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I ran a range of MAF adjustment voltages. They somehow managed to make it run rougher without changing measured A/F ratio by any noticable amount.
On mine that adjustment was a complete waste of time. Someone on another forum suggested it only has an effect up to ~1500rpm.
Howdy grimace, good fun setting up the sensors.
I'm interested to hear how you go:)
On rovergauge with a green tune installed it blanks the lambda readings,which tells me it sends the signal for open loop to the ecu,ie maf voltage.I'll put up some snapshots to illustrate some time. I imagine you'll likely need a cat tune colour to get it reading the sensors.
Here's a comparison between how rovergauge sees the different tune resistors,tune 5 is white,tune 2 is green.
https://www.aulro.com/afvb/images/im...14/10/1396.jpg
https://www.aulro.com/afvb/images/im...14/10/1397.jpg
http://ftp://homepages.vodafone.co.n...l/base%202.jpg
Now what is really strange is on my tune I do/did get the fuel trim displays, they are just locked at zero. Which you'd expect with no O2 sensors. Unfortunately rovergauge is on a laptop currently busy with other tasks but I'll check for screenshots later.
My saga started here: http://www.aulro.com/afvb/2037527-post44.html
Mine was originally on tune 2 (post 48 I write that it was showing fuel trims while on this map).
I swapped to tune 1 and it leaned out a little more.
Howdy,Just been reading a thread a couple of years back that discussed MAF servicibilty and how to tell if your's is good/bad .
http://www.aulro.com/afvb/technical-...upplier-2.html
Cockie55 talks of how you need to look at the MAF airflow voltage to see if the ecu is getting valid info from our maf to enable it to set the right mixture for a good idle.
I have been running my 14cux 3.9 classic range rover with precat o2 sensors(cats removed) and have found the idle to be slightly lumpy,feels and sounds like its missing very slightly,no biggie,just enough to wonder why?
As a comparison,i changed to a green tune resistor, yesterday to compare, set the co-trim to 1.25 volts and the idle is much smoother,powers better off the line too.
My reason for this was to see if my maf is working right and may have been causing that miss idle,as the "airflow signal voltage" is lower than i gather it should be at 1.4 volts at idle,where it should be up near 1.7 for a 3.9 litre v8.
This is depicted on the maf reading from snapshots on rovergauge where
28% equals my 1.4 volts,where i gather it should be up at 1.7 (32%)
Any experiences here? Does this mean my maf is on the way out,or just wont translate the correct mixture mapping for the ecu by under reading the voltage?
https://www.aulro.com/afvb/images/im...014/11/897.jpg
https://www.aulro.com/afvb/images/im...014/11/898.jpg
As an aside .In the top picture, the idle bypass position is down at zero,the car starts cold up at about 23% but slowly drops away to 2-5% then if you adjust the base idle to give a good idle 650-700rpm,it is nearly closed,or showing close to zero on the scale.
The only way to get it back mid scale,ie: recommended range 30-40% at idle,is to wind the base idle closed to restrict the airflow meaning a too low idle of around 500..
This lends me to believe there is an air leak around the plenum area somewhere as the stepper motor must be closing right up to compensate for extraneous air from somewhere,,
Maddening!! as i've removed all hoses,checked them,none missing,none split,removed the plenum,hylomar sealed it back,the only thing i havent done is the throttle plate setting,but seems to seat close to closed or .05mm on release of the throttle springs,had a good look and cleaned it up while plenum was off.Not really sure where else to look,done all the checks for air leaking,carb cleaner etc,seems fine??
This also could have been a additional cause for the lumpy idle running the white resistor tune cat map,not such a problem with the green tune currently,maybe open loop is more forgiving,but it means the stepper motor doesnt have much leeway to adjust currently,,
Once again any thoughts appreciated,cheers westy
Have you checked how clean the MAF wire is? I didn't ever measure voltages before/after on my japanese cars, but they always ran better following a MAF clean.
Also keep in mind the "natural variability" of english electronics.
Have you seen any change in RoverGuage with the different MAF adjustments? I did my remap back in July when the air was cool. Now we're warmer I've had it stall out at idle a few times. So I may need to revisit that.
Regarding the stepper motor. Did you set the base idle to ~800rpm while warm idling with the stepper air supply blocked off?
Gidday Dougal:)Yep,all the basics covered,maf cleaned out,love the term 'natural variabilty:) yes indeed,lucas,prince of darkness and 20 year old dry jointed solder from men in sheds,big land rover sheds:)
Yes,blanked off the back hose,also did the rovergauge stepper close first,as per your good tip.
That base idle for me had the iac closing off gradually to zero!!,but after a few days and a small base adjustment to get idle higher on tach,the rovergauge and the stepper seem to be stable,giving about 20% on idle,nice.that'll do,at least it has range now.
As an aside i tried a chinese copy maf today to compare direct maf voltage,and exactly the same figures,,so i can only imagine that 'natural variation' on my girl talks to the ecu at that voltage:)
I tried two chinese mafs and the first at ignition voltage only showed .40,the second .48,target on my original(and land rover spec) although slow to get there on igntion turn on,is spot on .35.
Conclusion,alls well:),might be my rovergauge connector or my cable vagaries give these readings,but since they are all consistent,no worries..
ps:,pulled up to test those maf's today at my local landrover bits supplier,and the car started playing up,ignition off,the a/c fans came on after a very short run,weird.
Then started up ,car wouldnt start and when it did idled like a pig...
I'd changed the ignition module the previous day..
Drove home,fetched the original ignition amp out from the bin,back in and ground cables double checked,now all is sweet,smooth...Britpart rubbish,or possible ground fault from the earth cable behind the distributor plate..