[Gmecm] MAP troubleshooting.
Cowen
captain_krill
Wed Sep 21 19:33:15 UTC 2005
Hanan,
I too had trouble with this, because I was mixing ECMs
and harnesses. Everything plugged in OK, but the 5v
ref from the TPS was shorted to the MAP output. I at
first (foolishly) thought that the TPS and MAP
connectors fit, so the wiring would be OK. Not in my
case! Are you using the factory harness?
The really strange thing is, mine started right up and
PERFECTLY for about 10mins, when it finally started to
try and correct for the MAP reading by dumping huge
amounts of fuel in! Then I was forced to find the
problem...
--- gmecm-request at diy-efi.org wrote:
> Send Gmecm mailing list submissions to
> gmecm at diy-efi.org
>
> To subscribe or unsubscribe via the World Wide Web,
> visit
> http://lists.diy-efi.org/mailman/listinfo/gmecm
> or, via email, send a message with subject or body
> 'help' to
> gmecm-request at diy-efi.org
>
> You can reach the person managing the list at
> gmecm-owner at diy-efi.org
>
> When replying, please edit your Subject line so it
> is more specific
> than "Re: Contents of Gmecm digest..."
> > Today's Topics:
>
> 1. MAP troubleshooting. (Tali Orlov)
> 2. RE: MAP troubleshooting. (Steve Ravet)
> 3. Re: MAP troubleshooting. (Darryl M Gilbert)
> 4. Re: MAP troubleshooting. (Darryl M Gilbert)
> > From: Tali Orlov <tashutali at gmail.com>
> Subject: [Gmecm] MAP troubleshooting.
> Date: Wed, 21 Sep 2005 13:32:53 +0200
> To: gmecm at diy-efi.org
>
> HI all.
>
> I am now in the process of converting my Jeep CJ8
> carbureted 258 to EFI.
>
> I bought at the junk-yard TBI system from GMC Safari
> truck, 1989 , 4.3 V6 .
>
> I connected my laptop to the ECM with ALDL I/F ,
> and I saw that the MAP
> sensor was giving a constant value. 4.4 Volt.
>
> I did not connected the MAP sensor vacuum port to
> the TBI yet because I am
> waiting for the manifold adapter, but I gave vacuum
> to the sensor with my
> mouth and also by connecting it with a hose to the
> bottom of the carburetor,
> below the throttles.
>
> no response from the sensor.
>
> The junk yard owner gave me another Map sensor but
> the results are the
> same.
>
> I also checked the signal voltage with a multimeter
> and I get a constant
> 4.4 volt.
>
> There is 5 volt reference signal to the sensor.
>
> Do I do something wrong or I got two bad sensors?
>
> Thanks.
>
> Hanan.
> > From: "Steve Ravet" <Steve.Ravet at arm.com>
> Subject: RE: [Gmecm] MAP troubleshooting.
> CC:
> Date: Wed, 21 Sep 2005 09:13:06 -0500
> To: "Tali Orlov" <tashutali at gmail.com>,
> <gmecm at diy-efi.org>
>
>
> From: gmecm-bounces at diy-efi.org
> [mailto:gmecm-bounces at diy-efi.org] On Behalf Of Tali
> Orlov
> Sent: Wednesday, September 21, 2005 6:33 AM
> To: gmecm at diy-efi.org
> Subject: [Gmecm] MAP troubleshooting.
>
>
> HI all.
>
>
>
> I am now in the process of converting my Jeep CJ8
> carbureted 258
> to EFI.
>
> I bought at the junk-yard TBI system from GMC
> Safari truck, 1989
> , 4.3 V6 .
>
>
>
> I connected my laptop to the ECM with ALDL I/F ,
> and I saw that
> the MAP sensor was giving a constant value. 4.4
> Volt.
>
> I did not connected the MAP sensor vacuum port to
> the TBI yet
> because I am waiting for the manifold adapter, but I
> gave vacuum to the
> sensor with my mouth and also by connecting it with
> a hose to the bottom
> of the carburetor, below the throttles.
>
>
> ----------------------------------------------
>
> If you are sure you've wired the +5, ground, and
> signal wires correctly
> then it sounds like you've got 2 bad sensors
>
> --steve
>
>
>
> > From: Darryl M Gilbert <dgilbert78 at juno.com>
> Subject: Re: [Gmecm] MAP troubleshooting.
> CC:
> Date: Wed, 21 Sep 2005 12:38:57 -0400
> To: tashutali at gmail.com,gmecm at diy-efi.org
>
> Hello: double check your wiring to the sensor. doubt
> if you have 2 bad
> ones in a row, but possible i guess
> Darryl..
>
> On Wed, 21 Sep 2005 13:32:53 +0200 Tali Orlov
> <tashutali at gmail.com>
> writes:
> HI all.
>
> I am now in the process of converting my Jeep CJ8
> carbureted 258 to EFI.
> I bought at the junk-yard TBI system from GMC Safari
> truck, 1989 , 4.3 V6
> .
>
> I connected my laptop to the ECM with ALDL I/F , and
> I saw that the MAP
> sensor was giving a constant value. 4.4 Volt.
> I did not connected the MAP sensor vacuum port to
> the TBI yet because I
> am waiting for the manifold adapter, but I gave
> vacuum to the sensor with
> my mouth and also by connecting it with a hose to
> the bottom of the
> carburetor, below the throttles.
>
> no response from the sensor.
>
> The junk yard owner gave me another Map sensor but
> the results are the
> same.
>
> I also checked the signal voltage with a multimeter
> and I get a constant
> 4.4 volt.
> There is 5 volt reference signal to the sensor.
>
> Do I do something wrong or I got two bad sensors?
>
> Thanks.
>
> Hanan. > From: Darryl M Gilbert
<dgilbert78 at juno.com>
> Subject: Re: [Gmecm] MAP troubleshooting.
> CC:
> Date: Wed, 21 Sep 2005 12:57:32 -0400
> To: tashutali at gmail.com,gmecm at diy-efi.org
>
> Hello: On your MAP sensor itself where the plug
> plugs into it is marked
> with the letters C B A, this is the numbers of the
> pins. Pin C should
> have +5 volts on it (measured from ground). Pin A is
> the reference (or
> ground, this ground goes to the ECM) Pin B is the
> output signal to the
> ECM. You could use a voltmeter with very sharp
> probes and probe through
> the wire insulation to make contact with the wire to
> verify this. If you
> probe say from a good ground to pin B and apply
> vacuum to the MAP you
> should see a change if you get enough vacuum
> applied. They can also be
> tested with a small hand held vacuum pump. The MAP
> is very important in
> having your TBI set up work properly. Something
> wrong with the MAP sensor
> or MAP ckt will give you all sorts of fits.
> Good luck
> Darryl...
>
> On Wed, 21 Sep 2005 13:32:53 +0200 Tali Orlov
> <tashutali at gmail.com>
> writes:
> HI all.
>
> I am now in the process of converting my Jeep CJ8
> carbureted 258 to EFI.
> I bought at the junk-yard TBI system from GMC Safari
> truck, 1989 , 4.3 V6
> .
>
> I connected my laptop to the ECM with ALDL I/F , and
> I saw that the MAP
> sensor was giving a constant value. 4.4 Volt.
> I did not connected the MAP sensor vacuum port to
> the TBI yet because I
> am waiting for the manifold adapter, but I gave
> vacuum to the sensor with
> my mouth and also by connecting it with a hose to
> the bottom of the
> carburetor, below the throttles.
>
> no response from the sensor.
>
> The junk yard owner gave me another Map sensor but
> the results are the
> same.
>
> I also checked the signal voltage with a multimeter
> and I get a constant
> 4.4 volt.
> There is 5 volt reference signal to the sensor.
>
> Do I do something wrong or I got two bad sensors?
>
> Thanks.
>
> Hanan. >
_______________________________________________
> Gmecm mailing list
> Gmecm at diy-efi.org
> http://lists.diy-efi.org/mailman/listinfo/gmecm
>
**********************END TRANSMISSION**********************
__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
More information about the Gmecm
mailing list