Hi guys, I got directed here from a few friends of mine, and gathered up quite a bit of info from these boards and dyi-efi. Just wanted to say thanks up front I'm a newbie here, so please let me know if I ask questions that have been asked a million times before, and I'll search harder for answers

Ok, here's the story: I run a 6000 lb 1975 Blazer in the rocks at low rpm. Mildly built '77 350 motor. I am in the process of prepping up a TBI system from a '90 F-body to fit my current engine, and getting rid of the Q-jet. This will be a custom install, so I'm modifying things accordingly.

I don't understand completely the ECM strategy concerning the knock sensor. Is it only to retard timing upon sensing knock, or is there something else I'm missing? Thanks for any help

 

Yup. You're right. All it does is retard the timing if the knock sensor tells it there's some knockin' goin' on.

I'd only recommend it if you're gonna use the EST (Electronic Spark Timing). If you're gonna stick with mech advance, then don't worry about it 'cause it won't work anyway. LOL

A lot of people unhook them when they're at the drag strip just to ensure the ECM doesn't confuse "bangin' gears" with engine knock. The ECM don't care if it never gets the signal. Only if it does get one.

 

Quite the contrary. Check the threads on code 43, the ECM forces knock to test the ESC system. When it doesn't get it rude things happen.

RBob.

 

You can run a TBI setup with a machanical dist.? Hows that work? I though the computer controlled dist with the Ignition control module actually fired the injectors?

 

Thanks RBob, got it. Looks like I'll be using the 43 patch and the VSS patch. I don't how I missed all that good info......

 

Yea, but that's if he's gonna use the ESC. If not then the computer can't do anything about it. That's why I said "If you're gonna stick with mech advance, then don't worry about it 'cause it won't work anyway."

And when I said this "The ECM don't care if it never gets the signal. Only if it does get one." I meant at the dragstrip. I've done it with no problems, but then hooked it back up for the trip home. Never got a code.

Does the ECM test on every WOT run? If not then I guess I got lucky. Also take into consideration that I did this on a '94 Z28 w/6spd. TBI could be a whole different story.

Sorry for the mis-info.