Discussion
Try this guy:
http://andyforrestperformance.co.uk/4436.html
Watched him race. Really knows how to make a Subaru go fast.
http://andyforrestperformance.co.uk/4436.html
Watched him race. Really knows how to make a Subaru go fast.
vxr2010 said:
Hi all can any one advise a trusted person for ecu repair please , it's for a Subaru Forester sti not a v8 , or if repair is a no go then what other options are there please , thanks in advance
Faulty ecu's are incredibly rare...what exactly is the problem ?There is BBA-Reman, Ecudoctor and there might be a couple of others.
Or it may just be cheaper to source another used ecu and have the immobiliser programmed ( although that may not apply due to being an import )
Two banks on the passenger side dropped 50 psi , he thinks it was over fuelling but it appears no damage caused , he has re ground the valves , timing was ok , he thinks possibly faulty injectors but two at the same time ? Or an ecu fault keeping the injectors open , it's being put back together today , no warning lights came on at the time , I have bought a code reader now any way
Two banks on the passenger side dropped 50 psi , he thinks it was over fuelling but it appears no damage caused , he has re ground the valves , timing was ok , he thinks possibly faulty injectors but two at the same time ? Or an ecu fault keeping the injectors open , it's being put back together today , no warning lights came on at the time , I have bought a code reader now any way
vxr2010 said:
Two banks on the passenger side dropped 50 psi , he thinks it was over fuelling but it appears no damage caused , he has re ground the valves , timing was ok , he thinks possibly faulty injectors but two at the same time ? Or an ecu fault keeping the injectors open , it's being put back together today , no warning lights came on at the time , I have bought a code reader now any way
Unfortunately the description you're giving makes no sense, some may be getting lost in translation thoughSo you're saying someone did a compression test and 2 cylinder have poor compression ?
Then someone has come to a rather strange conclusion about why ? With no sensible reasoning applied.
Then they have taken the engine apart to some degree ?
He has "reground" the valves....why ? And reground what exactly ?
Valve and seat recession on 01+ cars is not uncommon. Using cheap, or normal unleaded fuel will accelerate this over SUL, but regardless it is a problem
The heads will need rebuilt and valve clearances re-set, this will either mean new buckets or grinding the tops of the valve to achieve the correct clearance, and often it may mean either new or replacement valves too. Not really a DIY job although with great care and patience it can be done DIY.
But whoever is suggesting a faulty ecu would cause such a thing...I'd be cautious about them working on my car.
The thought is faulty ecu on the forester has opened up the injectors and has in turn cleaned the bores and debris has got into valve area , valves re ground and hopefully compression returns , hope that makes more sense , head gaskets changed very recently about two weeks ago , builder was thinking it may have been a fault as result of re build
if you are on facebook there is a chat channel called "General chit chat about stuff with wheels and fuel" request access then ping Gurmeet (he is friends with everyone) a message to ask nick to approve access
then chat to nick hulin he has had his Subaru reworked a few times and will know who to recommend for any investigation work
then chat to nick hulin he has had his Subaru reworked a few times and will know who to recommend for any investigation work
OK, petrol or diesel.
Petrol.
Scope the injector waveform to see if the injectors are being held open. If they are, additional evidence will be that the plugs will be very sooty, and the O2 sensor way way off the scale.
Poor O2 sensor readings can be caused by faulty ignition - the ignition waveforms can be checked, and can even be looked at during a run if you are careful.
If you have good injection waveforms, then in my experience the ECU is unlikely to be cooked. Bad injection waveforms are normally caused by something else, and sometimes the ECU.
Diesel.
More difficult, but check the common rail (is it common rail?) fuel pressure, and the rate of decline from an idle 1.3v to 0.5v - should be about 5 to 15 seconds on a decent injection system. If this is bad - do leak off tests on the injectors. If it's OK, look tot he injector waveform and see what's happening there. Diesel ECU's normally fail on the injection cycle, as there's a load of amps going to drive the injectors open.
You really really don't have enough information that you have shared to condemn the ECU.
In my experience the ECU is at fault about 5% of the time - so 95% of the time it's something else - you just haven't found it yet.
If the ECU is faulty, it's easier to replace it with a cloned used unit - you'll normally find them on the net for a few hundred quid.
Cheers
Petrol.
Scope the injector waveform to see if the injectors are being held open. If they are, additional evidence will be that the plugs will be very sooty, and the O2 sensor way way off the scale.
Poor O2 sensor readings can be caused by faulty ignition - the ignition waveforms can be checked, and can even be looked at during a run if you are careful.
If you have good injection waveforms, then in my experience the ECU is unlikely to be cooked. Bad injection waveforms are normally caused by something else, and sometimes the ECU.
Diesel.
More difficult, but check the common rail (is it common rail?) fuel pressure, and the rate of decline from an idle 1.3v to 0.5v - should be about 5 to 15 seconds on a decent injection system. If this is bad - do leak off tests on the injectors. If it's OK, look tot he injector waveform and see what's happening there. Diesel ECU's normally fail on the injection cycle, as there's a load of amps going to drive the injectors open.
You really really don't have enough information that you have shared to condemn the ECU.
In my experience the ECU is at fault about 5% of the time - so 95% of the time it's something else - you just haven't found it yet.
If the ECU is faulty, it's easier to replace it with a cloned used unit - you'll normally find them on the net for a few hundred quid.
Cheers
vxr2010 said:
The thought is faulty ecu on the forester has opened up the injectors and has in turn cleaned the bores and debris has got into valve area , valves re ground and hopefully compression returns , hope that makes more sense , head gaskets changed very recently about two weeks ago , builder was thinking it may have been a fault as result of re build
Nope, as said no logic whatsoever to that.Valve and seat recession is common on 01+ models, accelerated by the use of normal UL fuel as said before
If there had been so much fuel entering the engine to even stand a chance of causing such a scenario, it would be running like an absolute pig.
Whilst there will be running symptoms and some strange codes thrown over time, when valve seats do start to get bad the symptoms can often be very strange and nothing remotely like overfueling. And often quite random sometimes running fine, some not.
Some history etc might help here...you seem to be suggesting the engine has been apart twice ?
And there should be no hope about compression returning. If he has done proper tests and measurements around valves and clearances he should know why there was low compression in the first place and whether what he is doing should remedy it.
So were valve clearances ok ? What exactly is the recent history and reasons leading to taking it apart ?
And no, there is almost no chance the ecu is at fault.
Hi the history is , mileage around 110 k miles , the head gasket went about 5 years ago , bottom end seemed fine , then about 1 year later bottom end went , so had bottom end and head gaskets done , then head gaskets have then gone again as the subaru ones are not great , this time arp bolts and cosworth head gaskets , about two weeks after this re build then very lumpy idle and this has come down to loss of compression , he has re ground valves and is putting back together now , always run on super unleaded , I trust the re builder and he is confused as to fault , they should know what they are doing as thats all they do is subaru
vxr2010 said:
Hi the history is , mileage around 110 k miles , the head gasket went about 5 years ago , bottom end seemed fine , then about 1 year later bottom end went , so had bottom end and head gaskets done , then head gaskets have then gone again as the subaru ones are not great , this time arp bolts and cosworth head gaskets , about two weeks after this re build then very lumpy idle and this has come down to loss of compression , he has re ground valves and is putting back together now , always run on super unleaded , I trust the re builder and he is confused as to fault , they should know what they are doing as thats all they do is subaru
Not a single thing wrong with original Subaru gaskets, they'll easily handle 4-500hp when used correctly.500+ Then yes Cosworth gaskets are a good idea.
If this is a standard engine, then ARP bolts are an unnecessary expense too if you're trying to fix some sort of problem.
If it's just an upgrade then no problem, they're always good to have.
If all they do is Subaru then they should be well aware of the seat recession problems, and should also be well aware ecu faults are almost non existent, especially something as completely random and unlikely as they are suggesting.
Likewise if they have plenty of Subaru experience they should know the OEM head gaskets are very good quality.
If all they have done is re-grind, which implies just lapping the valves to the seats with some grinding paste, then expect to take the engine apart again. Unless they re-set valve clearances with either new shims/buckets or by removing material from the valve tip....then there is no chance whatsoever of the problem being fixed based on what your describing. Some replacement valves may have been needed too depending how had the wear was.
Although there would also be some concern about the short time period between the last "rebuild" and this new problem
Often with seat issues you'll get misfire fault codes appearing over time before hand with no apparent reason as to why.
vxr2010 said:
Hi , Steve what you say makes sense , the only valve recession seems to be when lpg is used which I dont , but the lack of compression sounds like valves , he said bores and Pistons are ok , I'm still left bemused and wondering what sort of bill to expect
Valve seat recession IS a well known issue on all 01+ cars. This is fact and I've seen plenty of them myself.LPG will make things worse again ( that said I've seen some high mileage LPG cars surviving ok ), but the problem is not in any way unique to LPG.
Id be shocked if any Subaru specialist hasnt seen the problems first hand by now, as it certainly isnt something new, and doesnt even require huge miles either.
You can be 95% sure the problem is as I'm describing, with the cure also as I'm describing. If they dont do what I've said, then the engine will be coming apart again pretty soon.
vxr2010 said:
The valves were checked and adjusted , the theory now is the injectors or ecu is faulty , he thinks the injectors have stayed open and caused piston wash and therefore crap from bores have contaminated the valves , hopefully I will know soon
There is no theory or logic in that suggestion...let alone any possibility of it happening.I'd even take it to the point that such a suggestion is complete and utter nonsense.
Well an update , I'm 1600 £ poorer which could have been mod money ,I wanted to do the r8 suspension , the fault appears .. A small piece of plastic blocked the variable cam timing pump , the ecu had a moment and dumped loads of fuel in and cleared a load of carbon out that stopped the valves shutting properly , no bore damage no valve damage and at last car finally back on the road , don't know where plastic came from , I do like the more simplistic v8 design of an engine , but such is life , I still think a v8 in the forester STI would be the nuts lol
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