Hi all,

Looking to pick your brains a bit!! My WRX has developed a nasty habit of idling really badly when cold, and it has even gotten to the point of stalling. It hunts around for a little while, but if you give it some gas it eventually evens out and behaves itself. Not a problem at all when it is warm.

I recently found a hole in my resonator box which should have had the pipe from the boost solenoid attached. This has snapped off either by me changing the air filter, or by the previous owner.

Can anyone tell me if such a hole could cause this sort of a problem? I haven't gotten round to plugging the hole yet (a job for tonight) but will this improve it / fix it?

Any help would be really appreciated.

 

Coolant temp sensor perhaps?
Do the fans keep coming on?

 

Hi, thanks for the reply...The fans seem to be working as normal, how else could I check for that? Please forgive me as I am not the most engine minded individual.

 

Normally if the temp sensor is playing up the fans come on because the ecu doesn't know if the engine is cold or warm.

Other suspects are the MAF (black box attached to the airbox with a connector plugged into it) or the o2 sensor could be faulty

 

this is very similar to the problems i am having.... would the problems you mention bring up a fault light on the dash? when subaru looked at the ECU there were no error codes but mine also will cut out but only once and when cold, when warm the revs sometimes drop but it doesnt cut out...

intersting to see what you find as the problem may be the same...

 

When my coolant temp sensor was going wrong all i got was the dodgy idle but no fault code ,but the sensor was at fault because it was changed and everything was fine.

 

I was thinking that the MAF could be on the way out...hope it is that rather than the o2 sensor as I have been told they are a fair bit more to replace!

I take it that the hole in the resonator box isn't causing this then? I was hoping it might be a quick cheap fix!

 

I don't have a CEL light on either. I checked the memory for codes but it came back squeeky clean! Shame I know it's lieing to me

I will persist and see if I can get a replacement MAF this weekend. I am going to see someone who may be able to sort me out with one.

 

MAF for the early cars is expensive (i replaced mine) and was more expensive then the o2 sensor (which i'e also replaced )

 

How much was the MAF? Seen a few around on here for £30, or did you buy new?

 

i bought a new for both and it was £211.65 (22680aa160) for the MAF and £159.04 (22690aa260) for the o2 sensor.

That's for a 1993 wrx

 

I have the same problem with mine replaced the maf made it slightly better,coolant temp sensor made no difference next on the list is the O2 sensor,i know my exhaust mani is cracked so that wont be helping but again no cel light and no codes

 

Well to let you all know, my problem is totally sorted now. The connection from the boost solenoid to the resonator box was the culprit!!

I fitted an aftermarket replacement with a new induction air filter which has all the relevant connections for the boost solenoid pipe (its made of metal too so no chance of snapping this one!) compliments of Sarnyboy (top bloke) and this has stopped it stalling from cold and also stopped the idle hunting altogether.

Had a replacement MAF with the kit but tried both my original and the replacement and no problems with either so I know it wasn't that causing it in the end. Nice to have a spare working MAF sitting in the garage given the price they cost new!

Would urge anyone having the same type of problem on a classic to check this solenoid pipe is connected before shelling out on sensors, could find like me that it was a really simple and cheap fix!!

Hope this helps someone out.

 

where is the resonator box and what pipe is it that goes to it?

 

Resonator box is large black plastic box directly connected to the MAF sensor from the air filter box. There are two connections on either side of it. This is in my WRX import.

 

You tried the idle control valve??

 

I dont currently have the ECU in, tried putting it back in the other day but it would not start... keys worked, fuel pump made noise and it turned over but just didnt seem to start... thank god when I put the Standard ECU back in it worked! (was there something i missed?)

which leads me to the next question... why would everything be OK with the Standard ECU but not with the PPP ECU? is it a faulty ECU (subarus thoughts) or is it something on the car, its got 1yr of warrenty left so if it was something on the car this isnt a problem but subaru are not wanting to change stuff over when they appear to have found the faulty part!

also does anyone know when/If Prodrive changed anything on the 05 ECU's?

cheers

Leon