Im helping out my buddy who lives in texas and Im in michigan so this is makign the tuning process reather interesting to say the least. Anyways. Its a 94 Blazer with a TBI 350 which he replaced the heads with a set of pro-topline TPI heads and an lt-4 camshaft (not the hot cam). So for the first chip I put in a stock timing curve from a SD l98 bin (cant remember which exact bin it was from though off the top of my head). The knock retard hits 10* and it knocks all over the place. Knock counter goes up as fast as you can count. So he put the stock chip back in and it wasnt any better (BJLF TBI bin has a weak timing curve). He says from what he can tell its not knocking though. Had him check the plugs and no signs of detonation. Im feeling something else is confusing the knock sensor or hes getting feedback from somewhere. In the datalogs after the truck shutsdownt he knock counter just keeps on going. I told him to unplug the knock sensor and leave it hanging to see what happens. Which he hasnt done yet. My feeling is that its not knocking because the timing curve wasnt that aggressive unless those pro toplines have some really efficient combustion chambers which I doubt. What are some possible things I can have him check to try and figure this out. Makes tuning over email a pain. Thanks in advance! Josh

IMO, really helping him, would be mentioning this board, and having him learn to do them himself.
How can you honestly expect to get the chip right for his driving style over the net/phone?.

Grumpy

I feel absolutely no different then you. But for some reason people are reluctant to dive into new things and learn. I dont know why. Maybe I like creating pain and suffering for msyelf but there is nothing quite like watching something you've built tweaked and tuned yourself run and fire up. I take pride in doing everything myself. (I cant do machine work but working on fixing that currently). Im working on him though. Im hoping I can get him a close chip and hten get him to take over from there. But soemtimes you do things for your friends not because you want to but because they are your friend. Thats where Im at right now. Though Im right there with you and do appreciate your input. Thanks

Josh

You'd have to be running a ton of timing to knock with those toplines i'd think.

I'd say maybe your running out of fuel, but then again i'd think you'd run outta air with that TBI anyway.

Like Bruce said, get your friend to get into tuning. You'll never figure this out from a thousand miles away.

-- Joe

Joe

Thanks. Its quite rich around idle so I pulled some fuel out on this new chip. I know a rich mixture burns alot faster then a lean mixture but I dont think this is the problem. On my TBI 383 Ive got a heck of alot more timing in then what I put in his. I went easy so as to not over do it since Im not there. Maybe I'll just have to beat him into doing it himself a little bit more. Thanks for the help. Any and all suggestions appreciated. THanks

Josh

There is probably a wiring problem or the ESC module is bad. If the knock counter is just running away when the engine is off, it is a problem in the knock system circuitry.

RBob.

RBob

Thanks alot. He had bought a new knock sensor as I recall and Im almost wondering if it DOA. I know its hard to beleive a new part could be Dead but Ive had it happen before. Ill have to ask him about the esc module though. Thanks alot. At least I have somewhere to start now.