Intake manifold tuning hack
Here's my ******* attempt at a cheap fix for the intake manifold tuning problem, P2076, on the LUW 1.8L engine.
There's a crank which drives a vertical rod up and down which in turn drives the vanes/damper to tune the intake runners for optimum air flow into the cylinders.
The rod has a ball on the lower end which snaps into a socket on the crank. On the upper end, a socket on the rod engages a ball on the vane/damper crank.
The failure that has repeatedly occurred on mine has been that the ball on the bottom of the crank keeps popping out of the socket resulting in a check engine light and P2076.
I've popped it back in with limited success. I tried to increase the ball's diameter slightly by adding a wrap of Scotch 33+ electrical tape, and that held up for a couple weeks. Another attempt, this time using some shrink tubing, failed right away.
This time around, I replaced the shrink wrap with a fresh layer, then drilled a 7/64" hole thru the ball and rod and then the crank. I made sure the hole in the ball was centered. Then installed the ball into the crank and drilled thru that. I had a little tool that holds the bit (for counter sinking) and was able to use that to hand drill the crank. There wasn't much room get a real drill into action there, but with a sharp (brand new) bit, the hand turning didn't take too long.
The 7/64" bit was chosen match the zip ties I have on hand. It allows the ribbon of the zip tie to fit thru the hole but the head is too big, and thus does not come thru as desired.
A small washer and another zip tie complete the fix.
I haven't trimmed the zip ties yet. They're easier to see that way. I sanded the first zip tie's head down for clearance on the back side of the crank, but it still rubs some when the crank turns, so some more engineering might be needed there

That is, I need to sand the head down on its end face rather than its top face.
The assembly seems to be working well, but only a few minutes of testing has elapsed thus far. The CEL is out - on its own - I didn't clear it - and the throttle response is way better!
The system should not exert much extraction force on the ball, so the zip tie should be adequately strong to keep it in the socket. I have seen the crank over rotate past bottom dead center, which will indeed pop the ball out, but the times I've seen it over-rotated, the ball was already out. That is, the ball probably came out first, then the crank over-rotated trying in vain to tune the intake.
Otherwise, if it does over-rotate with the crank attached, then that would indicate the computer is not properly detecting the position of the intake tuning vains/damper.
Anyway, as long as the crank doesn't go past bottom dead center, and heat doesn't make the zip ties brittle, this should be a durable repair. Fingers crossed.
Doug
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