Absolute Shower

Giving my car some stick the other day on the M5 and noticed fault codes PO301 303 and 304...she's done almost 30,000 now so about time for spark plug changing. Anyone know ace plugs for very modified motors? (mine's around 400 bhp, 1.6 bar...and includes clutch slip at times!!)

Gidney&Knowlesy

Spark plugs, then coil packs sometimes these have a habit of coming loose..........

Though get it seen too sooner rather than later....

PF7RB's are good....

[Edited by XtremeScoobies - 9/9/2003 2:57:00 PM]

Absolute Shower

Cheers M8...sparks on order today.

Pete Croney

Ant

A tired front oxygen sensor can also cause these symptoms. If the plugs don't fix it, this is the next place to check.

Absolute Shower

Cheers Pete...

I've heard high boost can blow the spark off the spark plugs and cause misfire...

Plugs must be changed anyway due to service...I'm going for the Blitz plugs...good for tuned motors so I've been told.

Abs

Absolute Shower

I had that when the car was almost new...car would run with fault light after about 200 miles...and run ruff (only at times). Dealer replaced front Oxy sensor and problem solved.

Got HKS sparks today...glad of that as me motor gave same error codes yesterday on the way back from Manchester...Can't give it stick till it's changed.

jmca

Abs,

Interesting about the oxygen sensor... It isnt near as bad above 3.5K revs - so would make me think on low revs when it's taking the oxygen sensor into account that this is the problem - also isnt the sensor ignored above 3K revs, which makes it smoother.

Would the oxygen sensor be subject to heat - does it work better when hot - being that the car is misfiring when cold i.e. when the sensor isnt working right.

Am I on the right track with this? Anyone who can confirm or contradict?

Regards

Johny.

Bob Rawle

Suggest the grade 7 plugs are not going to be good enough, probably need replacing every 5000-8000 miles, should be using grade 8 really and mapping adjusted to keep them clean on cruise.

bob

Nog

Folks, for a complete novice in the scooby under-the-bonnet World, how on earth do you get fault codes when driving along?

I thought fault codes were something that Subaru diagnostic equipment kicked out???

jmca

Hi Nog,

A site that can help you out with error codes, ECU - diagnostics / reset, sensors & their positions :

http://www.saxonfields.freeserve.co.uk/


Regards

Johny.


[Edited by jmca - 9/18/2003 11:10:29 AM]

Absolute Shower

Bought the HKS Irid plugs...installed them - that was a pain - and now she runs clean when cold and has even more go!! Love it.

Anyone know if the HKS plugs will last 30,000 or will they need changing like the 7's?

wigan wayne

ABS

I've just seen your thread and have the same prob with my car.
92 wrx.
Did the o2 sensor sort it?

Cheers
ww

Absolute Shower

Sure did...when performance air filter added before the fix the car would run dog-ruff. Once the sensor was changed...car ran lovely...hot or cold.

The dealer took ages to find the correct fault code...and until that time they didn't change/renew anything...

wigan wayne

Mine isn't showing a fault code but just get an intermitent mis
when cold in the morning and if i keep the revs at 2000.

But it boosts ok and runs ok over 2000, then only mis's a little on
tick over when warm. same as yours?

have you put the filter back on?

How much was the o2 sensor

cheers
ww

Absolute Shower

ww...it might be the plugs causing that...

I had the ruff running for months recently...but only in the last 2 weeks did the misfire fault codes appear...

I'd start with plugs first if they've done lots of miles...

Don't know price mate as dealer fixed...

wigan wayne

Cheers abs

I changed the plugs and 1 coil pack to try
to sort it but it didn't help, just better on boost etc which makes
me think it could be the o2 .

It runs very well above 2000 revs but on idle it is
missing, but revs don't fluctuate.

Absolute Shower

In that case I'd agree. Are you running different air filter?
As me motor would only show really bad signs of running (and fault light) with it fitted. It was running slightly ruff with standard filter but not enough to give fault codes etc.

wigan wayne

I've got the std airfilter at the mo.
Where is the o2 sensor situated?
easy fix? mines a 92 import wrx.

Absolute Shower

Um...don't know...don't think it's a massive job though - like I said dealer did it.

I'd say add new topic to general and ask for instructions, location for classic scoob (It's near the up pipe on me' new age - not easy to get at!).

jmca

Hi Lads,

I've had a similar problem now for a while as described above. I changed plugs, coils & leads.

After a bit of research & reading through threads on the oxygen or lambda sensor (good few posts recently) I thought it was def something worth trying. So I changed it & before where it was getting to be a pain to drive - the ROUGHNESS has gone & I've a drivable car back again.

Worth it - bit of a pain to get out though.

Wayne yours would be in the same postition as mine - in the exhaust manifold. You can see it if you look into the engine bay facing the drivers seat & look down - you'll see the sensor straight down sort of pointing out at the drivers side wheel.

When I took the old one of I kept spraying it with WD40 or similar shock spray & untightening & then back tightnening a small bit then spray etc. until it came off.

I'm going to re-gap the plugs back to 0.7 as I had them at 0.6 thinking it may have them or the coils.

Regards

Johny.

Absolute Shower

Johny...how much did your coils and leads cost?

Don't think mine need changing yet...(not sure what miles they last for though) as she's now running fine (no faults at 158mph the other day...best not say where though...)

Bob Rawle

Absolute Shower, if you are running 400 bhp then the HKS plugs will need changing every 5-6000 miles, assume you installed S35 or S40i's. Symptoms will be slight "rough" feeling in high load mid range, means the plug is struggling to jumpp spark under high cylinder loads.

Absolute Shower

Ahh! Only 5 or 6,000...they cost the earth too. Since they've been installed, the sweet running has become slightly less sweet after the high speed run etc. Just runs slightly ruff when cold again...might be coils.

I'll keep an eye on the plugs and look for the tips to be rounded like the last set.

jmca

ABS : This is interesting info...

I've had a few problems of late with misfiring when cold & at low revs until the engine gets warm.

Pete : Does a MY95 have a front oxygen sensor?

Actually going to continue on a seperate thread to save hijacking...

Regards

Johny.


p.s. Other thread - http://www.scoobynet.co.uk/bbs/threa...hreadID=249161

[Edited by jmca - 9/10/2003 8:16:36 PM]