Jump to content

Boost issues


Recommended Posts

Hi guys, I seem to have developed my first issue. When I'm driving along and give it a bit of throttle, we get to around 3K rpm and it just seems to give up. It feels like someone has just put a bung in the turbo. It spools, as I can hear it, and it vents, as I can hear the recirc valve through the ARC box. It's been farting a little recently on gearchange and this seems to have got worse too. It will rev past 3K on a light throttle, but doesn't like it much. 


Link to comment
Share on other sites

48 minutes ago, kershaw-330s said:


You could have a cracked turbo


Sent from my Nokia 3310 using Tapatalk

Worst case if it is, and you can't fix, I'll take it please 😬


Id definitely check out the housing and all your connections. Might of just blown a pipe off?

Link to comment
Share on other sites

  • 1 month later...

Well, today I tried to start the Impreza after a few weeks away at work. Not a chance. It turned and turned, I could smell fuel, and could hear the cylinders pumping, but no go. I've read the fault codes as best I can and have found the following :-

23 Mass Air Flow sensor circuit 

24 Open/Short in ISC valve circuit 

31 Throttle position sensor

32 A/F sensor #2 system

I take it that I need a new maf sensor, but the rest I don't know about. Would this be why my boost just wasn't happening and why I was getting pops and bangs? 


Link to comment
Share on other sites

Right, maf unplugged and it starts straight away. Idles a little roughest but is steady. I plug the maf back in, and it's lumpy and hesitant to rev. When I rev it, it splutters then builds. It was also quite smoky with the maf in. When I unplugged the maf when it was running, it died immediately. Sounds like the maf is knackered?

Link to comment
Share on other sites

Hi tom , sorry to hear it's not running right . Those codes and symptoms do point to a maf or misfire fault .

Shame you're not closer as we could've tried my maf on your scoob to see if it's fubar.

Have you tried taking the maf off and cleaning it with brake cleaner ?

If you do don't touch the wire inside and make sure it's thoroughly air dried before plugging it back in [emoji6]

The v1 / v2 mafs are normally pretty strong and don't fail as often as the v5 /v6 ones .

It's probably worth looking at the spark plugs too .as if 1 of them is wet or blacker than the rest it could indicate that there's a misfire, causing the unburnt fuel to pop n bang in the headers .

All the best ,bud

Link to comment
Share on other sites

Cheers Savage, luckily I've got a mate close by I can change the maf over with at some point. I may as well just get one, as I imagine it'll need to be changed at some point. I think it's mostly original stuff on there, so it couldn't hurt to refresh the plugs and leads. I thought it might be a coil playing up, but it's pointing more to the maf, so I'll start there. 


Link to comment
Share on other sites

I've decided to get a new maf, but thought that it may be wise to change the plugs and ht leads at the same time. I'll get NGK PFR7B plugs, but I'm not sure on the lead for it. I believe it's a V1 base, and most of the leads I've found are for later models. Any advice? Can't afford stupid things like Magnecors, as much as I'd like to, and would be happy with 'just above standard' units, or if standard are decent, they'll do. 

Here's a pic of the engine, just in case I'm wrong. 



Link to comment
Share on other sites

V1 and v2 don't have ht leads bud . They have individual coil packs on top of each spark plug.

They're prone to cracking and causing the spark to jump from coilpack to cam cover. Which in damp conditions can get worse and cause a misfire.

I'd visually check for signs of wear or arc'ing out on the coilpacks themselves, when fitting the spark plugs .

If the problem is still there after fitting the spark plugs and the coilpacks look iffy , I wouldn't bother fitting second hand ones (as they'll be 20 yrs old)

Either new classic ones or a newage coilpack conversion would be the best route .

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...