200kw AU Xr8 Chewin the Juice
 

Hey all, got a 200kw AU2 Xr8 with a stinky exhaust and drinking the fuel like there's no tomorrow. So ,air filter good plugs and leads O2 sensors new no faults using Forscan,runs well. When you get out of the car your clothes stink of exhaust especially if you walk past the back of the car while its running. So I disconnected the MAF sensor plug and it seems a whole lot better apart from the loss of low speed (1000 to1500rpm drivability),motor feels a bit perkier has a better exhaust note and has a bit of a pop on the overrun. Did a mileage test 80% highway 20% urban 11l per 100kms which seems to be in the ballpark. So can anyone tell me what the readings for the MAF should be on the Forscan dashboard at idle and under load.

Re: 200kw AU Xr8 Chewin the Juice
 

Forgot to mention I'm doing 2300RPM at 110Ks.What does the MAF sensor actually do if the motor can run pretty well with it disconnected?

Re: 200kw AU Xr8 Chewin the Juice
 

You checked your Cats for blockage ?

Re: 200kw AU Xr8 Chewin the Juice
 

Well I had the exhaust open a few month's back and they were dark but not sooty, its not so rich that it wont run properly it just stinks and is thirsty

Re: 200kw AU Xr8 Chewin the Juice
 

Your MAF voltage should run between 0 and 5V. At idle should be around 1V or less. The MAF measures accurately how much air is going into the engine, so that the ECU can determine exactly how much fuel to inject (adjust injector pulsewidth) to maintain the air fuel ratio as set in your tune.

The reason that it will run ok with it disconnected is because there is a MAF fail scenario configured in your tune. Whilst this scenario may have the car running ok, it is far from ideal and I would not recommend it as your engine could sound ok, but in reality could be running dangerously lean - and you would never know.

My recommendation if you believe you have isolated it to the MAF, would be to go and get some MAF cleaner. If you MAF can be disassembled, pull it apart to give a good clean with MAF Cleaner.

Interested to hear how you go with this as there seems to be a fair trend at the moment for dirty MAFs, including my own! I recently cleaned my MAF and corrected a poor idle issue.

Cheers
Stu

Re: 200kw AU Xr8 Chewin the Juice
 

Is the Forscan accurate in its readings?

Re: 200kw AU Xr8 Chewin the Juice
 

check fuel pressure with fuel pressure gauge incase faulty pressure regulator or blocked return line

Re: 200kw AU Xr8 Chewin the Juice
 

Do the v8 regs block like the IL6 ones. It doesn't look like it can be cleaned.

Re: 200kw AU Xr8 Chewin the Juice
 

Yes. What you see in Forscan is a mirror of what the ECU is seeing.

It may help, when I had a dirty MAF, the MAF voltages where bouncing around all over the place, whereas at a constant RPM, they should be fairly constant.

Cheers
Stu

Re: 200kw AU Xr8 Chewin the Juice
 

Thanks Stu that gives me a few things to test tomorrow.

Re: 200kw AU Xr8 Chewin the Juice
 

Hi,
It sounds similar to what I am finding. Although I wouldnt say my clothes stink from it.

With forscan, the maf v is constant at around 0.91v fully warmed up (90deg C) @ idle.

I also found that it lopes slightly with the maf connected and seems to idle smoother with it disconnected,
I also find that if it is warmed fully and in closed loop then switched off/on, the first 30 sec or so (open loop) seems to idle smoother until closed loop engages.

I have cleaned the maf (down the guts of the airbox with maf cleaner) but it does not seem to make a difference.

The filters, leads, plugs and bosch egos are new too.

The new egos definately change state alot quicker than the old ntk's, but we did discover a fault with Forscan displaying the wrong ego voltages (too high).

Too many parameters that can change the characteristics and not enough time to do it quickly, hehe.

Cheers,
Andrew.

Re: 200kw AU Xr8 Chewin the Juice
 

Andrew, to successfully clean my MAF, it had to be pulled apart to get right to the sensor wires.

Stu

Re: 200kw AU Xr8 Chewin the Juice
 

I read that you did that somewhere, but I think you have a bigger maf that can be disassembled.
Can the stock 175 maf be opened? I think it is rivitted together.

I suppose if the voltage is constant and just under a volt at idle then the maf would seem ok though?

Ta mate.

Re: 200kw AU Xr8 Chewin the Juice
 

Andrew the stock AU 5.0L you can pull the maf apart, i have done it couple of times on my ghia


cheers Dean

Re: 200kw AU Xr8 Chewin the Juice
 

How do I put up an image of my forscan page?

Re: 200kw AU Xr8 Chewin the Juice
 

Ta Dean.
will have a closer look one day.

Re: 200kw AU Xr8 Chewin the Juice
 

Hold CTRL and then press PRT SCRN key.

it will then copy the current screen (not just forscan either) into memory, then you can open Paint etc and then paste the image in, then save the file as whatever you want, probably a .jpg format.

Otherwise be slack like me and take a pic with the phone, as that is how I do all my posting here. :)

Re: 200kw AU Xr8 Chewin the Juice
 

just posted the forscan vid on u tube http://youtu.be/93rHGc7SoJg its out of focus might have to do it again. The main column reads timing-02#1-02#2-maf v- then stft 1 and 2looks like I have a problem on one bank Injectors??

Re: 200kw AU Xr8 Chewin the Juice
 

Looking at your video, it is hard to tell what is what, but I think was the MAFV (3 up from the bottom in the third column) does appear to be jumping around a bit compared to the RPM.

Here is a vid of a 5L that I tune. The MAF voltage is in the left column, 6 boxes down. You will note that it is sitting nicely around the 1V mark with only a variation of around 0.1V to 0.2V.
https://www.youtube.com/watch?v=fN6g4x1Bd_E

This video shows the same screen. MAFV is the same box, but is my car when the MAF was dirty and playing up. Much more variation in this one.
http://youtu.be/ac8sUe5V1e8

Hope that helps.

Cheers
Stu

Re: 200kw AU Xr8 Chewin the Juice
 

I think ill do another one tomorrow that's in focus.

Re: 200kw AU Xr8 Chewin the Juice
 

I managed to have a good look at the maf,
there are security Torx bits screwing it together, should have known that... DOH!

That's what happens when you tinker in the dark.

Re: 200kw AU Xr8 Chewin the Juice
 

Hi all I just posted a new video on the forscan readouts. You will notice that when I shut it down and restart it starts nice and lean then goes over to rich after a couple of secs sounds like you've pulled the choke out on a carbi engine. It seems that I may have a problem on the right bank. What about that maf reading-should it be stable??http://youtu.be/nE5_Zxr9dGs

Re: 200kw AU Xr8 Chewin the Juice
 

Hi Caprobbo.
that vid is better.
I am definately no expert with these things, but from what I can see,the maf only seems to jump around by 10mV, not sure if that is still acceptable. It also seems the maf and tp V is slightly higher than 1V at idle, they are normally just below 1V at idle.

It seems when you hold the throttle that the tpV does not alter by more than 0.2 V at nearly 3000rpm and your iac jumps up to around 50% there.
Can you switch the engine off and confirm you get a good smooth tpV from closed throttle to full throttle- about 4.5V)?
Could you do another vid also showing injector pulse width? And also confirm it is going into closed loop mode (at operating temp and running for more than 30 seconds).

If all that is acceptable then perhaps do a fuel pressure test and see if too high.
Another thing you can test with a fuel pressure gauge is an injector leak down test.
(Turn on ignition but dont crank, record max pressure then watch gauge over a minute or so to record leak rate), if pressure falls too fast you may have a leaky injector?

I made myself a pressure gauge from spare industrial machine parts - Japanese water pressure gauge that displays kgf/cm2, but I can convert that to psi well enough: )

Or buy an efi fuel pressure gauge from around 60 bucks.
Its not hard to check our engines fuel pressure as there is a schrader valve up front.

Perhaps Stu can jump in and correct me here or add more ideas.

Good luck.
Andrew.

Re: 200kw AU Xr8 Chewin the Juice
 

Yea I'm thinking a leaking injector on the right bank. Its weird how it runs lean on start up and then gradually goes to over rich. And it doesn't seem to go into closed loop mode at all even when driving, Forscan box continually says OFF for the closed loop mode and the engine gets up to 81Deg is that hot enough?

Re: 200kw AU Xr8 Chewin the Juice
 

I cant seem to get clear focus on the video but it looks ok on my computer??

Re: 200kw AU Xr8 Chewin the Juice
 

Forscan should show closed loop as either open or closed in the data window. I dont think you had it displayed in the vid, will check again.

Not sure about min temp but i reckon by 85deg C it should easily be in closed loop (engine has to be running for at least 30 seconds too).

The PID for closed loop monitoring Is called fuelsys I think, actually I think there are two PID'S called fuelsys, you have to choose both if not sure.

Re: 200kw AU Xr8 Chewin the Juice
 

Yea ok because I was sure I've seen that open loop closed loop display in the past so I will have a look for the second pid tomorrow and might be able to borrow a pressure gauge. More to do tomorrow, see how we go.

Re: 200kw AU Xr8 Chewin the Juice
 

I just checked my car.
it seems your TPV and IAC is about normal. I didnt expect the IAC to increase duty when the throttle was opened, but there you go.

Re: 200kw AU Xr8 Chewin the Juice
 

Yea cool I think ill get the injectors cleaned and see how that goes. Thanks for your input.Bret

Re: 200kw AU Xr8 Chewin the Juice
 

Hi all
The Tickford AU2 200KW is up to its old tricks again
Drinking the fuel, stinky rich exhaust small loss of power hunting at idle.

Cleaned the MAF
Its pulling 15" of vacuum at my altitude (1000m)

I've done a you tube clip of the scan readings https://youtu.be/JaYz8f5UuNQ

Can someone who has experience with these AU injected Windsor's have a look and give me an opinion

I've noticed the 02s seem to be uneven, they have done 2000k only
Took them out they were a bit sooty as expected
When the ECU is in open loop on cold starting the short term fuel trims start at about 18% rich and come down to about 3% till the ECU goes into open then they head straight up to 40% rich
Can someone tell me if the MAF,idle control,temp etc. are all in spec

last time it did this I replaced both o2s and it 95% fixed it
They are VDO brand,surely they couldn't be gone again with 2000k on them.

I also capped all vacuum ports to no effect
Would a bad cam sensor cause this,Ive tried disconnecting it to no effect

All help would be appreciated
Bret.