Lexus IS250 4GR-FSE Engine Carbon Build-up (merged threads)
02-18-14, 08:41 AM
#1216
Driver School Candidate
I dont know if it will prevent it completely, but it seems it will at least slow down the build up tremendously, judging by the Oil Catch Can experiement thread.
I still need to install my Mishimoto can this week.
Not sure of validity of this statement?
Lots have installed an OCC and from what I've gathered educationally from OCC's, it seems they will do a great job combating large buildups.
I still need to install my Mishimoto can this week.
Not sure of validity of this statement?
Lots have installed an OCC and from what I've gathered educationally from OCC's, it seems they will do a great job combating large buildups.The PCV system can use a catch can. This shouldn't be an issue on a normal engine. I haven't followed this all that closely as I really don't care much. I won't own one past the warranty period. That said, I'm surprised by the amount of fluid the catch cans are catching. Something is wrong internally when there is that much volume going through the pcv system. On a properly operating engine the pcv should be passing a little bit of water vapor and not much else. The obvious indication is that there's a lot of blow by and a problem with piston rings as Lexus has identified.
There's going to be intake carbon build up by the fact that there's an EGR system whether the PCV is being fixed or not. How much is attributable to each one is an interesting question. You would expect the PCV to be so small as to be meaningless, but it appears this may not be the case.
Either way, running detergent containing fuel over the intake valves is a better solution as it takes care of all sources of carbon build up, and is very effective - as can be observed by the fact that very few if any people in cold weather climates have carbon issues.
Last edited by jetboy; 02-18-14 at 08:44 AM.
02-19-14, 07:10 AM
#1217
I have 76K miles on mine. I have ran Mobil 1 synthetic since I purchased the car new with 5k mile oil changes. I am occasionally getting misfires after coming off the freeway to a stop. Nothing bad yet. I have been using 3m fuel injection cleaning system every 25K miles and just installed a OCC. I honestly don't want an engine overhaul unless I absolutely need it. Unfortunately, I am also getting cam gear rattle on cold start ups... Not really sure what to do with the car. It is in near excellent condition. I was hoping to get 250K+ miles out of it.
02-26-14, 07:15 PM
#1218
jetboy there is no EGR recirculation anymore, it's controlled by the exhaust VVTi gears. The actual carbon is oil vapors from excessive blow by. The service bulletin that adresses this concern has updated pistons and piston rings with more tension.
The catch can is the only way to extend the negative effect of the oil vapors, it can't be vented or you'll eventually set a system lean code.
As far as the original post, these things will run well into 200k, I've yet to see one of these come apart that has any wear on rod bearings or cylinder walls.
The catch can is the only way to extend the negative effect of the oil vapors, it can't be vented or you'll eventually set a system lean code.
As far as the original post, these things will run well into 200k, I've yet to see one of these come apart that has any wear on rod bearings or cylinder walls.
Last edited by autox250; 02-26-14 at 07:17 PM. Reason: typo
02-27-14, 05:31 PM
#1220
Well if you all have seen my other post, I'm experiencing these issues myself.. did not know it was this issue until recently. Sounds like maybe I bought the wrong vehicle.... (smh).
Probs should have ponied up for the 350. At least the dealership replacing everything will solve the issue for another few years...
Probs should have ponied up for the 350. At least the dealership replacing everything will solve the issue for another few years...
02-28-14, 10:05 AM
#1222
The actual work on average takes 2-3 days, dealer might keep it overnight for another test drive. I avg about 2 1/2 days start to finish. If its being held for a while maybe its not misfiring at the moment and wout that you cant submit a claim to Lexus for approval
03-18-14, 01:24 PM
#1223
Like mentioned earlier in this thread the permanent solution would be ECU reprogramming to occasionally run the cold start injector to clean the carbon build up on the intake valves.
It seems like carbon build up is a non issue for folks with cold weather starts where that seventh cold start injector is turned on and sprays the fuel into the intake track and washes off the carbon build up.
It seems like carbon build up is a non issue for folks with cold weather starts where that seventh cold start injector is turned on and sprays the fuel into the intake track and washes off the carbon build up.
The only downside to having a leaky cold start injector is fuel efficiency is not as good, and the air fuel sensors are constantly telling the ECU to trim the fuel because otherwise it runs too rich.
03-25-14, 08:28 AM
#1224
The cold injector wouldn't work, it's way too high in the tank of the plenum. The only reason port injection is effective is bc the fuel spray is practically on top of the valve. The lower manifold w the butterfly valves would prevent the fuel to reach one of two valves in every cylinder. What little help it might provide it will be to 12 valves
03-31-14, 07:11 AM
#1225
Driver School Candidate
The cold injector wouldn't work, it's way too high in the tank of the plenum. The only reason port injection is effective is bc the fuel spray is practically on top of the valve. The lower manifold w the butterfly valves would prevent the fuel to reach one of two valves in every cylinder. What little help it might provide it will be to 12 valves
I don't know how that's possible. The intake valves sit together in the same head cavity and neither intake valve has a lifter disconnect like the Honda system. I don't recall any butterfly valve that would obstruct intake air flow over one intake valve on each cylinder. Can you explain?
It should flow over every intake valve. The intake valves are the only ones we care about. The exhaust valves aren't the problem. Fuel *with detergent* flowing over them is the easy cure. It doesn't matter where in the intake the fuel is delivered. If it did, carbureted engines would have all sorts of problems. They don't.
This also helps explain why the issue is limited to very few instances in cold weather areas.
Last edited by jetboy; 03-31-14 at 08:11 AM.
04-02-14, 04:34 PM
#1228
04-02-14, 04:44 PM
#1229
From what I've read that is not entirely true. The carbon is a result of blow back from PVC valve. This contains oil and combustion vapors. I have read that ethanol can increase the contamints that contribute to carbon buildup. So ethanol free gas may help, but only a little. If I could get ethanol free gas I would. Overall its just better for your engine.
Last edited by tomiv9; 04-02-14 at 04:49 PM.
04-03-14, 04:24 PM
#1230
From what I've read that is not entirely true. The carbon is a result of blow back from PVC valve. This contains oil and combustion vapors. I have read that ethanol can increase the contamints that contribute to carbon buildup. So ethanol free gas may help, but only a little. If I could get ethanol free gas I would. Overall its just better for your engine.