A friend bought an 87 GN recently that had a Big Stuff 3 and it barely ran and had some issues. He just wants a street car to drive around so we converted the car back to stock ECM but now the car has no fire so is there something I am missing on the conversion from the BS3 back to stock ECM? Thanks
Switched a 87 GN from Big Stuff 3 back to stock ECM now no fire?
- Thread starter Steve
- Start date
- Joined
- May 28, 2001
Could be... How much of the OEM wiring remained when the BS3 was installed?
The BS3 used a jumper harness but I am not sure of the harness' manufacturer. I think we got it figured out. The 12 volt pink/black wire was cut and grounded at the injector harness plug. I guess the BS3 applied a 12 volt signal to the injectors as opposed to a ground like the factory ECM. I found the cut wire and reconnected it so the injectors had power and it fired right up.
It wasn't to bad. I really didn't have any BS3 experience starting out. I started by removing the BS3 and the jumper harness and associated wiring then installed the stock ECM with a new chip from Turbo Tweak. I tried starting the car after that and found that it would not fire at all. I checked spark and that was good then checked the injectors with a noid light and found no power at the injectors. I traced the injector harness back and found the situation with the pink/black wire I mentioned above. Fixed that wire and then It fired right up. My buddy was very happy. Send me a PM on what you want for your BS3 if you swap back because I may be interested. Thanks
boostjunkie
NEED MORE BOOST
- Joined
- May 27, 2001
Steve ask your bud if wants to sell the BS3 I may be a buyer . thanks Shawn
- Joined
- May 28, 2001
Big Stuff 3
C
coach
Guest
It's an aftermarket Engine Management system similar to a FAST XFI or Pro EFI
It replaces your factory computer and is much more tunable then the factory computer and chip.
Mike Licht
I was here first
- Joined
- May 23, 2001
check the MAF connection to ECU it has likely been spliced into the MAP sensor
Thanks for the advice. To make sure I understand what you are saying--on the conversion to BS3 the wires that normally run from the MAF to ECM are spliced and used to carry the signal from the 3 bar MAP to the BS3/jumper harness?
Mike Licht
I was here first
- Joined
- May 23, 2001
correct, many fast installs do that too. it can be done under the hood it can also be done behind the glove box
