. Those corrections will be applied to the table and smoothed out to make it nice and neat.

[kylefentz]

Alright boys and girls, finally got some FIC 1200cc injectors with solid data with a magnafuel boost referenced regulator and 8AN hose front to rear, no splices or brass barbed restricted bullshit. I rented some dyno time with some help from a very kind local tuner and put out 539 hp with this tune and got a decent log today of street driving. truck pulls hard and will paint stripes on demand. I guess this could be a " critique my tune" post but really im posting to finalize a thread. Initially after the injector install I added 30% to my VE and I gave up because I didn't see a change in my fuel trims, once at the tuners he added 30 more percent and values started changing. If anyone is a newbie at this like I am my suggestion to you is DO NOT GIVE UP. keep trying and don't be afraid to ask for help, because in the end when your doing 1000 ft rolling burnouts you will be happy you did.DPT Final Tune.hptcharlie log.hpl

[ryan_axberg]

You have your stoich AFR set to 19.78, should be 14.7

[kylefentz]

big injectors you have to double the stoich and half the injector flow rate.

[5FDP]

No you don't. Not on these computers. The injector flow rate allows for 254lb/hr injectors and those 1200cc's are no where close to that.

With the proper data installed there is no reason to touch the stoich or half anything flow rate related.

But you already went that far and tuned the whole thing so it doesn't matter now, keeping it as it is should be fine.