Issues when leaving efi
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
Issues when leaving efi
Carb.
Ok, without the ecm , will I run into issues regarding the AC, Cruise, CAGS and fan controls?
Anything else I'm overlooking? I already have an Aeromotive fuel pressure regulator to handle the high psi and return line issue for fuel.
Ok, without the ecm , will I run into issues regarding the AC, Cruise, CAGS and fan controls?
Anything else I'm overlooking? I already have an Aeromotive fuel pressure regulator to handle the high psi and return line issue for fuel.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
You need a way to control the ignition timing. Most people leave the computer in place for that. Otherwise you'd have to go to a mechanical/vacuum advance distributor.
You will not see any fuel related info displayed on the dash. That would be fuel economy and range. That info comes from the ECM and is based on injector pulse widths.
The computer controls the upshift light.
I don't know about CAGS -- I have an automatic. Most people want to bypass it anyway.
The computer controls the SES light and the data coming out of the ALDL port, so all your diagnostics will be gone.
The computer turns on the cooling fan when the AC is running and when the coolant is above 228°.
It also controls where the smog pump air goes, EGR and vapor canister purge. You may not care about those...
You will not see any fuel related info displayed on the dash. That would be fuel economy and range. That info comes from the ECM and is based on injector pulse widths.
The computer controls the upshift light.
I don't know about CAGS -- I have an automatic. Most people want to bypass it anyway.
The computer controls the SES light and the data coming out of the ALDL port, so all your diagnostics will be gone.
The computer turns on the cooling fan when the AC is running and when the coolant is above 228°.
It also controls where the smog pump air goes, EGR and vapor canister purge. You may not care about those...
Last edited by Cliff Harris; Aug 10, 2013 at 03:52 AM.
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
you need a thermo switch installed the head and wired to the fan relay in place of the ECM fan control.
Fuel pump ;
can be left running of the stock OP switch ( the pump relay operated by the ECM will no longer function.
AC ;C60 or C68 ?
With C68 you will need the circuit diagram to check and rewire because some functions run through the ECM.
CAGS ;
as noted most want it gone anyway
No ECM related sensors are used with a carb so there would no diagnostics/codes anyway
Need a reg HEI vac advance dist
