Air flow meter problem

R

Redsport

Ex. Club Member
Hi, hope someone can help with my our 2001 Micra Sport 1 lt, without warning the car became difficult to drive, it did not like low revs and I suspected some sensor fault. Our local friendly garage put it on his code reader and said it was the air flow meter, he disconnected it and the car drives fine. The Haynes manual says you can't change just the air flow meter? however on Ebay there are several such as this one

http://cgi.ebay.co.uk/Vauxhall-Air-...arts_Vehicles_CarParts_SM&hash=item1e5fa1f5ab

will this be ok? there are two odd screws holding it on, like a stardrive but with a pin in the middle, I need to take it off to check any part numbers.

I'm hoping to avoid having to change the whole throttle body, any ideas gratefully accepted! Thanks in advance:grinning:
 
hi redsport :grinning:
you can get the post 2000 type ones on ebay, and the oddball tool to remove it too (there are a few threads about them recently)
 
gtsnissanb said:
is it not a security torx frank the last one i did was
Click to expand...

I'll try in Halfords for the security torx, if not I can try and drill a hole in one? The chap in the garage said it was different to any sockets he had!
Thanks for the replies, I looked at the threads re soldering throttle bodies which I could have done, except ours is a later car, good job we've got the Focus to drive about in:grinning: The Micra otherwise has been 100% reliable and has a sheltered live in spite of which I've just found some rust in the front crossmember, not too bad though and I've welded lots of cars over the last 35 years:laugh:
 
:grinning:
Redsport said:
I'll try in Halfords for the security torx, if not I can try and drill a hole in one? The chap in the garage said it was diferent to any sockets he had!
Thanks for the replies, I looked at the threads re soldering throttle bodies which I could have done, except ours is a later car, good job we've got the Focus to drive about in:grinning: The Micra otherwise has been 100% reliable and has a sheltered live in spite of which I've just found some rust in the front crossmember, not too bad though and I've welded lots of cars over the last 35 years:laugh:
Click to expand...

be easier to knock the little pin out of the middle of the screw rather than drill a hardened torx driver
 
I've looked in Halfords and Maplins and I've seen lots of different security bits but not one with 5 pointed star on it , Nissan seems to have gone to great trouble to stop removal of this part! I've certainly not given up yet though! might try the slot in screwdriver trick as suggested!:grinning:
 
Today the set from Ebay arrived, one of them was a perfect fit, the sensor came off very easily and with the part number visible I've ordered a new one from Ebay. Out of curiosity I sprayed the old sensor with carburettor cleaner, refitted it and the car runs just fine:grinning:
 
Hi All, My first post here...

Micra 1.0 2001 (Y plate)

I've had a problem with my Micra for about 3 years which I've assumed was down to the throttle body/air mass meter (?) but I've always put off sorting it out, it starts first time, idles ok and doesn't stall but there's a big issue with the throttle response, when starting in first gear or if stationary and out of gear, pressing the accelerator has the opposite effect, the revs reduce to practically nothing and there's a sound of blowing from the front end of the car (may be the engine bay or underneath), to get it going I have to really drag the clutch and pump the accelerator on and off (to try to prevent it stalling.. although it never has). When it's heated up and been run for a while it's not quite as bad but still rough. There's a total lack of power too in the higher gears and it struggles to get up to 60 in 5th gear on the motorway. Like I say it's been like this for about 3 years and passes it's mot each time. The check engine is lit on the dash but it's been off the road now for a few months so the dead battery has reset that, usually I'd have to drive it again for a few days for the error to show again so when I've done an ECU check for the first time this week after charging the battery it all checked out ok. The MOT and tax has run out so I'm a bit stuck with that. I've left it running on the drive for around 45 minutes but no error message yet. I downloaded the guide relating to re-soldering the dry joints on the air mass meter and took out the air box today only to discover a completely different meter on the car so I guess that was for earlier Micras. I'm not sure which way to go with diagnosing the issue, I'm no expert and I'm worried that if I buy a new or used throttle body it might be something else causing this. I know nothing about replacing it also, the star screws are an added pain it seems reading this thread.

Is the throttle body most likely?

Thanks,
Tezz.
 
I forgot to mention.. is it common for there to be some dust and dirt particles around the top of the meter where it's exposed through to the airbox? My filter was admittedly very dirty and way overdue to be changed but I didn't expect to see the airbox to contain so many contaminates beyond the filter.
 
Tezz said:
I forgot to mention.. is it common for there to be some dust and dirt particles around the top of the meter where it's exposed through to the airbox? My filter was admittedly very dirty and way overdue to be changed but I didn't expect to see the airbox to contain so many contaminates beyond the filter.
Click to expand...

yes thats normal tezz, and surely the idea of the later bosch t/b with the removable maf, is that you can replace just the maf rather than the whole t/b ?
 
frank said:
yes thats normal tezz, and surely the idea of the later bosch t/b with the removable maf, is that you can replace just the maf rather than the whole t/b ?
Click to expand...
oh right thanks, I wasn't aware that was possible to be replaced so I was just looking into getting the whole thing swapped out. It's all new to me. I'll look into that tonight. Is it relatively easy to remove the maf?
 
I learnt this week that you can diagnose whether the problems being experienced are down to the maf sensor by simply unplugging it, mine was definately the problem so I've bought a new one although I'm guessing that the existing one could probably have just been cleaned as suggested above but as I've not taken it out so far I don't know, I haven't picked up the TS torx bit yet to swap it out with the new one as I don't know what size I need to buy?

I've seen this on ebay: http://www.ebay.co.uk/itm/Tamper-Security-Torx-TS-Star-Bit-Set-5-Sided-3389-/160574763149 which includes sizes TS10/15/20/25/27/30/40, does that include the correct size?

Thanks in advance.
 
I replaced the maf sensor this morning with a new one after also giving the meter a good clean where it's installed into and the car is running fine again now. The sensor that I removed looked perfectly clean so I guess they must just physically fail after a certain time.

For future reference in case anyone else is looking to do this too, the anti tamper screw was size TS25.
 
Tezz, just out of curiosity, as I have similar problems with my K11 / 1997, how do you unplug the MAF sensor, and do you know if the car can run without it being connected, or is it dangerous?

(I'm no engine expert, all I can say is where the throttle body resides under the hood.)

Thanks!
 
appleman said:
Tezz, just out of curiosity, as I have similar problems with my K11 / 1997, how do you unplug the MAF sensor, and do you know if the car can run without it being connected, or is it dangerous?

(I'm no engine expert, all I can say is where the throttle body resides under the hood.)

Thanks!
Click to expand...
The air flow meter itself is directly under the air box, once you take off the airbox cover and put the filter to one side, the bottom half of the airbox is push fitted onto the meter which has a rubber gaiter around the neck to make it an air tight fit, this is then secured tight with a jubilee clip (you'll need to crouch down low to the engine to see the jubilee clip underneath to unscrew it. The airbox base has just one screw on the right hand side which you will see looking down onto it.

With the earlier K11's it's actually a different meter altogether (although the airbox fitting and removal is the same) the maf sensor as far as I know isn't removable with the previous meters (correct me if I'm wrong other users!). It might be the case that yours has suffered with a dry joint on the circuit which was common, there's a step by step pdf guide that a guy put together in Australia a few years ago explaining how to do it. You'll just need some silicone sealer for a couple of quid and a solder iron to give that a go first. The pdf guide should be here on the forum someplace I would think.
 
Quick bump to say I also have strange running problems. It initially showed itself as a pronounced lack of power at 45mph in second gear, and through third gear too - it'll pull for a couple of seconds beyond those speeds, then flatspot unless you 're-tap' the throttle, where it'll pull again, flatspot. Repeat to fade.

Changing the spark plugs to shiny new ones has helped a lot. The old ones looked fine and were 'the right colour' but were under-gapped to 0.9mm - should be 1.08 or so according to the Haynes Book Of Lies.

Every drive being an italian tune up probably hasn't hurt either - it was previously used in Leeds owned by a woman, so probably short journeys everywhere, and I doubt it got much hard use.

Now when it's warm it seems to flatspot less, but it still happens. For example, after a twenty mile run the other day, it'd whip round to the limiter in second, no problem. No flatspots, at all.

I've got a 2002 K11, so I guess I can drop the MAF temporarily, but as this happens high up the rev range most noticably (a lack of power is most noticable where it generates it most) am I likely to cause any problems by hitting the revlimiter with the MAF disconnected?

As I tend to hit it often enough when it is, flatspotting not withstanding.

If I disconnect the MAF and it makes no change, I'll start a new thread with more details - probably after I have checked the valve clearances, pushed this tank of redex'd super through the engine mostly at 4000+rpm (also thinking gummed injectors, y'see) and put a new fuel filter in.

MAFs do seem to be a common point of woe on these lumps, though - hence the thought.
 
Hi all.... since I replaced my MAF sensor last year (along with all the other maintenance stuff done) I've had no free time so the car has been sat on my driveway ever since. The past few days I've got back on to getting everything sorted for it's MOT this morning. I just needed to replace the battery as the charging of the old one indicated that it was faulty. But anyway on to the point... This morning driving to the MOT was the first time it's been driven since and although it drives fine now, the engine management was still lit on the dash, I've not hooked the car up to the computer yet to see the error code but I asked the garage whilst I was there and they said changing the sensor alone wouldn't fix it and I would have to replace the whole MAF meter to sort the problem? They said they could hear it surging whilst it was up on the ramp. Is that the case that I need to swap the whole thing? I thought it was only the sensor failing that caused these issues? Is it just an old error left in the ecu, i.e. do I just need to reset the error somehow connecting it up to the computer? Any advice appreciated!

I've not put in the new spark plugs yet, they're still sat in my garage, reading the post above I'll def do that to get everything service wise completed. Is 1.1 gap correct?
Is Redex a waste of time btw? I've not used Redex for years, never really known if it did any good or not?

Cheers!
 
frank said:
i doubt if you have a maf fault then mate :)
Click to expand...
ah ok yea, maybe a dif fault causing it then, I guess I'll find out more when I hook it up. When I mentioned the engine managment light the garage guys jumped straight in saying it'll be the maf meter before I mentioned anything about changing the sensor. then they said I've wasted my time and need to change the meter itself.
 
Now that it's stopped raining here this morning I've hooked the car up to the laptop to get the error code, it's stating P0100 "Mass or Volume Air Flow Circuit Malfunction" (ECU code $10). The car does drive way better after changing only the MAF sensor although it did have a slight hesitation after starting it up again when I stopped for some petrol after having driven back from the MOT on the motorway for 10 minutes. So it looks like there's a further issue somewhere with the meter that I'll need to sort out. The garage mentioned that they heard the meter surging when it was up on the ramp too.

Is it possible to clean the meter out? (I remember reading somebody cleaning it out with carb cleaner) or are there other sensors that can be replaced or should I just bite the bullet and get an entire reconditioned meter? It's the Bosch 0280750051 that's installed. There's some remanufactured ones listed on Ebay for £180 ono by BBA Reman (161191F700 - NISSAN MICRA BOSCH THROTTLE BODY 1999-2003 WITH SENSOR: Item number: 390410882565) I don't know whether they'll be good to go or even they're official Bosch ones that they remanufacture. I'm burning money so far getting everything done so I'm hoping that there's an easy answer before having to replace the meter.

Any advice on what to do next?

Thanks all.
 
I've been looking into this a bit further online today, the P0100 seems to be typically associated with a faulty MAF sensor so I'm wondering now if the one I bought last year is causing the issue. When diagnosing these MAF related errors, they'll check the voltage of the MAF sensor to make sure it's at the correct frequency for the car it's installed in based on the manufacturers guidelines. Having an incorrect sensor frequency would throw up an error with the ECU so I'm hoping that might just be the case. I've contacted the company that sold the new MAF to ask them about it. It's got roughly a months warranty left on it.

The re-manufactured throttle bodies I mentioned above are genuine Bosch ones so I'll go for that if this doesn't help. I'd much rather find out exactly what it was that's causing this though instead of swapping out the whole thing.
 
I took the car for it's re-test today and have the MOT now. Bit gutted that the new MOT single sheet format includes the advisory stuff so the engine management warning is listed as well as "oil leak" (which they were unable to remember where when I asked them). There's no oil leak anywhere evident, I've had the car parked over a clean bit of cardboard since working on it to check for that and i've been all over the engine bay and underneith to check so I've no idea what that is. but anyway, I got a response from the company who sold the sensor but just got a basic installation guide back from them

1. CHECK ANY VACUM HOSES FOR SPLITS/LEAKS THIS CAN BE THE CAUSE OF SYMPTOMS
2. CLEAN INDUCTION SYSTEM SO THAT ITS, free of dirt/oil/debris
3. REPLACE AIR FILTER
4. Disconnect the battery then depress the brake pedal for 1 min (to drain system stored power)
5. Wait 15 minutes
6. FIT NEW UNIT
7. RECONNECT BATT
8. ** some vehicles will require OBD code reader to reset ECU and install part - please consult workshop

Battery was disconnected for weeks before changing the sensor and i took the airbox and pipes out, totally cleaned them and stuck in a new filter

What's the induction system? Is that the inlet of the meter? When I took the sensor out I checked around inside the meter to see if there was any dirt built up but all seemed ok so I just fitted the new sensor.

The error code is reset after the power is disconnected so it doesn't need to be reset via the ODBII. As far as I know it's generating a new error code as soon as you drive for a few seconds once it's been reset?
 
Can anyone tell me if it's possible to take off the rubber mesh on the top of the meter without damaging it?
I've sent my sensor back for a replacement just in case it was at fault but I want to take the meter out and clean it with carb cleaner before refitting the sensor.
 
Tezz said:
hi, yes it's the rubber mesh on the top of the throttlebody.
Click to expand...
well the throttlebody is just throttleplate inside a housing eh, which only regulates the flow of air into the engine basically, so cleaning that will do sweet F/A really,
the parts to clean or inspect or replace are the idle control valve, t/p/s and maf
 
frank said:
well the throttlebody is just throttleplate inside a housing eh, which only regulates the flow of air into the engine basically, so cleaning that will do sweet F/A really,
the parts to clean or inspect or replace are the idle control valve, t/p/s and maf
Click to expand...
I was intending on cleaning out all the dirt throughout the whole meter whilst I'm taking it apart for the sake of it if it's possible to get the mesh off.

I'm replacing the MAF but I don't know where idle control valve is or the Throttle Position Sensor? Are they the connectors on the back of the meter?
 
I managed to get some free time eventually today to take off the tps and the idle control valve from the meter but after getting the 5 sided star tool set out that I bought for taking off the maf sensor previously, the other two sensors both have a different type of security screw :( does anyone know which type I need to buy? I couldn't get a proper look at them.

Before doing this, the car has had problems starting. I have to kick over the starter motor about 10 times before it starts so I was going to get the new spark plugs installed. My socket set with the extender on wouldn't reach far enough to get them out though so I'll have to buy another one. I bought a set of spark plugs from Euro Car Parts, they were the Bosch Super 4. They're not like the usual plugs where you can set them to the correct gap with a gauge, it's like four prongs over the electrode and the description on the box says "With pre-set electrode gap" so hopefully they will be ok??
 

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