Thread: HEY -CLEAN YOUR MAF!

Originally Posted by gusthedog

I probably shouldnt have but I couldnt get maf cleaner either - so used crc brake clean! Worked a treat. I made sure I used the air compressor to make sure it was all dried out before I re-installed it though. Was recommended to me by a mechanic - that's what he uses. I also used it to clean the oil out of my ecu wiring harness. Also worked really well.

Thanks Mate, brake cleaner I can get. Might as well give it a go since you didn't have any adverse effects.

Holy S**t, that the best $26 I have spent on the Disco.

After reading this thread last night I found that my problem were the same as some of the guys on this thread so when out shopping today stopped by local car shop and picked up some of the CRC MAF Cleaner. When I got home removed the MAF and gave it a good spray, used almost half the tin, waited until it was dry, refitted then waited some more time before taking it for a spin.... Holy S**T it has now lost all the problems for surging and random gear changes and has power all the way up the Welshpool Road hill to Lesmurdie.

I am like a kid on xmas eve am so happy.

Just thought I would share this with everyone

When a MAF sensor is disconnected the ECU will default to a preditermaned Lambder to protect the engine ie. Richen up on a petrol and lean out on a Diesel the same is also true for the 02 sensor. Just a bit of random info for people who care.

In relation to earlier questions,

If you disconnect, in a manual you'll notice no real discernible difference in driving apart from a small loss of guts/torque. In an auto, more loss of acceleration, probably won't shift past 3rd (esp under load), just revs and then drops back to first and repeat.

The source of dirt other than air box/filter is the two rocker cover breathers feed into the inlet tract, just upstream of the MAF. Any blowby will force oil misted air back into the inlet and if you blow a head gasket and it fills with water, and oil water fills the airbox it really kills it.

The system compares air mass in (and there's a default volume of oxygen by mass in nayure) so it knows how much oxygen the engine receives based on this as a value of temperature. This is compared to the O2 sensors value of O2 mass out the exhaust. From this it will enrich or lean the mixture and also run closed or open loop modes of running depending on temps of air and engine running.

Post my BHG and MAF failure (which was undiagnosed) I had it to 3 dealers, 2 specialists, 3 auto mobs who all said the auto was dead (due to the not shifting issues I had, detailed above). So spent 3K on the auto and still had same issues. So I got a scangauge, plugged it in and started reading, driving and diagnosing. You could see it running normal when warm, open loop mode. Then, under load and getting into 3rd, would go into closed loop mode and go to cold start system when I would get no signal from the MAF. But then the O2 sensors say "Hey, we've got all this unburnt oxygen here" so ECU adds fuel. Then MAF would start working again and it thinks hey x amount of air, cut fuel accordingly.
repeat.
repeat.

Kangaroo's down the road in an auto while the ECU has a nervous breakdown.

Nice read! Bit of topic, I have a disco 1 duel fuel, how come disco 1's will not run at all with the MAF disconnected? Mine is broke atm and im thinkin maf, as when I was workin on it on many occasions before if I fogot to plug it in it would not start!

The sensor is different, it's either a flapper type (and so if it's like other I've seen the fuel pump runs because of it, airflow open the flap and is one of a few triggers for the fuel pump relay), or a hotwire type. Simpler (lucas) ECU, no direct ignition control (distributor) & no default limp mode probably.

Originally Posted by twodoors

Mmmm seen this advice before..... However other sites list it as a kill it or cure it option.... Thought id try it last xmas...... Guesss what... I had to buy a new one as the maf died within 1 hour of spraying...... Beware!!!!!! My spray was from autobarn .... About $30.... Then the$200+ new sensor.......
James

Bit of an older thread I know but; wheres a good spot to get a MAF sensor for d2v8? (wasnt fond of the price I was quoted just as an enquiry)
Dont need one yet though but like to know which way to jump before it happens

Under advice a couple of weeks ago from Ian 'justfishing' over here in Perth to clean my MAF on my TD5 with a brake and parts cleaner I did. Wow what a difference.

I cleaned mine a good hour after stopping the engine and I let it dry in the sun for a bit afterwards when I was removing the egr and changing a faulty thermostat so plenty of time to dry.

I noticed a big difference. Smoother gear changes, better throttle response and more power. I mean we're not talking massive amounts but definitely noticeable. I cleaned the sensor in the air filter and the MAP (i think it was the MAP ) as well at the same time.