Ok i was doing a search on the reason why my truck idles at 1000 rpms with my cable connected and ran into some disturbing info from some older post. I run a 10k resistor between A and B so this puts it in aldl mode right? Ok from what i hear this also disables some usefull stuff like spark burtst retard. That sucks cause it could in theory blow my engine if i get into too much knock. Is there anyway around this and do all 747 cpu require this resistor? I also remember some one saying that you only have to use the resistor to get it into aldl mode then you can remove it, is this true? Sorry to bring this up again but i have read some conflicting info and just want to the facts strait before i get into tuning my car. The truck by the way is a 91 4.3 s-10.

 

Yes you need to resistor to put the '747 ECM into ALDL mode. No you don't need the resistor to monitor the ALDL data stream. So if all you want to do is monitor the data stream skip the resistor altogether.

RBob.

 

ok thanks i just tried removing the resistor and the truck runs much better now and i still get data. I was under the impression that you had to have the cpu in aldl mode. Is there any advantage to this or is it just somthin the factory uses?