Andrew Posted February 18, 2003 Share Posted February 18, 2003 Took the car to the local Tuning Specialists yesterday to see if they could solve my detonation problem. They suggested a boost controller, but that's not an option atm, esp the price I was quoted....£650.00 They did however suggest an FCD with an AFR. FCD I was going to get anyhow, but never considered an AFR. So a few questions. 1/ Would AFR/FCD cure detonation? 2/ What exactly does an AFR do? I'm not after more power, just want to stop the car pre-detonating. Oh and for both FCD and AFR with labour +vat, I was quoted £350.....reasonable price? Will need to get a boost gauge fitted too, at some point ££££ permitting So for now I'm running millers all the time and easing of the pedal. Link to comment Share on other sites More sharing options...
Nathan Posted February 18, 2003 Share Posted February 18, 2003 A short, simple question: Why is the car detonating? All Supras (even imports) are quite happy on 1.2 bar with Super Unleaded. If you are running more boost than this an AFR won't help because your MAP is maxed anyway. If it's detting for any other reason then there is a problem that needs to be fixed, not more bits added on. Regards, Nathan TDI PLC PS: I wouldn't say £350 is overpriced for a good job, but I'd just like to know that you defo need the parts first... Link to comment Share on other sites More sharing options...
Andrew Posted February 18, 2003 Author Share Posted February 18, 2003 Why is the car detonating? Good question Nathan, to be honest mate I have no idea. The guy at the garage, pointed out that the J-spec is mapped to run at 100 ron. I mentioned the fact that I run Optimax 98-99ron and still suffer pre-detonation, this occurs when in 3rd or 4th at high revs, never happens bottom end. When I have added Millers +2 octane booster, I never get detonation. This lead me to believe it was the fueling. Coupled with the fact I seem to be producing high levels of boost, because I have hit FC. He told me an AFR would help with fueling? Are there other things that can cause pre-detonation? I just assumed it was down to my mods. Link to comment Share on other sites More sharing options...
Nathan Posted February 18, 2003 Share Posted February 18, 2003 Hi Andrew, Yes, the import IS mapped to 100 RON fuel but it's well known that the cars can run 97 or 98 RON with no problem, even at 1.2 bar. Indeed, theres plenty on this very BBS who are doing just that, and FWIW I will catagorically state myself that it is safe and would be happy to run my own car at that. So, a direct question, are you running more than 1.2 bar? If not, then I will say again that you have a problem and IMO an AFR adjuster won't help, especially if like you say it is the top end which is causing problems as the MAP sensor will be maxed at that point. An AFR adjuster will certainly shove more fuel in lower down but that isn't where your problem is, and it shouldn't be needed anyway as the cars do not run lean up to 1.2 bar.........unless your fuel pump is shagged for example. But then it could be dirty injectors...or a faulty knock sensor...or...or....the possibilites are endless. I fully accept that Millers solves the problem, but personally I think it's masking something that shouldn't be there in the first place. There's plenty of things that could cause det (you might even have a modded ECU with a map specifically for race fuel for example) but I won't go into detail here as thats what your tuner is for and besides, speculation gets you nowhere. BTW, I don't know who they are, and personally I don't really care, but I'd suggest you find someone else to work on the car who can actually tell you why a car is detting. I'd wager that no-one on this site knows or uses them.... Regards, Nathan TDI PLC Link to comment Share on other sites More sharing options...
Nathan Posted February 18, 2003 Share Posted February 18, 2003 I forgot to say that if you do not have an FCD then you are unlikely to be boosting more than .95 bar. If you are detting at that boost level then you REALLY have a problem that needs sorting out.... Regards, Nathan TDI PLC Link to comment Share on other sites More sharing options...
THOR Racing Posted February 18, 2003 Share Posted February 18, 2003 Ahh!!!! What a load of old cr*p! Sorry but I get fed up with so called tuning specialists talking out of their backsides! I'm never normally this articulate but lets check the obvious things first before wasting your hard earned cash! He told me an AFR would help with fueling? Ummm it won't help with fueling. It'll just let you know if fueling is a problem or not. i.e. if the engine is going lean. AFR = Air Fuel Ratio i.e. how much unburnt oxygen there is in the exhaust gas. Senses this by reading the O2 sensor. A car under fuel cut or hitting it will not suffer from Knock (detonation). No idea what you mean by pre-detonation. Do you mean pre-ignition? Which is totally different to knock. I'd check your spark plugs. Fueling (which if you run Optimax just on it's own should be fine.) Sounds like bad advice to me from someone who doesn't understand performance cars, especially the Supra. Juddering or slight misfiring at high RPM can be confused with knock (by some people) but I find it's normally down to the spark plug types used. (especially at the mod level most of use have on this list) Also if you're hitting fuel cut are you sure you're not confusing the two effects. As for price! Check out my site for comparison. I'm not saying you need an AFR meter. I doubt the narrow band O2 sensor will tell you much more than it's rich or lean. If it ever get's to the lean part at wide open throttle. Say goodbye to the engine. I strongly believe you haven't got this problem. But an AFR meter is a nice gadget to have, just I'm not sure you NEED one yet! When was the car last serviced? What plugs do you have? Had you ever diluted the fuel with normal unleaded prior to this? What's the history of the mods and when did this occur? Regards Pete Link to comment Share on other sites More sharing options...
Andrew Posted February 18, 2003 Author Share Posted February 18, 2003 I'll try and explain what happens. Accelerate hard through 1st/2nd no problems, accelerate hard in 3rd to 5000-5500 rpm, then bang and a jolt, very similar to Fuel Cut coming in, but I do not get any engine warning lights flashing or staying on. Engine continues as normal. Naturally I could be confusing FC with denotation, but I assume you only get the engine light coming on when you hit FC? Car was serviced 2 months ago, basic service. No idea what the plugs are sorry. I have diluted the fuel with normal unleaded before, but I have been running pure Optimax for 3 months now, nothing else. Mods are decat downpipes full straight through exhaust, never had this problem with that mod. Seemed to start when I added a Blitz induction kit. I have an HKS SUS dumpvalve but doubt that counts for anything. No electrical ECU mods afaik. Thanks for the help so far guys most appreciated. Pete I have been looking on your site for quite some time, infact it's bookmarked The tunners in question might not be worth going to in future, by what you guys are telling me. Unfortunatly I don't feel that confident with the electrical side of modding. Link to comment Share on other sites More sharing options...
Thorin Posted February 18, 2003 Share Posted February 18, 2003 It sounds like it's probably the plugs to me, get em changed and a colder grade than stock. Link to comment Share on other sites More sharing options...
Adam W Posted February 18, 2003 Share Posted February 18, 2003 You say the car is decatted but you have no fuel cut defender fitted? You'll be bouncing off fuel cut every time you floor it!! Link to comment Share on other sites More sharing options...
Darren Posted February 18, 2003 Share Posted February 18, 2003 What year is your car? Mine was hitting fuel cut but I never saw any lights on the dash and it was not as agressive as in the pre VVTI models. But it was def happening. Darren Link to comment Share on other sites More sharing options...
Alex Posted February 18, 2003 Share Posted February 18, 2003 Andrew, IMO your tuner is full of Shite.... But there are good ones. You're in Kent....TDI (Nathan) will be fairly close. Or you could try Abbey Motorsport - they are tuners but not Supra specialists. Someone competent needs to look over the car. Though it really does smack of poorly chosen plugs with the wrong gap. Link to comment Share on other sites More sharing options...
Andrew Posted February 19, 2003 Author Share Posted February 19, 2003 Well took the car for a hard run last night and it happened again in 4th at around 5000-5500 revs. Deffinatly not the fuel as I was running Optimax/Millers. I'll take a look at the plugs this weekend, I see you have some on your website Nathan, so I'll probably order those soon. Darren the Sup is a 95, I have hit FC before and the lights come on, if it also FCs without the light show and like Adam says I would be on it most of the time, then this could be my probelm. Well thanks for the help folks, you've saved me some cash, as an AFR is now out. Looks like new plugs/FCD/Boost gauge for me and see how it goes. Link to comment Share on other sites More sharing options...
Syed Shah Posted February 19, 2003 Share Posted February 19, 2003 Originally posted by Nathan Yes, the import IS mapped to 100 RON fuel but it's well known that the cars can run 97 or 98 RON with no problem I have to disagree with you there, that is a myth that they map all jap cars to 100ron. Only a few petrol staions there even have 100ron fuel! Having said that, this car probably has a aftemarket ECU with a very aggressive map requiring better fuel than standard. Link to comment Share on other sites More sharing options...
Nathan Posted February 19, 2003 Share Posted February 19, 2003 Originally posted by Syed Shah I have to disagree with you there, that is a myth that they map all jap cars to 100ron Never said they mapped ALL Jap cars to 100 RON fuel..... Out of interest, what RON do you think they map the import JZA80 to? Regards Nathan TDI PLC Link to comment Share on other sites More sharing options...
Syed Shah Posted February 19, 2003 Share Posted February 19, 2003 95-97ron, that seemed to be the norm for the petrol stations there. Having said that, it would be interesting to see the differences in the maps for the JDM vs the export Supras (UK 95ron). I wonder also what the Us cars are mapped to , since their fuels range from 89 all the way up to 104! Probably 91 as that is the 'premium' fuel in California. Any idea what that is in ron? As they quote the av of mon and ron. Used to have the basic convrsion written down, but seem to have lost it Link to comment Share on other sites More sharing options...
adi Posted February 19, 2003 Share Posted February 19, 2003 Youre hitting boost/fuel cut !! Thats all !! I hit boost cut a lot (until i sort it) and after the first few times the engine warning light just stops showing the fault,even though its still happening. This same thing will happen on yours (although i have a different model it is virtually the same engine system). Basically, the ECU shows it for the first few times and then stops warning you (no idea why). A simple check of the engine codes should tell you.. im sure it explains how to do that somewhere on this site. Fit an FCD off pete or something and as long as youre nor running too high boost you should be fine. Oh, and go back to your garage and tell them they're a pile of crap. There's something wrong with a garage who cant recognise a simple thing like boost cut, yet who are quite happy to recommend you fit things like boost controllers and even offer to set up an AFR for you. Link to comment Share on other sites More sharing options...
Terminator Posted February 19, 2003 Share Posted February 19, 2003 If you pull the EFI fuses for 10 minutes you will reset the ECU, and empty it of all codes. The warning light should operate for a few times again. Link to comment Share on other sites More sharing options...
adi Posted February 19, 2003 Share Posted February 19, 2003 Yep, but dont forget to check the codes first... Link to comment Share on other sites More sharing options...
Andrew Posted February 19, 2003 Author Share Posted February 19, 2003 Thanks, it's been duely noted that the tunners are a bunch of tossers FCD and boost guage will now be my priority. Link to comment Share on other sites More sharing options...
Andrew Posted February 24, 2003 Author Share Posted February 24, 2003 Problem sorted this weekend thanks to you guys and an FCD from TRL, cheers Pete Fitted myself, although easy it was like diffusing a bomb to me. Almost had a heart attack after I put it altogether, turned the ignition and nothing happened...dead. Took me a few heart-stopping seconds to realise the car had immobilised itself Drove up the motorway, no problems flooring it now Off the boost now though until Boost gauge fitted. Thanks again for all the help. Link to comment Share on other sites More sharing options...
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