Car runs different when scanning
Thread Starter
Pro
Joined: Jun 2001
Posts: 511
Likes: 6
From: Edmonds WA
Car runs different when scanning
When I plug in the ALDL adapter to read data, my 87 (OBD-I) runs differently. It idles higher and sometimes jerks when I let off the throttle entirely while on the highway.
I don't remember this happening in the past (but I used a different setup with a serial cable). Does this happen to anyone else when they connect up to scan?
I'm using a bluetooth adapter and running ALDLdroid on my phone.
I don't remember this happening in the past (but I used a different setup with a serial cable). Does this happen to anyone else when they connect up to scan?
I'm using a bluetooth adapter and running ALDLdroid on my phone.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Some scan tools and cables put a 10K resistor across the A & B pins of the ALDL connector. In some cases there is a switch to take this resistor out of the circuit. In Diacom the switch is electronic and I can put it in or take it out.
From the shop manual (10K mode):
• Closed loop timers are bypassed
• EST (spark) is advanced
• IAC will control engine idle to 1000 RPM ± 50 RPM
• On some engines, canister purge solenoid will be enabled
• P/N restrict functions will be disabled
From the shop manual (10K mode):
• Closed loop timers are bypassed
• EST (spark) is advanced
• IAC will control engine idle to 1000 RPM ± 50 RPM
• On some engines, canister purge solenoid will be enabled
• P/N restrict functions will be disabled
Thread Starter
Pro
Joined: Jun 2001
Posts: 511
Likes: 6
From: Edmonds WA
That explains it, then! I was wondering if, since it was running differently, it might also effect the data I was seeing (in my case, very high O2 values... running rich).
Thanks for the great info, guys!
Thanks for the great info, guys!
