White smoke from exhaust after changing knock sensor on 99' Limited 3.4L

DexterShaYang · Oct 19, 2026

Hey y'all. To start off I'd like to express that the most I can do when it comes to cars is basic maintenance like oil changes, brake pads, etc. I recently started trying to develop my mechanic skills but I have to admit that I definitely bit off more than I can chew this time(and probably shouldn't have started on my daily driver, yikes). I've had a knock sensor CEL for a while now and after watching videos and reading these forums, I thought that it would be a hard but simple enough job. I did manage to clear the knock sensor code, but I gained a P0100, P0110, and P0120 in the process and now I have white smoke(coolant?) coming out of the exhaust. I messed up big time and now I'm paying the consequences for it. Any help would be appreciated.

spartacus · Oct 19, 2026

Check the wiring and grounds all connected properly

spartacus · Oct 19, 2026

Also the vacuum lines are connected to the intake.

phattyduck · Oct 19, 2026

DexterShaYang said:
I have white smoke(coolant?) coming out of the exhaust.

Coolant has a sickly sweet smell. How does it smell?

Make sure you put the throttle body gasket on correctly and make sure all your electrical connectors are plugged in. Reset the ECU (remove negative battery terminal) and see what codes return.

-Charlie

DexterShaYang · Oct 20, 2026

spartacus said:
Check the wiring and grounds all connected properly

Would you happen to know the grounds I'd need to check? The only ground I really knew of was the one connected to the black diagnosis box thing and I made sure that was on tight.

spartacus · Oct 21, 2026

DexterShaYang said:
Would you happen to know the grounds I'd need to check? The only ground I really knew of was the one connected to the black diagnosis box thing and I made sure that was on tight.

Thread 'ground points'

Mar 27, 2006

anybody know where the ground points are on a 2000 T4R? i jus got some new ground wires and am planning to wire it on sometime soon... can anyone help?:awais:

2TH4IST · Saturday at 5:56 PM

Did you use new lower intake plenum to cylinder head gaskets? Did you clean the sealing surfaces good? It could be a bad or failed seal sucking coolant into the combustion chamber, causing the white smoke. Thos gaskets are known to rust out and fail, causing the last stud on both sides to rust and possibly break.

You have 1 ground when you do this job. It's on the intake manifold by the diagnostic connector. It's a 10mm head bolt. There might be another on the back of the pass cylinder head.

I know you didn't mention it, but did you torque the knock sensors to spec? Did you also replace the wire harness too for the knock sensors?

White smoke from exhaust after changing knock sensor on 99' Limited 3.4L

DexterShaYang

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spartacus

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phattyduck

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DexterShaYang

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Thread 'ground points'

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