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intermittent misfire (annoying)


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so i have bought a 93 Jap GC8 import WRX from a complete halfwit. with a so called slight clutch slip after having a new clutch fitted that turned out to be the n/s/r half shaft slipping in and out of the diff.


letting the car cool came the next 2 problems.


problem 1

coolant temp sensor replaced sensor, same issue!!!!! Traced wires back to ecu and wow this guy likes scotch locks every wire on 2 of the 4 connectors were scotched together, so 2 hours later and a few burns from my soldering iron sorted problem 1 fixed.

problem 2

driving car around on day one it started chugging and popping and farting for around 5 minutes then it goes.... no engine management light or errors on the ecu.  changed plugs coils and cam shaft sensor no change.... back to this shortly.


So the clutch that was fitted was 6 paddle ceramic clutch with no springs on the spinner plate. not a good idea on a standard box for road use.... bye bye second gear on day 4 stuck in traffic. replaced clutch and a second hand gearbox.. all back to normal although still misfiring every now and again....


about the car 

the car has a W6 Ecu with an ESL Chip inside its running roughly 298bhp 

td05 turbo seeping oil ( new one to be ordered)

front mount intercooler badly piped up no issues just could be neater (to be sorted)

defi boost guage (looks like it could make cups of tea if i can figure all the buttons)

no turbo timer (ordered a new alarm which incorporates this and remote start)

kosei racing 18in 8.5j wheels on 215/40/18s landsair (ordering new decent tyres through a mate in tyres)

standard brakes that need upgrading and a non working abs pump...

abs and engine check lights were removed prior to me buying the car....

their is no cat and just one box at the back stainless


so the intermittent misfire happens without notice. seems to be more if i drive casually it happens more than if i keep the revs high through the gears (30mph in first gear is abit noisy and very uneconomical  lol) changed plugs, coils and camshaft sensor... any ideas????


thanks for reading!!!!!! now get your thinking caps on as its P****** me of haha

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Christ almighty mate.....You must be !Removed! off.Has it got the restrictor pill in or has it been removed?


that would be an understatement mate.. I'm not to sure if it is i will be having a look at first light though as i have just had a look at what it is... i bet it is missing as all the vac lines have been changed due to the defi and the solenoid that is in their.


thanks for the tip on that bowthruster

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I had a few problems when i first got mine-all sorted apart from the arches! If there isnt a pill make sure you get a genuine one from subaru-i only paid about a fiver.

MY93-96 ... 3 port solenoid 2.0mm restrictor fitted into the vent pipe between solenoid lower port and intake


Just double check with subaru as the above size maybe just for a uk,cant find out if its Import or not?I'll try and find out for you.If not just ask subaru they'll know.


Let us know how you get on.Cheers

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If it's got a esl'd ecu did you get any paperwork saying who mapped it ?

As it might be unmapped and overfuelling or on the wrong map (if it has 2 maps)

Does your engine check light come on when you turn the ignition on ,is it working?

The 93 jdm wrx didn't have abs or a airbag , my 94 sti hasn't .

The buttons on the defis will probably be a peak hold and reset function .

Show me a pic of the vacuum lines from the boost solenoid and I might be able to see if it's plumbed in right [emoji6]

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Hi I'm on my mobile at the min as I'm out!

I have taken some pics il upload them when I get in later but looking at the vac lines their is no pill in their. Their is quite abit of paperwork from tuning developments including dyno sheets!!!! Il dig through them n see if anything links to the ESL chip inside.

Chat later and thanks again for the replys

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That air filter looks very oilley mate,is the maf ok?Oiled filters like that don't go very well with mafs,and it doesn't always show up as a fault code-I can vouch for that.I went back to standard box and genuine maf,and touch wood no problems.Not to sure on the pipework,im sure savage or someone with a bit more knowledge than me will advise you.

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the maf seems to be ok although can't be too sure.... Replacing the filter is on the todo list.... Iv just been sat in the car for half an hour on idle to keep warm in this beautiful British day! And the scar started missing while at idle almost stalling its self probably lasted 3-4 min n then it's back to normal again. It defo sounds as though it's firing at the wrong time!

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Easiest thing to do is have a look at your boost soliniod,how many pipes are coming out of it ?

I'd it's a two port one follow the top hose to the turbo and the little t peice should split left and right, left goes to wastgate, and right bit goes to turbo outlet nipple , this should have the restrictor pil in it about half way between the t peice and nipple, I'll get a pic of mine in a min for you

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Sorry fella my scoobs maf died and I forgot I posted on this thread .

That's a early 3 port boost solenoid set up it looks about right to me from the first video ,although it might not be a standard vac set up if it was tweeked before the remap

The sensor with the orange 'ish cap on the boost solenoid bracket measures atmospheric pressure .

The other black sensor on the bracket that has a vac line on it is the map sensor (manifold actual pressure ) the vac line to this on mine goes direct to inlet manifold .

Is it running a aftermarket dumpvalve and if so does it seal properly ?

What bar of boost does the gauge show ?

Cracked porcelain on the plugs somtimes causes similar symptoms when warm

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**** thats not good mate


I think I'm gonna change the maf on mine and hope that it sorts out the problem.


its not the plugs as they are all new ones as well as the coils.


she boosting 3/4 of a bar in first just short of 1 bar in second and 1.1 bar in the rest.


just had another problem that made me **** it.... chav in a civic type r was just sat up my !Removed! egging me on

for a race so left him for dust from the lights at the top of third gear it stated popping and slowed down.....

after slowing and allowing her to cool for a moment set back of driving and the car wouldn't go past 3 grand

when i got back home had a look and found out i blew my intercooler pipe off (thank f*** for that haha)

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Mines running fine now I've fitted the spare maf I had kicking about

I mentioned the plugs as they're a tight fit and if you're not careful when fitting the new ones can sometimes end up with a crack in the porcelain

Yeah I've popped a ic hose off before made my !Removed! nip too [emoji4]

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