miko_supra Posted January 15, 2010 Share Posted January 15, 2010 Started the car up after changing some spark plugs today and the car just died, so I unplugged the idle control valve and it started fine with a high 1500-1700 rpm Idle. I reconnected the plug on the valve (engine still running) and nothing happened. So I restarted the engine (valve still plugged in) and the car dies again. Do this a couple more times and eventually the car has a warm idle (under 1000 rpm) but the car is running VERY rich with black smoke out the back and it is hunting for an idle with revs constantly going from 500 to 750 rpm. I've checked all the hoses and connections round the engine bay and I even removed my piggy back ECU and have it running on the stock to rule that out (made no difference btw) So I took the whole control valve assy out of the car and dismantled it and gave everything a good clean. Everything seems to be moving ok. Put it all back together again and the problem is still the same. The last time I run the car was about a month ago when it ran fine and all I have done on the car since is spark plugs and a new FMIC. Is this definatly just an Idle control valve issue guys? Would this cause the car to run very rich also. Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 16, 2010 Author Share Posted January 16, 2010 I should have a spare o2 sensor knocking about, so I'm going to give that a go to see if it's causing the over fueling. Quote Link to comment Share on other sites More sharing options...
RobD Posted January 16, 2010 Share Posted January 16, 2010 I think if the idle control valve moves by you using your hands then its generally knackered anyway! Myabe worth PM'ing dude or chris w to confirm though bud! But to me i'd say it was Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 16, 2010 Share Posted January 16, 2010 Check the vacuum hosing around the MAP sensor. If it's off or holed, you'll be seeing atmospheric and fuelling for that, instead of a high vacuum. If you have a boost gauge, see what it's reading. -Ian Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 17, 2010 Author Share Posted January 17, 2010 Thanks for the replies. I'll be able to have another look at this tomorrow. Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 18, 2010 Author Share Posted January 18, 2010 Check the vacuum hosing around the MAP sensor. If it's off or holed, you'll be seeing atmospheric and fuelling for that, instead of a high vacuum. If you have a boost gauge, see what it's reading. -Ian Hosing all looks ok. The boost gauge is reading -15 psi. I've swapped over the o2 sensor and also swapped the ecu for spare ones I have, but they have not changed a thing. Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 18, 2010 Author Share Posted January 18, 2010 Having a little bit of a play around, sometimes the car doesn't start at all, but when I unplug the the vacuum hose from the MAP sensor it starts (still runs rich and rough though) then when I plug the vacuum hose back into the MAP sensor the revs perk up a bit and then within 10 seconds it gets rougher and rougher till it eventually dies. Now if the Sensor is plugged into the vacuum line at idle am I right in thinking that the fueling it will provide will be less than what it would be when unplugged and sensing atmospheric pressure. But then why would it then stall after 10 seconds?? Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 18, 2010 Author Share Posted January 18, 2010 Just to add, another thing I did to the car when it was last running was dump the pressure out of the aircon system and remove the heat exchanger for it. (eventually going to remove the ac pump aswell.) Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 18, 2010 Author Share Posted January 18, 2010 Eugh, I give up. I'm going to take it to AFR as running the engine trying to diagnose it in this condition is going to kill it. Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 18, 2010 Share Posted January 18, 2010 I had an overfuelling issue a while back that took about 3 months to diagnose, and the oil got contaminated with fuel - but as it was never put under any sort of load it didn't do any damage. I had to use an oscilloscope in the end to work out what was wrong, although these days the data the E-Manage can spit out is incredibly useful for diagnosing stuff. Don't suppose that's the piggyback ECU you have is it...? Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 18, 2010 Author Share Posted January 18, 2010 I had an overfuelling issue a while back that took about 3 months to diagnose, and the oil got contaminated with fuel - but as it was never put under any sort of load it didn't do any damage. I had to use an oscilloscope in the end to work out what was wrong, although these days the data the E-Manage can spit out is incredibly useful for diagnosing stuff. Don't suppose that's the piggyback ECU you have is it...? I have a hks f-con fitted to the car. I just can't think what it could be. The car had been sitting for about 6 weeks and only has about 1/8 of a tank of fuel in it. I put a gallon in yesterday from a petrol can. The only thing I can do Is start changing parts over and that just gets expensive and annoying. Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 18, 2010 Author Share Posted January 18, 2010 I had an overfuelling issue a while back that took about 3 months to diagnose, and the oil got contaminated with fuel - but as it was never put under any sort of load it didn't do any damage. I had to use an oscilloscope in the end to work out what was wrong, although these days the data the E-Manage can spit out is incredibly useful for diagnosing stuff. Don't suppose that's the piggyback ECU you have is it...? So what was wrong with yours in the end then? Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 18, 2010 Author Share Posted January 18, 2010 I'm going to replace some vacuum hoses just to be sure it's not a leak causing this. Am I right in thinking that these lines are the only ones that could cause over fueling? Quote Link to comment Share on other sites More sharing options...
miko_supra Posted January 28, 2010 Author Share Posted January 28, 2010 The car has been down at AFR for the week. They've swapped over the Fuel pressure regulator, which has resolved the fueling issue. Quote Link to comment Share on other sites More sharing options...
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