Fuel trim issue
I have 04’ RX300 (IIgen) and I’m struggling with a problem: my lex have different level of Fuel long-term trims. On bank 1 is about +15/20%, on bank 2 is about -5/10%. This causes to low idling and bad bibrations on dash. What I checked or/and replaced:
-new spark plugs (Denso)
-new valve cover gasket on both banks
-new air intake gasket
-set the right valve clearances
-all Ho2s sensors checked- all good- to be sure I changed the sides of the sensors- still the same issue with the fuel trims
-checked purge valves- all good
-time to time I get the check light with code p2196 (Ho2s sensor, signal stuck rich)
- changed ignition coils sides( from b1 to b2, and from b2 to b1)
- no intake leaks( checked with smoke, and foam)
my mechanic friend aks me to check the timing belt( i changed it 35kkm Ago), could I check it with TechStream? Like check the signal from camshafts sensors? Or I have to check it right on the belt?
or could exhaust leak could do this issue?
I have no more ideas what could happend to my engine
What does a compression test show for each cylinder, dry first, then with oil added?
I will check it, with oil change
It started from oil change, I used Motul 8100, 5w30 ( my parts shop guy recommended this oil, I have been using Millers before)
and here I have the second question, on how level should be the idling? i have about 850 on neutral and about 550/600 on D, I gues that is too low, am I right?
*** if you do this job yourself, I'm about to do mine, I strongly suggest purchasing a set of new seals those run @$25 on eBay.
Trending Topics
it is hard to take off the injectors?my mechanic said that injectors shoudn’t be dirty only on the one side of the engine, but maybe it will be better to clear it.
Celebrating Lexus & Toyota from Around the Globe
Can I please add, as we can see you have one bank rich and one bank lean.
It's common on our cars for people to do new stuff on the easy bank aka front bank and neglect the rear bank.
Couple of things.
(1): your MAF should be at 3.3g at idle, engine fully warmed up as I can see it is by your scanner data.
(2): I bought a whole set of six flow matched OEM fuel injectors on eBay from a seller with good feedback rating. Recommend only get flow matched if buying used. It's critical to get balanced fuel delivery. New OEM coils were expensive and I didn't want aftermarket so that's what I did.
(3): weak spark from old or fake clone ignition coils can raise fuel trims.
Good luck, plz keep us posted.
1. Right now I have about 3.5g
2. I will clean the injectors by myself or I will send it to Company which will clear the injectors and fix it if it will be needed
3. I have all 6 new sparks Orginal Denso, bought in my trusted parts shop
tomorrow I will go for longer ride to check if this clearing of the intake will helped for longer time
adding last data
Good luck
Last edited by Leeper; Jan 22, 2024 at 01:02 PM.
This is good preventative maintainence if your car has decent miles/kilometers on it though it may not be your issue. In looking at your issue it would be more likely a clogged/dirty injector than a bad seal but they are cheap and should be replaced anyway. As I mentioned in a prior post while doing this good idea to clean off your O2 sensors (one one top of engine easily accessed, one below also easily accessed no need to unplugged just loosen, spray with carb cleaner, wipe down, spray again, reinstall but make sure you wind the wind backwards so when your finish threading it back in the wire is straight. You should unplug the battery for a couple minutes then hook back up this will reset the ECU to relearn your driving style. Reset your windows and sunroof and drivers seat memory. This is free aside from the brake cleaner. As a result of my doing this my gas mileage went up considerably. I'll do this again after messing with the fuel injectors in case they are flowing differently I will assure the engine ECU learns again.









