Homer Posted February 5, 2006 Share Posted February 5, 2006 A recent dyno run at Surrey rolling road showed a big power loss over the entire rev range (since the last one). It also showed huge overfueling when above 4k rpm, at one point it drops below 9afr and seems to average 10.5 or so. Considering this car has stock 440cc injectors, stock ECU and no other electronics bar FCD this seems very wrong. It also seem to be creating a huge amount of soot out of the exhaust, and the plugs (Ik22's) are fouled with carbon deposits after just 1000 miles. Any ideas what to look into first? I have an auromotive FPR, could this be set to deliver too high pressure, also, could a faulty/dirty O2 sensor cause this? Quote Link to comment Share on other sites More sharing options...
TRD3000GT Posted February 5, 2006 Share Posted February 5, 2006 Any ideas what to look into first? I have an auromotive FPR, could this be set to deliver too high pressure, also, could a faulty/dirty O2 sensor cause this? Check the O2 sensor.. Best to just splash out a get a new one.. Next up Make sure that the FPR is set right and that there are no leaks in the vacuum line going in to it.. Quote Link to comment Share on other sites More sharing options...
Homer Posted February 5, 2006 Author Share Posted February 5, 2006 Check the O2 sensor.. Best to just splash out a get a new one.. Is there any way to check it before replacing? They're are over £100 so don't want to replace unless its necessary. Quote Link to comment Share on other sites More sharing options...
TRD3000GT Posted February 5, 2006 Share Posted February 5, 2006 Is there any way to check it before replacing? They're are over £100 so don't want to replace unless its necessary. You can remove it and try to clean it off with a lemon.. Cut it in half and jamm the sensor in to it and queese as much acidic juice on it to try and clean off the deposits.. Finally dry / whipe it off with a clean rag. Ive heard the guys in the US do this and it works well but I have not tried it myself! Quote Link to comment Share on other sites More sharing options...
Homer Posted February 5, 2006 Author Share Posted February 5, 2006 Thanks Chris, I'll give that a shot tomorrow! Quote Link to comment Share on other sites More sharing options...
b_have Posted February 5, 2006 Share Posted February 5, 2006 O2 sensor will only effect your closed loop fueling so wont be that. Dont have an FSE do you? sounds like a fuel pessure problem to me. Quote Link to comment Share on other sites More sharing options...
Alex Posted February 5, 2006 Share Posted February 5, 2006 What's your static fuel pressure? Quote Link to comment Share on other sites More sharing options...
Dragonball Posted February 5, 2006 Share Posted February 5, 2006 Idling rpm OK? Quote Link to comment Share on other sites More sharing options...
Homer Posted February 5, 2006 Author Share Posted February 5, 2006 Its an aeromotive fpr, I have a pressure gauge here but don't know how to use it! The idle is fine. Quote Link to comment Share on other sites More sharing options...
Homer Posted February 11, 2006 Author Share Posted February 11, 2006 Okay, just checked the fuel pressure and it seems fine - 41 psi. Any other ideas? Injector problem? Quote Link to comment Share on other sites More sharing options...
tDR Posted February 11, 2006 Share Posted February 11, 2006 Is it a rising rate FPR? These are a bad tuning solution IMO. Quote Link to comment Share on other sites More sharing options...
Homer Posted February 11, 2006 Author Share Posted February 11, 2006 Is it a rising rate FPR? These are a bad tuning solution IMO. Nope, its 1:1 Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 11, 2006 Share Posted February 11, 2006 Put the stock regulator back on, if you don't mind me asking why did you change it anyway? Quote Link to comment Share on other sites More sharing options...
Homer Posted February 11, 2006 Author Share Posted February 11, 2006 Put the stock regulator back on, if you don't mind me asking why did you change it anyway? I was advised to change it a couple of years ago by one of the tuners here. It was after a dyno run I did showed the car running a little lean (12.5) at 4.5k rpm. Plus, I was planning on going single turbo soon after so thought it a future-proof investment. Does anyone have a stock fpr I could buy (or borrow) to eliminate the fpr as the cause? Quote Link to comment Share on other sites More sharing options...
Ian C Posted February 12, 2006 Share Posted February 12, 2006 Okay, just checked the fuel pressure and it seems fine - 41 psi. Any other ideas? Injector problem? If that's 41psi while you are idling then it's too high. I agree with Chris, stick a stock one back on, plenty 2nd hand ones knocking around for buttons. That should fuel you OK up to 1.2bar on stock turbos as long as you've got a decent fuel pump. This is a good example of how a rising rate FPR or even just winding up the fuel pressure as a fuelling solution sucks. You cure a lean-ish spot at 4.5krpm but richen up everywhere else in the range... 12.5afr isn't worth worrying about at 4.5krpm anyway, some people actually map for that -Ian Quote Link to comment Share on other sites More sharing options...
Homer Posted February 12, 2006 Author Share Posted February 12, 2006 Thanks Ian, I can see the logic in what you're saying. Will locate and install a stock fpr and see how it works out. I don't doubt the advice I was given by Terry, but this did occur in the middle of the infamous "fpr" wars with Paul E Maybe I didn't need an uprated fpr at my current mod level... Edited to add - What should be the pressure at idle, I though it was 40psi? Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 12, 2006 Share Posted February 12, 2006 If that's 41psi while you are idling then it's too high. I agree with Chris, stick a stock one back on, plenty 2nd hand ones knocking around for buttons. That should fuel you OK up to 1.2bar on stock turbos as long as you've got a decent fuel pump. This is a good example of how a rising rate FPR or even just winding up the fuel pressure as a fuelling solution sucks. You cure a lean-ish spot at 4.5krpm but richen up everywhere else in the range... 12.5afr isn't worth worrying about at 4.5krpm anyway, some people actually map for that -Ian As Ian said mate is that pressure static or is that when idling with everything connected 9 pulling a vacuum). No need to revert back to stock, just need to establish the correct pressure. Quote Link to comment Share on other sites More sharing options...
Homer Posted February 12, 2006 Author Share Posted February 12, 2006 As Ian said mate is that pressure static or is that when idling with everything connected 9 pulling a vacuum). No need to revert back to stock, just need to establish the correct pressure. Its with the engine off and only the fuel pump running (See http://www.mkivsupra.net/vbb/showthread.php?t=58832 ) Quote Link to comment Share on other sites More sharing options...
Seb Posted February 12, 2006 Share Posted February 12, 2006 Sorry to hijack this thread, but my car's overfuelling as well - around 10.8 from 4000rpm onwards with a low of 10.6. I'm wondering if the Tom's ECU has something to do with it - it raises boost to around 0.9-1bar. What should AFRs be normally? Quote Link to comment Share on other sites More sharing options...
Ian C Posted February 12, 2006 Share Posted February 12, 2006 BPU'd cars that run 1bar of boost overfuel anyway, because the injectors are running at 100% duty - run 1.2bar to use up all that extra fuel -Ian Quote Link to comment Share on other sites More sharing options...
Seb Posted February 12, 2006 Share Posted February 12, 2006 Cool, thanks Ian! Quote Link to comment Share on other sites More sharing options...
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