a few questions to answer...any help appreciated

[The Alchemist]

did my first customers car this week with EFIlive......quite an experience and I have a few questions as a result...and a few pearls of wisdom as well. We have a dyno dynamics dyno at work (for the record) and the car was a 2000 Holden SS with a bigbore, extractors, large t/B , large MAF and large intact pipe, engine standard.

One thing I noticed was that the engine AFR sat at 14.4:1 with the o2's "on" at idle and light throttle regardless of what I did to the VE table or the injector table or MAF table???? I can not find anywhere a "target AFR closed loop" table so I can modify it to 14.7:1.
I found the open loop table and sucessfully changed that which had the desired effect on AFR when in open loop mode but nothing for "closed loop" mode.
Can anyone help me here?
The weird thing was , that when I used the bidirectional controls and activated AFR control I could change it by 0.1 AFR and see the change on the dyno wide band, and when I had it set on 14.7:1 I got 14.7:1 on the dyno AFR, turn it off and back to 14.4:1 we go. Very strange.......

Secondly , when the car came in it had very lean mixtures when in open loop mode indicating that the physical changes made to the intake and exhaust had overrun the standard engine calibration. It took me a while but I found that the biggest effect on AFR is made by changing the MAF calibration!!!!

In fact before I adjusted the MAF table I tried the IFR table and VE table, both had hardly no effect on getting my AFR's back up to the" 14's" at all! (when in open loop) It was a very frustrating time......I was being very cautious as it was a customers car not my own :)

Turned out that the MAF needed around 5% increase at idle load , once off idle needed a 10% increase up to 2000rpm/light load say 45 KPA then a 15% increase up to 5000rpm full load 100kpa, then around 19% up to 6000rpm full load (Which interestingly enough only moved one calibration point on the MAF table) This adjustment to the MAF table gave me mixtures I could work with when using the VE table from there on.

I have another 2 customers next week thankfully both with standard MAF's, so the job should be much more straight foward!

I'm assuming that checking the AFR's while in open loop is a good starting point when using the EFILIVE system? Is this what other tuners do? To be honest I was surprised at how far out thing were to start with. Obviously the new larger MAF had a major effect and i thought that people here should know.

In the end the car made huge torque, infact it had 95% of its peak torque available at just 2000rpm !!!! It made 210KW at the wheels in 3rd gear shootout mode, which was down a bit and what I'd thought it would make as I have dynoed many "standard" ones making similar rwkw figures but no where near the torque this thing had :)

cheers Mike

[GMPX]

When you say the car had a 'larger' MAF, do you mean it was hogged out or was it a real 85mm MAF?.
If it was the 85mm MAF you would have needed to use the MAF Flow table from an 85mm MAF, with that table wrong things would have been hit and miss.

You will find the cars you get with std MAF's will be alot more straight forward. I am not a believer of changing the MAF or IFR table unless the engine has a different MAF or Injectors.
You will find the values in the PE table will match pretty close if none of that has been messed with.

Cheers,
Ross

[The Alchemist]

Hi Ross, thanks for your reply...It was a real 85mm MAF and man was it a challange as I had no 85mm MAF table.
Do you happen to know where I could get one ? I have designed my own as you can see by my post but to have the correct one would be great.
Any ideas on my other questions?
Mike

[GMPX]

Head on over to - http://stealthv.nitro-nights.com/tunes.htm
Download say a 6.0L truck file, I am pretty sure they all ran an 85mm MAF (Anyone confirm?).

Cheers,
Ross

[The Alchemist]

downloaded a truck 6l file and had a look at the MAF calibration....for a given HZ it runs a lower Grams/sec airflow figure.

I found I had to increase the airflow figure at a given HZ to get the mixtures right, verified that on the dyno. Increasing the airflow would increase the fuel delivery I'd have thought.......

cheers Mike

[The Alchemist]

Hi there, did a second customer car today...the whole process went much more smoothly. This car also had a larger MAF and T/Body etc etc ....

This time I tuned with the MAF until I got the mixtures I wanted then fine tuned the VE table, although it needed a little alteration. Noteworthy was that when you were at low RPM day 1800-2000rpm the airspeed would drop off at about 85-90 KPA leading to a rich mixture just at that point. This was almost tuned out my dropping the VE table away at that point to a very low effecientcy thus reducing the fuel delivered and correcting the rich mixture.

It turns out that a 5% MAF table increase for idle MAF levels say up to 8g/s then up to a 10% MAF increase for the rest of the table gave me the best mixtures to tune with.....
The car made 217rwkw on a dyno dymanics dyno.

Cheers Mike

[joecar]

Alchemist,
Good info, thanks.
Looks like you'll be writing the book on how to tune...
8)

[leres]

One thing I noticed was that the engine AFR sat at 14.4:1 with the o2's "on" at idle and light throttle regardless of what I did to the VE table or the injector table or MAF table????
Do you guys have oxygenated fuel in New Zealand?

I just happened to be reading Probst's Corvette Fuel Injection & Electronic Engine Management (http://www.amazon.com/exec/obidos/ISBN=0837608619/craigsefidiagnosA/):
Under the Oxygen Sensor's control, oxygenated fuel is metered to deliver an air/fuel ratio to about 14.2:1 at the injectors. The resulting exhaust is about the same as the exhaust from buring gasoline formulated without oxygen, the traditional 14.7:1.
Otherwise, could there be a leak that allowed air to enter the engine without being measured by the MAF?

[Blacky]

One thing I noticed was that the engine AFR sat at 14.4:1 with the o2's "on" at idle and light throttle regardless of what I did to the VE table or the injector table or MAF table???? I can not find anywhere a "target AFR closed loop" table so I can modify it to 14.7:1.

Try looking at {B3601}, under
Engine Calibration->Fuel->Mixture->Parameters.

Regards
Paul

[The Alchemist]

yes Paul, I saw that "engine Calibration->Fuel->Mixture->Parameters." and it has a defined stoch figure of 14.63:1 that the pcm uses as a reference point. Changing this seemed to make little difference to the 14.4:1 I was getting.
However what I have discovered is that on later model pcm calibrations there is a "lean cruise" section where the AFR can be defined via a seperate map. The car I was originally working on was a 2000 year and had no such calibration in its PCM and is probably hard coded.

[Delco]

yes Paul, I saw that "engine Calibration->Fuel->Mixture->Parameters." and it has a defined stoch figure of 14.63:1 that the pcm uses as a reference point. Changing this seemed to make little difference to the 14.4:1 I was getting.
However what I have discovered is that on later model pcm calibrations there is a "lean cruise" section where the AFR can be defined via a seperate map. The car I was originally working on was a 2000 year and had no such calibration in its PCM and is probably hard coded.

Never change that number , when you say you were seeing 14.4 is that on a external wideband O2.

You can change the switching point of the O2 sensors in the calibration if required but I would not recomend it.
The PCM runs in closed loop except when its cold or in PE mode so it will always be trying to achieve 14.63 - a external wideband can see a slightly different mixture as the PCM is just trying to hold the fuel at its desired O2 switching point which can be defined.

For you main tuning you should be adjusting the MAF table PE table and spark table, VE table has no affect unless you move it enough so the PCM thinks the maf is incorrect then it will use the VE table.

I hope these are your own cars and not customers you are charging for tunes while you learn ?????

A modified or ported maf is a complete unknown and not a linear device anymore , something like a 85mm factory MAF has a proper maf transfer function that the factory has spent a lot of time getting right.

Any tuning done on a ported maf is at best going to be a botch unless you can spend about at least a solid week on tuning to get the transfer function right.

[The Alchemist]

hello Delco, thanks for your help...so its normal then to see a slightly different AFR when on light throttle...thats good to know...it liked to sit bang on 14.4:1...that was on our dyno dynamics dyno wideband...

So why is there a VE table? and why do you have the ability to alter it if it does "nothing".?? That I can't understand......I can confirm that changing it produced very small changes in AFR and I mean very small compared to when you alter the MAF.

The Maf's on both these cars were supplied and fitted by the local Holden Dealer I have no idea of their specs or original except I know that they are larger than the std Maf sensor and that the cars both arrived here with very large LTFT's across the whole range and left me with LTFT's in the order of -0.8 to -1.5% and made another 20kw at the wheels!
Will check with them brand and source if that helps.

As far as to whether or not I'm "charging while learning" depicts a number of assumptions on your part now doesn't it?????? Needless to say this has been a very educational experience :) And thats all I have to say about that "Forrest Gump" :)

[GMPX]

So why is there a VE table? and why do you have the ability to alter it if it does "nothing".?? That I can't understand......I can confirm that changing it produced very small changes in AFR and I mean very small compared to when you alter the MAF.

Correct, when the MAF is 'functional' the PCM still calculates what is known as the 'Speed Density' airflow values, these are calculated airflows independent of the MAF reading, however, they are used as sanity checks for the MAF readings.......now, when the MAF becomes a door stop then altering the VE table WILL directly alter the final AFR figures.
Oh, the MAF is also not used during cranking.



The Maf's on both these cars were supplied and fitted by the local Holden Dealer.

The 85mm MAF has 5pins as the IAT is built in, the std MAF has 3 pins and a seperate IAT.

Anyway, good too see they ended up running better and by the sounds of it you had some fun doing it!!...but Delco is right, unknown MAF's will produce mixed results for you.
FYI, my own car when it was internally stock I fitted an 85mm MAF (with screens still fitted), I used the 85mm MAF flow table and the AFR's etc stayed exactly the same as before, I think from memory it picked up 'some' power, I did notice the car felt more responsive.

Then after the engine had a cam fitted I went MAFless as the 85mm MAF didn't really like the lumpy idle (Delco, you were right!!) and I could never get it to idle good (Note: a tuner I am not!!).
Once the MAF was removed it really changed the behaviour of the car totally.

Cheers,
Ross

[Delco]

hello Delco, thanks for your help...so its normal then to see a slightly different AFR when on light throttle...thats good to know...it liked to sit bang on 14.4:1...that was on our dyno dynamics dyno wideband...

So why is there a VE table? and why do you have the ability to alter it if it does "nothing".?? That I can't understand......I can confirm that changing it produced very small changes in AFR and I mean very small compared to when you alter the MAF.

The Maf's on both these cars were supplied and fitted by the local Holden Dealer I have no idea of their specs or original except I know that they are larger than the std Maf sensor and that the cars both arrived here with very large LTFT's across the whole range and left me with LTFT's in the order of -0.8 to -1.5% and made another 20kw at the wheels!
Will check with them brand and source if that helps.

As far as to whether or not I'm "charging while learning" depicts a number of assumptions on your part now doesn't it?????? Needless to say this has been a very educational experience :) And thats all I have to say about that "Forrest Gump" :)


You will find the DD or autronic wideband is always at 14.4 when any car is at stoich - its just how they are , mine is the same.

Wasnt making assertions or anything BUT until you learn how to use the software I would say its morally wrong to use a customer as a guninea pig unless they are fully aware and ready to accept the concequenses.

From your posts to date I can see some fundamental errors and if it was me I would be asking theose people ( wether customers or not) to come back at some stage for a free retune as I believe they need it.

Dont worry it is a steep learning curve but once you have a lot of tuning time under your belt ( preferably on a car you ae driving every day so you can assess what you have changed) then it will become a breeze.

Personally I would not tune a car that has a modified or non standard MAF , the time taken to get it to a level I would call right is more than anyone could charge for the tune.

Better to put a std maf or a large known calibrated maf on - better still throw the maf and spend a few days tuning the VE table to get it right.
The first VE table you do on any combo will take weeks to get right - by that I mean the combo of cam/head/capacity after that each identical car will only take a few hours to touch up to account for variences from car to car.

Everytime a new model comes out I spend a few weeks getting the VE table 100% right so then I can use that as a base starting tune on a customers car - I then only need the customers car for about 6 hrs on the dyno/road to get it spot on .

keep on truckin :)

[The Alchemist]

Hey Delco thanks for that.....its a great help esp about the 14.4:1 AFR readings ..... I've been speaking to the first customer, today, who was on his way down to Wellington ( a 4 hour trip from here) and he was wrapped with the car and said how much easier it was to drive...good feedback. With respect to your comment on "getting them back" I had in fact mentioned to him to pop in next week so I can touch a few things up that I had "learnt" from my second customer...if that makes sense...of course at no charge to him :)
Anyway I was pleased with his feedback....

I have a few questions if you don't mind that pertain to tuning with the software as I undertstand you have a lot of experience....
1: what were/are the fundemental errors so I can address them and fix them? (saying that but not eluding to what the errors are sort of leaves me hanging)

2:Why do dealers sell on to people large MAF's that bugger up the PCM in the first place? Our local holden dealer had no idea that the Maf's lean out the mixtures so much. ( the LTFT do correct it but its not the same as having them right in the first place)

3:Would you mind explaining how to tune the VE table while not using the MAF, is there a setting in the software to set this up or do you disconnect the MAF and ignore the error code???? My first customer has offered ( at no charge to him ) to allow me to do some more work with his car along these lines. As I am serious about this business I would like to get this right.

Just to let you know I own a Diesel/Petrol/Turbo workshop in New Plymouth NZ and have a lot of experience with tuning on our DD dyno using LINK, Power FC, Microtech systems and even methanol burning TQ's. I have to say though, that the EFILIVE software leaves those behind in terms of complexity and depth and I am very much in the learning process with regards to this. So any help is very much appreciated.

Cheers Mike

[Delco]

Hey Delco thanks for that.....its a great help esp about the 14.4:1 AFR readings .....

I have a few questions if you don't mind that pertain to tuning with the software as I undertstand you have a lot of experience....
1: what were/are the fundemental errors so I can address them and fix them? (saying that but not eluding to what the errors are sort of leaves me hanging)

2:Why do dealers sell on to people large MAF's that bugger up the PCM in the first place? Our local holden dealer had no idea that the Maf's lean out the mixtures so much. ( the LTFT do correct it but its not the same as having them right in the first place)

3:Would you mind explaining how to tune the VE table while not using the MAF, is there a setting in the software to set this up or do you disconnect the MAF and ignore the error code???? My first customer has offered ( at no charge to him ) to allow me to do some more work with his car along these lines. As I am serious about this business I would like to get this right.

Just to let you know I own a Diesel/Petrol/Turbo workshop in New Plymouth NZ and have a lot of experience with tuning on our DD dyno using LINK, Power FC, Microtech systems and even methanol burning TQ's. I have to say though, that the EFILIVE software leaves those behind in terms of complexity and depth and I am very much in the learning process with regards to this. So any help is very much appreciated.

Cheers Mike

MAF table really needs to be corrected on those vehicles ( better still put a std MAF on and retune) I did go into lenghts to say that was the problem and how much time it requires to get right.

If you have any issues that you need to bounce of somone send me a email or ring - my website is www.chipmaster.com.au , I am not as scary as I sometimes come across on the net :D

Dealers are only concerned about $$$ in thier pocket , in fact if GM knew then the warranty would be void on those cars. The aftermarket maf thing is a big scam , much like big mouth cold air