Hi all
My 99 sti at idle or stopped in traffic is going between almost stalling and 8 or 9 hundred rpm. It does this once warmed up. It seems to be running rich too.
There are no fault codes showing up either. I replaced the lambda sensor but there ws no difference.
Could it be the idle control valve or the maf.
In normal driving there's no difference an the car runs fine an seems to boost ok.

 

Change the coolant temperature sensor and see if that improves it?

 

In case it is the maf - don't be boosting at all! The case check will only show a failed sensor, not a "failing" sensor!

 

Get the maf sensor changed ASAP. Don't drive it hard until you do. If you do you stand a very good chance of melting a piston.

The MY99 is notorious for this.

 

Are these symptoms of a failing maf then rather than a totaly knackered one?

 

Could this not be the idle control valve? Don't they give these symptoms?

 

That's what I thought mate, all the symptoms point to it. However do I take the chance? I'll clean the icv an see how that goes an start it up etc. Tbh not confident in existing mafs reliability now.

 

Many people, myself included used to change them every year regardless! An £80 spend every year can save £3k on the long run!

 

I'm thinking along those lines too Brun. Where u find them for eighty quid?

 

Now it is a few years back so i guess they are a bit more pricey now. In the past i had them from Scoobyclinic and APi

 

MAF ! Almost no doubt. As above drive off boost and get it done with an original part ASAP.

Good Luck, Call if we can help.

David APi 01926 614333

 

Haveyou gota VTA dumpvalve? my old 99 uk turbo was doing this and turned out out to be the dump valve, put a recirc on and solved the problem.

If the new maf doesnt solve it try that.

Hope you solve it soon.

 

i would have said clean the icv and block the d/v off to test it and of course any vacuum leaks

 

I'm on it troops maf ordered. Scooby going nowhere till it's fitted.

 

Totally agree, no point mucking about..

 

Where did you order it from?

 

Import car parts £111 scoobyworld wanted 130

 

I have erratic idle and at times it will stall if allowed to, I have already stripped and cleaned the icv and also cleaned the maf with carb cleaner(newage maf conversion) - this solved the problem temporarily but is now back which tells me it's the icv but shall try disconnecting the lambda to see if the idle returns which would indicate a lands fault instead.

If I was you I would try cleaning the icv and it's housing to see if this cures the problem, it's a shame you leave miles away as I have 2 virtually brand new v5-6 Mafs sitting in my garage that you could have tested on your car.

 

Advanced automotive sell Mafs for £78 to P1woc members

 

Bugger wish I'd known that lol
Cheers for the tip I'll join snow tryin get my next maf from them. I'm going to clean the icv too!

 

If you plan on getting the car mapped in the future I would suggest going for the newage maf conversion, they are much more robust and will save you a fortune in the long run

 

.....or just go mafless

 

What parts are needed and what has to be done for this conversion?

Thanks

 

Save yourself even more trouble and go for a mafless remap using Alcatek [ was Simtek ] or similer replacement ecu. Features 2 maps and plenty of control functions. About £900 + VAT fitted and mapped for a 99 car

The MAF for any New age car is well over 250 quid to buy and they still go wrong. We must get at least 3 calls a week for secondhand ones; 'cos they are really expensive from Subaru '

Frying pan and fire comes to mind going from 99 MAF to 01 on MAF in my
opinion.

David APi

 

Yeah that was the idea No. 2.

Thanks for suggestion.

 

Ive got a Q45 maf (from a Nissan 350Z/300zx i think), in my MY00 Classic, according to Rich FB Tuning they are pretty much fit and forget.

I went through 6 mafs in my last car. (99 uk turbo)
Luckely had one replaced under warrenty as it was only three months old.

 

Fit and forget AFTER you've mapped it.

Don't fit it and hope. They flow air differently and cannot ever be considered a straight fit.

From our side we call it plug and pray.

Good luck

 

yeah. forgot to add, mapped to suit. oops

 

Lol,plug and pray...good one

 

XXXXXXXXXXX update XXXXXXXXXXXXXX

After fitting a new Maf sensor (and a nice new green panel filter) the problem was still there albeit to a lesser extent. Car ran alot smoother and no longer reeked of petrol from the back.

Car revs still fluctuated slighly.

One phone call to david at APi and i checked my turbo inlet hose. The jubilee clip wasnt done up tight if at all. Id had a sports catted DP fitted by my local and up till now trusted garage prior to all my previous woes. They said they removed the turbo during fitting as the studs were a nightmare to remove. They obviously didnt check the hoses

One new Lambda (unnessessary) and Maf (probably nessessary)later problem solved by two mins with a small socket set.

Thanks again to scoobynet massive in particular David at Api