timmyt

Hi,

Hoping somebody could give some advice.

Bought a standard 2000 plate UK spec turbo with 60,000 on the clock, 6 months ago. Haven't been completely convinced with the performance and have noticed a couple of flat spots.

Decided to get it on the rolling road this afternoon and it seems my suspicions were right. Car was only pumping out 191 bhp and approximately 200 lbft torque. The guy running the RR then noticed that the Air Fuel Ratio was vey high. Sitting at anything between 18 to 21 and reaching upto 22 at one point.

Decided to cut the RR short at that point for fear of destroying the engine.

They put the car on the diagnostics and found nothing. Problem it was getting late and they didn't want to start pulling things apart.

Their best guess was a dodgy fuel pump and thought checking the pipes for blockages and probably a new pump was in order.

Has anybody got any ideas?

Problem is it's going to be expensive guess work without knowing where to start for sure.

In addition what sort of power should I be expecting from an 8 year old standard car. It's been fully serviced etc.

Cheers

Tim

Syph

I'm no expert but it could be the ecu telling the car to run rich due to a bad signal. you might want to start with the lamda.

I'm sure if i'm wrong someone will point it out tho.

Jolly Green Monster

iTrader: (4)

MAF would be most likely culprit.

reset the ecu and see how the car drives.. if worse then replace the maf.

yes it could be the fuel pump also..

Simon

Jolly Green Monster

iTrader: (4)

the number quoted look like AFR not lambda and are lean not rich.

Simon

timmyt

Hi Guys,

Thanks for the quick response.

The numbers quoted were the AFR figures as you said Simon.

I had my suspicions about the MAF sensor as so many people have mentioned problems with these on previous posts.

How do you reset the ECU?

Can I clean the MAF or should I just replace it?

Any recommendations for fuel pumps? If I'm going to change it then I was thinking I may as well go for a performance pump.

My concern is also that if I reset the ecu then go out for a thrash to see if there is a difference then if this hasn't resloved the issue am I running the risk of knackeing the engine.

Sorry I'm firing all these questions at you but I'm new to Subaru's and could do with all the help I can get.

Thanks

Tim

Jolly Green Monster

iTrader: (4)

Tim,

you can reset the ecu by disconnecting the battery for a while or I have on my website the reset sequence under the help pages.

Do NOT drive the car hard full stop at the moment.. once the ecu is reset all the learnt fuel and ignition tables will be reset.. it will learn slowly to a failing maf sensor as it slowly fails.. by resetting the ecu it should then run like a dog.. idle will be hunting and possibly stalling at junctions.

The best pump and cheapest is a walbro 255.. I also have a brief fitting guide on my website.

Of course perhaps the best course of action would be to take it to a specialist.. where are you located, so can advice of nearest etc..

Simon

Syph

My bad!!

Told you i was no expert!!!!!!!

timmyt

Hi Simon,

I was just looking on your website, very helpful thanks.

I'm in Bedfordshire. Nearest big town is Luton!

I can try the ecu reset in the morning but are you saying that it's only going to be any good if the MAF sensor is okay and the car can relearn everything? Or is the car going to become a nightmare particularly if the MAF sensor is knackered. Problem is as a novice how will I know if things are going well or not once I've reset the ecu?

A specialist would be handy.

Any ideas?

Thanks

Tim

timmyt

Syph,

Thanks for replying anyway, it's appreciated.

Tim

timmyt

Simon,

Just re-read your post.

Think I've had a couple to many whiskeys and my brain isn't functioning

Are you saying that by resetting the ECU the car will learn everything and run fine pretty quickly if the MAF is okay.
However if the MAF sensor is knackered and I reset the ecu that the car will struggle to learn and run like a dog?

Have I understood you correctly?

Thanks

Tim

johnlogie

iTrader: (4)

I paid £125 for a maf from subaru and the dude fitted it for me for free as u need security torques

timmyt

Hi Johnlogie,

I can see I may be taking a trip to my local dealer if the reset doesn't work. My next question was going to be can I fit a MAF sensor myself but I assume that's a no from what you have just said.

Thanks

Tim

johnlogie

iTrader: (4)

U can if u got the right tool mate. Mine was a security torque(its got a wee nipple on it so u cant get a nornal torque on it). Its a 2second job m8, 2 torques, they should do it for imo if u've just spent 125quid on a pishy sensor

shogo10

iTrader: (1)

You can test the maf by starting the car and letting it idle then disconnecting the maf sensor plug if the car stalls and cuts out maf is good if however it continues to idle then it's knackered.
Not a full proof way of telling if the unit is on it's way out but is an indicator.

timmyt

If I have to go the new sensor route then I will push for them to do it. I agree at that cost they should just chuck it on for free. The problem is my local dealer hasn't got the best reputation so we'll see what happens!

Thanks

Tim

johnlogie

iTrader: (4)

Ive spent a fortune in mine mate maybe thats why they're alrite with me,lol

timmyt

Hi Shogo10,

I'll give that a try as well.

If that works and the MAF seems good should I then reset the ECU and see what happens from there?

I can see I'm going to have a busy morning.

Thanks

Tim

timmyt

Johnlogie,

That would probably expalin it. I haven't set foot in mine before so I'll probably get stung for a fortune

johnlogie

iTrader: (4)

The joys of owning a scoob mate. I moan about spendin a fortune on it but it still brings a big smile on ur face every time i drive it.
Im off to Knockhill next week for my first trackday, hope i dont blow it up again!!
Im on my 3rd engine in 3months mate

Jolly Green Monster

iTrader: (4)

yes correct

Jolly Green Monster

iTrader: (4)

try ZEN Performance - Performance upgrade solutions for Japanese cars - Subaru & Mitsubishi Specialists

timmyt

Hi,

I tried Shogo10's idea this morning and disconnected the MAF sensor while the car was idling. It cut out instantly. I know you said it wasn't a definitive answer but I assume that's a good sign.

With what's just happened I shall give the ECU reset a go and see what happens. If the MAF is fine and the ecu relearns etc. and runs fine is there a chance that will then eliminate my AFR issues or is just a way of proving that the MAF isn't knackered?

Do you think I should give that a go and see what happens or am I better off just getting booked in a ZEN's?

Thanks for finding the ZEN details for me, appreciate it.

Tim

timmyt

Right, I have reset the ECU. The car done everything your instructions said Jolly Green. No error codes were showing and the car ran smoothly from the off as if nothing had changed. The engine management light started blinking to show the ECU was reset and all was fine.

I assume that means that my MAF sensor is probably okay?

So what next. Does the reset possibly mean the other issues have been resolved. I assume the only way of finding that out is another session on the rolling road?

Or has resetting the ECU only meant I can eliminate the MAF from my check list and probably start focusing on the fuel pump?

If that's the case then I'll probably will take a trip to ZENS.

Any adivce?

Thanks

Tim

sponners

iTrader: (4)

when was the fuel filter last changed?


.....seen a scoob once that could barely rev due to blocked filter.
(figured out after 2 blown engines)

joz8968

iTrader: (13)

WTF. How, why, what? Oil pump sticking? Massive det on WOT on the straights? Please enlighten us...

Jolly Green Monster

iTrader: (4)

did you sort this Tim?

maf is unlikely the throw and error code

other options are fuel pump failed, pipe off the fuel pressure reg, split inlet pipe etc..

Simon