ClubLexus - Lexus Forum Discussion

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-   SC - 1st Gen (1992-2000) (https://www.clublexus.com/forums/sc-1st-gen-1992-2000-6/)
-   -   Misfire continued + OBD2 data short/long fuel trim? (https://www.clublexus.com/forums/sc-1st-gen-1992-2000/961714-misfire-continued-obd2-data-short-long-fuel-trim.html)

ISFFUN Apr 5, 2021 03:29 PM

Update 2: misfires appear to be gone now and that noise quieted down - maybe just something in the head that wasn't getting oil from dry cranking?? dunno

Car doesn't smell like gas anymore, but the oil is still saturated with it. I can smell it through the cap/dipstick. Anyone know how this affects combustion with unburnt fuel in the oil? Should I plan change the oil even though I just did it (argghh)


https://cimg1.ibsrv.net/gimg/www.clu...f882d5f4c5.png
cleaned up
https://cimg5.ibsrv.net/gimg/www.clu...ca63bf88ed.png
back together
https://cimg3.ibsrv.net/gimg/www.clu...3e3f3a3bc1.png

1997Soarer Apr 7, 2021 08:13 PM

So what's the verdict on this.

ISFFUN Apr 8, 2021 04:15 PM

The main issue is solved which was the crank sprocket / gear had missing tooth. I replaced it and it solved the misfire.

What needs more investigation:
-There's likely a vacuum leak under the intake valve cover gasket.
-There's a vacuum leak in the brake booster
-Compression is 178psi on cyl #5 which is 7-10psi less than others so I wonder if there's a possibility that there's a valve problem there or a ring issue.

1997Soarer Apr 13, 2021 11:29 AM

Damn that crank trigger wheel strikes again

Well now that this headache is over, lets look at your others.

Vacuum leak under intake valve cover gasket? Try replacing the PCV valve grommet. And if the PCV hasn't been changed in the last 15k, do it. I discovered that the PCV valves like to get stuck open / clogged at about 15k, even with 3k full synthetic oil changes. I have since deleted the PCV system entirely.
Brake booster vacuum leak? Do you still have the vacuum valve in the brake booster hose? It was located in the middle of the original brake booster hose. If you do still have it, make sure it still works and its in the correct orientation. If yours is works correctly (air can only go one direction) then yes, you may need to replace the booster

There isn't really a quick fix for cylinder 5, but if you can solve the first two issues you can still enjoy the car if it stays at that range.


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