3rd & 4th Generation (1992–1996 & 1997–2001)Toyota Camry Discussion for years: 1992-1996 & 1997-2001
Topics of discussion range from fuel economy, safety, modifications, performance all involving America's favorite family car, the Toyota Camry.
I have a question... does the 1997-2001 Toyota Camrys shut off their fuel injectors to save gasoline while coasting? If so, does it occur in gear or in neutral???
I'm really curious about this.
Thanks!
-LSS
__________________
2001 Toyota Camry 2.2L-I4, automatic transmission with 157,000 miles.
Definitely not in neutral, otherwise the engine would quit with no fuel. If it's a stick, the fuel shuts off in gear at 0% throttle, the engine continues to turn because it's coupled to the wheels still. I'm not sure how the strategy works with an auto since the converter probably wouldn't be locked when you lift off of the throttle.
Injectors are always running, with 0% throttle. else you would run in a lean state and burn your piston rings. there is no spark turn off.
You cant' run lean when there is no fuel! I'm not sure of the strategy on that particular Gen Camry, but as a rule decel fuel cut has been used in most cars since mid-late 80's.
Engines get fuel from the injectors 100% of the time when the engine is started and running. Otherwise they would die immediately when idling with the throttle closed. Obviously the amount of fuel delivered is dependent on the amount of air being introduced to the engine.
No, your injectors do not just "cut off" when coasting.
EDIT: Your engine control module is capable of shutting off injectors briefly when the TPS senses sudden closure of the throttle to avoid a spike in emissions that would be caused by a suddenly rich condition. I don't consider this a shutdown of the injectors when coasting, because it is a very brief occurrence.
I'm surprised at the misinformation in this thread. The service manual for a 1994 camry (EG1-235) has a page dedicated to fuel cut. In a 5sfe, if you are over 2500 rpm and let off the throttle, the injectors will stop. They will resume operating when the engine goes below 1400 rpm. This happens regardless of whether you are in gear or not.
The Following User Says Thank You to uuuuu For This Useful Post:
Fuel pumped up by the fuel pump, flows through the fuel filter and is distributed to each injector at a set pressure maintained by the pressure regulator.
The fuel pressure regulator adjusts the pressure of the fuel from the fuel line (high pressure side) to a pressure 284 kPa (2.9 kgf/cm, 41 psi) higher than the pressure inside the cylinder head, and excess fuel is returned to the fuel tank through the return pipe. The pulsation damper absorbs the slight fluctuations in fuel pressure caused by fuel injector from the injector. The injectors operate on input of injection signals from the ECM and inject fuel into the cylinder head.
The control system consists of sensors which detect various engine conditions, and a ECM which determines the injection volume (timing) based on the signals from the sensors.
The various sensors detect the intake air pressure, engine speed, oxygen density in the exhaust gas, engine coolant temperature, intake air temperature and atmospheric pressure etc. and convert the information into an electrical signal which. is sent to the ECM. Based on these signals, the ECM calculates the optimum ignition timing for the current conditions and operates the injectors.
The ECM not only controls the fuel injection timing, but also the self diagnostic function which records the occurrence of a malfunction, ignition timing control, idle speed control and EGR control.
3. INSPECT FUEL CUT RPM
(a) Increase the engine speed to at least 2,500 rpm.
(b) Use a sound scope to check for injector operating
noise.
(c) Check that when the throttle lever is released, injector
operation noise stops momentarily and then resumes.
HINT: Measure with the A/C OFF.
Fuel return speed:
1,500 rpm
The fuel cuts off momentarily.. Not for a long period of time. It only takes half a second or so to drop from 2500 RPM to 1500RPM. As far as Running all the time, basically that is what is happening. When it cuts off for that 1/2 second (estimation), there is a pressure regulator with a return line that will get more pressure than the standard pressure with the 1/2 second of the injectors stopping on throttling down and it will open the return spring and allow the fuel to pass back to the tank.
As far as the information listed on this thread, your information is a little off as well. If you read the quote i posted above, you can clearly see it cuts the injectors "momentarily" when the throttle is released.
OP
If you want an Engine Retarder, I suggest getting a vehicle that uses Diesel Fuel.
That is simply a test to check the fuel cut in neutral with car not moving. It ABSOLUTELY does cut the fuel during decel in gear! It takes a whole lot longer to go from 2500 -1500 when your moving.
I'm telling you that the injector cut out is minimal. If you are running at 2500 RPM then drop to 2000RPM, and push the throttle your injectors are still going to be pulsing. Just because the transmission is in gear doesnt mean that the fuel is going to stay cut out until 1500 RPM. At 2500RPM, your injectors are dumping fuel into your cylinders to keep up with the engine, when you let off the throttle, it cuts out for a minimal amount of time, then the ECM sends the signal back to the car and starts pulsing fuel into the cylinders again. It doesnt just completely stop pulsing though.
I'm telling you that the injector cut out is minimal. If you are running at 2500 RPM then drop to 2000RPM, and push the throttle your injectors are still going to be pulsing. Just because the transmission is in gear doesnt mean that the fuel is going to stay cut out until 1500 RPM. At 2500RPM, your injectors are dumping fuel into your cylinders to keep up with the engine, when you let off the throttle, it cuts out for a minimal amount of time, then the ECM sends the signal back to the car and starts pulsing fuel into the cylinders again. It doesnt just completely stop pulsing though.
Ok this will be my last post on this subject, have a look at your instantaneous MPG on your trip computer if you have one. Cruise along at we'll say 3200 rpm in top gear, now close the throttle and watch as your fuel usage miraculously goes to "0". That is decel fuel cut, when you have slowed down to low rpm, we'll say 1200 or so, fuel usage goes back up. This is not rocket science, it has been done for the last 25 years on most vehicles. Oh by the way, if you want to check the neutral thing, put it in neutral at speed and you will see it uses enough fuel to idle.
Based on this thread, I was curious about just how long it would take to drop from >2500 rpm to around 1500 rpm...so I tried it out. In third gear, the engine went from 2700 rpm to 1400 rpm in about 20 seconds.
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Fuel shutoff
95 Camry
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