1997 2000 Turbo coughing, backfiring, powerless and cutting out under acceleration
 

Hello all I'm new to Scoobynet and have the problem listed in the title, any ideas as i have been told its the MAF thats causing it, its the F type purple sensor type.

cheers

How does it idle? MAF failure shows in rough, uneven idling.

You don't say what mods you have, if any?

Hey up Shag, You've the same Maf as I have on my98 and my car was doing what you are describing. The MAF's are fixable. Undo the connector plug and undo the 2 screws that hold the connector to the Maf housing now behind are soldered pins and usually one of the soldered joints has failed. You need to be careful as it's still held in place via the soldered joints even though you have removed the 2 screws. Carefully lever the connector out a little at a time and then when it's out a bit lever it down and you'll gain enough room to get a small tipped soldering iron in and resolder all the connections even if they look fine. Carefully get the connector back in place, replace the 2 screws and put a bit of silicon around the housing to water proof it. Clean the Maf's strand and mesh with brake cleaner and refit the Maf. Test by starting the car and pray it was the connectors. It was on mine and It's been 100% for 6 months now.

Exactly the same issue I had with my 1998 Terzo, changed the maf and it sorted the problem :)

Sorry for late reply, bought the car with this issue and looked up the common problem of rough idle and it all seems to point to the MAF, that's good info thanks guys and gals if any, the mods are unknown but I know it has a FSH and the turbo was replaced, I still have the old one and 2 spare coil packs so if anyone needs a pack let me know, will try that fix tomorrow firez34 cheers for that, parts seem hard to find, the ticket has run out on it and the pre cat and cat has been removed, I have a weld in sport cat but space is limited on these cars but I hope the garage can weld it in as they won't MOT it without a cat

The car idles like its hunting and has a low level misfire and when you pull away it gets to about 2k then coughs and splutters then rev it a bit and floor it and its backfiring loud and powerless but rev it out of gear and its almost as if the problem isn't there, weird but I guess it's the MAF

It's the Maf - get a new one

Ok more help needed, fitted a brand new MAF and is still the same, any other suggestions that could cause this, it has new plugs new leads new coil pack, just been serviced, new cam belt etc etc, could it be the CTS ?

Boost pipework leaking/split/loose maybe?

Paul

was going to change the TMIC this weekend so can check it then, as i'm new to this with scoobies can anyone tell me where to find all the boost pipes, i know the obvious ones like IC to TB Y pipe and MAF to turbo but are there any others hidden, and if there arent any damaged or loose ones what else could it be ?

You need to get someone who knows Imprezas to look at this for you, or else you'll chase your tail and spend money with it.

Dont really know anyone with one to be honest so i'm a bit stuck

There are a couple of small boost pipes that come directly off the turbo and a few in front of these which go onto the purge control canister they are the small vaccum hoses.

Ive seen the canister its just in front of the MAF pipe, i think its a weekend job as i cant see anything by the time i get in, somebody has bypassed the boost solenoid and put a manual boost controller in the bay, i would like to put it back on the solenoid as it has been mechanically disconnected but not electrically, would this cause a problem and does anyone know the configuration of the pipes?

Would the CTS not cause a similar problem ?

It would be best to put the original boost solenoid back on as manual boost controllers are known to be problematic an can cause fuel cut etc if they have not been adjusted properly. If the boost solenoid is still plugged in but not mechannically attached the ecu could be getting confused as it is getting a different reading from the manual boost controller. Maybe worth doing a diagnostic check aswel to see if it throws any codes up.

Ok will try that, drove to work this morning and it was kangarooing and coughing and spluttering worse than ever and it wasn't even on boost ! What the hell can it be apart from embarrassing

Doing a reset on the ECU, battery disconnected and waiting to see if it makes any difference

not to sure if urs is single coil or not mine has the 4 coils and i had a problem with spluttering thort it was the airflow changed it, wasnt the problem and then after blowing my engine up i noticed on removal of the engine broken wires to the coils where the wires outer sleeving has gone brittel and split + cracked also the wires to the injectors so just have a check around them its worth a look :)

Single coil in the middle on mine, have noticed the loom going to the pack and other sensors looks as if the corrugated outer has gone brittle and come away but the wires look ok

tape them up dude could be arking out :) worth a try can be the simplest of things

It's worse when it's from cold which is odd, when its up to temp it's not as bad but still does it, just annoying me now and the check engine light comes on with ignition but goes off once it's running

I'd go for taping the wires first mate then go from there.. Have you done the eml test? With the wires above the pedals? See what code that brings up

Do you have bad fuel consumption since this has been happening? Could maybe be your oxygen sensor? They can affect your off-boost and part throttle acceleration and make it seem 'coughy' and 'spluttery' like you said. Might be worth a try

Ok problem partly solved, the MAF to turbo pipe which is in the most poxy place I have ever seen has rotted away at the turbo end and had a massive hole underneath which I couldn't see, have repaired it with a coupling which luckily I had and fitted it on perfectly and in amazement the issue disappeared but not completely so there are clearly more air leaks but it doesn't fast idle or run lumpy but coughs now on low revs and low acceleration but push the pedal down and it takes off, I took some pics of the ecu and its a 8S ecu whatever that is but still need to make this engine run as sweet as, changing the intercooler and pipework this weekend so hopefully it might solve it, the tmic looks battered so could be that, I also need a new MAF to turbo pipe or is there a better pipe out there for this car to avoid this problem again.

Cheers for everyone's help :)