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    Unplug MAP sensor

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    farrellapparel
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    Unplug MAP sensor

    Post  farrellapparel on Fri Sep 08, 2017 9:43 pm

    Hi, I have a 1985 LeSabre w/ Olds 307. My MAP sensor was doing crazy things intermittently so I unplugged it. Do you think it should be replaced or is it not so important 9back in 85?) thnx - John
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    Re: Unplug MAP sensor

    Post  GM B-Body Forum on Fri Sep 08, 2017 10:34 pm

    It will definitely run without it, just not optimal or max effeciency, since its what helps determine the air fuel ratio along with the narrow band o2 sensor on these obd1's Theyre not very expensive, id try a new one.


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    1979 Caprice Sport Coupe, 400hp Vortec 350, Th350, GM 8.5 w/disc brakes, 3.90 gears Detroit Truetrac, 2.5" stainless duals w/ x-pipe, Dynomax race bullets.
    1984 Caprice Sedan, 305 motor, 700r4
    1978 Caprice Sedan, 305 motor, th350
    1993 L99 Caprice, 4.3 v8, 4l60 trans
    1972 Ford F-100, 302 windsor, c4 trans
    2001 BMW E46 330i, 3.0L
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    farrellapparel
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    Re: Unplug MAP sensor

    Post  farrellapparel on Sat Sep 09, 2017 1:15 am

    OK, I'll get a new MAP sensor. Since I figured you'd know - if I delete the catalytic converter, what should I do with the sensor that plugs into the exhaust? Does eliminating the cat hurt performance because of it?  thnx
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    Re: Unplug MAP sensor

    Post  GM B-Body Forum on Sat Sep 09, 2017 8:56 am

    Nope deleting the cat won't hurt it, the o2 sensor is before it any way so you'll be good, you might notice a tiny bit more power and fuel mileage once you remove it, if it was really bad and getting to the point of clogging up. Now for the sensor, I dont know how its setup on an olds 307, but the sensor location on a 305 was on the driver side maybe a foot down from the manifold and was no where near the cat, so you could remove the cat without touching it. I might be reading your post wrong but it sounded to me that your saying youd have to remove the sensor if you removed the cat. If your keeping it all original id keep all the sensors still attached.


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    1979 Caprice Sport Coupe, 400hp Vortec 350, Th350, GM 8.5 w/disc brakes, 3.90 gears Detroit Truetrac, 2.5" stainless duals w/ x-pipe, Dynomax race bullets.
    1984 Caprice Sedan, 305 motor, 700r4
    1978 Caprice Sedan, 305 motor, th350
    1993 L99 Caprice, 4.3 v8, 4l60 trans
    1972 Ford F-100, 302 windsor, c4 trans
    2001 BMW E46 330i, 3.0L
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    farrellapparel
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    ECM & MEM-CAL in 1984 Buick 307

    Post  farrellapparel on Tue Oct 03, 2017 1:37 am

    Can anyone explain what I need? I keep getting a 41 OBD code. The car runs perfectly but occasionally will choke and sputter / barely idle. Then it snaps out of it and runs fine for another 10 minutes. Distributor is new. 41 code says bad "MEM-CAL." Should I find a used MEMCAL or just get an intact ECM on ebay? I am unfamiliar with this stuff. Thanks, John
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    Re: Unplug MAP sensor

    Post  GM B-Body Forum on Tue Oct 03, 2017 7:14 pm

    If memcal is showing its definitely the ecm, you can go to your local auto parts store an order a reman, but you have to remove and keep the old chip/prom from the old computer, if the chip itself is bad that wont fix the issue, if you aren't able to locate a new chip (if it needs it)then I would suggest removing it all and go carbureted.

    Is it showing 3 different 41 codes? Or,just mem cal? Because it could also be cam sensor, crank sensor, or faulty icm ignition control module.


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    1979 Caprice Sport Coupe, 400hp Vortec 350, Th350, GM 8.5 w/disc brakes, 3.90 gears Detroit Truetrac, 2.5" stainless duals w/ x-pipe, Dynomax race bullets.
    1984 Caprice Sedan, 305 motor, 700r4
    1978 Caprice Sedan, 305 motor, th350
    1993 L99 Caprice, 4.3 v8, 4l60 trans
    1972 Ford F-100, 302 windsor, c4 trans
    2001 BMW E46 330i, 3.0L
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    Re: Unplug MAP sensor

    Post  farrellapparel on Tue Oct 03, 2017 7:53 pm

    Just 41 code. It starts/runs fine. Just wants to almost die every ten minutes for 10 seconds - then it's fine. It is 1984 so it has computer but I think I know what you mean - go zero electronics.

    I tested ignition control module - it's good, and the distributor looks brand new. Since it starts fine I figured that would rule out cam sensor. Does MEMCAL = "chip?" If I get a new/used ECM, why not get chip that comes with it? Why must chip remain with orig car? In the meantime, I will try the 5 or so ways to reset the ECM and see if that makes a dent. Thanks

    http://www.ebay.com/itm/1226519-CXZ-1984-BUICK-OEM-ENGINE-CONTROL-MODULE-UNIT-PCM-ECM-ECU-/291555074672?_trksid=p2385738.m2548.l4275
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    Re: Unplug MAP sensor

    Post  GM B-Body Forum on Tue Oct 03, 2017 9:40 pm

    They just dont make the chip not sure exactly why, there were only so many different combinations, seems like they would. The icm can test fine but once heated or if it experiences shock or,vibration can go haywire, then once cooled down acts fine again, however it seems you have timed its episodes and,they seem consistent. Perhaps the chip is bad or sensor and the computer is going into limp mode, I'm not an obd1 expert, obd1 might not have a limp mode but those episodes are pretty consistent. Oh and the other sensors can act the same way, fine then once up to operating temp they can go haywire. A lot of times they dont just fail. Mem cal indicates the on board chip/prom yes. There's just so many things it could be it gets frustrating. In my last post when I said carbureted I meant no electronics haha its already carbureted, I was thinking of fuel injection. If you do remove everything you can still use the same carb, it'll work with out being plugged in.


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    1979 Caprice Sport Coupe, 400hp Vortec 350, Th350, GM 8.5 w/disc brakes, 3.90 gears Detroit Truetrac, 2.5" stainless duals w/ x-pipe, Dynomax race bullets.
    1984 Caprice Sedan, 305 motor, 700r4
    1978 Caprice Sedan, 305 motor, th350
    1993 L99 Caprice, 4.3 v8, 4l60 trans
    1972 Ford F-100, 302 windsor, c4 trans
    2001 BMW E46 330i, 3.0L

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