Engine Noise

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CWR33

CWR33

10 Year
Joined
Feb 29, 2012
Threads
41
Messages
451
Location
Dallas Texas
So after the lone star jamboree I noticed that my engine was louder than normal. In the past I couldn't even tell it was on. Now when I turn it on it is really loud. It sounds like a huge fan or like its trying to breath really hard. I checked the air filter, it's clean as a whistle. I just ran a tank of gas with a bottle of engine cleaner mixed in. Also the noise doesn't really go away and a the rpms are a bit irregular at some points. But it shifts fine for the most part, I compared the rpms at idle to my buddys 100!and they were normal. However when I start it the rpms go up above 1500 or so and when I drive it the rpms are high at first. Any suggestions???
 
Both of my 100s did the same thing. For no apparent reason, they would go from idling at 400 to 800-900. I fixed by disconnecting the battery, cleaning MAF, throttle body, reconnecting battery, turning on and allowing it to idle for 15 minutes so that the ECU could re-learn everything. Worked like a charm.
 
My guess is any of these three:

1.Leakage somewhere on inlet manifold/piping between maf and cylinder head.

2. Dirty or faulty sensor or throttle body.

3.Exessive dirt in inlet manifold/pipes, although this most usual on turbo engines with egr, and would most likely result in poor engine performance.
 
pfran42 said:
Both of my 100s did the same thing. For no apparent reason, they would go from idling at 400 to 800-900. I fixed by disconnecting the battery, cleaning MAF, throttle body, reconnecting battery, turning on and allowing it to idle for 15 minutes so that the ECU could re-learn everything. Worked like a charm.
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I'll try that, thanks
 
fan clutch, everybody gets paranoid about sounds after they go wheeling hard. You seem to pay attention to every little thing wrong and wonder if it was like that before you went bouncing around in the mud and rocks.

if it sounds like a prop fan is under the hood its the fan, if it sounds like a V8 under the hood something is wrong.
 
2000UZJ said:
fan clutch, everybody gets paranoid about sounds after they go wheeling hard. You seem to pay attention to every little thing wrong and wonder if it was like that before you went bouncing around in the mud and rocks.

if it sounds like a prop fan is under the hood its the fan, if it sounds like a V8 under the hood something is wrong.
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It's defiantly not a normal sound, it's a roar. It sounds similar it an 18 wheeler accelerating from a stop..
 
CWR33 said:
It's defiantly not a normal sound, it's a roar. It sounds similar it an 18 wheeler accelerating from a stop..
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did you hit a lot of mud lately? sounds like your fan clutch is going nuts and running the fan. The engine does run at a higher RPM on a cold start. Around 1200-1500 is normal. Once the engine hits around 80*F (water temp) it will drop to around 900RPM, when the motor gets to 181*F (water temp) the RPM's will drop ti 650-700RPM. This is what I have noted with SG, not sure if that is for all 100's. But for mine this is the case. When my fan runs on a cold start it sounds extremely loud. I'm sure it's normal since temps are starting to rise into the 90*F range. That fan will be running a lot more this summer.
 
Yes it poured the second day of the jambo. So what do I need to do to fix the noise if the fan clutch is the case.
 
Alright, so i went to auto zone today. They had MAF spray but I was told not to trust it. So I bought some RXP fuel additive and reset the ECU and it's fixed. I'm not sure which one did it but it all worked out. Thanks for the help, especially Pfran.
 
Glad you got it resolved. I have been using CRC MAF since day one on my 100 without any issues. Very easy to apply and it works.

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I do want to find one to clean the MAF i just need to find the right stuff. I may do the throtle body this weekend.
 
That's what I was told to stay away from. Would there be any chance the MAF differs from Toyota to Lexus?
 
CWR33 said:
That's what I was told to stay away from. Would there be any chance the MAF differs from Toyota to Lexus?
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Would there be any chance that the guy at the auto parts store doesn't know what he is talking about? The same guy handing out tech advice on CRC products could change career paths and end up delivering pizzas by this time next year.
 
No it was a guy who was in there buying things himself. He said that he had used it on his Lexus and that it fried the sensor.
 
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