DEFENDER2.NET - View topic

↓ Advertise on Defender2 ↓

Home · FAQ · New Posts · My Posts · PMs · Search · Members · Map · Calendar · Profile · Donate · Register · Log In

Home > Td5 > MAF Sensor

Page 1 of 1

Print this entire topic ·

Tank

Member Since: 25 Jul 2014
Location: Fife
Posts: 431

MAF Sensor

OK so I changed my MAF sensor as it was reading 4.4 on my friends Nanocom.

It has made a real difference and the car picks up and runs better.

One question though, how does the MAF work ?

Looking at it, its a plastic tube with some sort of sensor in the air flow part and some mesh gauze at either end of the plastic tube ? Would be interested to know how it works ?

Also

How and why do they break / go wrong. If its only handling air why would it break ? Mine was a bit oily ? Is that a problem.

Damn thats two questions, gona get ribbed for that !

Be gentle with your answers as I know you are all nasty people on this forum

17th Nov 2015 5:16pm

dorsetsmith

Member Since: 30 Oct 2011
Location: South West
Posts: 4554

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.

i found this

17th Nov 2015 5:52pm

custom90

Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20613

From a laymans and point of view most of them go downhill due to being contaminated over time.
The filter does a good job but over a long period they do get a bit dirty.

I personally don't believe such things can be cleaned sucessfully myself without further problems due.
Best to replace in my opinion.

Mine is a 2.4 not a TD5 and has been in since new and hasn't caused a problem at all.
It could likely do with being changed over though..

17th Nov 2015 7:45pm

Tank

Member Since: 25 Jul 2014
Location: Fife
Posts: 431

Thanks Dorsetsmith

I had done a Google search before I asked and I suppose what I was after was a non techy response but yours was interesting so thanks

Tank

17th Nov 2015 8:41pm

Tank

Member Since: 25 Jul 2014
Location: Fife
Posts: 431

Thanks Custom90Steve

Defender has 167,000 in the clock so could be original MAF

17th Nov 2015 8:42pm

custom90

Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20613

If that the case then it most certainly would be a good idea to change.

17th Nov 2015 8:48pm

Loz2286

Member Since: 31 Aug 2015
Location: High Wycombe
Posts: 121

OK...I'm really a Series guy so anything involved ECMs is alien to me. My 110 is 15 years old with 134k on the clock. Seems fine to me, but I have no comparison in performance. How would I know if my MAF is FUBAR? 1999 Td5 110 CSW
1961 Series 2 88 LPG

18th Nov 2015 4:27pm

mk1collector

Member Since: 17 Sep 2009
Location: West Yorkshire
Posts: 6772

If you unplug the maf and take it for a run there should be an improvement in response which indicates the maf is dud or if you look on the bas tuning (site sponsor) website there is a guide to check with a multimeter. Bas also sell new mafs

Ray
My build thread
http://www.defender2.net/forum/topic17615.html

18th Nov 2015 5:54pm

Page 1 of 1

All times are GMT

Jump to

< Previous Topic | Next Topic >

Posting Rules

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum