MAF setting 3.9EFI

[knuts2au]

A young ex Landrover Mechanic i was talking with the other day said about checking the MAF sensor. On the outside terminals it should measure 174ohms resistance, if not adjust it, as mine measures 272ohms i am wondering what effect it has on things. I thought the adjustment on the back of the MAF was only idle mixture, or does it do more :?:

[DEFENDERZOOK]

<span style="color:blue">can you post a pic of the maf.....?</span>

[knuts2au]

it's a standard hotwire, 14cux i think they are, the sticker peeled of long time ago, it has a hole with a blanking plug which give access to the multi-turn trimpot inside. Can't grab a photo at the moment, too bloody hot outside (44), and windy (40Km/h gusts) and not sure where my camera cable is.

[disconut]

Off the disc,

The MAF sensor is located in the intake system between the air filter housing and the turbocharger. The ECM uses the information generated by the MAF sensor to control exhaust gas recirculation (EGR).
The MAF sensor works on the hot film principal. The MAF sensor has 2 sensing elements contained within a film.
One element is controlled at ambient temperature e.g. 25 °C (77 °F) while the other is heated to 200 °C (360 °F) above this temperature e.g. 225 °C (437 °F). As air passes through the MAF sensor the hot film will be cooled.
The current required to keep the constant 200 °C (360 °F) difference provides a precise although non-linear signal
of the air drawn into the engine. The MAF sensor sends a voltage of between 0 and 5 volts to the ECM, proportional to the mass of the incoming air. This calculation allows the ECM to set the EGR ratio for varying operating conditions.
Inputs / Outputs
The MAF sensor receives battery voltage (C0149-3) via the ECM on a brown/orange wire. Signal output on a slate/light green wire from the MAF sensor (C0149-2) to the ECM (C0158-11) is a variable voltage proportional to the air drawn into the engine. The MAF sensor is provided an earth (C0149-1) via the ECM (C0158-20) on a pink/black wire.
The MAF sensor can fail or supply an incorrect signal if one or more of the following occurs:
• Sensor open circuit.
• Short circuit to vehicle supply.
• Short circuit to vehicle earth.
• Contaminated sensor element.
• Damaged sensor element.
• Damaged wiring harness.
• MAF sensor supplies incorrect signal (due to air leak or air inlet restriction).
In the event of a MAF sensor signal failure any of the following symptoms my be observed:
• During driving, engine speed may dip before recovering.
• Difficult starting.
• Engine stalls after starting.
• Delayed throttle response.
• EGR inoperative.
• Reduced engine performance.
• MAF signal out of parameters.
In the event of a MAF sensor failure, the ECM will use a fixed default value from its memory.

Trev.

[knuts2au]

Turbo?, one should be so lucky, it's a 3.9l V8i, no cat, no EGO sensor. Still can't find that camera lead, was on the table before Christmas....

[disconut]

Pulled it off the TD5 disc, but the principal of operation for the MAF should be the same?

Trev.

[Rovernaut]

Originally posted by knuts2au
A young ex Landrover Mechanic i was talking with the other day said about checking the MAF sensor. On the outside terminals it should measure 174ohms resistance, if not adjust it, as mine measures 272ohms i am wondering what effect it has on things. I thought the adjustment on the back of the MAF was only idle mixture, or does it do more :?:

I'm very interested on your post!.
Which out side terminals are you talking about.
The 1st terminal on the left and the last one on the right on the connector of the MAF.
Mine measured 171 on the above.
But what about the ohm measurements on the other terminals?

[discowhite]

http://www.aulro.com/albums/album17/532562774UVpTkt_ph.sized.jpg

this is DW's 14cux 5am MAF.
my outside terminals measure 56 Ohm. its a 3.5L so the value might be
differant.
dose your terminals look like this??


phil.

[knuts2au]

Yep, thats the same looking air flow meter, i notice the left outside terminal actually doesn't have a wire connect to it in the mating plug on the loom, so must only be there for measuring purposes? I'll adjust before i go for a run into town this afternoon and see if it does make any difference.

[knuts2au]

Well i adjusted it back to 174ohms, and took it into down, it seems to idle smoother, but it does that some days, then again it could be my imagination. Going to call in and see an old friend i had forgotten about who is a LandRover specialist and RR owner ( the young mechanics father) and see if i can find out the rest of the story.
I got a picture of the MAF and connectors but can't work out how to attach it to the post?[/img]

[Rovernaut]

Originally posted by knuts2au
Well i adjusted it back to 174ohms, and took it into down, it seems to idle smoother, but it does that some days, then again it could be my imagination. Going to call in and see an old friend i had forgotten about who is a LandRover specialist and RR owner ( the young mechanics father) and see if i can find out the rest of the story.
I got a picture of the MAF and connectors but can't work out how to attach it to the post?[/img]

knut2au, to post a pic, first you have to upload it to a web hosting photo site and link the image from there. ie photobucket.com.
Or just upload it to your gallery and lets us know it's there.

[Rovernaut]

Found this info on RPI's site.
How to adjust MAF and throttle position meter.
These pics are from their site also..
https://www.aulro.com/afvb/images/imported/2006/01/53.jpg

https://www.aulro.com/afvb/images/imported/2006/01/54.jpg

Find the Throttle pot on side of plenum. There are three (3) wires coming from this unit to a multi plug. Do not disconnect. Wire colors are Red, Green, Yellow. Red from volt meter to red wire of pot. Black wire from volt meter to Green of pot. Volts should read .33 to .35 volts if not, loosen the two (2) screws that hold it in position and turn it to get the correct voltage. If you cannot get the correct voltage setting, undo and remove the throttle pot, make the fixing holes elongated and you will be able to get the right voltage.

Please note that the following air flow meter settings should be made when the engine is warm.

The air flow meter wires can be accessed by pulling the rubber boot carefully backwards along the cable. Under here you will find the following wires. Red with Black trace = Sensor ground, Blue with Green trace = air flow signal, Brown with Orange trace = Ignition live 12 volts and Blue with Red trace = CO trim value. A digital multi meter should be used and connected to the sensor ground and CO trim value wires. The values that you are trying to achieve are below and these are adjusted by the screw on the side of the airflow meter.

Air Mass meter setting (non cat). The voltage reading on the CO value here should be between 1.0 and 1.5. If you have the Tornado ECU chip fitted then 1.5 volts should be aimed for.

Air Mass meter setting (cat). The best setting for the CO value here is 1.8 volts.

When setting your Throttle potentiometer and Air Mass/flow meter, you should also check the resistance scaling, using an Ohms meter and checking from highest to lowest resistance, smooth scaling is essential for the correct basic workings of all these units.

All High performance and big capacity Hot Wire V8s should consider upgrading to the 4.6 Air Mass Meter as shown abovehttps://www.aulro.com/afvb/

[DEFENDERZOOK]

<span style="color:blue">im sure ive got my copy of these notes from the good ol days....
these specs were not written in the workshop manuals.....



do you think i could find my notes when i need them......?
but that figure of .35 rings a bell so too does adjusting the throttle pot....
on the later models the throttle pot was not adjustable....

with those that were adjustable....care was needed when tightening the
screws as it would move slightly as the plastic flexed throwing out the reading...
so make sure the reading is correct after tightening the securing screws....

if and when i find my notes....i will post any info that i think may benefit others on this forum....

until then......</span>

[sclarke]

Well done Rovernaut

Do you have the link to that website.....

i think ours needs a tune as 24l/100k on the hwy is not real good...

[DEFENDERZOOK]

<span style="color:darkred">a note to anyone checking any resistances on late model vehicles.....

must use digital multimeters.......analogue meters can damage delicate
electronic(read expensive) components......</span>

[Rovernaut]

Originally posted by sclarke
Well done Rovernaut

Do you have the link to that website.....

i think ours needs a tune as 24l/100k on the hwy is not real good...

http://www.v8engines.com/

Lots of interesting stuff on this site Clarkey, are you thinkin of getting back into the V8 scene?????????????? LOL.
No info on kero burners on this site. VROOOOMMMMMMMMM!

[sclarke]

Originally posted by Rovernaut+--><div class='quotetop'>QUOTE(Rovernaut)</div><div class='quotemain'><!--QuoteBegin-sclarke
Well done Rovernaut

Do you have the link to that website.....

i think ours needs a tune as 24l/100k on the hwy is not real good...

http://www.v8engines.com/

Lots of interesting stuff on this site Clarkey, are you thinkin of getting back into the V8 scene?????????????? LOL.
No info on kero burners on this site. VROOOOMMMMMMMMM![/b][/quote]

Michelle's Disco is a 94 V8.... So that is why i'm having a squiz....

[Rovernaut]

As Knuts2Au posted earlier the ohm reading of 174 across the end maf terminals gave me a reading of 1.28 volts on the MAF.
1 volt gave me a reading of 108 OHms.
I presume that since the readings change on adjusting the screw on the side of the MAF means is functional???
Or if the sensing wires are broken, will the figures still change.

As per the potometer I can't get those figures as stated in my RPI post.
I can only get fractions of volts.
And the wires are coded as Brown, green and Blue