On acceleration RPM gage pegs to 0 and car vibrates
10-20-10, 07:17 AM
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On acceleration RPM gage pegs to 0 and car vibrates
I have a 1992 SC400 with 114K miles. Until yesterday the car ran perfectly. This morning when I started the car I experienced the following problems even though the check engine light is not registering a problem. Instead of the cold start normal operating rpm of 1100, the RPM gage reads 550 and the car misses and vibrates. When I depress the gas pedal, the RPM gage reverses its direction and pegs on 0 RPM. Letting off the accelerator the RPM resumes its functioning and reads 500. Increasing the RPM to 750, the gage again pegs on 0. Furthermore, when I increase the engine speed there is a drop in voltage supplying power to the accessories. The interior fan decreases to about half speed. To evaluate whether it was only a cold start problem, I let the car idle and warm to its normal operating temperature. The problems continued to exist and the RPM gage always pegs on 0 if engine speed is increased. The car has limited power based on driving it in and out of the garage.
If I were to attempt to drive to the dealership would I be damaging the car if the problem is only a sensor? If the problem is electrical will I be damaging other sensors by driving the car? Are there sensor checks I can perform without the scan tool? Do I need to have a tow truck haul the car to the dealership and not attempt to do anything on my own? I am adept at mechanical work but I am not that confident about electrical problems other than alternators and regulators.
If I were to attempt to drive to the dealership would I be damaging the car if the problem is only a sensor? If the problem is electrical will I be damaging other sensors by driving the car? Are there sensor checks I can perform without the scan tool? Do I need to have a tow truck haul the car to the dealership and not attempt to do anything on my own? I am adept at mechanical work but I am not that confident about electrical problems other than alternators and regulators.
10-20-10, 10:15 AM
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On most cars that usually indicates a bad crank position sensor (I'm pretty sure the 2JZ will have one too).
Make sure the rubber around your crank pulley has not separated!
EDIT: You need to test the alternator too if you've had oil dripping on it at any point. A bad part inside of there will send voltage the wrong way or not regulate it right, fry the battery, and cause major electrical issues.
Make sure the rubber around your crank pulley has not separated!
EDIT: You need to test the alternator too if you've had oil dripping on it at any point. A bad part inside of there will send voltage the wrong way or not regulate it right, fry the battery, and cause major electrical issues.
10-20-10, 12:43 PM
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Thank You
Techgeek,
Thank you very much for the advice. I will check the rubber around the pulley and the alternator tonight after work.
Toughguy48
Thank you very much for the advice. I will check the rubber around the pulley and the alternator tonight after work.
Toughguy48
10-21-10, 08:25 AM
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Additional Problems
TechGreek,
I checked the rubber around the crank pulley and it seems to be in good condition. I also visually checked the alternator for any kind of oil leaks that may have been dripping from the power steering unit. Again, it appeared to be clean.
I restarted the car. It starts easily, but is clearly not firing on multiple cylinders. The RPM gage continues to peg on 0 when increasing the engine RPM above 800.
Do you recommend that I remove the alternator and take it to a shop to be tested? Also, would an alternator electrical problem cause missing on multiple cylinders?
Toughguy48
I checked the rubber around the crank pulley and it seems to be in good condition. I also visually checked the alternator for any kind of oil leaks that may have been dripping from the power steering unit. Again, it appeared to be clean.
I restarted the car. It starts easily, but is clearly not firing on multiple cylinders. The RPM gage continues to peg on 0 when increasing the engine RPM above 800.
Do you recommend that I remove the alternator and take it to a shop to be tested? Also, would an alternator electrical problem cause missing on multiple cylinders?
Toughguy48
10-21-10, 08:56 AM
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Yes it could be. I had an issue where my Thunderbird SC's RPM's would go to 0 and buck every once in a while. Everyone in the world said crank shaft position sensor.
I ended up finding a harness that had come loose from it's mounting point and was rubbing on the back of the pulley. That harness went to the ignition coil and alternator.
Your car HEAVILY depends on the battery/alternator in my opinion. I wouldn't go as far as to take the alternator out and get it tested. If you have charged the battery (or can tell it's charged with a volt meter) then you can eliminate that.
The only other thing I could possibly think of is a bad ground/broken ground somewhere. How's the main ground off the battery? If your grounds aren't good, then you'll have the ECU freaking out.
Have you checked time on it yet? Pulled the dizzy cap and checked the rotor? Oil would have been coming from the o-ring in the dizzy.
I ended up finding a harness that had come loose from it's mounting point and was rubbing on the back of the pulley. That harness went to the ignition coil and alternator.
Your car HEAVILY depends on the battery/alternator in my opinion. I wouldn't go as far as to take the alternator out and get it tested. If you have charged the battery (or can tell it's charged with a volt meter) then you can eliminate that.
The only other thing I could possibly think of is a bad ground/broken ground somewhere. How's the main ground off the battery? If your grounds aren't good, then you'll have the ECU freaking out.
Have you checked time on it yet? Pulled the dizzy cap and checked the rotor? Oil would have been coming from the o-ring in the dizzy.
10-21-10, 10:27 AM
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Put a meter on the ignition coil for sure.
http://www.turbosupras.com/pdfs/JZA8...0(2JZ-GTE).pdf
GTE but similiar (minus coil packs)
http://www.turbosupras.com/pdfs/JZA8...0(2JZ-GTE).pdf
GTE but similiar (minus coil packs)
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10-21-10, 01:21 PM
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TechGreek and Silva001,
Thank you very much for this information. I will do the tests this coming week. My brother-in-law is a wizzard with electronics so he will help me. This forum is fantastic.
Toughgy 48
Thank you very much for this information. I will do the tests this coming week. My brother-in-law is a wizzard with electronics so he will help me. This forum is fantastic.
Toughgy 48
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