[Gmecm] 749 SCORE sunbird GT 181 merc efi harness--
David Allen
davida1
Tue Sep 27 15:58:33 UTC 2011
Alan, the computer-to-underhood section is the important part. You can narrow it down to just a few wires that need to go to other places on the car.
The ECM interface between the Distributor system and the Direct Ignition System (DIS) are identical. The settings in the ECM need to match the system in use, but the same signals are used in the harness.
Thanks,
David
----- Original Message -----
From: alan mays
To: David Allen
Sent: Monday, September 26, 2011 11:28 AM
Subject: Re: [Gmecm] 749 SCORE sunbird GT 181 merc efi harness--
Hi david,
About the wiring harness-- im sensing that perhaps I was supposed to get the DS under dash section with the fuse box too?? i just figured it was the computer-to under hood section. The turbo bird had the distributor, im now wondering if a regular port efi bird like the one I saw yesterday--That ds fuse box wiring section would be the same-fat chance?
--- On Sat, 9/24/11, David Allen <davida1 at hiwaay.net> wrote:
From: David Allen <davida1 at hiwaay.net>
Subject: Re: [Gmecm] 749 SCORE sunbird GT 181 merc efi harness--
To: "alan mays" <truckeez at yahoo.com>, "GM-ECM" <gmecm at diy-efi.org>
Date: Saturday, September 24, 2011, 12:33 PM
I have all the diagrams for this ECM on my tuning laptop. Unfortunately it's not here with me (I'm still overseas). The guys at Code59 have the wiring diagrams for the Sunbird configuration and the SyTy configuration.
I have always been able to make a good harness by modifying what I have. It's very hard to get a custom harness made and shipped in "ready to use." They may not be painful, however they also are not always exactly right for the application. It's better to take a used harness and make a custom one that is EXACTLY what you need!
Thanks and good luck with your project!
David
----- Original Message ----- From: alan mays
To: David Allen
Sent: Saturday, September 24, 2011 12:14 PM
Subject: Re: [Gmecm] 749 SCORE sunbird GT 181 merc efi harness--
Hi--Scored one Yesterday, spied a sunbird sold at a copart salvage auction in S texas and tried to find out where it was going-first gal wouldn't tell me, Second call I weaseled the info from them, had to go to San Antonio and spend 5 hrs in extreme heat but I got it, looks like I might have to have a more suitable harness custom made. I can now get one out quicker since I know which leads under the dash are for the ac controls.
I never did find the aldl port in that car, I did label most stuff under hood that i recognised but it was getting late and I didn't want to have to spend motel money and come back the next day so some I didn't spend the time to figure out what they were--o2 sensor was one I didnt figure out--and 1 or two under the intake manifold.
Im kinda confused why the harness sort of makes a big loop and heads back thru the firewall on the driverside???? and it split into two parts there--the second side ot that combo plug obviously headed to the headlights/headlight door motors. anyway im thinking it will be expensive to have painless make me a new harness but once I got all the leads labeled -thats the next step---This car unfortunately was an automatic ---There was a lead at the ds--front of the engine,, im now thinking that was for VSS and the lead back at the bellhousing was torque converter lockup.
Glad I finally found one after looking two yrs.
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--- On Thu, 8/25/11, David Allen <davida1 at hiwaay.net> wrote:
From: David Allen <davida1 at hiwaay.net>
Subject: Re: [Gmecm] 181 merc efi harness
To: "alan mays" <truckeez at yahoo.com>, gmecm at diy-efi.org
Date: Thursday, August 25, 2011, 2:35 PM
It's super-easy to add in the ALDL port. Only 2 wires are necessary for the computer to communicate. The serial-data and the ground. All the other "fluff" is for factory diagnostics of the remainder of the vehicle.
Just pull out as much length of the ALDL as possible and cut it off.
The fuel pump wiring is routed differently on all the cars. It is a very simple circuit so I always just build my own. You DO NOT NEED the oil pressure switch in the fuel pump circuit. I can explain why it is there if you care but let it suffice to say you don't need it. The fuel pump circuit needs these things: Pump, Relay, Fuse, signal from ECM. Nothing more, nothing less.
I'm with you 100% on the junkyard stuff. GM's controllers are nearly bulletproof and available everywhere. Plus there is the stealth factor because it is all factory parts.
Sincerely,
David
----- Original Message ----- From: alan mays
To: Gmecm at diy-efi.org
Sent: Thursday, August 25, 2011 2:28 PM
Subject: [Gmecm] 181 merc efi harness
Thanks for the input,
On the GM board there seem to be factions just like the bigger efi/diy- when I first signed up there were guys trying to lure me to the Megasquirt crowd, but im a junk yard dawg---some are more inclined to use the 730 rather Than the 749------Its plain to see why. i have another lead on a turbo bird, The aldl ports on these are not part of the engine/efi harness ---Instead they are part of the dash wiring harness, how do ya'll deal with that-- hours of fun pulling all of it--or is there an easier way to add just that part in??
I know the vss is also part of the dash harness on some but remember an attermarket in line add on vss from a speedometer supplier that could be used.
As far as the rear part of the car --the fuel pump in tank is the only rear lead to worry about--what section of the harness does that tie into?
TFtI
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