93 Camry V6 LE suddenly loses all power at specific throttle position
#1
01-09-2011, 02:04 PM
93 Camry V6 LE suddenly loses all power at specific throttle position
My ‘93 Camry V6 LE with 260,000 miles suddenly loses all power at a specific throttle position. I am very easy on the car and hardly notice the problem in the hot Texas Summers. However, in colder weather that requires a little more throttle for specific speed or acceleration the problem is very difficult to handle. It is particularly bad when the ambient temperature is around 50 degrees F or below. The engine temperature seems to have no effect. The problem exists when the engine is first started cold, and is still there when the car is running on the highway at normal coolant temperature.
The ECU is reporting no codes and there is no check engine light. I can force a code to prove the ECU will report codes and light the check engine light.
The car runs smooth up to about half throttle. Instantaneously, when a bit more throttle is applied it loses all power and goes to idle RPM.
I can be in park, add throttle slowly up to half throttle and 3000 RPM, add a bit more throttle, and suddenly all power is lost and RPM goes to idle. I must back off, let it recover, and gently go back up to 3000 RPM. A little more and it loses all power and speed again. If I keep adding throttle it never regains. As the throttle nears full, the engine goes into convulsions of total miss-fire. At this point my son checking the exhaust says he thinks it is getting too much fuel.
I can ease the car up to 70 MPH and 2500-3000 RPM on the highway at about half throttle, add just a little throttle, and lose all power and RPM goes to idle instantly. Again, I must back of and ease the throttle back up to slowly accelerate to 70 MPH being careful not to reach the throttle position that causes the sudden drop in power. Going downhill is easy, but when I hit an incline and need a little throttle to maintain speed I exceed the critical point and lose it all. I can be going 50 MPH with the same result. Speed or load on the engine, or engine RPM do not seem to be key factors in producing the problem.
I can be on a city street in lower gears easing the car up from 20 MPH to 30 MPH at 1500 to 2000 RPM and suddenly lose all power and instantly drop to idle RPM when the throttle position goes just over that half-way position.
I have found no vacuum leaks. I found a very small fuel leak at the fuel filter, replaced the fuel filter, the leak stopped, but the accelerator problem did not go away.
I have been advised that the Fuel Pump is not likely the cause because the problem occurs at both no load and full load and does not appear to vary with demand for fuel. Also it is very sudden in nature, it does not slowly worsen with demand.
I checked the throttle position sensor with an ohm meter. The resistance measured in the correct range with no sudden changes as the throttle was slowly increased from zero to full. Others have advised me that Throttle Position Sensors develop internal mechanical failures that cause them to fail beginning at certain positions. My local parts store expert would not sell me a new throttle position sensor. He said if it failed in this way the ECU would produce a code and light the check engine light. He went on to say that any sensor with input to the ECU would result in a code and light if it failed, particularly, with such a well-defined and catastrophic point of failure. He said this type of sudden dramatic failure is very unlikely to be related to fuel or vacuum. He said my problem more likely relates to ignition, with a sudden loss of correctly timed spark. Once again, he said there is no input device that would cause this at a particular throttle position with no code. He said throttle position inputs would not suddenly change ignition. He believes the ECU itself is failing and must be re-flashed or replaced.
Does anybody know where can I get my ECU tested and/or re-flashed for a reasonable price?
Has anybody seen this problem before and successfully solved it? Or, do you have suggestions for further diagnosing the problem?
I have had very bad luck with both dealers and repair shops with this type of problem. They often solve the problem with educated trial and error, starting at a price in the hundreds of dollars and ending up weeks later at thousands of dollars with the car finally working. My Camry is my only transportation and I do not have a lot of money available for trial and error. I appreciate any help you can give.
The ECU is reporting no codes and there is no check engine light. I can force a code to prove the ECU will report codes and light the check engine light.
The car runs smooth up to about half throttle. Instantaneously, when a bit more throttle is applied it loses all power and goes to idle RPM.
I can be in park, add throttle slowly up to half throttle and 3000 RPM, add a bit more throttle, and suddenly all power is lost and RPM goes to idle. I must back off, let it recover, and gently go back up to 3000 RPM. A little more and it loses all power and speed again. If I keep adding throttle it never regains. As the throttle nears full, the engine goes into convulsions of total miss-fire. At this point my son checking the exhaust says he thinks it is getting too much fuel.
I can ease the car up to 70 MPH and 2500-3000 RPM on the highway at about half throttle, add just a little throttle, and lose all power and RPM goes to idle instantly. Again, I must back of and ease the throttle back up to slowly accelerate to 70 MPH being careful not to reach the throttle position that causes the sudden drop in power. Going downhill is easy, but when I hit an incline and need a little throttle to maintain speed I exceed the critical point and lose it all. I can be going 50 MPH with the same result. Speed or load on the engine, or engine RPM do not seem to be key factors in producing the problem.
I can be on a city street in lower gears easing the car up from 20 MPH to 30 MPH at 1500 to 2000 RPM and suddenly lose all power and instantly drop to idle RPM when the throttle position goes just over that half-way position.
I have found no vacuum leaks. I found a very small fuel leak at the fuel filter, replaced the fuel filter, the leak stopped, but the accelerator problem did not go away.
I have been advised that the Fuel Pump is not likely the cause because the problem occurs at both no load and full load and does not appear to vary with demand for fuel. Also it is very sudden in nature, it does not slowly worsen with demand.
I checked the throttle position sensor with an ohm meter. The resistance measured in the correct range with no sudden changes as the throttle was slowly increased from zero to full. Others have advised me that Throttle Position Sensors develop internal mechanical failures that cause them to fail beginning at certain positions. My local parts store expert would not sell me a new throttle position sensor. He said if it failed in this way the ECU would produce a code and light the check engine light. He went on to say that any sensor with input to the ECU would result in a code and light if it failed, particularly, with such a well-defined and catastrophic point of failure. He said this type of sudden dramatic failure is very unlikely to be related to fuel or vacuum. He said my problem more likely relates to ignition, with a sudden loss of correctly timed spark. Once again, he said there is no input device that would cause this at a particular throttle position with no code. He said throttle position inputs would not suddenly change ignition. He believes the ECU itself is failing and must be re-flashed or replaced.
Does anybody know where can I get my ECU tested and/or re-flashed for a reasonable price?
Has anybody seen this problem before and successfully solved it? Or, do you have suggestions for further diagnosing the problem?
I have had very bad luck with both dealers and repair shops with this type of problem. They often solve the problem with educated trial and error, starting at a price in the hundreds of dollars and ending up weeks later at thousands of dollars with the car finally working. My Camry is my only transportation and I do not have a lot of money available for trial and error. I appreciate any help you can give.
#2
01-09-2011, 06:19 PM
Does the RPM drop and go to idle, as if you took your foot of the gas pedal?
Or once you reach the problem point, the more gas pedal you provide, the engine reacts by bogging down. As if it is not getting enough fuel, or the ign spark is too weak.
You imply the engine needs time to get back to normal after this event happens. Do you need to stop the car and wait or can you take you foot of the pedal, then reapply and things get back to normal?
Is it always the same RPM range, or is it a combination of RPM and engine load. Going hill results in the problem happening at a different RPM, etc?
Or once you reach the problem point, the more gas pedal you provide, the engine reacts by bogging down. As if it is not getting enough fuel, or the ign spark is too weak.
You imply the engine needs time to get back to normal after this event happens. Do you need to stop the car and wait or can you take you foot of the pedal, then reapply and things get back to normal?
Is it always the same RPM range, or is it a combination of RPM and engine load. Going hill results in the problem happening at a different RPM, etc?
#3
01-10-2011, 05:10 PM
As I reach the problem point the engine definitely reacts by bogging down – not going directly to idle RPM. Significantly more throttle brings it down to idle RPM pretty quickly. If I accelerate just to the problem point where the engine bogs down, and back off the accelerator slightly the engine recovers its power and gets right back to normal. The problem occurs in just about any RPM range. It is definitely load related. Examples: 3200 RPM in park under no load. Any RPM while driving from 1500 RPM just starting out to 3000 RPM on a smooth open road. While holding the throttle just below the problem point going uphill you can reproduce the problem at any point on the hill from the start at 70 MPH and around 3000 RPM to the top at maybe 45 MPH and 2000 RPM. At any point, if you push the throttle just over the problem position the car will immediately bog down and drop speed and RPM significantly faster, then recover if you ease the throttle just under the problem point. The recovery takes a while on a hill and may not occur until road levels or starts downhill due to the load.
I just finished a 150 mile highway round trip at 40 degrees F outside temperature.
At higher outside temperatures I can go 70 MPH and have enough throttle to go up normal hills without losing speed. On this trip at 40 degrees F outside I could maintain 60 MPH on flat road, 50 MPH up small inclines, and 70 MPH on small down grades.
If I am parked in the driveway, I can accelerate smoothly up to 3200 RPM where I hit the problem point. Slightly more throttle causes the RPM to start falling off slightly, and more with more throttle. At some point of additional throttle the RPM’s drop to around idle. More throttle causes severe mis-firing. I can let the throttle back to just below the problem point and the RPM’s recover to 3200. Recovery is quick if the throttle was only advanced to just over the problem point. It takes a little longer if the engine was allowed to get into a bad state of operation.
If I am on the city street at about 2000 RPM the same events occur: Just below the problem point the car is going smoothly at about 2000 RPM. At the problem point RPM and speed start to drop slightly. They drop off more with more throttle and quickly drop to near idle RPM. When I ease the throttle back just below the problem point everything recovers and the car re-gains its RPM and speed.
If I am on the highway at 2500 RPM and throttle just below the problem point everything is smooth. At the problem point RPM’s and speed start to drop off slightly. With just a little more throttle the car starts to get jerky – alternating between trying to accelerate and bog down. More throttle quickly drops the RPM’s and speed significantly. It is this situation that takes some time to recover. The added load of highway driving results in more time and effort for the car to get back up to speed with so little working range of throttle to provide acceleration under load. I lose speed and RPM going uphill because the added load requires more throttle than is available under the problem point. Going downhill I recover what I lost going uphill. On the uphill, I lose speed and RPM holding the throttle just under the problem point. I lose speed and RPM much more quickly if I advance the throttle to the problem point.
Thank you for any help you can give.
RT
I just finished a 150 mile highway round trip at 40 degrees F outside temperature.
At higher outside temperatures I can go 70 MPH and have enough throttle to go up normal hills without losing speed. On this trip at 40 degrees F outside I could maintain 60 MPH on flat road, 50 MPH up small inclines, and 70 MPH on small down grades.
If I am parked in the driveway, I can accelerate smoothly up to 3200 RPM where I hit the problem point. Slightly more throttle causes the RPM to start falling off slightly, and more with more throttle. At some point of additional throttle the RPM’s drop to around idle. More throttle causes severe mis-firing. I can let the throttle back to just below the problem point and the RPM’s recover to 3200. Recovery is quick if the throttle was only advanced to just over the problem point. It takes a little longer if the engine was allowed to get into a bad state of operation.
If I am on the city street at about 2000 RPM the same events occur: Just below the problem point the car is going smoothly at about 2000 RPM. At the problem point RPM and speed start to drop slightly. They drop off more with more throttle and quickly drop to near idle RPM. When I ease the throttle back just below the problem point everything recovers and the car re-gains its RPM and speed.
If I am on the highway at 2500 RPM and throttle just below the problem point everything is smooth. At the problem point RPM’s and speed start to drop off slightly. With just a little more throttle the car starts to get jerky – alternating between trying to accelerate and bog down. More throttle quickly drops the RPM’s and speed significantly. It is this situation that takes some time to recover. The added load of highway driving results in more time and effort for the car to get back up to speed with so little working range of throttle to provide acceleration under load. I lose speed and RPM going uphill because the added load requires more throttle than is available under the problem point. Going downhill I recover what I lost going uphill. On the uphill, I lose speed and RPM holding the throttle just under the problem point. I lose speed and RPM much more quickly if I advance the throttle to the problem point.
Thank you for any help you can give.
RT
#4
01-10-2011, 05:16 PM
One more note:
On the highway, when I slowly add throttle, and reach the problem point, the first symptom is the car starts to jerk. It goes back and forth between trying to accelerate and bogging down right at the problem point. Above the problem point it bogs down.
RT
On the highway, when I slowly add throttle, and reach the problem point, the first symptom is the car starts to jerk. It goes back and forth between trying to accelerate and bogging down right at the problem point. Above the problem point it bogs down.
RT
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