Bipes ACU operates BACKWARDS!?
 

Hi all,

I'm running a Bipes ACU on a '91 1.6 with a Greddy turbo. In a nutshell, the Bipes pulls timing when there's not airflow, and stops pulling timing when there IS airflow! Yes, the 1.6/1.8 switch is set properly.

In more detail: the issue is that when set to display timing retard and I’m cruising at engine RPM high enough for the Bipes to be pulling timing, it seems to indicate that it’s pulling the expected timing only when the throttle is closed. When the throttle is opened, the LEDs indicating degrees of retard turn off. Switching the display to airflow also shows the opposite of what I expect—the LEDs are mostly on, then turn off with higher airflow. The 1.6/1.8 switch is in the correct position! When I try it in the 1.8 position (even though this is wrong), the airflow reverses appropriately and lights up more LEDs with higher airflow, but it idles at only one led instead of the expected 3-4, and when I drive around with the 1.6/1.8 switch set to 1.8 I never see retard occurring at all. Pulling the circuit board from the enclosure shows that it’s a version 1.6 Bipes, and seems to be in great condition. The temp sensor jumper is in the default location. The car operates perfectly in all other respects.

Any ideas?? Who likes puzzles??

verify with timing light.

I used one of these 10 years ago and it was a good solution for its time.

Thanks for the reply! I'm not too sure how I can do this, though--the only time I ever see the 'retard' LEDs light up is with the throttle closed at high rpm, which usually occurs while coasting at high speed (when I can't be looking at the crank with a timing light). Do you have any suggestions on other conditions I could try to verify? Are you thinking that maybe the display is reversed and it's actually pulling timing correctly?

Easy test. Use a timing light...

eh, embarassing solution--I missed with the airflow wire, and attached it one spot too far to the right. Posting in case anyone else ever has this issue. I'll show myself out.

lol I checked TWICE to make sure this wasn't a necro-bumped thread from 1995

No, I'm real and from the present day--I just came into an old Bipes off Craigslist and figured it would do until I go megasquirt. let's call it a "period-accurate modification".

I'll let it slide because you're the first person in the history of n00bs that actually spelled Greddy correctly, and not "Greedy" like every imbecile out there. :D

Aw, you noticed!