SMARTLY Posted November 9, 2012 Report Share Posted November 9, 2012 Yes, more the valve is open the more the flow so more "pressure". Good luck. Quote Link to comment Share on other sites More sharing options...
Vipercar93 Posted November 11, 2012 Report Share Posted November 11, 2012 Some of the older cars rely on an adjustable blade that adjusts the amount of cool air against the hot air from the matrix. This means the matrix is always hot and coolant is always passing through it, it's down to the adjustment blade to decide how much hot air you want. Quote Link to comment Share on other sites More sharing options...
Rich Posted November 14, 2012 Author Report Share Posted November 14, 2012 I'm gonna leave the coolant for now and sort it next year when it's warmer and dry, I'll just top it up over the winter. I'm really wary about using a sealant in case it blocks the system up. It's been mentioned to me that although I've cleaned my MAF sensor twice it may be faulty and could be the cause of my low mpg. How can you check whether this is working ok? I can get a used one on ebay for about £25 or a new (non OEM) one for around £40-£50. I don't really want to get a new one for testing purposes as it's just wasting money but I might get a used one. Quote Link to comment Share on other sites More sharing options...
liner33 Posted November 14, 2012 Report Share Posted November 14, 2012 you should get a voltage reading with your new toy , the car would run quite poorly if it was faulty , you can try unplugging it on some cars and see if it runs any differently Quote Link to comment Share on other sites More sharing options...
Rich Posted November 14, 2012 Author Report Share Posted November 14, 2012 Will I need to drive the car to get readings for the MAF or can I just do it at idle and can I test the O2 sensors at idle or would recording the data on a run be better? The guy who mentioned it to me did have running issues but he also has a wideband so could see the car was running rich. Using his scangauge he noticed it was the MAF at fault. I don't actually have any running issues though, the car seems to drive fine. Quote Link to comment Share on other sites More sharing options...
liner33 Posted November 14, 2012 Report Share Posted November 14, 2012 How rich was it? But yes you can do it at idle just rev it a few times Quote Link to comment Share on other sites More sharing options...
Rich Posted November 14, 2012 Author Report Share Posted November 14, 2012 He didn't say but he had the CEL on and the car was kangarooing. His theory is that if mine is on the way out/not working properly it could be reading too high everytime the engine load increases meaning it's taking more time and trimming to sort the mix out so it's using more fuel over a tankful. The only way I think I will know for sure is to buy another MAF and run it with that for a tank to see what happens. I have found another sensor on ebay, which is new but bought from China and never been used but it's not a Denso one. I'm assuming that all of these are made in the same factory though? I'm gonna let that auction finish and maybe offer him cash to collect as he's not far from me. Quote Link to comment Share on other sites More sharing options...
Rich Posted November 14, 2012 Author Report Share Posted November 14, 2012 When I got home I plugged the laptop in while the engine was still warm and revved it abit while recording. The AFR from the MAF is - Min: 1.92 g/s and Max: 357.54 g/s The O2 sensor for the pre-cat (Bank 1 Sensor 1 I presume?) is - Min: 0.050 V and Max: 0.865 V Long term fuel trim for bank 1 is - Min: -53.9% and Max: 99.2% Short term fuel trim for bank 1 is - Min: -10.9% and Max: 55.5% These were at between idle and revving to around 3k....what do you make of them? Quote Link to comment Share on other sites More sharing options...
Rich Posted November 16, 2012 Author Report Share Posted November 16, 2012 Right, just got to work and recorded the drive, which is 5 miles and all 30mph, these are the figures I've got. I also measured the intake air temperature, see what you make of that. MAF Sensor: Min: 1.530 g/s Max: 447.970 g/s Long term trim bank 1: Min: -95.3% Avg: 2.8% Max: 99.2% Short term trim bank 1: Min: -100% Avg: 5.7% Max: 99.2% Bank 1 voltage: Min: 0v Avg: 0.054v Max: 1.275v Intake temp: Min: -24°C Avg: 23°C Max: 146°C Quote Link to comment Share on other sites More sharing options...
liner33 Posted November 16, 2012 Report Share Posted November 16, 2012 Not a lot really , ideally it needs to be connected to a wideband but .85 lambda is 12.50/1 so a bit rich , try it when idling and hot and dont rev it and see if the lambda goes up to 1.00 But 146 degrees intake temp must be wrong as is the -24 i suspect , the temp sensor is often in the maf so perhaps you should change it to be sure , but only fit oem not pattern Quote Link to comment Share on other sites More sharing options...
Rich Posted November 16, 2012 Author Report Share Posted November 16, 2012 Not a lot really , ideally it needs to be connected to a wideband but .85 lambda is 12.50/1 so a bit rich , try it when idling and hot and dont rev it and see if the lambda goes up to 1.00 But 146 degrees intake temp must be wrong as is the -24 i suspect , the temp sensor is often in the maf so perhaps you should change it to be sure , but only fit oem not pattern The guy I've been talking to said everything seems fine apart from the intake temp. I think if the STFT and LTFT are in double figures then you have an issue. It might be worth changing the MAF then, I'll see if that one on ebay is still for sale, it's used but is OEM. The voltage on the O2 sensor from my drive to work this morning was 1.275v (see above) so do you think this is ok? Quote Link to comment Share on other sites More sharing options...
liner33 Posted November 16, 2012 Report Share Posted November 16, 2012 No 0.05 v and 1.275v dont really tell you anything , 1.275 us full lean is no fuel present so you were slowing down with no throttle in which case the injectors switch off , 0.05 is pretty much full rich the sensors will swing from one voltage to another its how narrowband lambdas work thats why a wideband is better since it gives a stable reading I think the temp sensor readings mean the maf is faulty , if the car thinks its really cold it will adjust the afr , thats how a lot of the these tuning boxes work, they trick the car into thinking its colder than it is so the ecu ads more fuel Quote Link to comment Share on other sites More sharing options...
Rich Posted November 16, 2012 Author Report Share Posted November 16, 2012 I'll play the drive back later and watch the voltage change to make sure it is fluctuating. The intake temp is reading an average of 23 degrees, would you say that is normal and maybe the min and max are just values it can go between? Still learning here so not too sure. I think it's worth changing the MAF to be sure though. Quote Link to comment Share on other sites More sharing options...
liner33 Posted November 16, 2012 Report Share Posted November 16, 2012 Yeah thats probably about right but at times the car thought it was -23 and +140 neither are right so perhaps its got a loose connection inside Quote Link to comment Share on other sites More sharing options...
Rich Posted November 16, 2012 Author Report Share Posted November 16, 2012 It wouldn't be the wiring at fault would it? This is the MAF sensor I've seen on ebay, the rest seem to be pattern parts. A new one is over £100. http://www.ebay.co.uk/itm/Toyota-Celica-1-8-190-vvti-vvtli-MAF-sensor-air-flow-gen7-t-sport-corolla-mr2-/290802398208?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item43b52c7400 There was also this one but it's not OEM - http://www.ebay.co.uk/itm/Toyota-Mass-Air-flow-Meter-Sensor-22204-22010-MR2-MR-S-Lexus-Celica-/300809959320?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Car+Make%3AToyota&hash=item4609abb798 Quote Link to comment Share on other sites More sharing options...
liner33 Posted November 16, 2012 Report Share Posted November 16, 2012 I'd buy new , a Skyline one was £280 Quote Link to comment Share on other sites More sharing options...
liner33 Posted November 16, 2012 Report Share Posted November 16, 2012 its possible that the wiring is loose , check the connections with a multimeter but its more likely to be the maf itself , possibly just a dry joint inside Dont forget you can always sell the old one Quote Link to comment Share on other sites More sharing options...
Rich Posted November 16, 2012 Author Report Share Posted November 16, 2012 I'd buy new , a Skyline one was £280 That's ok if you have the money and planning on keeping the car! its possible that the wiring is loose , check the connections with a multimeter but its more likely to be the maf itself , possibly just a dry joint inside Dont forget you can always sell the old one How would I check the connections with a multimeter? Sell it if it's dodgy? Quote Link to comment Share on other sites More sharing options...
Rich Posted November 17, 2012 Author Report Share Posted November 17, 2012 Looking at the min and max figures for the fuel trim are they that high cos of the min and max intake temp readings? So when it's reading it as a minus temperature it's adding loads of fuel? Filled up earlier from half a tank and it was 21.5 mpg! The car passed the mot today as well so emissions are ok, I was concerned it might effect that. Quote Link to comment Share on other sites More sharing options...
liner33 Posted November 17, 2012 Report Share Posted November 17, 2012 The cat could be correcting poor emissions that's if they did a proper test as many don't Quote Link to comment Share on other sites More sharing options...
Vipercar93 Posted November 18, 2012 Report Share Posted November 18, 2012 I'd buy new , a Skyline one was £280 That's ok if you have the money and planning on keeping the car! its possible that the wiring is loose , check the connections with a multimeter but its more likely to be the maf itself , possibly just a dry joint inside Dont forget you can always sell the old one How would I check the connections with a multimeter? Sell it if it's dodgy? TBH Essex to save time, and money, I would just replace the AIT sensor. A multimeter cannot really tell you if it's bad, unless it's really bad, but at this point the ECU should pick it up and throw a code. To see if the connection is loose you would need to datalog the sensor during driving. The min/max readings are a red herring to a potential problem, but it's within the allowable limits the engineers put into the ECU programming so these readings can't be that bad. It could be as simple as you have a sensor that is heated so these readings are during the time it was warming up and could be ignored. Need to check into a bit more, what readings do other people get? Find out exactly which sensor you need to replace by checking your service manual (AIT is usually in the air box or in the pipework BEFORE the turbo). In turbocharged cars they sometimes run another AIT temp sensor in the intake as well which is a different sensor than the MAF. It depends on how the engineers set up the ECU tuning as to what sensors are used, or not used. Sometimes they opt for measuring with a MAP/TIP instead of a MAF. Both use calculations to work out air density. MAF's can measure AIT if placed in the air box, but it's an 'expensive' option for them when all you need is a simple 'thermometer'. Depends how the engineer was feeling on the day. A proper AIT sensor is usually cheaper, but it's another part to control during the build process which adds complexity during production. You better not be putting dodgy parts up for sale! That's abuse of the trust the buyer gives a seller. Unless of course you tell them Quote Link to comment Share on other sites More sharing options...
Rich Posted November 18, 2012 Author Report Share Posted November 18, 2012 I've just bought a used MAF off a low mileage MR2 so will see what happens when I swap that over. Why would the engineers put extreme min/max temperatures in the ECU though when the car would never be exposed to those kind of temps? If my MAF is dodgy then no I wouldn't sell it without mentioning that, I'm not into the habit of ripping people off! Quote Link to comment Share on other sites More sharing options...
liner33 Posted November 18, 2012 Report Share Posted November 18, 2012 A multimeter cant tell you if the sensor is bad but it can check continuity from the pin on the harness back Quote Link to comment Share on other sites More sharing options...
Rich Posted November 18, 2012 Author Report Share Posted November 18, 2012 A multimeter cant tell you if the sensor is bad but it can check continuity from the pin on the harness back So what do I set the multimeter to and where do the prongs go....positive on the battery and negative on the pin, would I test all the wires? Quote Link to comment Share on other sites More sharing options...
Vipercar93 Posted November 18, 2012 Report Share Posted November 18, 2012 I've just bought a used MAF off a low mileage MR2 so will see what happens when I swap that over. Why would the engineers put extreme min/max temperatures in the ECU though when the car would never be exposed to those kind of temps? If my MAF is dodgy then no I wouldn't sell it without mentioning that, I'm not into the habit of ripping people off! They could have extreme temps because some MAF's must be heated up with a built in heater before they operate correctly. During the heating process they could give for some pretty funky readings. Quote Link to comment Share on other sites More sharing options...
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