1992 Lexus ES 300 1992 es300 low power

Tiny
SLEDBOY2K
  • MEMBER
  • 1992 LEXUS ES 300
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 198,000 MILES
I recently bought the neighbors 1992 ES300. Had a blown head gasket on the front bank. Replaced the gasket, had the head checked and milled. Checked compression, 180 all the way around. MDrove away from the house and noticed it was way low on power and smells like its running extremely rich. I changed plugs, cap and rotor, engine temp sensor, fuel pressure regulator. I noticed that after driving 20 miles, the plugs on the back bank(cylinders1, 3, 5) have a nice shiny coat of carbon on them, black as coal. The front bank, (cylinders 2, 4, 6) look new. I thought maybe a o2 sensor. I switched the front o2 sensor to the back and then put a new one on the front. Even tested the voltage through the diagnostic port under the hood as the manual suggests. No change. Starts fine, sounds decent. As the engine warms it runs poorer but still runs, barely, no power at all. The only thing I can think of that would only affect 1 cylinder bank would be the o2 or the ecm. Am I missing something?
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Wednesday, October 13th, 2010 AT 2:11 PM

5 Replies

Tiny
KHLOW2008
  • EXPERT
Hi sledboy2k,

Thank you for the donation.

Have you confirmed the timing belt had been correctly installed?
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Wednesday, October 13th, 2010 AT 3:40 PM
Tiny
SLEDBOY2K
  • MEMBER
I checked the timing and its spot on
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Wednesday, October 13th, 2010 AT 8:45 PM
Tiny
KHLOW2008
  • EXPERT
Apart from the O2 sensor and ECM, other items that can cause the problem are :

1. Valve timing. Timing belt installation.

2. Fuel injectors, could be stuck open thus flooding the cylinders.

3. Valve clearance. Insufficient clearance would result in compression drop, especially after warming up.
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Thursday, October 14th, 2010 AT 6:37 AM
Tiny
SLEDBOY2K
  • MEMBER
Engine sounds good and is in perfect time. I'm ruling out valves for the moment just because most people I have talked to said the hydraulic valves don't really ever need much adjustment(if any). I think I can rule out stuck injectors because the odds of all three sticking by themselves at the same time is pretty long, but something is definitely holding them open because it guzzles gas as well as burns awefully rich. Found a thread on toyota nation, a guy with exactly the same problem (one bank running rich, the other normal) turns out his ecu was bad, something about the drivers for the O2 sensors or fuel mixture. Going the give that a try before I junk it. Tested the voltage per the service manual and noticed the rear bank was only measuring 1 volt at the o2 sensor while the front was somewhere around 2.3 volts. I'll find out next week whether or not it was the ecu. Thanks for all your help guys.
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Thursday, October 14th, 2010 AT 11:24 PM
Tiny
KHLOW2008
  • EXPERT
Keep us updated. We would like to know what went wrong too.
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Friday, October 15th, 2010 AT 8:52 AM

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