Intake Valve Cleaners?

[herut]

At 86,000 km, I'm looking to clean my GDI intake valves via a spray into the throttle. Although I have read quite a bit about the CRC product and it looks very easy to use and is effective, I'm not able to source it here locally. Therefore they sold me the Liqui Moly ''Throttle Valve Cleaner'. (Product 5111).  I realize this is designed more for the throttle TB cleaning then for intake valves but it was wondering whether anyone had experience using this product to spray in and clean intake valves? And, if you have, is it necessary to leave the product 'heat soak' at the end of the service? The Liqui Moly instructions do not say so but I read where various other spray products did require that step. Any advice greatly appreciated. thanks!
Jeff

[Jocko]

Seems a bit of a waste of time and money for such a low-mileage engine. Mine has done 240,000 km and has never been touched. Do you have a particular problem that makes you want to clean the intake valves?

[olduser1]

Just use good fuel, enjoy your Jazz

[herut]

Hi. Thanks for the replies. Last month I cleaned plugs (front and...rear #%&*), changed air filter, cleaned MAF sensor with electric contact cleaner, changed oil/filter, changed CVT fluid [Honda brand] and filter, and removed PCV valve and thoroughly sprayed it with carb cleaner (very difficult to access/remove pop-out PCV on LDA3 engine). But my gas mileage has gone from a fairly constant 7.1 l/100 km to 8.3 l/100km this month with largely city driving, and recently with AC on. A year ago under similar driving habits it was a more acceptable plus or minus 6.7 l/100 km. Not sure why the poor fuel economy, so I thought I'd try the intake valve cleaner after reading of rather widespread issues of carbon buildup on GDI valve engines (not just on the Jazz.)
If anyone has an idea why the drop in fuel economy, let me know! Was going to clean my MAP sensor next since I understand that can also be a 'culprit'.
Jeff

[Lord Voltermore]

Check your tyre pressures and also whether brakes might be binding slightly.   

I too  doubt inlet valves would be an issue on such a low mileage engine.Mostly due to an older engine burning oil  ,and modern oils have decent cleaning additives. 

Incidentally  CRC and Liqui Moly   both make throttle valve cleaner AND valve cleaner as separate products. .  So its not the same stuff  -  or is it?  I suspect there is only a limited number of chemicals suitable for the job and it  may just be a matter of how concentrated it is, or application method.     

I am suspicious of some of these on- line reviews, which hype up  the need for a cleaner, then give apparent reviews of 10 products.  Most  people will go for the top recommendation. , Not the also rans that are reviewed as  "nearly as good and not much more expensive"     Many such reviews, even from apparently independent magazines etc, have a financial interest.

The liqui moly may help clean the throttle valve.  You could also consider using a dose of fuel injector cleaner into  the fuel tank.   Some cleaners are fairly weak and only intended to keep the injectors clean when used regularly.  Others   are concentrated cleaners that claim to be effective with just one treatment.   Needless to say these cost about 3 times as much  .

[herut]

Thanks Lord Voltermore. I just put BG44K in the fuel tank which in the past seemed to improve gas mileage pretty well. So we'll see what that does.
My old cheapy OBD scanner (I used with Torque Pro) died on me and I am awaiting a new BAFX reader. Perhaps STFT and LTFT readings will give a clue, although I'm quite a noobie at truly understanding that stuff. Is there any site where you can report your OBD readings for 'analysis'? That would be great. No apparent fault codes. O2 sensors also give out around 50,000 miles, (i.e. 86k KM or so), yes? But I cleaned the upstream one bc those things are quite expensive to replace. I guess a reading on the O2 will determine its health.

[Lord Voltermore]

I dont know much about obd readings either  ,but I'd think replacing 02 sensors (or cleaning them) could affect fuel consumption .If the sensor is now giving a slightly different reading than the original sensor  the ECU wont 'know' the result is slightly wrong and may adjust fuel/air mix  management settings to bring the value back to what the old sensor was reading..

Another thought  occurs . E10 fuel tends to give higher fuel consumption than E5 petrol or 100% petrol.  Has the petrol  specification  changed locally since last year?     


Also  I believe some makes of  MAF sensors  (including top brands  and original equipment) do not always respond well to being cleaned and should be replaced if necessary.  . I'm not sure about Honda.  Some after market replacements  are not great either.     

Same may be true of a MAP sensor.   I thought most  cars either  have a MAF  or a MAP   although some do have both,in which case the MAF reading may be preferred, with the MAP just as a back up .   

But random swopping of sensors in the hope of improvement can get expensive. Better wait for the OBD analysis.     I cant help with this.   But if you post the results on this site others may know if they are abnormal , or can compare them with their own results.
 

[herut]

Thank you for the advice. (I too wondered whether my mpg got worse after MAF cleaning--havent scraped up my knuckles to get to the MAP yet.)

Will update after my new OBD reader arrives!
Jeff