TT chip and octane

[Steve Wood]

Particularly at low throttle, exhaust leaks can suck a lot of air back into the exhaust and that fools the O2 into thinking the engine is lean.  It tells the ecm to add more fuel.  As the rpm increases, this seems to diminish as the exhaust pulses are coming closer together.

Makes me wonder if the knock sensor has been hearing exhaust gas blowing out under boost.

Any ways....trying shaking those injector leads once it is back together

[Shimy87]

I never thought of that, it would be great if this eliminated the knock problem!!!

[Shimy87]

Car still had a slight miss at cruise so I swapped coil/wires from mine and gone. Rock auto sells a few coils. Any i should avoid or any i should try to get?

[SuperSix]

I'm an AC/Delco fan for such items. That coil pack/ignition module was purchased "known-good/used" from a TB.Com member, FYI. Maybe Delphi.

[Shimy87]

Back to working on this beast. replaced coil, wires and plugs. The vacume booster failed so replaced that. car runs really good, still dosent like boost. Spools quickly and staying under half throttle and up to 8-9 lbs of boost were all good, more than that and knock jumps in...alot.

chip says 20-18 on timing. if I lower the adjustable timing in the chip is that only for WOT or does it lower it all over? winter is coming so will probably send chip in then to be burned for exact combo in car.

[Steve Wood]

affects wot only.....  but something is still strange.  It should run close to 15 psi with no problem.  Got another gauge to verify the boost level? Run a hose from under the hood straight to another gauge

[Shimy87]

Can't get the other gauge out of my car. I set it to 14 psi ( by this gauge) and its better, not gone. Sometimes it pulls with no knock, sometimes it records 3 at worst. But really falls on its face when it starts to pull timing. Its random so maybe its hearing something else, gotta check the usual suspects for something hitting.

[Steve Wood]

I don't think it is real but whatever it is hearing? I have no clue. I had a cam in my car that set the sensor off a 2800 rpm when going wot. It jerked all the timing. Get above 3200 and it would not do it. Changed the cam and it stopped.