Had car in garage today for new cam belt with all the tensioners and water pump etc

While I was at it I thought I'd stick some new plugs in so opted for ngk iridium IX ones heat grade 7

Now boost level used to read about 0.50 on my blitz turbo timer gauge

Now it seems to be about 0.20?

Erm help? They the wrong gap?

Cars a 99 uk turbo with full exhaust, decat, stainless headers, panel filter and uprated fuel pump

 

more like is the timing right mate, also 0.5 is too low never mind 0.2,.
plugs should be gapped at 0.6 mm

 

yeah I did wonder that too to be honest

well thats read in kg/cm2 or some funny unit not bar

 

mine done this last week after my plug change, and now it only boosts to 8 psi!!!

 

What plugs did you use mate? Do you have similar spec as mine?

 

mines a 2003 wrx ppp, and i used ngk tatanium 7's

have u had it on a code reader?

 

they read the engine after doing work and it read knock sensor, but it had come up with that last week and was still boosting fine

 

Bob Rawle said to me after having a misfire niggle to gap the heat grade 7 plugs to 0.65mm (I just used a set of metric feeler gauges).

Perfect

 

Would the gap cause it to not boost as hard tho?

Rutt_Dj

what you going to try next?

 

My missfire seems to have something to do with my maf sensor! So im changing that and hopefully that will take the car out of limp mode! Fingers crossed

 

ok let me know how you get on, bloody cars try and look after them and they still play up

 

Will do mate. My maf is in the post so i will let you know fri/sat hopefully

 

What grade/type plugs were in originally?...you know the saying - aint broke don't fix? If the old plugs were working ok, why replace them with a different type especially on a car running mimumal mods)? If they are a different grade/type, I'd first try sticking the same grade an type as what was in originally (PFR6B ?s )

Generally speaking if the gap is too wide or you have the wrong plug you generally find out when the turbo kicks in at low ish revs and you can feel/hear it misfiring, somtimes pretty hard (juddering), and sometimes slightly (holding back).

God knows what the blitz's 0.5 is, can you quote that figure in a English unit of mesurement please? ....It should be running at around 1 bar (typically a Uk TD04 classic does 0.9bar held from 28000-5500rpm and peaking at 1.1bar around 3000rpm and dropping towards 0.5bar at max rpms).


Personally I'd say its a timing issue; its very easy to get the one cam pulley a tooth or two out when putting tension on the belt, where the engine appears to run/idle pretty much ok (no missfire), but the engine is low on a power, not so free-revving and very laggy when driven.

Also bear in in mind - its a old car, those plugs leads boots are probably a bit perished by now so by disturbing them to remove plugs its can open a crack in the boot which then causes a weak spark at the plug. Being a double ended coilpack (unlike teh early JDM coil on plug cars - which have their own issues), one duff lead will affect the spark on two cylinders. Changing plug heat range and gaps can also cause interesting glitches in a detriorated ignition system as the plug may require more spark energy to fire....and the spark always travels the path of least resistance...if that out is of the boot and onto the top of the spark plug base or cylinder head (instead of the electrode), then that's what it'll do...however typically the car will misfire pretty badly when it happens (bucking and juddering under load etc.)

 

Cheers ali for the reply, it didn't seem to hesitate at all or miss fire could just feel its not boosting half as hard as it usually does.
Done a kg/cm2 conversion and its only running 0.2 of a bar last night with a peak of 0.5 from what i remember it used to run at least 0.50, the display isnt in the easiest place to read.
It was running grade 6 before and fair enough if its not broke dont fix it, but was advised to go with these

 

in my opinion irriduim plugs are a waste unless your runing big big power.

 

Well had it back in garage and still puzzled, it doesn't miss fire at all, but highest it will boost is 0.5?
Could it be MAF sensor? Car doesn't miss fire, just not boosting what it should

 

Did they check the timming marks mate ?
plugs will cause a noticable missfire

 

Mine is doin the same mate. My maf will be here tomorro so i will let u know

 

In that case I think the timing needs to be rechecked.

Your knock sensor error codes also need checking out, but if the car was boosting ok with that code present before, then that's probably a red herring.

As for MAF...IMO typically they don't suddenly die..unless its been dropped or cleaned with a caustic cleaning fluid. I personally wouldn't buy a new one, but if I had a spare one knocking around or could borrow one, I would try it just to see if it made a difference just to rule it out.

 

He says timing was spot on, yeah thats what i thought so it cant be due to plugs.
Cheers fella be good to hear if it improves, i took mine off and cleaned it with brake cleaner but still same.
Did wonder if my actuator had problems, but surely it would start failing over time not instantly

 

mate.. your car is ok. you then take it for the cam belt done and all of a sudden its not ok..
this should surley ring a few bells.

 

Yeah i hear you, its back in on Tuesday for them to check it out, will get them to check timing out.
Only had car 3 weeks, just want to be enjoying my first impreza...
Bloody cars!

 

I will back u up on that, this is also my first impreza, and iv only had mine 2 month, i put a timing belt on mine the 3rd day i had it to be sure it was done

 

does the car run fine when cold as had someone had belt done and car was fine when cold but when hot it wouldnt run right,double checked timing and it was i tooth out,redone the belt and all was good.it only takes it to be one tooth out and it can cause all sorts of problems,who done the belt for you.

 

sounds like a boost leak check all vacuums around turbo/boost solenoid as had same thing and they where cracked the old pipes tend to go rock hard remember to keep restrictor pill which should be between compressor side and t piece

 

It runs fine when cold or hot mate, no miss fires, garage who always looks after my cars, he a decent bloke and has a tuned evo him self

 

Checked vacuums, they're silicone so shouldn't be a problem. What's restrictor pill exactly? Sorry to ask new to the subaru world

 

http://www.google.co.uk/imgres?imgur...ch&um=1&itbs=1

http://www.google.co.uk/imgres?imgur...ch&um=1&itbs=1

 

cheers for that, mines all after market silicon hosing so i'm guessing they won't have them now, what pressure were they set to limit boost to?

 

Well got in it today and its thrown o2 sensor on fault code
This related?