Cylinder misfire help (1 Viewer)

[TFAF]

I need some expert advice on a major engine problem with my 06 LC. I’m not a mechanic and hope I explained everything correctly. My 06 LC has 187K miles, owned it since 20K, well maintained and never missed a service and no mechanical issues till last month when we had the secondary air injection pump and valves replaced at dealer. Two weeks later the check engine light starts flashing with VSC. The LC would shutter during acceleration. I stopped at AutoZone and they read the code – misfire cylinder #8. Guy at store said it would most likely be the coil pack or plug. When I went to install the coil pack, I found the spark plug was damaged and the electrode was smashed down. I then purchased a new DENSO plug and installed the new plug and coil pack. Car started fine and idle was real smooth. I drove it about 3 miles, it ran great, and then entire dash lit up, I heard clunking and the LC cut off and would not restart. Had it towed back to the dealer.


The dealer did some troubleshooting/testing and said that cylinder 8 had low compression and would have to take the head off to investigate. At this point, I suspected that something had possibly dropped down into the combustion chamber when they replaced the secondary air pump causing the mechanical damage to the plug. I shared my suspicions with the service manager and he said if they caused it they would cover the repairs and if they didn’t it was on me. The dealer proceeded and took the head off and said that there is damage to #1 and #8 valves and no scoring in cylinder #8. They are saying they could not find any damage from anything dropping into intake so it’s on me. They are now saying it was caused by a bad timing belt install.


I had a new timing belt and water pump installed at an independent shop that has certified Toyota and Lexus mechanics. I have driven this vehicle over 1500 miles since timing belt change to include driving from the coast to the mountains with no issues.


So my question – can these problems be caused by the timing belt install and if not - any ideas what would cause the damage to the spark plug. The dealer still cannot answer that question and claims the secondary air injection valve replacement work did not cause the current issue.

 

[2001LC]

My two cents. First let me say sorry dud.

Did you floor it (high RPM) just before all this started?

A bad T-belt job very well could have caused damage to valves. But why did it take 1,500 miles is very strange. Being a VVTi engine I suppose it may not have gotten into higher RPM until just recently. The timing change of VVTi effect may have put valve nearer to piston. I suppose a #8 valve could have bent over a bit hitting the spark plug.

I'd also venture to say upon further investigation the damaged valves had weak springs and/or very tight valve gap. This would not cause contact, but could explain why not all 8 cylinders were damage.

This would be easily proven with pictures and statement from the dealer, showing/stating the timing belt not installed properly. You're owed a shinny new engine, so all not bad.

 

[TFAF]

I dont recall any real high rpms. Fairly normal driving ….city, lots of interstate, and I even towed my ~5,000 lb boat after the timing belt replacement.

Dealer mechanic mentioned something about the camshaft being rolled ? during timing belt change could be the issue with the install??

I would have thought a timing issue would have showed up immediately. The LC ran great with no change in performance or gas mileage.

 

[2001LC]

Not sure what they meant "cam shaft rolled". Rolled out of position, possible jump a tooth or more.

Was it a full T-belt job WP, all pulleys and tensioner. Did they advise you to replace all parts. Did they test tensioner. Did they leave a holding pin in tensioner. Did they kink belt. Pulley bolts not torqued. Whatever we could go on guessing, but key point is the Dealer said "bad T-belt install". They must have a basis for that statement. Pin it down in writing and get picture.