Toyota dealer pushing injector cleaner
09-07-13, 06:42 PM
#16
Lexus Champion
Best way is to let your tank get near empty and then put in a bottle of the stuff at the gas pump. Then fill up. This is to help the Techron mix properly with your fuel.
10-02-14, 03:04 AM
#18
Have any of you guys with high miles (like 200k+ miles, preferably on a GS4) used this Chevron Techron FI Cleaner? If so, what were the results? I am considering this but a bit worried with my high miles.
My car:
GS400, 250k miles,
Long term fuel trim is a bit a high (+15%) for both banks
Short term fuel trim is I think in normal range (+/- 5%) for both banks.
Fuel trim absolute variance bank-to-bank is always less than 5%, if that.
Current Condition: Reason I am considering injector cleaner is because my LTFT trim is consistently a bit high but STFT is mostly within a normal range; so I think the car is constantly needing 15% or so more fuel and making minor adjustments. This is also reflected on my mpg; currently at about 16-18 mpg mixed city/highway when I usually have been getting around 20 mpg. I record every gas fill up and track mpg as a way to keep an eye on the car's health. Also, I have a 3.76 final drive so mpg might a bit lower than most. Recent drop in temperature has not affected my mpg and has been like this even when it was warmer (in the midwest) a few weeks ago.
What I have done so far: Cleaned TB, MAF, checked/replaced vacuum hoses, checked exhaust leaks, replaced some exhaust gaskets that looked worn, checked all O2 sensors voltage and shows that normal wavy curve (and O2 fuel trim reflects that of the STFT), etc, reset ECU but I cannot get the LT fuel trim to go down. Still not sure if LTFT is stored or deleted by disconnecting battery though... (yeah, I know, watch it just be the LTFT stored in memory that needs to be cleared lol).
I might shooting blindly but my next guess was dirty injectors. Dirty/older injectors, output is not as great, injectors working overtime, higher LTFT, lower mpg.... so clean injectors is my thought process. If anyone has tried this Chevron Techron FI Cleaner (or other brand please specify), I would really appreciate any input. Thanks in advance.
My car:
GS400, 250k miles,
Long term fuel trim is a bit a high (+15%) for both banks
Short term fuel trim is I think in normal range (+/- 5%) for both banks.
Fuel trim absolute variance bank-to-bank is always less than 5%, if that.
Current Condition: Reason I am considering injector cleaner is because my LTFT trim is consistently a bit high but STFT is mostly within a normal range; so I think the car is constantly needing 15% or so more fuel and making minor adjustments. This is also reflected on my mpg; currently at about 16-18 mpg mixed city/highway when I usually have been getting around 20 mpg. I record every gas fill up and track mpg as a way to keep an eye on the car's health. Also, I have a 3.76 final drive so mpg might a bit lower than most. Recent drop in temperature has not affected my mpg and has been like this even when it was warmer (in the midwest) a few weeks ago.
What I have done so far: Cleaned TB, MAF, checked/replaced vacuum hoses, checked exhaust leaks, replaced some exhaust gaskets that looked worn, checked all O2 sensors voltage and shows that normal wavy curve (and O2 fuel trim reflects that of the STFT), etc, reset ECU but I cannot get the LT fuel trim to go down. Still not sure if LTFT is stored or deleted by disconnecting battery though... (yeah, I know, watch it just be the LTFT stored in memory that needs to be cleared lol).
I might shooting blindly but my next guess was dirty injectors. Dirty/older injectors, output is not as great, injectors working overtime, higher LTFT, lower mpg.... so clean injectors is my thought process. If anyone has tried this Chevron Techron FI Cleaner (or other brand please specify), I would really appreciate any input. Thanks in advance.
Last edited by kit cat; 10-02-14 at 03:08 AM. Reason: added that FT is consistent bank to bank...
10-02-14, 02:27 PM
#20
Hey bud,
LTFT is what gets stored in the memory banks of the ECU so yes it would stay there every time you turn ignition off and then on but you can erase it by removing the battery terminal for 5 mins or so and press on the brake pedal to dissipate any capacitors charge, after that reconnecting it. LTFT learns off of the STFT during closed loop operation.
STFT is a real time fuel trim and changes to what the oxygen sensor is doing during closed loom operation and that doesn't get stored.
If you have a +15% LTFT that means your fuel system was running lean and the ECU commanded the Fuel injectors to open +15% more pulse width to compensate to get back to the stoichometric value (14.7:1) fuel ratio for emissions.
Check the voltages on the oxygen sensor again and see if the pre cat oxygen sensors are going up to around 0.8 - 0.9V when you quickly do a sudden acceleration.
LTFT is what gets stored in the memory banks of the ECU so yes it would stay there every time you turn ignition off and then on but you can erase it by removing the battery terminal for 5 mins or so and press on the brake pedal to dissipate any capacitors charge, after that reconnecting it. LTFT learns off of the STFT during closed loop operation.
STFT is a real time fuel trim and changes to what the oxygen sensor is doing during closed loom operation and that doesn't get stored.
If you have a +15% LTFT that means your fuel system was running lean and the ECU commanded the Fuel injectors to open +15% more pulse width to compensate to get back to the stoichometric value (14.7:1) fuel ratio for emissions.
Check the voltages on the oxygen sensor again and see if the pre cat oxygen sensors are going up to around 0.8 - 0.9V when you quickly do a sudden acceleration.
Last edited by vijayn; 10-02-14 at 02:33 PM.
10-02-14, 08:11 PM
#21
Hey bud,
LTFT is what gets stored in the memory banks of the ECU so yes it would stay there every time you turn ignition off and then on but you can erase it by removing the battery terminal for 5 mins or so and press on the brake pedal to dissipate any capacitors charge, after that reconnecting it. LTFT learns off of the STFT during closed loop operation.
STFT is a real time fuel trim and changes to what the oxygen sensor is doing during closed loom operation and that doesn't get stored.
If you have a +15% LTFT that means your fuel system was running lean and the ECU commanded the Fuel injectors to open +15% more pulse width to compensate to get back to the stoichometric value (14.7:1) fuel ratio for emissions.
Check the voltages on the oxygen sensor again and see if the pre cat oxygen sensors are going up to around 0.8 - 0.9V when you quickly do a sudden acceleration.
LTFT is what gets stored in the memory banks of the ECU so yes it would stay there every time you turn ignition off and then on but you can erase it by removing the battery terminal for 5 mins or so and press on the brake pedal to dissipate any capacitors charge, after that reconnecting it. LTFT learns off of the STFT during closed loop operation.
STFT is a real time fuel trim and changes to what the oxygen sensor is doing during closed loom operation and that doesn't get stored.
If you have a +15% LTFT that means your fuel system was running lean and the ECU commanded the Fuel injectors to open +15% more pulse width to compensate to get back to the stoichometric value (14.7:1) fuel ratio for emissions.
Check the voltages on the oxygen sensor again and see if the pre cat oxygen sensors are going up to around 0.8 - 0.9V when you quickly do a sudden acceleration.
And thanks for the advise on the upstream O2 voltage reading under acceleration... are you thinking the ECU is incorrectly adding fuel even when the O2 is sensing it's running rich?
10-02-14, 08:13 PM
#22
PS: I disconnected the battery and cleared the LTFT today (verified both banks ST and LT FT are at zero % at idle after I re-connected battery) but its back up to 15%ish after a few miles of driving. I noticed that the ST and LT FT increases when idling at a stop light or even when crawling during traffic... Time to go do some more research.
10-02-14, 11:56 PM
#23
Oh good, to me it definitely sounds like its compensating for a lean mixture then.
Yes your right the learning of the LTFT will only happen during warm idle and light - medium throttle (cruising - closed loop). But the value that its learnt will apply all the time not only in closed loop.
Its common after high mileage engines to slowly have deteriorating oxygen sensors, so they may put out the wavy type signal but they are only cycling from maybe 0.1V to 0.4V when they should be cycling from 0.1V to 0.9V (during closed loop).
Doing the voltage test to see if it goes up to 0.8V- 0.9V will tell you whether the oxygen sensors are the problem. If they are fine then there might be a leak after the MAF sensor or MAF sensor is reading lower voltage than normal because its contaminated with oil - but you have already cleaned it aye?
When was the last time the fuel filter was changed? It could be partially clogged. And yeah the injectors could also be clogged so putting some inj cleaner will hopefully clear some of that. - I highly recommend taken them out and getting them cleaned with a ultra sonic cleaner though as this way you can physically see them before and after visually. And also you can just change all seals/o-rings and filter baskets at the same time.
Yes your right the learning of the LTFT will only happen during warm idle and light - medium throttle (cruising - closed loop). But the value that its learnt will apply all the time not only in closed loop.
Its common after high mileage engines to slowly have deteriorating oxygen sensors, so they may put out the wavy type signal but they are only cycling from maybe 0.1V to 0.4V when they should be cycling from 0.1V to 0.9V (during closed loop).
Doing the voltage test to see if it goes up to 0.8V- 0.9V will tell you whether the oxygen sensors are the problem. If they are fine then there might be a leak after the MAF sensor or MAF sensor is reading lower voltage than normal because its contaminated with oil - but you have already cleaned it aye?
When was the last time the fuel filter was changed? It could be partially clogged. And yeah the injectors could also be clogged so putting some inj cleaner will hopefully clear some of that. - I highly recommend taken them out and getting them cleaned with a ultra sonic cleaner though as this way you can physically see them before and after visually. And also you can just change all seals/o-rings and filter baskets at the same time.
10-03-14, 08:39 AM
#24
Pole Position
an increase in short term fuel trim can also be caused by a leak on the intake manifold. has recently been work performed in that area? after i changed a knock sensor on my gs 430 i had a leak on the intake manifold and checked the short term fuel trim. when i fixed the leak it was gone. but it was more than 15%, i had more like 25-35% st ft.
10-03-14, 07:10 PM
#25
http://youtu.be/gg9ppeUMpK4
Try this out, it worked well for me. But he also mentioned chevron techron as also being good as they both use pea, I noticed a smoother idle, and acceleration at low speeds
Try this out, it worked well for me. But he also mentioned chevron techron as also being good as they both use pea, I noticed a smoother idle, and acceleration at low speeds
10-05-14, 07:50 AM
#27
Oh good, to me it definitely sounds like its compensating for a lean mixture then.
Yes your right the learning of the LTFT will only happen during warm idle and light - medium throttle (cruising - closed loop). But the value that its learnt will apply all the time not only in closed loop.
Its common after high mileage engines to slowly have deteriorating oxygen sensors, so they may put out the wavy type signal but they are only cycling from maybe 0.1V to 0.4V when they should be cycling from 0.1V to 0.9V (during closed loop).
Doing the voltage test to see if it goes up to 0.8V- 0.9V will tell you whether the oxygen sensors are the problem. If they are fine then there might be a leak after the MAF sensor or MAF sensor is reading lower voltage than normal because its contaminated with oil - but you have already cleaned it aye?
Yes your right the learning of the LTFT will only happen during warm idle and light - medium throttle (cruising - closed loop). But the value that its learnt will apply all the time not only in closed loop.
Its common after high mileage engines to slowly have deteriorating oxygen sensors, so they may put out the wavy type signal but they are only cycling from maybe 0.1V to 0.4V when they should be cycling from 0.1V to 0.9V (during closed loop).
Doing the voltage test to see if it goes up to 0.8V- 0.9V will tell you whether the oxygen sensors are the problem. If they are fine then there might be a leak after the MAF sensor or MAF sensor is reading lower voltage than normal because its contaminated with oil - but you have already cleaned it aye?
And yep, MAF sensor was recently cleaned.
When was the last time the fuel filter was changed? It could be partially clogged. And yeah the injectors could also be clogged so putting some inj cleaner will hopefully clear some of that. - I highly recommend taken them out and getting them cleaned with a ultra sonic cleaner though as this way you can physically see them before and after visually. And also you can just change all seals/o-rings and filter baskets at the same time.
an increase in short term fuel trim can also be caused by a leak on the intake manifold. has recently been work performed in that area? after i changed a knock sensor on my gs 430 i had a leak on the intake manifold and checked the short term fuel trim. when i fixed the leak it was gone. but it was more than 15%, i had more like 25-35% st ft.
My LTFT has creeped up to the low 20% but I've never seen my STFT get that high... hopefully it's just something stupid.
Thanks for all the advise everyone
.
10-05-14, 12:27 PM
#28
[/QUOTE]Thanks for all the advise everyone .[/QUOTE]
Thats cool mate, hopefully you fix your problem. The other problem it could be is the fuel pump is stating to deteriorate - this would also make your power/acceleration decrease too.
.[/QUOTE]Thats cool mate, hopefully you fix your problem. The other problem it could be is the fuel pump is stating to deteriorate - this would also make your power/acceleration decrease too.
10-05-14, 11:37 PM
#29
I've been monitoring my O2 today and it's been cycling as low as almost zero and all the way up to 0.8 something volts so I'm going to rule out the O2 for now...
I bought a 2 bottles of Chevron Techron FI cleaner so when my gas gets low next, I'll try adding this to my gas tank.
Also have been looking into clogged fuel filter and started looking into parts. Hopefully it's just the filter and not the pump...
I bought a 2 bottles of Chevron Techron FI cleaner so when my gas gets low next, I'll try adding this to my gas tank.
Also have been looking into clogged fuel filter and started looking into parts. Hopefully it's just the filter and not the pump...
10-05-14, 11:40 PM
#30
By the way, are you guys using the Chevron Techron FI Concentrate Cleaner?
http://shop.advanceautoparts.com/p/c...5740/7080568-P
There was also a Chevron ProGard Fuel Injector Cleaner, which I didn't get since it didnt say Techron but just wanted to make sure.
http://shop.advanceautoparts.com/p/c...system+cleaner
http://shop.advanceautoparts.com/p/c...5740/7080568-P
There was also a Chevron ProGard Fuel Injector Cleaner, which I didn't get since it didnt say Techron but just wanted to make sure.
http://shop.advanceautoparts.com/p/c...system+cleaner