HRH Posted July 9, 2009 Report Share Posted July 9, 2009 Bought a 93 Hardbody 4x4 with KA24E TBI motor. It has 139k miles. PO had for a week and head gasket blew. Had shop XYZ replace head gasket, rebuild head, and timing chain. Said it ran fine for a day, then the rattling noise happened, which he thought was timing chain, but it's most certainly detonation. This morning, probed the computer, found Air Intake Temperature Sensor code. Went to find it, it was missing! So got new one, replaced, and the ECU now says 55 which means everything is normal. Did this solve the problem? Of course not. Checked timing. 30 degrees static. Yeah, not good. Ran it down to 10 degrees per spec. Changed F***ing autolite plugs someone put in to NGKs. Still detonation. Ran it to 0 degrees, ran slow, ALMOST got rid of detonation. HERE'S THE WAY IT HAPPENS: It starts up, and knocks like an SOB on cold startup, clearing off in about 3-5 seconds. Then idles normally. It will free-rev normally if you push the throttle slow, up until about 2500 rpm. If you give it a hard whack of throttle, there's detonation. After putting in a full tank of 92 octane, driving to the gas station carefully at 0 degrees timing, knock is still there, though it doesn't happen accelerating slowly, but right at where you even out (like 1/8 throttle, just maintaining speed) it knocks, but straight decel or accel it does not unless romped on. It also begins to detonate if you get to high up in the revs. Haven't had it past 3500 yet. So that's it, any ideas? I'm leaning towards fuel or something at this point being the ECU's happy, though of course we know that doesn't mean anything. Plugs looked normal even being shitty autolites when I took them out. Quote Link to comment
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