Hi all, This is my first proper thread so go light on me lol.. The car is a 2004 (on a 53 plate) WRX blobeye.


I recently bought my first impreza The mods at the moment are..

TD05-16G Turbo..

Front Mount Intercooler..

A very loud and annoying dump valve (apparantly HKS)

Large cone induction kit..

Front mount intercooler

Pink injectors.

Uprated fuel pump

De-Cat up pip and straight pipes until the down pipe which has a sports cat

Also a raptor backbox from scoobyworld (which I must say is amazing!)


I use the torque app on android to read and reset codes (I also have a pc usb lead but my laptop is rubbish and it does not seem to work with ecuexplorer or romraider? driver issue probably.


It started with PENDING misfire codes on cylinders 1 and 3. These would just go away and never actually put the CEL on. The code that would was P0134 which is no activity bank 1 sensor 1. If I wiped the code it would go away for a few days then come back.

Eventually I started noticing that the misfires on cylinders 1 and 3 would bring on the CEL.

I had a new o2 sensor fitted yesturday (DENSO) and cleared the codes. This morning I check my codes and had a pending misfire code on cylinder 1.

I clear this and drive to work and check codes again and now have pending misfire codes on cylinders 1 and 3

Im going to wait and see if the P0134 code comes on again which means i've just wasted £150...

Questions are has anyone had this issue before? I know 1 and 3 are both on one side..

The cars revs remain in place on idle no ups and downs and I don't actually notice any misfires..

If I rev it up after warming up and standing still it will give a bang or pop which surely means its not running lean and its rich?

Whats my next step? Looking at past receipts it had a big service about 45k miles ago. (Its now at 70K) So plugs were changed.

Would the MAF sensor cause this??

Would the misfires have bought up a no activity for o2 sensor?

Any help appreciated!

 

Oh and I'm not getting any lean codes or anything else..Just cylinder 1 and 3 misfire and o2 sensor no activity which may now have been fixed..

 

Do you get the misfire codes mostly in the same gear? I was getting a misfire code for no.1 cylinder mostly when driving at around 3000rpm in 4th gear going up hills at half throttle or pulling hard on the flat. I swapped no.1 + no.3 coils over which made no difference. I have now replaced the neutral position switch on the gearbox and I can't get the code to come back. I could get it to come back on demand if I wanted to before by going in 4th gear and accelerating.

I can't help with the O2 sensor problem, but it sounds like you've fixed that anyway.

 

Not really noticed which gear the misfire comes. Weird thing is I don't actually feel the misfire. The whole car does shake like made when its in idle once warmed up..so Im presuming its doing it out of gear too. But saying that no codes are thrown up when idle..

 

I take it it has been mapped for all those mods ?

 

if you get your laptop and lead sorted check if the neutral position switch is working

 

Yep had an ecutek remap..

 

Sound's like the same problem I've got. And like you don't feel the misfire but get misfire codes the same as you. I was going to change the coil packs at some point, but it's not botherd me so far, so it got put down the list of job's todo But will have ago at swapping them over like Broomer has said

 

JDM stig's post is worth mentioning again.................have a Google and search on here on misfire CEL's and the Neutral Position Switch

Shaun

 

Would that cause the misfire readings only on cylinders 1 and 3 though?

 

I wonder if cleaning the MAF would help...or resetting the ECU if I get that cable working..

 

First two things I would check are nps and plugs / and gaps
I replaced my plugs with the recommended gap and it is pants
Re gapped at 0.65 and now all good

 

Which software and where to check if its working

 

Romraider, logging, Dashboard, switches,
check NPS and as you go from neutral and any gear it will change from 0-1 to show the switch is working and being seen by the ecu.

 

The neutral position switch may seem to work when just switching from gear to gear when stationary. Over time the switches plunger wears shorter until it's bearly long enough to sense you are in gear. At certain revs once in gear the plunger on the end of the switch rattles in and out of gear very quickly and confuses the ecu bringing up the misfire code. The plunger wears in different places in each gear which is why mine was worse in 4th. I couldnt feel any misfire in mine.

 

Ok this gets weird now..I got into car when I finished work (when I left for work in morning I had cleared the codes and had got two misfire codes that were pending but had not lit the cel on when I did get to work) when I got back home I did a quick scan and all codes had cleared themselves!?! Lol does this mean it was the o2 sensor all along and the car was just learning this? Sorry for poor writing I'm on a mobile now

 

Neutral Position Switch

Brings on all kinds of fictional codes but easily solved with a £40 part.

Definitely

 

Right today while at lights sitting idle my CEL came back on...cylinders 1 and 3 misfire =(

 

This is while in neutral..so not in gear..

 

do a compression test mate, mines started to come on(missfire cylinder 4), and its reading 60 psi on that cylinder so im going to swap my heads out for some jdm 1's.
obviously there are other things that can cause misfire codes but its best to start with the cheaper options that you can check yourself.

 

No. The switch tells the ecu whether it is in gear or not. When the switch is faulty it flits on and off and gives the ecu lots of information. Too much for the ecu to handle and it throws cel codes cos it cant cope lol.

 

Oh..I'll try get my laptop plugged in and have a look if it's switching..don't understand how it would affect just cylinder 1 and 3..

 

you need to log it while the car is moving really.

Could be any code - particularly misfire codes but also random cam position sensor faults

 

My laptops dead lol only works while plugged in..what else could I check if I plug it in I'm the morning in idle...hoping to do a ecu reset too..any other readings I should get?

 

Nope. Just neutral position switch

 

Just listen to Duncan!