Hi Guys,

My 93 wrx RA is a pain to start from cold. when it's warmed up it's fine, first turn of the key and needs no throttle. So i'm guessing that the cold start valve is either funked or just needs cleaning.

Could it be anything else?

Also where about's is the CSV located on the early impreza? Got some carb cleaner and was going to give it a try. Not been bothered to work on my imprezas before, normally drop them off at the garage but i feel like getting my hands dirty.

cheers,

matt.

 

there is no cold start valve..

the ecu monitors the coolant temp and increased the injector pulse width whilst the engine is cold and reduced this to the normal amount as the engine warms up.

the coolant temp sensor could be faulty but usually they fail fully and the ecu defaults to very rich cold start and fans running as it doesn't know if engine is hot or cold.. this is normally accompanied by the CEL.

warm start problems is usually the crank sensor failing, cold start is probably related to coil packs or spark related but it is less set in stone it could be several things tbh.

Simon

 

Im having trouble with mine it starts ok but when its half warmed up ie about 3 min it starts to hesitate for a few minites then goes back to normal

 

yup fans on and the cel. thought that the cel was on due to the decat. thanks for that will sort out the coolant temp sensor. any ideas how much they are and how hard to change?

 

forgot to say - have a new set of plugs that can go in so will get them in as well. might as well do a mini service on it while i'm at it.

 

no cel on the 93 for cat..

the sensor is on the cross pipe on top of the engine.. follow the top rad hose.. it is a bitch to get to but just unscrews.. there is two sensors, one for the gauge and one for the ecu.. the one with the bigger plug is for the ecu the other with the spade connector the gauge.

If you have decatted the downpipe and it has a lambda boss in the top that you have blocked, swap the lambda sensor from the headers to the downpipe as they last longer there..

Simon

 

could be several things.. same year car?

 

doh! knew there was a reason i don't norm do anything myself on the impreza give me an rs turbo and i'm fine

cheers for that will give it a go tomorrow or thursday, providing i can get a new sensor.

lambda is in the dp but it's right down the bottom. if best, i can get it moved as the dp will be coming off soon to be heat wrapped. equal length headers are also going on and they don't have a lambda boss in them.

should get it remapped soon really . what are the ecu options for a 93? currently standard so not much afaik.

 

Hi Simon mines a 95 sti ra

 

I would say it is probably a lambda sensor.

Simon

 

Apexi PowerFC or ESL mappable board..

Simon

 

where is that ? Was thinking it was maybe the coolant senser. What symtoms are there when the lamber senser fails then?

 

ok so moving slightly off topic, i have the following mods (nothing fancy - yet )

decat dp
straight through centre section
after market bb (h&s)
induction kit
ngk pf7b - to fit
my02 wrx intercooler - to fit if i can be bothered.

so what are the advantages to each ecu set up or is it even worth it for the mods i have or what would i need to make it worth while? ideally i'd be looking to get to about 300bhp.

 

most likely in the headers on your car.. look at air filter and follow down to headers and you should see the sensor sticking out..

or if it is a late 95 then it will be in the top of the downpipe.

basically the ecu monitors the afr in the exhaust on idle and cruise to correct the mixture.. if the sensor is failed the car runs the wrong fuelling.. it could be something else but that sounds the most likely on your car for what you mention.

Simon

 

it's your thread you can go to nearly any topic you like

ESL mappable board ideal for that set up..

Simon

 

ive changed the downpipe to a decat and i had a senser in it but was told it was a cat fire senser wouldent a lamber senser throw up a engine management light?

 

rough idea of cost please?

 

mine didn't when i had one go on my 94 wrx the other year.

 

if you had the cat on fire sensor then as expected the lambda sensor is in the headers on your car.. when you replace it more it to the downpipe

 

no cel when lambda fails

 

JollyGreenMonster.co.uk

although I am about to knock £50 off the ESL live board

 

worth me getting an uprated walbro before going any further though?

 

Yes.. the standard pump is okay but getting a bit tired now.. and walbro cheap

 

one site i looked at i noticed that the walbro uprated was cheaper than a standard one

 

would the lamber senser make the knocklink light up more?How much for a replacment?

 

I got a 95 WRX improt and Im having a bit of trouble with starts....? Soemtimes it fires up first time and is fine... Sometimes it wont start and I have put pump the accel to get it started??

I got some ngkpf7b`s on the way cus im guessing its the plugs?

 

an OEM part is not cheap.

unlikely to effect the knocklink, it only effects fuelling on cruise and idle, if it were very rich it could cause carbon build up in the engine whcih may then cause preignition and therefore pickup on the knock link.

if it is hessitating on boost at all then it maybe coil packs.

Simon

 

if you touch the accelerator at all during cold starting it often won't start.. it could be as simple as that.

 

Hi Simon its got new coil packs a year ago its ok when warm just a few minites into running then it goes ok ,where is the best place to get a lamber senser and how easy to fit in the headers?

 

It just seems to help it along? Im worried that it wont turn over if I dont give it a little gas....