4+3 OD indicator light in cluster
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,061
Likes: 99
From: Seattle WA
4+3 OD indicator light in cluster
Anyone know where it gets its signal - ECM or from the OD solenoid itself? I can't find any documentation on the indicator light in the FSM or electrical supplement.
The reason I ask is because I'm thinking about an ECM conversion to speed density, but the 4+3 went the way of the do do bird before SD came out. It looks easy to convert the OD full manual control, but I don't want to lose the indicator.
The reason I ask is because I'm thinking about an ECM conversion to speed density, but the 4+3 went the way of the do do bird before SD came out. It looks easy to convert the OD full manual control, but I don't want to lose the indicator.
Last edited by 89onlyZ51; Jan 7, 2008 at 08:14 PM.
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,061
Likes: 99
From: Seattle WA
By manual, I meant take the computer-control out of the loop. All you need to do that is disconnect pins A7 and C7 from the ECM and then connect them together. C7 is grounded when your OD button is pressed. When the computer wants to engage OD, it grounds pin A7.
Do this, and the computer will be out of the loop. You'll select OD by using the button in all 4 gears, and your 4+3 will become a 4+4 to boot.
Do this, and the computer will be out of the loop. You'll select OD by using the button in all 4 gears, and your 4+3 will become a 4+4 to boot.
Melting Slicks
Joined: Aug 2003
Posts: 3,401
Likes: 397
From: Lakeville MI
The OD shifter switch is only a momentary switch.
With the ecm out of the loop, you would need a latching relay to keep OD engaged unless you want to hold the button down.
I hadn't thought much about Callaway's still using a MAF. Just curious, why the switch to SD?
By the way how does a Callaway currently handle the extra fueling needs when the MAF is maxed? Via PE enrichment or is there an FMU or something else going on?
I'd be curious to see a copy of the bin file if you can read it out and are willing to share.
Sorry for all the questions, but we don't see many Callaway related posts, or cars for that matter.
With the ecm out of the loop, you would need a latching relay to keep OD engaged unless you want to hold the button down.
I hadn't thought much about Callaway's still using a MAF. Just curious, why the switch to SD?
By the way how does a Callaway currently handle the extra fueling needs when the MAF is maxed? Via PE enrichment or is there an FMU or something else going on?
I'd be curious to see a copy of the bin file if you can read it out and are willing to share.
Sorry for all the questions, but we don't see many Callaway related posts, or cars for that matter.
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,061
Likes: 99
From: Seattle WA
Crap, that complicates things about the OD button.
Callaways used the stock TPI setup with a proprietary AIC (Callaway Microfueler) controlling two additional high-flow injectors. It did the trick at the time but is crude compared to what's available today.
The Microfueler reads boost & rpm and supplies additional fuel to the two aux injectors based on those two inputs. There are some dyno runs over on the Callaway board that show very unstable A/F ratios and power output during boost witht he Microfueler. (The MAF saturates at about 2400 rpm.) Other owners have had good results swapping out the MF'r to a more current AIC like one from SDSEFI or splitsec.com.
I want to switch to SD with a 2-bar MAP so I can gain better control of fuel AND spark under boost. The SyTy bin looks promising, but it's enough different than a SD 'vette bin that I may take the 'vette bin and modify it for 2-bar MAP.
When I get some garage time, I'll read out the prom from my '87 callaway and share it although I believe they used the stock bin in '87. It will be interesting to see what's in there.
Callaways used the stock TPI setup with a proprietary AIC (Callaway Microfueler) controlling two additional high-flow injectors. It did the trick at the time but is crude compared to what's available today.
The Microfueler reads boost & rpm and supplies additional fuel to the two aux injectors based on those two inputs. There are some dyno runs over on the Callaway board that show very unstable A/F ratios and power output during boost witht he Microfueler. (The MAF saturates at about 2400 rpm.) Other owners have had good results swapping out the MF'r to a more current AIC like one from SDSEFI or splitsec.com.
I want to switch to SD with a 2-bar MAP so I can gain better control of fuel AND spark under boost. The SyTy bin looks promising, but it's enough different than a SD 'vette bin that I may take the 'vette bin and modify it for 2-bar MAP.
When I get some garage time, I'll read out the prom from my '87 callaway and share it although I believe they used the stock bin in '87. It will be interesting to see what's in there.
