VAVolvo Posted March 3, 2006 Report Share Posted March 3, 2006 I know some car have em, do the 850s have something like a Intake Air Temp Sensor, would it be with the MAF sensor, or would it be somethiing, or somewhere else? Link to comment Share on other sites More sharing options...
andrew_the_fox Posted March 3, 2006 Report Share Posted March 3, 2006 probly jus the maf no? the engine's gotta know somehow that the air is cold or hot. MAF is my guess. but wait for a pro's opinion :lol: Link to comment Share on other sites More sharing options...
Volvoson Posted March 3, 2006 Report Share Posted March 3, 2006 I am not a pro, but I don't think our cars have a built in IAT sensor. Lots of people have thought about installing an aftermarket one and wiring it up themselves, but I can't confirm nor deny that anybody has actually done it.I have heard that if you plug into our OBD-II port, you won't see an IAT when you do see other parts on the car, so one more reason why I doubt we have one... Link to comment Share on other sites More sharing options...
Slater Posted March 3, 2006 Report Share Posted March 3, 2006 I am not a pro, but I don't think our cars have a built in IAT sensor. Lots of people have thought about installing an aftermarket one and wiring it up themselves, but I can't confirm nor deny that anybody has actually done it.I have heard that if you plug into our OBD-II port, you won't see an IAT when you do see other parts on the car, so one more reason why I doubt we have one...Correct, our cars do not have a dedicated IAT. The MAF has a temperature circuit, but it is not accessable via the OBD-2 port.BTW I have an aftermarket IAT installed in my intake manifold. I used it to do a lot of testing of parts and mods. If you search I used it to determine the huge intake air temperature drop by disabling the EGR system, by venting the hood via removal of a portion of the weatherstrip at the back edge of the hood, etc.Nothing like hard data to back things up with... Link to comment Share on other sites More sharing options...
VAVolvo Posted March 3, 2006 Author Report Share Posted March 3, 2006 Correct, our cars do not have a dedicated IAT. The MAF has a temperature circuit, but it is not accessable via the OBD-2 port.by the way I have an aftermarket IAT installed in my intake manifold. I used it to do a lot of testing of parts and mods. If you search I used it to determine the huge intake air temperature drop by disabling the EGR system, by venting the hood via removal of a portion of the weatherstrip at the back edge of the hood, etc.Nothing like hard data to back things up with...Wow, good info. Do you know where I can find out which circuit is the temp. circuit for the MAF then? My MAF has 4 wires, 3 lead back to the ECU and the green one goes to the fuel injectors. I think one of the wires that returns to the ECU is the MAF signal wire, so I can only ASSUME that the other two could be the temp. circuit. Can anyone confirm this? Link to comment Share on other sites More sharing options...
VAVolvo Posted March 6, 2006 Author Report Share Posted March 6, 2006 Alright, I looked into it. The MAF has 4 wires:Green: 12v powerGreen/Red: power groundWhite: signal to ECUWhite/brown: signal groundI think the IAT is built into the MAF and serves as mulitple functions. Link to comment Share on other sites More sharing options...
WhiteT5 Posted March 6, 2006 Report Share Posted March 6, 2006 Info on the MAF:DescriptionThe MAF sensor measures the engine intake air mass and supplies the ECM with continuous signals, which the module uses to compute the following:*Injection period*Ignition timing*TC boost pressure (only turbo)*Post–running of the engine cooling fanThe TCM also uses the information to perform gear–change computations.ComponentsThe MAF sensor consists of a plastic housing containing a connector, electronic circuitry and an aluminium heat sink. The measuring element consists of a hot film, consisting of four resistances, which is cooled by the intake air flow.The MAF sensor, which receives a 12 V supply from the main relay, has separate power and signal grounds. The sensor signal varies from 0 V to 5 V, depending on the air mass, and increases with the flow.Since the working temperature is relatively high (179°C/338°F), and the flow and temperature –sensitive resistances are mounted on the side of the hot film, a burn–off function is not required.The ECM will adopt a substitute value if the MAF sensor signal is lost or becomes faulty.The sensor is mounted on the air cleaner (ACL) cover. Link to comment Share on other sites More sharing options...
Guest Guest Posted March 6, 2006 Report Share Posted March 6, 2006 Seeing as the IAT is going to be used to trim fuel because of the changes in air density its entirely possible (And likely) that the temperature circuit inside of the MAF alters the signal before it is sent to the ECU. -mAydAy Link to comment Share on other sites More sharing options...
josh_S70GLT Posted March 6, 2006 Report Share Posted March 6, 2006 FYI - I am able to grab IAT through ODB-II in my S70PS - using software from www.obd-2.com Link to comment Share on other sites More sharing options...
Slater Posted March 7, 2006 Report Share Posted March 7, 2006 FYI - I am able to grab IAT through ODB-II in my S70PS - using software from www.obd-2.comCorrect, because IAT was a required sensor for full OBD-II implementation. The 850s do not have a readable IAT signal because they are not a full OBD-II implementation.See this for more information:http://volvospeed.com/vs_forum/index.php?s...ndpost&p=529282 Link to comment Share on other sites More sharing options...
PullMyFinger Posted March 7, 2006 Report Share Posted March 7, 2006 Slater - Any tips on your IAT install? I was looking to do the same on my 850.I see that there are plenty of temp gauges available in the correct temp range, some even come with 1/8NPT sensors. Is that all there is to it? What about the location on the intake manifold? Wondering about the best spot to drill and tap when I have the mani off this weekend.any pointers would be great! Link to comment Share on other sites More sharing options...
Slater Posted March 7, 2006 Report Share Posted March 7, 2006 Slater - Any tips on your IAT install? I was looking to do the same on my 850.I see that there are plenty of temp gauges available in the correct temp range, some even come with 1/8NPT sensors. Is that all there is to it? What about the location on the intake manifold? Wondering about the best spot to drill and tap when I have the mani off this weekend.any pointers would be great!No need to drill and tap. There is an 1/8" NPT rigth in the fonrt of the manifold. Just unscrew the fitting that's there, T what was there to the port right next to it or to the vacuum tree, and thread the air sensor into the 1/8" NPT hole.I used a Cyberdyne digital temp gauge. Works great.Just make sur eyou don;t use teflon tape or pipe thread compound. Temp sensors need to be threaded bare into metal parts as that is how they ground. Link to comment Share on other sites More sharing options...
OzzyR Posted March 7, 2006 Report Share Posted March 7, 2006 Could the outside air temp read out be used? Obviously not the sensor itself, but an air temp sensor just wired up to it? Ive moved this sensor to the air box but that only tells me the pre-intercooler air temps Link to comment Share on other sites More sharing options...
Slater Posted March 7, 2006 Report Share Posted March 7, 2006 Could the outside air temp read out be used? Obviously not the sensor itself, but an air temp sensor just wired up to it? Ive moved this sensor to the air box but that only tells me the pre-intercooler air tempsI guess you could, but it's not threaded. Since it's post-intercooler, it will need to be threaded to prevent leaks/blowing out/etc. Link to comment Share on other sites More sharing options...
PullMyFinger Posted March 7, 2006 Report Share Posted March 7, 2006 No need to drill and tap. There is an 1/8" NPT rigth in the fonrt of the manifold. Just unscrew the fitting that's there, T what was there to the port right next to it or to the vacuum tree, and thread the air sensor into the 1/8" NPT hole.I used a Cyberdyne digital temp gauge. Works great.Just make sur eyou don;t use teflon tape or pipe thread compound. Temp sensors need to be threaded bare into metal parts as that is how they ground.Great, thanks! Link to comment Share on other sites More sharing options...
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