wrxadz

right my problem is this i have a 93 wrx which i have not had long and when the car is first started it stutters and hesitates at low revs, the stutter is accompanied by a clicking which sounds like it is coming from under the dash on the drivers side i have heard that the boost solinoid clicks but this has been bypassed by a gated boost valve running 0.9, the click tends to corresepond to the hesitation ie 1 click hesitates and stutters 1 click stops and is fine almost like a switch is being turned on and off if you get what i mean, this problem tends to stop when the car is wramed up which leads me to belive it is some kind of choke but not knowing much about imprezas i thought i best ask.

the car also has a slight miss fire at just under 4k but i belive that to be the plugs as my coil packs look fine and it wasnt missing untill i let a garage do a plug change for me (new i should have done it myself).

any help appreciated

cheers Adam

Jolly Green Monster

iTrader: (4)

mostlike coil packs need replacing.. they corrode over time..

but also worth checking the plug gaps are 0.7mm..

the 'choke' is controlled by the ecu which enrichens the mixture dependent on the coolant temp.. the temp sensor can fail and this is usually accompanied with the radiator fan on when the engine is cold.. this could be the clicking if this has failed as the fan may click in and out and the relay can be heard.

So check the fan isn't on when the engine is cold.. check the plug gaps..
failing that then it is an expensive set of coil packs I am afraid, you can set the plug gaps smaller and if it improves then the coil packs need changing for sure.

Simon

Jolly Green Monster

iTrader: (4)

oh and the clicking could also be related to the boost solenoid not being connected.. why has it been bypassed? if bought like this it could be done to mask a problem.. might also be worth resetting the ecu and checking for fault codes.

ECU Reset and Error codes
Turn OFF the ignition

Connect Error code Connectors and Test Mode Connectors :
2 black connectors under dash, connect black to black and 2 green connectors under dash, connect green to green, they are by your left knee when sat in the drivers seat and often taped back to the loom if they haven't been used before.

Turn ON ignition but don't start the engine

Engine Check lamp comes on

Press accelerator pedal to the floor

Then return it to the half-throttle position and hold it there for two seconds

Release foot off the pedal completely

Start the engine

Check engine light error code is indicated by Pulsing lamp

If an error is detected then Check the ECU Code

If no error is detected - drive the car sensible for a couple of minutes
i.e. until warm (do not use boost or high rpm!)

When the ECU has been reset the Check Engine Light will flash

An Error Code is indicated by a flashing check engine light
of varying length of flash,
a flash of around once a second is the okay code and indicates all is well.

If an error code is detected Check the ECU Code

Turn ignition OFF and Disconnect Connectors

If there is a fault Check the Appropriate Sensor


Error Codes
An Error code is defined as a slow flash followed by fast flash
i.e 2 slow and 3 fast = 23 Mass Airflow sensor.
A continuous on/off at the same speed is no fault found.


Code Fault
11 Crankshaft position sensor

12 Starter switch

13 Camshaft position sensor

21 Engine coolant temperature sensor

22 Knock sensor

23 Mass air flow sensor

24 Idle air control solenoid

31 Throttle position sensor

32 Oxygen sensor

33 Vehicle speed sensor 2

35 Purge control solenoid valve

42 Idle switch

44 Wastegate control solenoid valve

45 Pressure sensor / Pressure exchange solenoid valve

51 Neutral position switch

I hope this helps you solve the problem
but I hold no resposibility for any damage you do!



© 2006 JollyGreenMonster.co.uk, all right reserved.

wrxadz

thanx for the quick reply i by passsed the boost solinoide because when i bought the car it wouldnt boost over 0.5 bar so i assuemed that it was faulty and so bypassed it i had no problems doing the same thing on my 200sx and the impreza seemed to respond well i forgot to mention that this hesitation only occurs when i am pulling away and once the car is moving it seems to be fine so i guess you could say its and on off accelarator problem, any ideas?

adam

Jolly Green Monster

iTrader: (4)

if the ecu picks up a fault it will drop the boost to 0.5bar..
it could be the boost solenoid that was at fault or it could be many things..
reset the ecu and reconnect the solenoid and clean all the pipes out that connect to it and see if there is any error codes etc..
Simon

wrxadz

cheers mate did all that when i got the car it was the boost solinoid at fault and the boost valve sorted things but the car has always had this hesitation i can drive round it but it is just really annoying me if i dissconect the solinoid (it is still plug in as it throws up the check engine light when dissconected) could i then drive the car and see if the problem persists just to rule out the boost solinoid i realy dont think that is the cause of the problem but it realy has got me

Jolly Green Monster

iTrader: (4)

unlikely to be solenoid if it is only plugged in electrically but shouldn't hurt to try.

have you reset the ecu?

I would look at coil packs.. they break down inside over time due to the heat cycling.

Simon