ecu pulling ignition back 11.5 degrees
so i had a random boost hesitation last week which i was worried about so i took my car over to thwaites to see mark, he plugged his laptop in and went for a spin in the car.
when he came back he said that the ecu was pulling back the ignition by 11.5 degrees between 2200 rpm and 3600 rpm, he checked all of the vac lines/dump valve/sensors etc but couldnt see anything wrong with the car. he re-set the ecu and told me to run it for a week and to fill up at a different filling station to rule out a bad batch of fuel so ive been out in the car today and filled up from a shell garage miles away and all seems fine,it boosts fine,temps are fine,no smoke and no unwanted noises. could a bad batch of fuel cause this issue? he said it could also be the knock sensor picking something up. my car does have piston slap due to the type of pistons used and clearances needed so could the knock sensor have picked up on that and mis-heard it? perhaps a spacer under the knock sensor would help. car is 2007 hawk sti on std ecu mapped by scoobyclinic @350bhp engine has covered just over 10k forged 2.5 closed deck block std rods with arp bolts mahle 2618 pistons new crank acl bearings rebuilt avcs heads with upgraded valve springs/retainers 11mm head studs cosworth head gaskets 10mm oil pump japspeed fmic forge dump valve full de-cat 3" downpipe to a 2.5" system with vortex backbox vf43 rebuilt turbo 750cc injectors walbro pump scooby-clinic cone filter induction kit obp 3 port oil catch can any ideas on other things that could cause it? will deffo invest in an aftermarket ecu now |
i've seen some really sloppy engines but never bad enough for a false knock reading down low like that. Only time i've seen that is when something is loose and rattling about at low RPM or as suggested a bad tank of fuel assuming all is well with the engine.
There's no need to shim the knock sensor, if its purely down to engine noise you can adjust the feedback/fine learning thresholds around the low load area or you can adjust the knock sensor settings at that area to account for the new noise levels in the standard ECU. As an example I once stupidly left a spanner sitting on the intercooler of my own car years ago, resulted in some tremendous knock readings but once the rattle was removed all was fine. Same goes for heat shields, brackets, bolts and poor fitting down pipes. |
Originally Posted by bludgod
(Post 12017387)
i've seen some really sloppy engines but never bad enough for a false knock reading down low like that. Only time i've seen that is when something is loose and rattling about at low RPM or as suggested a bad tank of fuel assuming all is well with the engine.
There's no need to shim the knock sensor, if its purely down to engine noise you can adjust the feedback/fine learning thresholds around the low load area or you can adjust the knock sensor settings at that area to account for the new noise levels in the standard ECU. As an example I once stupidly left a spanner sitting on the intercooler of my own car years ago, resulted in some tremendous knock readings but once the rattle was removed all was fine. Same goes for heat shields, brackets, bolts and poor fitting down pipes. It must be either the pistons or bad fuel, my pistons do sound nasty on tick over (like a skeleton wanking in a biscuit tin) but they quieten down when revs build up. I've had a knocking engine in my 1st Impreza and I know exactly how that sounds. I'm now 1/4 through the new tank of fuel and all seems fine. :freak3::freak3: |
Didnt clinic build the engine?
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Originally Posted by Tidgy
(Post 12017425)
Didnt clinic build the engine?
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Wouldnt have had that issue when it left then so somethings changed.
Did they do all the mods to it? |
Originally Posted by Tidgy
(Post 12017470)
Wouldnt have had that issue when it left then so somethings changed.
Did they do all the mods to it? i only popped into thwaites as its 20 mins away and thats all i had time for. ideally i need to stop fekking around and get an aftermarket ecu on there but whenever i get some cash it just seems to vanish. car has ran perfectly in my ownership (almost 1 year) been all over in it and in feb was at the clinic having a health check on the rolling road and all was good. mark said all the sensors are fine/lines are fine and there is absolutley no det going on. ive never had to top the oil up or the coolant and apart from a ****e idle (due to drive-by-wire/fmic/open cone induction kit) it has been perfect. all seems fine with it now so will see how i get on, kev spoke with me about the link ecu so i really ought to start saving hard for it. |
Ah i get ya, if it was a problem with the engine it would have been present from day 1 unless somethings failed.
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