I'm new to cars and need some help with my 93 Totoya Camry.

Tiny
BRITTANYISWAYCOOL
  • MEMBER
  • 1993 TOYOTA CAMRY
  • AUTOMATIC
(To be specific I'm new to the maintenance and repairs of cars.)

My car has been turning off when I come to a red light or whenever I am driving slow (15-25mph).

I parked my car once and decided to see how long it would take to die.

The first time I turned my car on and let it sit, it died at around 2 minutes 30 seconds.

The second time it died at around 1 minute 50 seconds, but it turned back on by itself.

The third time it didn't die, so I quit the "experiment at 3 minutes and turned it off.

What I noticed though was that the dial (x1000rpm) would move up and down on its own.

Another thing I noticed was that I'd buy a gallon of gas, and at 4 miles it would already be empty.

My friend told me that it was probably the fuel pump.

** It's not the battery (after we had it changed it kept dying at the lights or during slow drives)
** It's also not the alternator (I had to call a man to tow my car and he did a test where he unhooked a part from the battery and the car was still on, and then told me it wasn't the alternator for sure).

My friend also thinks it could be some wiring because when I try to start my car sometimes it would smell like burning plastic.

If it is either or both of those things would I be able to have some friends fix it for me if I get the parts, or would I have to take it to a shop to have them lift heavy parts of the car?

If I have to take it to the shop how much would it take?
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Wednesday, April 20th, 2011 AT 3:02 AM

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Tiny
CARADIODOC
  • EXPERT
A stalling problem such as you described is usually caused by a sensor, or the wiring to it could be rubbed through and grounded out. To suddenly stall and then be able to be started again in a few minutes is not a generator or battery problem.

First of all, if the fellow who removed the battery cable was my employee, I would have fired him on the spot for doing that to your car! No professional today is that ignorant. That was a stupid man's trick that was done decades ago to tell if the generator was working. If the engine kept running, it was assumed it was okay. There are all kinds of things that can still be wrong with the generator even though it can keep the engine running. The voltage might be too low, or, there is a common problem that causes it to only put out one third of the current it is supposed to be capable of. More importantly, part of the battery's job is to smooth out the "ripple" that all generators produce. That ripple, without the battery, can cause system voltage to go too high. Had he increased engine speed with the battery cable removed, the voltage could very easily have reached over 30 volts. I did that as a demonstration every year for my students to prove what can happen. 30 volts will instantly burn out any light bulbs that are turned on, it can damage the generator itself, and it can destroy every computer module on the car. Fortunately your car doesn't have many computers. Most newer cars since the mid to late '90s and newer can have up to 47 computers. If only a quarter of them are destroyed, the car might be not worth repair.

That important issue aside, it sounds like you're relying on too many "friends" who are sending you in a bunch of different directions. Not one of them has done any testing to have a hint of a proper diagnosis. You need to have people all pulling in the one right direction. A dozen people can tell you why you're in pain, but you have to agree, unless it's a hang nail, sunburn, or you cut your foot off with a chain saw, without testing, all anyone can do is guess. How many "fixes" are you going to try before you give up? Also, every time someone puts in a new part or makes some adjustment, they are introducing a new variable that your Engine Computer might have to relearn. That relearning process occurs after a specific set of conditions are met. Until then, the engine could very likely run worse.

The best thing you can do is leave the car with a mechanic and provide as many clues as possible. You have already noted way more helpful things than most people. The high fuel consumption is likely related but that means the fuel pump is working just fine. GM cars have a history of pumps failing while driving. That is not the way they usually fail on other brands of cars. As I mentioned earlier, it is very common for some engine sensors to fail by becoming heat-sensitive, and they will work again after they cool down. It is probable that a diagnostic fault code has been stored in the Engine Computer that will send the mechanic to the correct circuit or system that needs further testing. On a few rare occasions they can lead straight to the defective part. It is very important to not disconnect the battery until someone has read those codes. Disconnecting the battery will remove the power from the computer's memory and that valuable information will be lost.

Whether or not there are any codes, the mechanic will connect a hand-held computer called a scanner that can display live sensor data while the engine is running. That may show him which sensor signal is dropping out when the engine stalls.

I know no one likes to spend money unnecessarily, but visiting a mechanic is less expensive than listening to everyone's ideas and getting nothing solved. If you can be without the car for a while, you might look for a nearby community college with an automotive program. They are always looking for live work for their students, but they will only take in cars that fit what they're currently teaching.

In the meantime, check under the car for signs of fuel leakage. The Engine Computer can't command so much fuel as to only get 4 mpg. A leak can cause low fuel pressure which can cause stalling.
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Wednesday, April 20th, 2011 AT 4:54 AM
Tiny
BRITTANYISWAYCOOL
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Thank you for your response, I really appreciate it!

I got it to the mechanic and he said that it was the idle control solenoid. After he said that he also told me that it could have the possibility of not even being the problem explained above.

If I switch that out do you think it'll fix it?
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Sunday, April 24th, 2011 AT 4:27 PM
Tiny
CARADIODOC
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What do you mean by "not even being the problem explained above"? Are you referring to his diagnosis of the solenoid, my description of a sensor, or your first description of the stalling problem?

I would tend to disagree with his suggestion of the idle air control valve but keep in mind I'm not there to see how he came up with that. The way this works is the Engine Computer makes tiny adjustments to that valve to control how much air enters the engine ONLY when you are not pressing the gas pedal. At the same time it varies how much fuel enters the engine. Those two things control idle speed.

That valve can fail two ways. One way is electrically. The computer will detect that, set a diagnostic fault code in memory, and turn on the Check Engine light. The second way for it to fail is by the air passage becoming blocked with carbon buildup. That is very rare today with the cleaner fuels we're using. You can prove to yourself if that valve is working. When you start the engine, its speed should jump up to about 1500 rpm for one or two seconds without you ever touching the gas pedal, then it will drop right down to the normal 800 or so rpm. That's called the "idle flare-up". All engines do that.

The other common complaint when there's a problem with that valve is the engine will tend to stall when you pull up to a stop sign. That is when it's the computer's job to maintain an idle speed high enough to prevent that. The clue is it will not stall if you hold the gas pedal down about 1/4". THAT part does agree with the first sentence in your original post.

I guess after rereading that first post, you might indeed have a problem with that idle air control valve because there is one important observation you didn't mention. Once the engine stalls, can it be restarted right away or do you have to wait for the engine to cool down? Some of the important sensors often fail by becoming heat-sensitive. It generally takes longer than two to three minutes for that to happen, (15 to 30 minutes is common), then the engine will not restart until that sensor cools down for at least half an hour. Also, those failing sensors should be setting a fault code.

If there are no fault codes, AND if the engine can be restarted right away after it stalls, it could be that valve. Before you replace it though, verify you're not getting that nice idle flare-up when you start the engine. If you do get it, that valve is working. If you do not, pull the hoses off first and spray in some carburetor cleaner while the engine is off. If you see any black stuff come running out, wash that valve well with that cleaner. You might even have to remove it to give it a good scrubbing. Check the mating ports on the engine too to see if there is carbon in there.
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Sunday, April 24th, 2011 AT 9:31 PM
Tiny
BRITTANYISWAYCOOL
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"Once the engine stalls, can it be restarted right away or do you have to wait for the engine to cool down?"

Sometimes when we're at a light it'll take a while (max three lights) to turn back on, and sometimes it'll turn on right away afterwards. It's random.
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Monday, April 25th, 2011 AT 2:58 AM
Tiny
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If it can be restarted right away, that suggests it's not a sensor getting hot and failing. If it really is a problem with the idle air control valve, the engine should restart right away if you hold the gas pedal down about 1/4".
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Monday, April 25th, 2011 AT 3:21 AM

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