TCC locking up at 74MPH at W.O.T

[Fast355]

I don't know how I missed it before!

Part of the problem I've been trying to get rid of ever since I upgraded the motor to Vortec heads is counts knock under W.O.T. (Wideband AFR's 12.5-1) and now knock counts when I lift off. I could get about 200 KC's in a W.O.T. test run from 30-70 MPH and another 900 KC's if I reached 74 MPH and the TCC locked.
I would get noticeable a knock count increase when the TCC would lock and drag the RPM back down under load.

Interesting, just looked at the last log I had with the TCC not locking and it I still got about 800 KC's in 3rd gear at 3400RPM @ W.O.T. with 27.8º timing.

False knock? I would try a new OEM knock sensor torqued to the OEM value.

[tamperedchevy]

what octane fuel do you run? i run 93 on the stock cam and 195* thermostat and all the engine mods(headers, afpr and whatnot) with top rpm/map spark at 29 and no knock. is something rattling around down there causing false knock?


oops, didnt see fast355's post on page two. he already asked about the false knock

[Kitch]

I fitted a new AC-Delco Knock sensor and torqued it into place when I put the new Vortec engine into the van.
It could be false knock but if it is I don't know how to eliminate it.
It could be noise from my narrow body ComCams roller rockers or it could be the aggressive lobes on the cam as there is a bit of lifter noise that I can't adjust out at idle.
I use 98 octane fuel in it.
I had the brand new Vortec crate engine pulled apart and zero decked and I've now got 9.6-1 compression ratio, it could be that my cam is too small CS 252XFI HR-13 has 202º intake and 212º exhaust at .050 and I've got too much cylinder pressure.
The combo makes more power than the stock TBI motor did and it idles with 18" of vacuum @ 600RPM in gear but I can't get it to break traction if I stand on it.