Map sensor

Discussion in 'Wanted section' started by Roger, Apr 13, 2019.

  1. Roger

    Roger Fresh Recruit

    Map sensor and precat lambda sensor needed!!
  2. SKINY

    SKINY Registered User +

    Ebay for the sensor and Jay on here likely have a MAP sensor buddy :)
    Myweegem5 likes this.
  3. Jay

    Jay Admin

    Yeah I have a few old MAP sensors from EP82 GT spare if you need one.

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  4. Myweegem5

    Myweegem5 Member

    Jay mate if you have still got a spare one of these I'm also looking for one if there in good working order. Hoping this will solve my problem!
  5. SWJ

    SWJ Member

    How often do map sensors fail?? There are three pins as fair as I know?? Ground, Sensor and Voltage I think?? And I don't think any of them go over 5 volts?? Have you checked yours with a DVOM?? Is it truly at fault??
  6. Myweegem5

    Myweegem5 Member

    I have checked mine with a multimeter and a vacuum pump. The results I got are out of spec when comparing to the info I found for testing it. I rechecked a number of times but still get the same results. I bench tested the MAP sensor on its own and also tested it on the car connected up. I also tested the ground wire and power supply to the sensor from the ECU side and it checks out fine at 5 volts.

    I have a remaining DTC (diagnostic trouble code) number 31 for the MAP sensor which I can't clear and my car is not idling or accelerating well and it also keeps dying after warm up and won't restart on its own without some extra throttle until has cooled down. The only code I have is #31 and either way I don't think the car will run right until this issue is solved. Although if I knew there was some way to repair a MAP sensor then maybe that would work but I have not seen or heard of any repair for them if they are faulty and I believe they are a common issue with these cars. So this is why I am looking for a good MAP sensor that's known to be in good working order so I can be certain of ruling it out as the issue.
  7. SWJ

    SWJ Member

    Uh WOW! That looks to be pretty through trouble shooting ... thanks for sharing. :)

    That said it looks like your simplest option is to take "Jay" up on his offer. :)

    But most likely, that may give you a working part that is better than the dead one you have now?? So there is that. Plan B and I have not done it myself ... but it makes sense. Change it over to a GM 3 bar map sensor. It is 5 volts also and has three inputs, I would think all youd need to match the wires up??? And only one of them is (Hot, 5 volts.) It should work as most of the piggy backs and Standalones use the GM 3 bar sensor. But as I said ... I've not done it!

    Where are you, are you in the US??? Are parts hard to find where you are???
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  8. Jay

    Jay Admin

    Hi mate, let me know the part number on your sensor and I'll have a look.

    In the meantime...



    That might help troubleshoot.
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  9. Myweegem5

    Myweegem5 Member

    No probs, I'm in Ireland and I have been interested in alternatives if it worked safely and correctly but I'm not looking to complicate things any further if possible so I'd rather the original sensor. It just seems more straight forward for my current situation. Are you also having MAP sensor issues?
    Last edited: Jul 10, 2019
  10. Myweegem5

    Myweegem5 Member

    Cheers Jay, my sensor is the later one for Starlet GT Turbo with part number 89420-10050
    I tried to look at closer at the pics you posted there to read it but I can't make it out properly. Thanks for sending me that info but is there any other way you can send it or any other way I could view it as I'd really like to get a read of that.:)
  11. dac69er

    dac69er Super Moderator

    as that manual is only mentioning measuring vacuum, i assume this is from an n/a engine manual?
    i wouldnt have thought those values would be valid for a map sensor that needs to measure boost. but the method of testing is good.

    in regards to using a GM 3 bar map sensor. this would be a larger range than the standard sensor and throw everything out. whilst it may run, your fuelling and timing would be out. this is fine if you have a different ecu, but not if you have the stock ecu.

    a generic 3 pin 2 bar sensor would get you a damn site closer, but without knowing the exact range of the stock sensor you may be a little bit out.

    what voltages were you getting at different vacuum/pressure settings? i would have though that if you are getting a linear change between 0v and 5v between -1bar and +1 bar, then even if it is a bit out of tolerance, it should be near enough to run reasonably well? it almost sounds like its not connected. i didnt think map sensors were that prone to failing on toyotas of this era?
    Myweegem5 likes this.
  12. Jay

    Jay Admin

    God dammit.. my brain sometimes is not entirely engaged. Yes that's from the 4efe manual. The 4efte version would be practically impossible to obtain at this stage.
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  13. Jay

    Jay Admin

    Only joking..




    You might need to use the Google translate app though. Save the images to your phone (make a folder called TGTT) then you should be able to zoom in beautifully even offline.
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  14. Myweegem5

    Myweegem5 Member

    Ok so I actually somehow seem to have deleted a lot of my MAP sensor tests results from my phone, there may have been beer involved there. Anyway I know I did a lot of tests and Im annoyed with losing the results but i do have a recent test result. It's not as extensive as my earlier tests but I believe everything I tested earlier checked out ok such as power supply, ground ect.
    With MAP sensor connected and plug back probed:

    I have 2.6v on signal wire.
    I have 4.97v on reference wire.
    Unplugged I have 4.97v on reference wire

    2nd Test with vacuum pump:

    I have 2.1v at 5 in-HG vacuum.
    I have 1.3v at 20 in-HG vacuum

    Comparing with all the info and guides I was following to do the tests wit my results and earlier results it pointed towards the map sensor being out of spec and to change it. I did retest several times and to be honest I'm quite tired of looking at it and a little fed up with it at this stage. I also had vacuum tested all the vacuum hoses in that area and none were leaking.

    Jay thanks for tying mate but I've downloaded google translate, converted the Jap language to English and all it really did for me was make me laugh at the funny translation it gave me back lol!:D It done a fairly good job on 90% of the text but for me I have to be honest and say I can't really be sure of following it correctly. If you happen to have a better translation of it and can send it to me that would be good as I'm sure it is useful info.
  15. SWJ

    SWJ Member

    Thanks for info! And actual working running car is not the best place for my mad plan ... admittedly. :)

    But taking voltage scaling into account now ... I found this.:

    GM 1 bar (doesn't count) 2 bar good to 14.7 psi and the 3 bar 44.1 psi the last chart shows load percentages and values at various voltages ... quite a huge swing between the three and two Bar??? Who knew?? A bit more work then just matching wires ... apparently it would also require a "piggy back to address fueling??" Oh well it was a thought. More research required, thanks for the insight. :)
  16. Djaniero

    Djaniero Registered User +

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