Need help diagnosing AIR/FUEL problem.

[Don_G]

My truck suddenly started idling very lean. It was throwing no codes, but I had been suspicious of the TOY AFR sensor for a while. The truck had tended to run at 15.3 AFR on my WEGO III wideband, when the ECU was in closed loop mode and the OBD was reporting a steady 14.7. Suddenly Tuesday it started running at 18-19 AFR - and stumbling a lot.

I replaced the studs in the AFR sensor mount (one was broken) - no help.

I replaced the Toyota AFR sensor ($250 counting tax.) No help.

I checked the AFR wiring tonight - all good.

The only thing left on the trouble-shooting chart is the dreaded "replace ECM".

Anybody got a 2001-2004 3rz 4wd std trans ECM they will let me try to see if that's really the problem? I can swap it in and out and get you back on the road in less than an hour.

[AxleIke]

Wow new trucks suck. Used to be you could fix that with a screw.

Good luck man. You've had a rough time of late.

[Don_G]

:violin:

"If it weren't for bad luck I'd have no luck at all,

Gloom, despair and agony on me!"

What can I say, I'm old and my old man liked to watch HeeHaw! :boobies:

(Although I'm very sure the hooters were more important than the music!) :D

[hanksyota]

Don,
i wish i could help you, but im so damn confused. (enter tc, "it doesnt take much")

[00regcab]

first off.

is the urd kit tunable?

if it is, do you know how to tune it?

is it running 18-19 only at idle? or throughout the rpm range?

ideal is 14-15.5, youd probably even be safe with 16.

[Don_G]

first off.

is the urd kit tunable?

if it is, do you know how to tune it?

is it running 18-19 only at idle? or throughout the rpm range?

ideal is 14-15.5, youd probably even be safe with 16.

Yes, the URD is tuneable. Yes, I know how to tune it. It is running at very high AFR ratios across all RPMs and flow rates while the system is closed loop. When the system goes open loop the ratios drop to where I had tuned them with the additional injector. Long story.

I checked the operating AFR with a wideband WEGO III before I installed the URD stuff (Additional Injector controller with Timing control (AICTC) and AFR Calibrator (AFRC)). The stock system was running at 15.3 closed loop. I used the AFRC to set it to 14.7. This required an AFRC setting of 9.1. Gadget told me this was highly unusual and that there was something wrong with my truck. I told him that it'd been running faultlessly, and that it was probably just a bias in the sensor. I tuned it all up anyway, and tuned the AICTC for open loop response as well. I noticed within a week that my idle (and low-load closed-loop cruise) AFR had moved back up to 15.2 or so. Tuesday I saw that the idle AFR was up to 18 and higher, and the OBD II showed that the fuel trims were greatly negative (-20% ; consistent with an 18 AFR operating point. ) I took the AFRC out of the loop and the AFR pegged to 19.5, showing that the AFRC was still working. (At 19 AFR the engine stumbles at idle, just as you'd expect.) I connected the AFRC back up and had to use a setting of 4 to get an AFR of 14.7. Gadget says this is unheard of.

The WEGO III wideband AFR is freshly calibrated (and it calibrated to free air at the same potentiometer setting as before.) The WEGO III AFR meter also shows all the correct ratios when the system switches to open loop. It also matched the dyno AFR within 1/2 point - the dyno tailpipe AFR showed 0.5 leaner, as you'd expect.

The closed loop system is failing rapidly, and will probably not be driveable past the weekend the way it is going south. One operating hour after I set the AFRC to 4, the resulting closed loop AFR had leaned out from 14.7 to 15.0.

It is throwing no codes unless I let the ratio stay at 19.5 for a long time, then it sees that the rear O2 sensor has not flipped state (from lean to rich) for a long time, and says the O2 sensor is bad. (But it's not, it toggles right nice at an AFR of 14.7, just like it should.

I am not convinced that the fault is in the ECM or the Toy AFR. I am afraid it is some long-term adaptive response of the ECU to some other fault. If I had an ECU to try for an hour I could tell for sure. I can't even find the cost of an ECU, but I'm sure it is a Hellacious number: and I have no confidence that a new ECU will fix the problem. Gadget suggests swapping ECUs to find out.

EDIT TO ADD: The original ECM part number is 89661-04B20, this has been superceded by 89661-04B21 and sells for $550.00 plus tax online. $660 at the local dealer.

[ziggy428]

sorry, mines too old. good luck to you though. Thats why I like working on dirt bikes. You can just switch jet numbers. Todays auto computers make me want to :suicide:

[Turbo4Runner]

Oh come on fella's, its just a computer.. They are your friend, I promise.. :)

Have you checked to confirm you do not have a vacuum leak after the Air flow meter (like TB gasket or intake gasket? Some stock paper gaskets do not hold up well to boost). Also, is there any change to o2 readings under WOT?

I highly doubt the ECM failed unless you recently put the truck in the drink. I'd lean more towards vacuum leak if you are richer under WOT then you used to be, i'd say clogged injector if its leaner under WOT.

Closed loop won't tell you much other then whatever the problem is its small enough to compensate for it to get you back to 14.7:1. That's kinda why i'm leaning towards a leak.

Good luck!
--Ben

[Quick Draw]

sorry, mines too old. good luck to you though. Thats why I like working on dirt bikes. You can just switch jet numbers. Todays auto computers make me want to :suicide:

x2... I can do anything with a dirt bike....just keep me the hell away from computers!

[Don_G]

To save me some typing, here's what I sent gadget this AM:

**************
Gadget,

I took the ECM out last night to get the part number.

This morning I put it back in, with the AFR Calibrator left out of circuit.

The Toyota closed loop operating point is now at 14.5-14.7. The only thing I can think of is that I was not removing the power long enough to reset the ECM before now. Obviously the latest Toy A/F sensor is in the proper range.

Still, I'm afraid there must be some control-loop function that will again get perturbed if I go back to the same AFR Calibration profile. I was trying for 14.3 AFR at idle and no-load, transitioning to 12.7 AFR at zero MAP and higher.

I am wondering if the ECM in my truck is watching the bank one sensor two (rear O2 sensor) transitions, as well as the front A/F sensor that the AFRC twiddles. If so, maybe your rear O2 simulator would be of benefit?

Have you any examples of other 2.7L w/ Toy A/F sensor AFRC maps that I can look at?

Is there any history in this year-model (2004) of AFRC maps where you tried to set the closed loop idle and cruise AFR to 14.3 or lower? I believe at these AFRs the rear sensor will only transition to lean under deceleration, which may not be often enough.

You have said before that you've seen problems if you set the AFRC map below "7". Is "7" the right number, or was it some fraction higher than 7.0? What AFR did this "setting floor" yield? Looking at the typical Toy sensor I think the slope looks reasonable down to 12.5 AFR, hence my lowest target closed loop AFR of 12.7. Is this too low? I guess this whole paragraph is an attempt to elicit the practical control range of the AFRC.

Thanks,
Don
*****************

Ben, no vacuuum leaks - I went down that road exhaustively many days ago. Keep thinking, though. I obviously need all the help I can get.

[Don_G]

Here's the response from URD (Brian, not Gadget):


*********

Don,

What is the lowest number in your AFR map? I think you are trying to richen it up too much too soon.

Brian
*****************

I hope I get a response from Gadget that answers at least ONE of my questions!

[RedRunnertc]

Have you checked the MAF sensor? Could need to be cleaned. The gunk will make it think there's less air than there really is (the crap acts as insulation, so it takes less voltage to make the temp), so it's cutting the fuel to accomodate ... but then I don't know squat about forced induction...

[00regcab]

closed loop doesnt matter really, that seems like something in the main ECU/M over the URD controller, as the o2 sensors control all closed loop action.

Do you have the OEM o2 sensors still hooked up and in the exhaust pipe? If you do not, thats what would be causing this in closed loop mode.

a piggy back system (like the urd controller) will not have closed loop tuning capabilities.

My car runs ungodly rich closed loop, but open loop its fine. Its just the way piggy back systems work.

[Don_G]

Yep, MAF has been checked and needlessly cleaned. Air flow as logged by my OBDII is very smoooth and matches expectations. When I hit full boost at 5500 RPM I am running 20 pounds per minute - roughly 1.5 times the normal sea level max flow, which matches with the reported 8 PSIA max MAP pressure. For comparison, the local air pressure shows -2.5 to -3 PSIA (-5 to -6 in Hg.) That 2" pulley made a big difference! Very smooth and repeatable flow at idle, too -0.36 at 630 RPM to .43 at 750 RPM.

I think I'm seeing some long-term integrated ECM response to the loop disturbances introduced by the AFR Calibrator. I suspect that the richer AFR settings cause the rear O2 sensor to not toggle often enough (it switches from Hi to Lo output voltage as the cat output switches from rich to lean. Since the cat output will always be rich if I'm trying for 14.3 at cruise, then it may integrate up a correction factor that I can't see on the OBDII - only the results thereof. Since it took 2 weeks to ramp out of practical operating range any experiments will take a long time. That's why I want to get some answers from Gadget.


I think it significant that after an ECM reset and leaving the URD AFRC out of the circuit, the closed loop response sits nicely at 14.6 and appears stable at idle and cruise. I'll bet it'd be happy for weeks without integrating up to a problem, but I don't really want to be tuning this thing for more months. One month has been expensive and tiring enough.

When I ask what I think are simple questions relating to control range and typical settings, I get platitudes like "don't be abrupt", and "don't try to go so far". But I never get any definitive answers like "don't try to go below 13 AFR" or "don't change more than 0.x AFR between adjacent cells."

I am afraid that the useful control range of the AFRC will be pretty small. I had wanted to use it to blend from 14.3 AFR at cruise to 12.7 AFR under max closed loop load, then to 12 AFR open loop. Right now looks like I may not be able to choose any other cruise/idle mixture other than 14.7, and may only be able to blend to 13.5 max closed loop. Sort of defeats the purpose of buying a $230 AFR Calibrator if you have no useful control range.

[00regcab]

wait a minute, youre running a twin screw type supercharger and youre not hitting full boost until 5500?

somethings wrong there.

[Turbo4Runner]

^^^ x2 on that.. I hit full boost way before that! Isn't there a supercharger vs. turbo thread around here somewhere...? :D

You said "suddenly" which makes me think there was no known change, correct? So something is operating differently then before...

That makes me think that any result you get from tuning adjustments is just covering something up.

Have you by any chance been able to log injector pulse cycles before and or after?

[thefatkid]

If you are trying to tune durring closed loop operations (and trying to richen it) it will sway all closed loop fuel trim to a leaner mixture. You can't fool the toyota ECU unless they have that built into the URD tuner. AFCs usally fool the MAF to richen or lean the fuel mixture, not the Air fuel raito sensor. Try only tuning durring Open loop driving (80% throttle or better) and see what happens.

On a side note I perfer tuning with the SMT system. For me it is more user friendly.

[Don_G]

Brian,

The whole purpose of the URD AFR Calibrator is to let you tune the closed loop response of your truck. AFR Calibrator (http://www.urdusa.com/product_info.php?products_id=1230100028) It controls the Toy AFR output to the ECM. Having said that, Gadget told me tonight not to try any tune commands smaller than 6. Now 10 is a neutral 14.7 AFR, 6 worked out to be 13.5 on my truck. So my fears seem to be realized: I paid $280 to be able to control my Air Fuel Ratio a whopping 1.2 ratio points. Woo fucking Hoo.

Considering that Gadget himself says that best power is arrived at by 12 AFR at WOT or even 10 under full boost, then that leaves a whole lot of low RPM performance unrealized. The closed loop response is very important because ITS A FUCKING TRUCK FOR GOD"S SAKE and the Toy ECM stays closed loop for about 14-15 seconds after you floor it below 4000 RPM. So when you hit a soft spot at 2000 RPM in 2nd gear, instead of going straight to a 12:1 AFR and max power, I will be stuck at 13.5:1 until it goes open loop - even at full boost.

At 2000 RPM I am getting 5 PSIG (5 PSI of boost, but only 2 PSIAbsolute ["above sea level"]). The boost starts to come on strong by about 3500 RPM (8-9 PSIGauge or so), but it does not hit the full 11 PSIG (8 PSIAbsolute) until around 4500 RPM and stays there past 5500, rolling off by a PSI or so at 6000 RPM. If you look at the Magnusun charts this makes sense - the SC efficiency keeps rising with SC RPM right up to 16000, which my setup (2" SC pulley) hits around 5500 RPM. The Mass Air Flow keeps going up with RPM, and that is what hits a max of 20 PPM at full boost at 5500 RPM. I can easily hit 5500 RPM at zero boost, and the MAF is not near 20 under that condition.

Gadget also told me tonight not to try to change the AFR except under boost, "that the ECM does not like it", and "nobody does that". I guess I'm an odd duck, since I always figured that I was spending all this money on performance. Performance for me does not start after 15 seconds, or above 4000 RPM - it means when I step on the GO pedal I get all the plant is capable of. And that's not at all what I'm gonna get. I guess if it does not stumble, ping or knock then I'm supposed to be happy.

Brian, WTF is an SMT system?

[Don_G]

You said "suddenly" which makes me think there was no known change, correct? So something is operating differently then before...


Have you by any chance been able to log injector pulse cycles before and or after?

The "suddenly" was just that the ECM's undesired response to tuning was wiped out by the reset.

Yes. I have hours of logs of everything the OBD II system reports, including injector pulse width.

Apparently, in spite of AFRC fooling the ECM about the AFR, the ECM (over many hours of operation) integrates either the secondary O2 sensor states, or the fuel trims and tries to warp the system back to "normal". Thus over weeks of driving the closed loop response that I'd carefully set to 14.7 at idle and 14.3 at 85 MPH cruise drifted ever higher, finally reaching ridiculous levels like 18 or 19 at idle and around town. If you only utilize the AFRC while in boost (and you don't live in CO where you might be in boost for hours in a week), then apparently this issue does not arise.

My problem now is to figure out which the ECM is responding to. Apparently Gadget does not know, since "nobody does that". The problem is it takes over a week of driving (and I went over the I70 Pass that week) before even the first hint of the problem shows up. That's how long it took to go from 14.7 closed loop idle to 15.1 or so.

Shit, I guess I needed a hobby! :rolleyes:

[thefatkid]

Well everything I've ever learned in toyota school has said, the 2nd o2 is only to dectect catalyst efficeincy. It will have no change on fuel trim levels.

I'm not familar with any AFC that "fools" the air fule raito sensor so I can't offer much help here. I can say that tuning durring closed loop will net problems with all driveability (from my turbo landcruiser experience at slee).

I'm not a fan of split second products, the interface is hard to use/not user friendly. SMT is a tuner from a subcompany of unichip, not plug and play like unichip but it can; alter timing open or closed loop, adjust for complete fuel trims (larger injectors), add fuel under boost, control injectors/Nitrous/Methanol, and other things. You can load/change settings while driving with the SMT, very helpful for "on the fly tuning".

I'll have to try to read up on your setup more.

[Don_G]

Brian,

I agree with your assessment of the URD/SplitSecond user interface. To say it sucks is being kind. Aside from the requirement to kill the engine to download any tuning changes, the whole software interface is buggy, awkward and slow. Add in the fact that the OBD II scanner must be rebooted after every engine kill and you wind up losing at least 5 minutes AFTER you find a place to safely pull off the road.

As you can see I am frustrated.

From here out, map will be "tuning map" and MAP will mean "Manifold Absolute Pressure".

The URD AFRC setup allows you to create a custom map of closed-loop AFR for every cell in the plane of MAP vs RPM. Each cell is 500 RPM x 0.5 PSI delta pressure. As a practical matter you will only want to enrichen the mixture from the factory norm. (I'm going to ignore methanol and NOS systems here.) The map gives you a reasonably fine-grain control of closed-loop AFR for any engine load.

In those cells where you enrichen the mixture with the AFRC, the Additional Injector Controller (AIC) lets you add fuel from the 5th injector. If you do it right (and it's not easy since none of he units on the various control maps directly correspond to each other) the resulting Toyota ECM closed loop fuel trims can be closer to zero after you tune than before. This actually improves power, driveability and throttle response dramatically. I have hours-long logs of driving over mountain roads where the sum of the Short Term and Long Term Toyota fuel trims is very near zero, and the Toyota AF sensor is reporting 14.7 AFR in closed loop, while the WEGO III AFR meter is reporting the richer AFRs that I want. The mountain driving lets you hit almost every cell on the map that can be hit - some combinations of pressure and RPM cannot be reached.

But then I start to get what I can only think of as a long-term creeping decay. Over days and weeks of driving using the same control maps (no tweaking at all) the ECM starts to adjust the overall closed loop response. The Toy AF sensor continues to report 14.7 closed loop via OBD II, but the WEGO III starts to see ever more lean readings. It made me think something had broken, until the reset proved that it was indeed a very long-term ECM response. The only explanation is the the ECM has it's own AFR calibrator loop and is changing the bias on sensor in parallel with the URD AFRC. What the ECM is using for the error signal on this long-term response I do not know, but the OBD II reports both a Total Bank One Fuel Trim (that differs from the sum of the Short Term and Long Term Fuel Trims) and a Bank One Senor Two Fuel Trim (B1S2 is the O2 sensor after the cats). Whether these latter two are real, and actually used by the ECM, or in what manner they are used by the ECM I do not know. Unfortunately I did not log them, since they did not seem to do anything in the short term - but maybe they change over the very long term. I will be monitoring them now.

I want to be working on the rest of the truck, not still wasting my time and mucho gas money running week-long experiments trying to deduce from the plant response all the control loops that a team of 6 Japanese engineers took years to design! Speaking of which, there is a region between 2000 and 2500 RPM (normal highway cruise RPMs) over a wide range of MAP where it is very obvious that the ECM has a lot of additional ad hoc rules and reponses. The Toy fuel trims will be very different depending on the RPM/MAP trajectory followed to get there. It really fights to stay lean in that region - right where it's tested for fuel consumption and emissions.

BTW, the AIC also has a Timing Control, but it only allows you to retard the timing, which I have not needed, and which seems to cause enough additional retard to reduce power. I have it out of circuit.

[Turbo4Runner]

You may want to consider going to a stand alone engine management solution. It's a bit more of a pain in the initial setup but I can assure you that with some work you will be able to get rid of any tuning related problems you have now. Personally I have not found any piggy back system I didn't think was a POS, SMT included (no offense). I mean, the concept itself is mearly a hack or work around. You are only fooling your electronics, not actually reconfiguring them to appropriatly compensate for the changes that were made to the engine.

It's kinda like putting the formula on a sticky note in your truck to get the correct MPH after you regear instead of just changing the speedo.. :)

Additionally, if you were so inclined you could use the stand alone to go to a speed density system and get rid of the MAF all together.

MegaSquirt (which is what I use) can be had for around $350. Something to think about! :)

Good luck!

[Don_G]

Whatever I do now, I will do after some serious homework.

I bought the URD stuff based on glowing reports on the main forum -- all who had troubles with the URD setups were assumed to be ignorant dummies who could not read instructions.

There was no mention in the URD website (or any of the directions that came with the setup, or arrived later) of all the limitations that truly exist.

I am worried about all the extraneous jobs the ECM does on my truck. Particularly ABS. I hope to keep the truck for many years and I need it to pass emissions.

[thefatkid]

MegaSquirt (which is what I use) can be had for around $350. Something to think about! :)

Good luck!

Not emissions legal, DonG has OBD-II and they require a hookup to the DLC2 when running on the Dyno at AirCare. No DLC2 and you have a instant fail (visual).

Your setup is not emissions legal either but it is harder to catch on an older truck (hence why my 4runner passes with a 3.4l supercharged). Though mine has a correct functioning MIL and "updated" hood stickers.

This is why the piggyback (or hack as you like to call it :) ) is the norm for most newer vehicles. It fools the newer ECU into thinking its functioning normally and giving a pass on all monitored functions (no MIL).

[thefatkid]

Don your truck has no traction control. Your abs function will not change with engine problems/changes/swaps.

[Don_G]

Is there a separate controller for the ABS? I thought the ECM did it all....


I also have a "Supercharger smog sticker". Would not have started the SC end of this without it.

[Don_G]

Brian,

As stated above, my truck stays closed loop for 14-15 seconds after WOT (unless it reaches 4000 RPM first), Gadget says that means my truck is broken.

I have seen several people on the main forum say theirs does this too (at least they say "several seconds"). Are all our trucks broken, or is the delay real and built-in?

[thefatkid]

I'm not actually sure, is used to be over 80% throttle was open loop. Could I bother you to come by Burt somtime to check it out (freebie of course) I'm curious about what is going on. Also if you know of a stock 04 4 cylinder that I could throw the scan tool on that would be cool. I'll also keep my eye out for one at Burt to drive and confirm Open/Closed loop durring WOT.

80% throttle or better is usally where I tune. At lower engine speeds and lower loads 14.7 is the most efficent. Luggin should be rich at 12.5 to 13.5 but you souldn't be lugging. At wide open I tune for a 13-13.5to1, I've found most Toyotas that are forced fed like to be around this raito. That would suck if they did change the closed loop operation to include WOT, tuning would be next to impossible.

I'm going to SMT my truck soon, I have experience with them and like tuning with them. I just have not decided on bigger injectors or 7th from Underdog (1st gen charger).

[tacotoy]

don are most of the people that have this "problem" have a 2002-2004 taco? if i remember correctly everything was throttle by wire at that point( i might a little off on my years) that might be a legitimate delay if that is the case????

[Don_G]

don are most of the people that have this "problem" have a 2002-2004 taco? if i remember correctly everything was throttle by wire at that point( i might a little off on my years) that might be a legitimate delay if that is the case????

tacotoy,

The 3.4L V6 went throttle-by-wire somewhere in there. I believe the 4 cyls never did. I'm pretty darn sure my actual throttle shaft is mechanical cable driven.


For those who care, I checked my boost vs RPM tonight:

1500 RPM/4PSI Boost/1.5MAP
2000 RPM/5.5 PSI Boost/3 MAP
2500 RPM/7.0 PSI Boost/4.5 MAP
3000 RPM/8.0 PSI Boost/5.5MAP
3500 RPM/9 PSI Boost/6.5MAP
4000 RPM/10PSI Boost/7.5 MAP
4500 RPM/10.5 PSI Boost/8.0 MAP
5000 RPM/11.0 PSI Boost/8.5MAP
5500 rpm/11.0 PSI Boost/8.5MAP
6000 RPM/10.0 PSI Boost/8.0MAP

Remember that for an improved Roots SC the efficiency of the SC improves right up to 16000 SC RPM (5500 Eng. RPM). Also, flow losses increase with RPM above 4000 RPM and will cause a bit of pressure rise with RPM. Also remember there is no wastegate on a SC - no flat ceiling on pressure. What you really care about is mass flow rate and that's a smooth ramp with RPM. Also, my Volumetric Efficiency is very nice and flat across engine RPM. I don't think anything is broken in the SC.

It's the mixture control I'm having problems with.

[Don_G]

I'm not actually sure, is used to be over 80% throttle was open loop. Could I bother you to come by Burt somtime to check it out (freebie of course) I'm curious about what is going on. Also if you know of a stock 04 4 cylinder that I could throw the scan tool on that would be cool. I'll also keep my eye out for one at Burt to drive and confirm Open/Closed loop durring WOT.

80% throttle or better is usally where I tune. At lower engine speeds and lower loads 14.7 is the most efficent. Luggin should be rich at 12.5 to 13.5 but you souldn't be lugging. At wide open I tune for a 13-13.5to1, I've found most Toyotas that are forced fed like to be around this raito. That would suck if they did change the closed loop operation to include WOT, tuning would be next to impossible.

I'm going to SMT my truck soon, I have experience with them and like tuning with them. I just have not decided on bigger injectors or 7th from Underdog (1st gen charger).

Brian,

I don't know of another 2004 4cyl.

I also seem to remember some hearsay about 80% being the switch to open loop. I just found in the 2003 manual (I have an on-line copy) that the nominal OBD-II reported idle TPS is ~10%, and the nominal WOT is ~75%. Can't get much closer to typical than my readings! (That's in DI-44, for trouble code P0120 . Mine is not throwing codes.)

I can bring it by sometime, but I don't know what we'd learn without a comparison. Thanks very much for the kind invitation!

[Don_G]

http://i21.photobucket.com/albums/b265/don700/Picture1.png

Here's a plot of Mass Air Flow/RPM vs RPM. It is proportional to Volumetric Efficiency (I just did not try to change the units from "Pounds of air per thousand RPM" to "liters of air per liter of displacement" The important part is the "top shelf", as this is a plot of an hour's drive that includes all throttle and load conditions. The top shelf represents WOT for a given RPM. If it was flat across RPM the SC would be keeping the same efficiency. If it was sloping down at higher RPM it would mean I was restricted or SC efficiency was dropping. The slight upward slope says that overall volumetric efficiency is rising with RPM. I think it looks pretty good.

This run did not have any rev limiter hits in it. If it did you would see a very slight drop in VE from 5500 to 6000 RPM.