Ian C Posted April 1, 2004 Author Share Posted April 1, 2004 Originally posted by Chris Wilson Glad the injector idea worked out Ian. I have never seen a J-Spec on bigger injectors without ecu kludging that runs right myself. Why should it? It needs remapping, the O2 sensor will only try and trim an existing hard map. Maybe the ecu has some inbuilt stuff that sends it into limp home mode if the O2 sensor tries to trim outside a set parameter. have you tried a new O2 sensor? I am not advising you run big injectors with a stock ecu, just wodering why it worked initially, but not now... Maybe you should ring me in the pub more often, my most creative ideas seem to hatch in there Maybe send beer money And I WAS impressed by the speed of the injector swap, it took all of what, err 4 / 5 pints long! I really should send you the 440's to clean up, although I don't like the idea of paying for them to be cleaned for one quick test There is also the question of maybe something is causing some overfuelling but the ECU can compensate for it with 440's in... I've tried another O2 sensor, in fact on you supply, I borrowed it off Brian's wrecked Supra. I've swapped them around a few times... (incidentally, the replacement ones don't warm up anywhere near as fast as the stock ones, dunno if that matters to anyone) Anyway, it had this problem with the ECU kludgatron plumbed in and mapped. It just cropped up at the start of February. Maybe the Apexi thing had suddenly stopped altering the airflow signal properly? I may well plumb it into the field harness and try it again, especially to just lean off the mix at say 2500rpm low throttle and see a) if it works, and b) if it's possible to get a closed loop response. It's a good job you aren't using pints to measure how long this problem is taking to fix -Ian Quote Link to comment Share on other sites More sharing options...
Ian C Posted April 1, 2004 Author Share Posted April 1, 2004 Originally posted by Ian C All the plugs looked exactly the same regarding blackness and wetness every time I've taken them out so I think the problem is across all six cylinders evenly, plus if it was just one injector the others would be pulled down to a lean state to compensate for the richness produced by one of them and that would be a noticeable engine condition I reckon. Do you reckon that daft little pipe by the TPS with the check valve in it could have something to do with idle control and all that then? I'll have to have a look at another Soop to see how that one behaves... Actually, if people can fit it in around checking their ECU voltages for me , can they see if they get any noticeable vac/pressure around that load of hoses? -Ian Never mind any of that, that little pipe is strictly Evap system only, nothing to do with the idle or throttle. Still no idea what the "throttle opener" is though... -Ian Quote Link to comment Share on other sites More sharing options...
mark brown Posted April 1, 2004 Share Posted April 1, 2004 I have 550cc injectors on my J spec and it ran miles too rich initially. Had to fit an AVCR, reduced the fuelling by 16% at idle to get that right and between 13%- 8% from idle to three quarters throttle to get it to run properly. Mark Brown Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted April 1, 2004 Share Posted April 1, 2004 Originally posted by Ian C Never mind any of that, that little pipe is strictly Evap system only, nothing to do with the idle or throttle. Still no idea what the "throttle opener" is though... -Ian Is it a little Sputnik shaped casule with adjustable threaded rod on it? If so it's just a damper to slow the closing of the throttle plate down. IAC valves and their control maps are relatively slow to respond, to stop cyclical hunting, so makers use a damped piston to delay throttle valve closing over the last few degrees so the ECU control functions can "catch up". It's very unlikely to be the source of your troubles. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted April 1, 2004 Share Posted April 1, 2004 Originally posted by mark brown I have 550cc injectors on my J spec and it ran miles too rich initially. Had to fit an AVCR, reduced the fuelling by 16% at idle to get that right and between 13%- 8% from idle to three quarters throttle to get it to run properly. Mark Brown And, if Mark doesn't mind me saying so, boy, does this car run well Quote Link to comment Share on other sites More sharing options...
Digsy Posted April 1, 2004 Share Posted April 1, 2004 So Ian's car used to run apparently OK on 550's but suddenly the ECU can't compendate for the fueling? IIRC lambda sensors can be damaged by running rich so that would point to a knackered or slightly damaged lambda sensor BUT Mr. C has checked / swapped this out already... Odd. Nothing seems to add up. Quote Link to comment Share on other sites More sharing options...
Ian C Posted April 1, 2004 Author Share Posted April 1, 2004 Originally posted by Chris Wilson And, if Mark doesn't mind me saying so, boy, does this car run well Well, he's using the same bit of kit as me, the AVCr, which you set up for me, and it had been running fantastically until February (I never found a stock-turbo based Supra that was faster, and I've raced a few ) Darren - tell me about it I couldn't check anything tonight as I'm feeling under the weather, so still dunno if the fuel pressure is too high or whatever. -Ian Quote Link to comment Share on other sites More sharing options...
Adam W Posted April 2, 2004 Share Posted April 2, 2004 Does the AVCR do fuel mapping then or are you using an SAFC for that? My ancient steam powered Mk3 standard ECU will quite happily run my 680cc injectors (standard are 440) at idle and closed loop and maintain perfect 14.7:1 a/f ratios with no SAFC etc connected. I drove it to work and back for a couple of weeks like that last summer after my old SAFC fried itself. So I would be very surprised if yours won't run 550's *at all*. Try plugging the SAFC back in and leaning it right out at idle, see if that helps? Quote Link to comment Share on other sites More sharing options...
Ian C Posted April 2, 2004 Author Share Posted April 2, 2004 Sorry, brain fade, I meant s-AFC, I'm sure Mark Brown did as well - the AVCr doesn't do jack to fuelling. So, a MkIII will run 680's without any adjustment barring stock closed loop control. And I know the MkIV can run 550's under the same conditions. Anyone know what effect a resistor pack with too much or too little resistance would have on injector duration...? -Ian Quote Link to comment Share on other sites More sharing options...
Adam W Posted April 2, 2004 Share Posted April 2, 2004 I don't think it would have any effect on injector pulsewidth, it would just put a slightly different load on the injector drivers, unless it was way out I can't see it being a big problem. Quote Link to comment Share on other sites More sharing options...
Ian C Posted April 2, 2004 Author Share Posted April 2, 2004 Well, having had a look on SupraForums there appears to be a few people with the same symptoms, at least one stocker and one big single with replacement fuel system so I'm thinking it's caused by a stock thang that is on my car and US spec cars that isn't removed when going single turbo, and happens one day at random... Great -Ian Quote Link to comment Share on other sites More sharing options...
dandan Posted April 16, 2007 Share Posted April 16, 2007 I stumbled across this thread when searching for injector o ring part numbers. From memory Ian this was a dodgy SAFC or connections to the SAFC wasn't it? Quote Link to comment Share on other sites More sharing options...
Alex Posted April 16, 2007 Share Posted April 16, 2007 The SAFC itself was fubar'd. Quote Link to comment Share on other sites More sharing options...
dandan Posted April 16, 2007 Share Posted April 16, 2007 What a bastard. Anyway, back to part no. searching... Quote Link to comment Share on other sites More sharing options...
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