Problem I Cant Solve Is200

[Wotan2666]

Hi guys i hope you can help me more i try to solve this problem for 3months now i have this issue. My lexus is200 1999 193 000km started to have high fuel consumption 3 litres more then normal and it has less power and last week i find out first i buyed fuel on Shell and i had consumtion around 10litres normaly by that speed i had 8,5 after my tank was empty i filled up on Avanti fuelstation and i had consumption 11,5 litres by the same speed, i changed oil, airfilter, yesterday i changed sparkplugs so i had to disconnect the Battery from ECU after i changed the plugs connected the batter i had better feeling by driving my car today it was again back where it was high consumption less power output, i had no faulty codes in my ECU i did the check a month ago. And i rly dont know where should i look for the problem some idea ? I would like to ask if there exist some list of every sensor values that are correct that i can maybe check this values and maby find some they are not as they should be. Thanks

[James Trendall]

Sounds to me the way you drive and the ECU is learning how you drive.

When you disconnect the Battery it resets the "map" which is basically custom to the way you drive the car. When you reset the ECU it will default back to Toyota's "map"

Reset the ECU once more and start driving gently is the only advice i can really give on this. Sorry.

[Wotan2666]

Sounds to me the way you drive and the ECU is learning how you drive.

When you disconnect the battery it resets the "map" which is basically custom to the way you drive the car. When you reset the ECU it will default back to Toyota's "map"

Reset the ECU once more and start driving gently is the only advice i can really give on this. Sorry.

I know that. but i did not resetet my ecu for the first time and i never drove gently after reset and never had that way high consumption, and i dont think the ECU will give me less power that way

[steve2006]

Check your CTS ( Coolant Temperature Sensor) these tend to go out of specification as they age and so give false engine temperature readings to the ECU.

If the ECU then thinks the engine is cold it will enrich the fuel mixture increasing your fuel consumption and the engine will be down on power due to overfueling.

This will not flag any codes either.

You can check the sensor but for what they cost it may be best just to replace it with an OEM Lexus part.

[Wotan2666]

Check your CTS ( Coolant Temperature Sensor) these tend to go out of specification as they age and so give false engine temperature readings to the ECU.

If the ECU then thinks the engine is cold it will enrich the fuel mixture increasing your fuel consumption and the engine will be down on power due to overfueling.

This will not flag any codes either.

You can check the sensor but for what they cost it may be best just to replace it with an OEM Lexus part.

ok i will try just a question on my dashboard i see the engine temperature in the middle can it still be the CTS ? Becose i was thinking about the CTS but i thought when the oil temperature indicator on the dashboard show normal temperature then the CTS should be ok too but i will try check it in ECU. Thanks for the tip

[steve2006]

Not sure about the IS but on the LS there are 2 sensors 1 for the dash gauge and the other for the ECU, if it is the same on the IS the ECU one may be faulty even if the temperature gauge shows correct.

[Wotan2666]

ok thanks i will try, i did find this part in Japan OEM for 20 dollars so i will buy it with some other stuff and i will give feedback if it rly was CTS or not

[rincewind]

Before you start spending money on replacement parts which may not be needed I'd get the codes read. That should point you in the right direction.

[Wotan2666]

yea i know im going to look my ECU tomorow i will give you feedback

[Wotan2666]

Well i read the ECU what do you think guys

[Wotan2666]

im thinking about the manifold pressure when i was driving it only was getting hight to 44kpa can it be that i have weak pressure?

[JasonB]

8 degree timing advance doesn't look right. I'd check the belt hasn't skipped a tooth or possibly a vvti fault but I'd expect a code for that.

[Wotan2666]

i go on monday to my old Lexus garage they always could solve my problems so :) i will visit them and i give you feedback what it was

[r3dd3v1l]

Check the obvious, fuel lines, spark plug condition, airfilter etc

M

[Wotan2666]

so i was by 2 Technicians in 2 different Lexus service and 2 different Countries they both did the complet chech diagnostic and they say the car runs perfect but both told me that the issue could be carbon in chamber and in oil so they said i should buy Product called Pro Tec and make the engine flush ... so i buyed the whole pakage: engine flush, oil booster, nano seal, fuel line cleaner, valves and injection cleaner, air intake cleaner and guard petrol. I used the products for fuel cleaner ... 2 times and i can say the car runs a lot better i will now change the oil again after 5000km 2x