rudboy

Guys,

Still in desperate need of some advice,

My95 wrx with red top engine,

Car is starting now but it doesnt really want to! Struggles after starting then idles low, ye have to blip the throttle to stop it from stalling,it starts back firing after about 30 secs, as if its over fuelling.

We have tried 3 different Mafs all known to work on the doner cars. all were of the same colour but different codes, no real difference between them.

Also swapped the lambda sensor,Ecu, temp sensor checked,unplugged crank sensor and wouldnt start,plugged back in and it did, done the same with the cam sensor and same happened, it wouldnt start with either un plugged,

Dont think its the coils as it starts and isnt off any cylinders.new plugs were fitted about 200 miles ago,Also had the decat removed for mot at same time.

Does anyone Know what the pressure at the fuel rail should be at idle??

Stuck between a rock and a hard place!!

Cheers.

scoobyricht

iTrader: (4)

with the vac line off the fuel pressure should be 3bar

rudboy

nice one scooby richt.

rogos

cambelt might have jumped some teeth? it does happen on scoobs.

rudboy

Cheers rogos,

My mechy did mention this before but thanks for reminding me as im sure he aint checked it yet.
fingers crossed,

think i'll post a link to a video of it starting, might help diagnose.

Splitpin

In addition to other comments, another obvious thing to rule in/out: Dumpvalve. Is whatever is on the car right now working properly, or is there a possibility that it has either jammed or broken? If the DV is open you'll get symptoms very similar to those you're reporting.

If in any doubt about this, remove the dumpvalve completely and use something to block the three pipes you're left with, then try and start it. If the symptoms clear up or alter significantly, you're onto something.

rudboy

Yeah the dump valve is already removed due to it failing about 6 months ago. good point tho, will get the mech to double check the plugs to make sure they aint losend though.

Cam belts been checked today but all mark are ok.

Running out of ideas.....

Does anyone know if the subarus are known to blow head gasket between cylinders? ie-no water loss but compresion getting from cylinder getting to the next to it?? known of it happening on other makes of cars.

rudboy

Anyone got anything else that they reckon mite be worth checking??

Cheers.

Splitpin

Tried removing and cleaning the idle speed control valve and its associated pipework? Also try disconnecting the throttle position sensor and idle switch (if there's a separate one on that MY of car) and then starting the engine. See if the behaviour alters in any way.

And no it is next to impossible for a head gasket to fail in the way you describe. It's certainly impossible on the later steel head gaskets as coolant can pass in the gap between the cylinder seals. Whether the fibre gaskets are the same I'm not 100% certain though.

Also, obvious question, but by the sound of things the engine is not the original one fitted to the car. Would it be correct to assume that it was idling fine before this problem started? Or, putting it another way, is the car running the correct ECU/mapping/hardware configuration for the engine now in it?

rudboy

Splitpin,

we tried disconnecting the throttle position sensor and trying to start it, wouldnt even offer with it disconnected.
cheers for the info on the head gasket theory,

Yeah yer rite the engine is an upgrade, was installed in nov last year.
no real issues until now.

It would always start first turn every time, although when its cold it start to be a little non responsive on the throttle responce, nothing too serious, just like it was not getting enough feul or spark for a split second and then it would give a jolt when the missing link kicked in, like i say it was only when cold and only started happening lately,

Now we cant even get it started unless its sat for about 24 hrs and even then its just luck if it catches.

When/if it starts it idles very roughly but not erraticaly at say 450-500rpm it struggles to take any throttle and gives pops and bangs whilst doing so, as if its over fuelling. we have checked the spark and there is a definate good spark.

Its as if its flooding the engine instantly, removed a plug after turning over for a few seconds with no start, Plug was totally soaking/dripping wet.

What exactly does the Cam sensor do? does it just tell the ecu to spark a few degrees after its told the injector to inject?

Does anyone know where i can get my hands on schematic wiring diagrams and flow chart diagrams from??

Heids done rite in,

Cheers,

Rudboy

f4la k

iTrader: (1)

rudboy, as you say its like its over fueling. your injector seals could be leakin and fuel is leaking past the injector causing it to foul the plugs. You can either pull all the injectors and change the bottom orings( use only original subaru replacement orings) or you can split the exhaust at the downpipe and check and see if the exhaust is full of petrol. Your best bet would be to split at downpipe and see if it has alot of petrol in it. If so you need to replace injector orings. Hope this helps...

rudboy

f4la k,
cheers for the info i've passed it onto my mechy, he'll get on it the morn.

rudboy

bump

biggi

iTrader: (3)

Do you have a upgraded mapped ecu, if so have you checked that the map applied has not gone corrupt, this has happened before, its worth a check.

rudboy

na its not been mapped, im using a apexi avcr on it,
I will be getting it mapped, if we eventually get the bugger running..........

cheers.

rudboy

Rite,

Update,

changed out new spark plugs fro the old ones and the car started first turn..... God knows why but it did and its starting every time since, Idles fine but maybe a bit slow in returning to idle after the foot was lifted off.

Got a gas analyzer on it and the readings are sky high,2.50co% 300ppm hydro carbons.

Swapped out the MAF- no real change to readings
Lambda- no real change to readings
Ecu- no real change to readings
Map- no real change to readings
checked Fuel pressure reg, -Ok.
checked coolant temp sensor- ok.

With the sti ecu it runs with no Check engine light with only one lambda plugged in. Temp gauge fine/normal.

Wrx ecu,with one of the lambda unplugged it runs with the temp gauge off the scale(temp fine) and the check engine light is on.

Is there any suggestions as to how to get the emissions down?

Definetaly still over fuelling.

Stuck again.

markjmd

iTrader: (11)

Do you actually have a CAT fitted to the car or the moment, or did that come back off after the MOT?

rudboy

Yeah the cats still on as its not had its mot yet.

rogos

you might have an injector dribbling or as already mentioned an injector seal may be leaking? have they been checked yet? you also stated earlier that when you checked a plug (which one?) that it was soaked (with what petrol?) if it was soaked with petrol then the bore may have been borewashed? if it has it could cause the rings to allow oil into the combustion chamber and that would put the emissions up.

rudboy

Mate,
not removed any of the injectors as yet, we did unplug the injectors one by one to see if it dropped any cylinders it did, then we unplugged 2 on the right and as soon as we unplugged the 3rd one it concked out, reckoning there ok, i realise its not a cast iron check but think we're happy that they aint leaking much if any??

Where can i find details of subaru injectors? the ones in me motor are grey,

It was the front left plug that was removed and yeah it was soaked with petrol. the cars probably ran for 25-30 mins in total in between un plugging and plugging back in of all the components mentioned. would bore wash still be an issue?