spluttering.... is itmy m.a.f. sensor?
 

started the car up last night to go to work. set off and its seemed to splutter and cough from about 15-25 mph. so i give her a little throttle, and it generally went away.

straight away i thought it may be either the dumpvalve i have fitted or possibly the m.a.f. sensor. its a uk my99 classic by the way.

just popped out now to go to the shops, and the same thing happened when i set off. again gave it some throttle to rid of it, and made a note to check the engine over when i got back.

seemed a little hesitant when i was stoping, starting in traffic.

anywho got home, and tried the m.a.f. out, by unplugging it while the engine was running.

first time it cut out after a couple secs. plugged back in turned engine on. this time i blipped the throttle cable a little and unplugged the m.a.f. again. it didnt stall. spluttered etc and kept running.

tried it again two more times, and it stalled again, then kept running again.

is this my m.a.f. sensor telling me its time to change it?

the cars due a service next friday, and is defo in need of an oil change and probably spark plugs too.

can someone shed any light on this matter for me please? the fact the engine only cut out two out of four attemps worries me. is it the m.a.f. or maybe the dumpvalve?

car has a lot of miles (128k) but the engine is less than 60k old.

really appreciate any input on this. the car is standard apart from the dumpvalve and full decat (jase at scoobybits replaced the lambda sensor when fitting the decat downpipe too)

cheers

andy

just done two ecu resets, and nothing... just the correct 0.5 sec flashes.

im stumped now. just thought however that it seems to do it from cold more predominantly.

as said in the above post, my engine was cold last night when it did it the first time, and this afternoon... but this morning before coming home from work, i warmed the engine up for 5 mins, and didnt really notice anything as bad.

this is doing my head in now. im not too keen to run the car until next friday, especially if it keeps doing this. plus im doing a run to newcastle next friday afternoon too. god forbid if my car dies on the motorway:lol1:

anybody on the morning shift offer me some help? m.a.f.? water temp sensor. ive heard these dont show up on the ecu fault code check light.:wonder:

andy

p.s. again this morning warmed the engine up before driving home. no spluttering etc, but seems a little lumpy when pootling along around 2-2.5k revs.

Andy, had the same problem myself fairly recently.

WEnt to Halfords got some Injector/Carb cleaning spray.

Took out the MAF got sprayed some on the sensor "bubble thing" then, got a cotton wool bud and carefully rubbed, the amount of crap that came off.

Did it twice more, (after leting it dry).

Then took out my sports panel filter, and cleaned out both sides with a small brush.
Then sprayed some Inector/Carb spray ON THE OILDED SIDE.

No hesitation no running problems.

I do this once every 4-6 weeks ( live by a sand quarry) no problems.

Hope this helps.

Regards


Alan MaC

Easiest things to check/change are the MAF and the idle control valve.

The idle control valve should be a bit sooty and not full of gunge.

If the Lambda sensor wasn't a Subaru OE part, it might have failed.

If you've recently been tinkering with the dump valve, check the installation.

J.

couldnt tell you whether the lambda sensor was a oe subaru part. jason swapped them when he noticed mine was dud when having the downpipe fitted. trust him enough not to put knackered parts on my car.

any ideas on how to clean the m.a.f./idle control valve sensor?

as alan mac said about carb cleaner, but im not sure on a method.
car has a k&n panel filter on it, so which side would be the oiled side?

andy

oh, for the record, i started the car up again when going to pick the mrs up. was cold obviously, unplugged the maf and it didnt stall, just spluttered again, but kept ticking over...

have just bought some spray stuff from halfords. its in a green/yellow can and is called electrical contact cleaner.

please someone tell me quick before i take my maf apart if this will do harm or good.

http://i64.photobucket.com/albums/h1...n/DSC00065.jpg


on the back it says the following...

"a powerful solvent based cleaner specifically designed for cleaning ignition compontnets and other precision parts. it is safe to use on metal as well as most surface coatings and plastics. it will effectively remove deposits of oil grease or dirt."

note: this product contains a high level of flammable materials. avaoid spraying on or near hot surfaces or naked flames. not recommended for use on live electric circuits/other energised systems.switch of all power beofre use and ensure product has fully evaporated before reconnecting power.

directions... spray from distance of 15-30cms. product will evaporate rapidly. any excess should be wiped off where necessary.

any suggestions. im soo thick at this cleaning malarky.

As your cars a my99 spec mate, i dont think you can clean the maf

ISCV is easy, you just take it off and spray with cleaner and then spray a rag and clean the hole where it goes :)

iscv...?

Idle speed control valve ;)

where abouts is it??

was gonna try the maf today and then see how it goes. if not, be a little pop to scoobybits in the morning to test it out.

On top of the engine, sticking out of the right hand side of throttle body.

Just undo the two screws and pull it out

I wouldnt do the Maf mate as im sure you cant clean them, im on my fourth in 6 months :eek:

will leave the maf then. just swap it tomorrow for new one.

erm throttle body? where abouts am i looking to start with. the only parts i know are the manifold and the turbo.

paint me a picture so to speak...

Just of the front of the top mount i/c, the pipe leads into the throttle body

Bonnet up, looking in fron the front of the car.

From the back...
- Intercooler
- Intercooler/throttle body hose.
- Throttle body.
- Inlet Manifold

On top of the throttle body there's a blob with an electrical connector on it. That's the ISCV. Throttle body also had the accelerator/throttle cable, cams/springs etc attached on the left.

Don't clean the MAF on an MY99. It'll break. Earlier ones are "hot wire" and are relatively hardy. The MY99 ones are "thin film" and about as hardy as a soap bubble.

J.

right, ive got the air filter box off. took a pic.
where is the idle valve in the second pic?

http://i64.photobucket.com/albums/h1...n/DSC00067.jpg


http://i64.photobucket.com/albums/h1...n/DSC00068.jpg

Its right to the left of the D/V in the pic

think this may be it???

i took off the two screws, and its a similar shape to a cigareete lighter. was quite greasy inside with like oil on it. not very sooty at all.

http://i64.photobucket.com/albums/h1...n/DSC00070.jpg

for the record, after i put it all together, i turned the engine on and unplugged the maf again. spluttered slightly, but kept on running without fail. im really thinking its the maf, and the ecu trying to compensate for it being knackered. is this a decent enough theory?

andy

I have had exactly the same probs as yourself MY00, after a new maf and o2 sensor all was fine.

Yep thats the ISCV :thumb:

But it does sound like Maf failure mate

James

right thanks guys, i do actually really appreciate your help on this one. defo getting it changed tomorrow. i dont care how busy jase is, il make him a cuppa and keep him sweet lol.:lol1:

for the sake of £90 over a £3k engine rebuild.... erm no brainer.

You say you have a decat, have you had it re-mapped yet as this could cause the maf to fail

nope. not had a remap. but to be honest, the car doesnt get driven hard, and jase sorted the lambda sensor out when fitting the domnpipe.

the car had a backbox and centre decat done months ago, then about 4 weeks ago had the downpipe fitted too.

You should get it re-mapped, as the engine is probably running lean and you could get a costly rebuild, also you will notice a real improvement in performance

see what your saying fella. i am looking for a remap evenually but i havent got £700 odd for it to be honest. i assume plenty of other people run classics with decats and not remaps.

i believed it to be only the newages that really required remaps for decat exhausts.

Well Brian its a remap or a knackered engine, if its running lean!

It does not matter how long or short your journeys, if the cars running lean that means your doing damage, serious damage.


Best of luck m8.

just curious to the other people that have decats without remaps... ive done an ecu reset so usually on later classic, would they not recognise and learn from the new settings so to speak. all i have done is remove the cat off the system, surely the ecu will learn to this especially after a reset.

i haveny any supporting mods, and didnt want to remap until i have these ready.

Andy FFS,

It's Wynn's Fuel Injecton Intake & Carb Cleaner from Halfords and other places.

It has a WD40 Type Straw to get in there.

I wouldn't tell you donkey dirt ( remember me, I offerered to help lend your pal a set of wheels??)

On the subject of your K&N Filter, as I said, gentle brush both sides to get rid of the crap.

On the top side ( the one with the colour) spray a bit of the can on also (just a bit) it will blow through in a clean way.

Do as I suggest ( if you want to) in the first reply to your post.

I am confident it will help.

Good Luck, if it works, that's a cheap drwaing of my Scoob from you;) ;) ;)

Regards Alan MaC

Ask anyone, you cant clean 98 onwards mafs :cuckoo: