Lexus IS250 4GR-FSE Engine Carbon Build-up (merged threads)
07-06-10, 11:44 PM
#258
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Ethanol has a low specific heat, so it will always have a lower mpg number. It's not related to deposits in any way.
07-07-10, 06:56 AM
#261
07-07-10, 10:28 AM
#263
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I was just looking at the BG product website and according to them the best way to do it is to run the fuel injection cleaner first to "pre-soak" build up and that makes the 44k more effective. It also says after that to run their gas additive with every tank after the 44k is used? Seems a bit pricey and unrealistic. Then they have the CF5 which they say to use every 5k as a preventative measure. I did read some posts here where people had the top engine cleaning done and it didn't fix the issue at hand, the only explanations I can think of are the cleaning wasn't thorough enough or the build up in the top engine is not the cause of the problem, I would be interested to see an explanation from someone who is more mechanically inclined than myself. Is it the consensus that this is an inherent problem with the direct injection and it can't be "fixed" just dealt with?
07-07-10, 10:38 AM
#264
I guess the BG44k is for the injectors which COULD also suffer from carbon buildup and contribute to crappy idle.
Found this:
"the 44K is about twice as strong as the CF5. Both are excellent products. Use the 44K for the initial cleaning then use the CF5 every 5K thereafter"
The CF5 I think I could use. It couldn't hurt anything. I am not expecting a miracle.
Technically the additives will not hit the valves much, I am not sure when the injectors fires.
I am gong to order both. My car has 12k mileage so far I think it runs like new still.
Found this:
"the 44K is about twice as strong as the CF5. Both are excellent products. Use the 44K for the initial cleaning then use the CF5 every 5K thereafter"
The CF5 I think I could use. It couldn't hurt anything. I am not expecting a miracle.
Technically the additives will not hit the valves much, I am not sure when the injectors fires.
I am gong to order both. My car has 12k mileage so far I think it runs like new still.
07-07-10, 10:58 AM
#266
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So you don't have any problems so far? It will be interesting to see how it goes as you put more miles on it. But not 4gr drivers are experiencing these problems so I guess it is kind of hard to quantify the results.
07-07-10, 11:27 AM
#268
Here is some info I got from a seller on Ebay
"44k is 2 to 3 times as strong as cf5. cf5 can be use every time you fill up. 44k should only be used every 5 thousand miles. "
So I guess do the 44k only every 5k, to me the cost isn't bad. Less than $20 a pop
"44k is 2 to 3 times as strong as cf5. cf5 can be use every time you fill up. 44k should only be used every 5 thousand miles. "
So I guess do the 44k only every 5k, to me the cost isn't bad. Less than $20 a pop
07-07-10, 11:57 AM
#269
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As I understand this, the 350 also has direct injection but the engine was designed differently so that they are not experiencing the pronounced carbon build up (of course, they have the other recall issue). I also understand that carbon build up can be a problem with DI engines. While I am not an engineer having this problem begin at very low mileage IS unacceptable and likely a poor design issue. Since the top engine cleaning appears to be at best a temporary solution I don't feel it should be the responsibility of the 250 owners to try to figure out what additive or process can help this. I would suggest that 250 owners with this problem continue to contact Lexus Corporate for them to figure out what to do (i.e. if it will be recurring, extend warranty)
07-07-10, 02:03 PM
#270
As I understand this, the 350 also has direct injection but the engine was designed differently so that they are not experiencing the pronounced carbon build up (of course, they have the other recall issue). I also understand that carbon build up can be a problem with DI engines. While I am not an engineer having this problem begin at very low mileage IS unacceptable and likely a poor design issue. Since the top engine cleaning appears to be at best a temporary solution I don't feel it should be the responsibility of the 250 owners to try to figure out what additive or process can help this. I would suggest that 250 owners with this problem continue to contact Lexus Corporate for them to figure out what to do (i.e. if it will be recurring, extend warranty)
If you think speed of build up is unacceptable, there are other more expensive european cars where this occurs more severely in a shorter amount of time.
It will be nice if perhaps we complain enough Lexus will give us free head cleaning for the lifetime of ownership but somehow I don't think it will happen. I don't think it's a bad suggestion but before that happens I would like to do preventative maintenence on my car.
The BG induction service in the video looks easy enough to do (and fairly non intrusive), it cost maybe $120 at some dealers. I am concerned what might get dislodged into the first catalytic converter. But then the exhaust temperature of 800F actual driving it may eventually get burnt up.