EvilBevel

>>The funny thing is that I was expecting the mixture to get a bit richer when I lowered the boost. Should that have happened?

No, lower boost is less air coming in = less fuel needed for that mass of air, but the map would still "aim" for 9 % CO
[Edit]... I mean the lookup value in the fuel map for the lower MAF voltage would show "less fuel", I don't mean the ECU is actively trying to enrich the mixture.


>>Would these cause the leaning out? Or am I being paranoid and worrying for nothing?

Don't think you are paranoid... perhaps the best thing to do is get the car back to standard intake wise first (remove APS thing, refit standard filterbox) and see if that makes any difference at all to the MAF readings.

Another tought...could you sent me the raw log file so I can compare a bit closer to my readings ? Maybe it's just 02 sensor that's giving wrong data ?



[Edited by EvilBevel - 5/3/2002 12:50:20 PM]

dmel

Is it possible that Wrexy's lambda sensor is undereading? Has anyone heard of such failures in lambda sensors?

Another question concerns MAF voltages. Do people running higher boost see higher MAF voltages? i.e. higher than ~4.1V. At the top end the MAF sensor seems to loose its linearity. From the logs it seems that MAF voltage does not increase in line with rpm. Obviously there are factors that would reduce the flow of air at higher rpm such as compressor efficiency and boost tail-off but surely not at that extent. Nevertheless, it may be the case that the ECU is aware of the (possible) non-linearity and compensates accordingly.

One final thought. Could it be that the APS Wrexy is using, make air more turbulent thus not allowing the MAF to take accurate readings?

[Edited by dmel - 5/3/2002 5:31:22 PM]

WREXY

Thanks for having a go fellas. I'l plug in the ECU that my friend will bring to me next Friday and I'll take it from there. I'll let you all know of course.

At one stage I thought I may have had a VF28 turbo, cos I had heard that some found there way into UK Euro spec cars from the factory. I went and checked, but it was the little TD04.

It wouldn't be the APS would it? I doubt just the APS induction kit would cause this. Would it?

What about the FCD? Could it cause this? It has an adgustable screw , stuffed if I know what it's for. It's in the 12 o'clock position.

If anyone comes up with anything new, feel free to post here.

Cheers,

Wrexy.

[Edited by WREXY - 5/3/2002 10:17:04 PM]

WREXY

Hi Peeps,

I couldn't wait til Saturday to do the logs of the new MAF sensor and ECU reset so I went out and did them tonight.

Results show that there is no difference, I'm still running lean. The good news is that I did 3 runs and there was no knock correction. I'm posting 2 runs below. Ambient temp was around 25 deg Celsius. First run was with 1.17 bar (17 psi) boost although you won't see it cos of the FCD. The second run as you will see cos the FCD is not cutting in was no more than 13.2 psi.

Car is a MY00 with, AE 802 ECU, APS cold air induction, 5 Zigen exhaust mid and backbox only (catless mid), Blitz DSBC set at 17psi boost on the first run and 13.2psi on the second run, FCD and Blitz BOV.

Why do I run the same, that is lean, even when I lower the boost?

Why am I still running lean?

Any ideas?

Here's the first log with 17 psi boost,




Here's the second run with 13.2 psi boost,



Cheers,

Wrexy.

SCOSaltire

yeah, MAF looks fairly similar...
tho perhaps reads more air... esp when increasing after the small dips... increases quicker...

tha air / fuel correction looks very different tho...
no negatives now... and smaller times for correction - matches the smaller times for the MAF voltages to rise..

ur throttle voltages are much more constant..

in the old one... the knock correction only decays once the timing was below 34.... then increases once its reached 23..
at this point the MAF values are increasing slowly up from 3 to 3.5

in the new one... no knock correction
and similar values to above.. except... the MAF voltages never reach the low values of the old one...

low MAF voltages in the dips are:
old:- first=2.6; second=2
new:- first=2.9; second=2.6

seems as though the new MAF responds quicker.. and reads more air.. perhaps it is more sensitive... more linear / no jumpy threshold?

this is pure guessing..

john banks

Very puzzling. I do believe your lambda sensor readings are representative judging the airflow and your injector pulse widths - mine were 17-19 on boost, but airflow was >4.4V - but my lambda voltage was about 915 mV. What else could it be?

Cosie Convert

Wrexy

Just be pleased you've got a good un that doesn't run stinking rich

WREXY

SCOSaltire,

Thanks for that analysis mate. Good one! I don't know what some of the graphs mean, but picked up a little from what you wrote.


When Stephen Done was asking everybody what ECU they had, that is, AE800, AE801, AE802, and everyone was saying that the AE802 ECUs were slugs, I had disagreed and I had written that, when my friend from OZ, (a tuner), came here to fit the bits I had bought from his shop, he drove my car before the mods and he had said that my car felt quicker than any other stock scoob he had driven in OZ, and he drives plenty of them cos he tunes them.

I don't know if it's just my ECU being a one off or whatever. There are no fault codes. The funny thing is that I was expecting the mixture to get a bit richer when I lowered the boost. Should that have happened? I don't have a downpipe just a mid and backbox exhaust wise and then the APS induction kit with the boost controller. Would these cause the leaning out? Or am I being paranoid and worrying for nothing?

My runs were done in 2nd and 3rd gears. I think in higher gears mixtures are supposed to get leaner. Is this true? I Didn't find a road close enough to me, where I could stretch it out in higher gears, before the lambda sensor would get hot and read lean. The log took place after 7 minutes of slow driving, before I got to the place where I give second and third gear.

Andy, I'm happy mine is a good one. I have read lots of your posts and they are very informative (John Banks also), and from what I understand, you know what's going on. I'm a little frightened though, cos I don't know how safe it is. I'm not technically minded so I don't know.

My main question now is, Is it safe? What happens when we get to our usual 40 degree summer days here in Greece, in 2 months time, for a couple of months, everyday and I'm in 5th gear and I have a couple of people in the car, going up a hill?

Also if anyone has any ideas on my questions in the third paragraph of this post, it would be appreciated.

Cheers,

Wrexy.



[Edited by WREXY - 5/3/2002 12:21:54 AM]

john banks

To me it looks way off spec and I would want to get to the bottom of it. The alternative is monitor it a lot.

john banks

I wondered about the lambda, but then the injector pulse widths are narrower than expected for your airflow compared to the two MY99 and my MY00 that I have logged.

WREXY

Theo,

You have mail my friend!



John,

What would cause the injector pulse widths to be narrower than expected for my airflow compared to the two MY99 and your MY00 that you have logged? Faulty injectors?

Cheers,

Wrexy.

john banks

No this is the ECU signal. So the ECU seems to be underfuelling for a reason - it just backs up that it is lean and that the lambda sensor probably isn't lying. But I'm damned if I can think of the cause!

Cosie Convert

Mmm Suppose the MAP was reading atmospheric pressure incorrectly, what would that do to the fueling ? Probably nothing but just a thought

john banks

Mine was OK rogered in a similar way in my Delta Dash log I was going to say that if the fuel cut lifter affected the atmospheric value that might have an effect, but WREXY's atmospheric pressure reading was normal too.

paulwadams_my99

Actually saying that i did a run last night and my atmospheric pressure is constantly 14.4, your looks a little higher but maybe thats right?

Paul.

paulwadams_my99

John,

I know u aint gonna like this But there is no drain on the earth to the lambda is there Wrex? I.e an afr of any kind?

Cheers

Paul

I really should spell check these first
[Edited by paulwadams_my99 - 5/3/2002 3:30:08 PM]

[Edited by paulwadams_my99 - 5/3/2002 3:30:49 PM]

WREXY

Does any body else want me to e mail my raw logs to them for an analysis?

Cheers,

Wrexy.

paulwadams_my99

me please, and then i'll show u mine

WREXY

Paul,

I don't have an AFR on the car. Just a knocklink, an STI boost gauge (lamco) the boost controller and a turbo timer.

Cheers,

Wrexy.

john banks

Paul re earthing Mine is still connected the botcher's way, but I suppose one car might get away with it and another not if there is a poor lambda earth? But then as I said his narrow pulse widths seem to support it being lean?

WREXY

Could I have a bodgy ECU then?

WREXY

Paul,

I have sent you my logs. Thanks for your ones. They look perfectly safe.

Cheers,

Wrexy.

john banks

Can you swap with a friend and see?

WREXY

I have no friends with a scoob close to me, however on Wednesday one of my friends may come over from far away. I'll ask him to bring his AE 802 cos he has PPP on his car and I think his 802 may be lying around somewhere.

Cheers,

Wrexy.

WREXY

It's organised. On Friday I'll have the ECU.

Has anybody else done any logs that has an APS induction kit fitted?

Cheers,

Wrexy.

EvilBevel

Wrexy, John is right (not that I doubted him) ... your injector duty cycles seem pretty low for a given MAF voltage.

Really really strange ...

Unless Stephen Done tells me I'm talking bollox... I think IDC is mainly related to RPM/Airflow/TPS, so it would indeed seem that your ECU is doing funny things ? MAF voltages seem to be within the expected range (although I can not compare with my VF23, I see 4.4 volts at 5.800 RPM, even though my setup is "tricked" by the Unichip, it should read even more)

The ECU must have another fuel map than expected...
It's the only logical explanation I can think of right now, but I can't get my head round it. Yet.

Not much use, I know, but best bet is indeed to plug in another ECU to see what that gives. Forget what I said about faulty sensors etc... the ECU seems to compute low IDC's for a given MAF voltage. At 4.12 volts / 4600 RPM I see 16.6 ms, you see 13.3 ms tops.

Stephen ?

Theo

john banks

I get 4.4-4.5V out of my MAF. I have not seen full boost lambda voltage below 890mV even when on a hot blast, but it did seem leaner tonight than on other occasions - it is not inconceivable that the MAP sensor does contribute to fuelling. Only way to find out is to disconnect it and run again at standard boost if the ECU swap does not work?

WREXY

John,

Can I just clarify what you said? Do you mean if the ECU change doesn't work, i should disconnect my MAP sensor, (not MAF) and try?

Cheers,

Wrexy.

john banks

I meant take the fuel cut lifter off the car in case it is affecting fuelling if you get nowhere with another ECU.

Cosie Convert

I think John meant disconnect the FCD