Sambo Posted October 31, 2014 Share Posted October 31, 2014 I've been trying to diagnose my AE85 richness problems without spending any money (aimlessly wandering the internet). It does sound as though there's a good chance that there is some issue with the oxy sensor. From what I can tell, the factory 02 sensor location on a small port 4age is in the 2-1 section of the exhaust (please correct me if I'm wrong). On my apexi headers it's about 150-200mm from the engine on a single runner. I would have thought that this was less than ideal as it's only getting a reading from one cylinder. Would this be a major problem? Quote Link to comment Share on other sites More sharing options...
kpr Posted October 31, 2014 Share Posted October 31, 2014 its probably fine where it is. have had wide band on a stock small port, with no 02 sensor connected and afr was fine. so unlikely the problem. could try unplug and see if any difference Quote Link to comment Share on other sites More sharing options...
Sambo Posted October 31, 2014 Author Share Posted October 31, 2014 Will do. Cheers. Would a faulty sensor sending bung signals put it out much? Quote Link to comment Share on other sites More sharing options...
kpr Posted October 31, 2014 Share Posted October 31, 2014 Doubt would put it out that much. I'd be looking at the water temp sensor and wiring first, if you haven't already. its the green one on back of head. Quote Link to comment Share on other sites More sharing options...
ajg193 Posted October 31, 2014 Share Posted October 31, 2014 Silly question, but are you running non standard injectors? Quote Link to comment Share on other sites More sharing options...
Sambo Posted October 31, 2014 Author Share Posted October 31, 2014 Doubt would put it out that much. I'd be looking at the water temp sensor and wiring first, if you haven't already. its the green one on back of head. I'm pretty confident in the wiring, the guy who did it is pretty switched on (pun intentional). Silly question, but are you running non standard injectors? Not a silly question, the condition improved dramatically when I purchased and put the correct injectors in! Edit: Still not sorted though. Quote Link to comment Share on other sites More sharing options...
magpie-man Posted November 1, 2014 Share Posted November 1, 2014 I've been trying to diagnose my AE85 richness problems without spending any money (aimlessly wandering the internet). It does sound as though there's a good chance that there is some issue with the oxy sensor. From what I can tell, the factory 02 sensor location on a small port 4age is in the 2-1 section of the exhaust (please correct me if I'm wrong). On my apexi headers it's about 150-200mm from the engine on a single runner. I would have thought that this was less than ideal as it's only getting a reading from one cylinder. Would this be a major problem? The AA1car.com website has plenty of information on how engine sensors work and how to diagnose faults: http://www.aa1car.com/library/o2sensor.htm If you scroll down to the bottom of that page you'll find some related pages on O2 sensors. I had similar problems with high fuel consumption with a 3SFE Toyota engine following a blown head gasket. Leaking glycol can poison the O2 sensor. The sensors can also give up the ghost with old age. To test the sensor you need to place a multi-meter on the sensor outputs and watch the voltage output while the engine is running (and the sensor has reached full operating temperature). If the sensor and engine computer are working properly the voltage should hover around 0.5 volts. O2 sensors come either as 2 wire or 4 wire. The 4 wire version have a heating circuit to keep the sensor hot. You have to work out which wires are which. The location of the sensor shouldn't matter. If all your fuel injectors are delivering the same amount of fuel, the air fuel ratio which the sensor is detecting from only one pair of cylinders will be the same as the other cylinders. However if one of the fuel injectors is partially blocked (running lean) the other injectors will deliver a richer mix to bring the overall air fuel ratio to the "correct" ratio. So testing and cleaning the fuel injectors could be worthwhile. Also check the connections and wiring to the injectors is OK. With a poor connection one of the injectors may not be opening a closing correctly. KPR's post could be on the right track with the water temp sensor. If this is faulty the engine computer may think the engine is running colder than it actually is, and deliver a rich air fuel ratio. The aa1car website has a good page of water temp sensors. It's easy to test by checking the resistance across the sensor with a multimeter. Hope this helps. Quote Link to comment Share on other sites More sharing options...
Sambo Posted November 1, 2014 Author Share Posted November 1, 2014 Great post, thanks mate. I'll check out that site. Quote Link to comment Share on other sites More sharing options...
ta63-1uzze Posted November 1, 2014 Share Posted November 1, 2014 just a side note if using aftermarket or home made exhaust systems, you need to have the sensor placed so that it is not horizontal or on the downward angle as condensation and fuel vapors etc. will collect in the pintail and that will fuck it too. need a slight angle so fluid wont collect in it. there is some etiquette to observe when handling them too, you cant clean them with solvents, if you drop it that can fuck it too, they are a very sensitive bit of equipment , they can also "wear out" but not in the general terms, basically they start to slow down and the signal frequency is to slow , so even though they appear to be working with out an oscilloscope you wont see the up and the down of the signal. so testing them via millimeter may tell you that It is working to some degree but it could still be the problem . if it isn't switching fast enough you will get a round about situation where the ratio is for ever going to be to rich then too lean over and over , as its not responding fast enough. also misfire for long periods of time will also foul/fuck the sensor as it is very sensitive, using the wrong kind of sealant can also have adverse affects too . on a side note seeing as it is only running on one branch you also need to know that that particular cylinder is in good working condition, so doing a compression test and a leak down test across all cylinders and comparing the data, they need to all be with in at least 10 percent . other wise you could be pushing shit uphill if that one particular cylinder isn't healthy it will bring the rest of the cylinders into a incorrect afr situation. pan pacific and dasco sell good aftermarket o2 sensors at reasonable prices. and if you are interested go and have a look at how a lambda sensor works, they are an amazing bit of technology almost like 2 in one sensor with a great frequency they are super fast to switch and give great feedback tot the ecu , great idea very techy Quote Link to comment Share on other sites More sharing options...
ta63-1uzze Posted November 1, 2014 Share Posted November 1, 2014 I'm pretty confident in the wiring, the guy who did it is pretty switched on (pun intentional). Not a silly question, the condition improved dramatically when I purchased and put the correct injectors in! Edit: Still not sorted though. shit didn't read that bit before , if it was in an over fueling situation that is enough to fuck it. they don't like being doused in excessive amounts of fuel. check your fuel pressure regulator too that needs to be working well too : ) Quote Link to comment Share on other sites More sharing options...
magpie-man Posted November 1, 2014 Share Posted November 1, 2014 pan pacific and dasco sell good aftermarket o2 sensors at reasonable prices. I fitted a Fuelmiser O2 sensor from Repco. Much cheaper than a Toyota OEM. The only problem with it was it not including colour codes for the wires in the box. Seemed to do the trick once grafted onto the Toyota plug. One note: do not solder the wires as this can generate thermocouple voltages (I am lead to believe). Quote Link to comment Share on other sites More sharing options...
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