Accelerator sticking again!!!!!

[JH32552]

Hi again Guys :-)

Once again, my '94 Camry scared the bejeezus out of me, by reving out of control. I was driving a mountainous back road and all of a sudden the car was doing 40 mph on it's own. It was ROARING out of control so badly that I had to shut the car off in Drive. I would get out, pull the linkage back to an idle then start the car and, without touching the gas proceed on my way home. This kept up, until I had a very steep incline to go down. I kept the car in low, and kept touching the brakes. Then, I was smelling my brakes, and decided to just stop and, hopefully, someone would come by with some tools! And they did.......

To make a long story short, I got a 10mm wrench and took the cover off the box that (I think) holds the cruise control and throttle cables. It has sand and dirt all over the guides, springs, and throttle cables. I sprayed it with WD40, kept moving them, and it loosened up nicely. Then I drove the rest of the way home w/o incident.

THis morning, I cleaned all the oil and crud out and was going to blast it w/PB spray, and thought I would ask here if perhaps silicone would work better for me. I live on a dirt road, and there is always a lot of sand around that sticks to anything oily. Wouldn't silicone lubricate equally well, w/o the stickiness that all this sand and dirt sticks to????

(Oh, I checked and cleaned the throttle housing with an old toothbrush and carb cleaner too, but it was the cables in the covered box area that was the problem.)

Any thoughts on this would be appreciated
Jackie

[Brian R.]

Silicone is just another type of oil. It is silicon-based instead of hydrocarbon-based. Dust will stick to it also. Get an evaporating teflon spray. If it doesn't leave an oily residue, it will be fine. You can also try a graphite lock lubricant.

Don't forget that if the cable is too chewed up, rusted, dinged or whatever, it will never slide freely with a dry lubricant. You will need to get a new cable if you want it to be reliable.

[JH32552]

Originally Posted by Brian R.

Don't forget that if the cable is too chewed up, rusted, dinged or whatever, it will never slide freely with a dry lubricant. You will need to get a new cable if you want it to be reliable.

Thanks Brian, and the cables themselves looks like new. Bright n' shinny, the whole nine yards!

I will look for that evaporating teflon spray when I go to town. And, why didn't I think of using graphite? We used to use that for everything years ago. Geeeeze!

Also, one thing I did learn through this ordeal; I will always carry a cheap set of tools in this car from now on. AND, some spray lubricant! But then again, you can practically rebuild this car with just a 10 and 12mm wrench! LOL!!! Thanks again Brian

Jackie (with a few more gray hairs now)

[JH32552]

GRRRRRRRRRRRRRRRRRRRRRRRR!!!! This throttle sticking deal is going to get me killed! I took the car to town after spraying the heck out of it will PB spray, and the throttle stuck again!!!! I sprayed the cables and springs near the throttle body, in the box that houses the cruise control, and cleaned out the throttle body AGAIN with carb cleaner. What else can I do here? I did notice that it seems to be hanging up at the first (closest to firewall) lever in the cruise control box. The cable moves freely, but the spring loaded arc type lever doesn't take up the slack in the cable when it sticks. And, when I spray the crap out of it, it seems to be fine again for another 100 miles or so.

Does anyone have an idea what else I can do to keep this from happening again????

Jackie

[jdmccright]

It is possible that there is dirt and crud inside the cruise control actuator. You don't mention if this happens when the cruise control is on or off, but the throttle and cruise control are mechanically linked through that actuator. If it is sticking, then it ought to be replaced...I do not know if the unit can be opened for repair or cleaning.

Does the CRUISE light on your instrument panel flash when you turn it on? If so, there is a trouble code stored in the ECU. Download the Body Electrical System service manual stickied at the top (BE) and read the code (page BE-168).

Another but less likely possibility is that the little magnetic clutch that engages the cruise control is not disengaging or has a short circuit. This may also require replacement of the actuator.

Perhaps you can disconnect the cable from the actuator to the throttle to prevent this until you can look at it?

[JH32552]

Originally Posted by jdmccright

It is possible that there is dirt and crud inside the cruise control actuator. You don't mention if this happens when the cruise control is on or off, but the throttle and cruise control are mechanically linked through that actuator. If it is sticking, then it ought to be replaced...I do not know if the unit can be opened for repair or cleaning.

Does the CRUISE light on your instrument panel flash when you turn it on? If so, there is a trouble code stored in the ECU. Download the Body Electrical System service manual stickied at the top (BE) and read the code (page BE-168).

Another but less likely possibility is that the little magnetic clutch that engages the cruise control is not disengaging or has a short circuit. This may also require replacement of the actuator.

Perhaps you can disconnect the cable from the actuator to the throttle to prevent this until you can look at it?

I just drove the car about 80 miles and it behaved perfectly. No, I wasn't using the cruise when the problem occurred. When I do use the cruise, the light comes on steadily as it should (?) it does not blink. I did consider removing the actuator arm from the cruise to the throttle, and now I will.... just to see if it happens with it disconnected.

Is there anything else electrical that can be making this happen? Or, perhaps a sensor? It surely seems to be more of a mechanical thing to me though. I mean, it sticks, I spray, and it's fixed. WEIRD, huh?

Thanks for your suggestions, and I'll let you know how I make out with it :-)
Jackie

[pcushion]

The throttle was sticking on my 1997 Camry LE becuse the TB was full of gunk. When we were at a stop, the throttle would be hard to press, but then release, launching the car forward. Maybe the same this is happening here wher the throttle butterfly valve is being stuck in the open. Take the freash air intake off the TB and open the valve ... If it's pretty dirty in there, that could be it. You'll have to take the TB off and clean it with a scotch pad and carb cleaner. That's what I ended up doing and it fixed it.

Let us know how you do .... Paul - Dunstable, MA

[Mike Gerber]

I agree with pcushion that it's likely to be a sticking throttle valve inside the throttle body. If you didn't clean that before, do it now. There are 2 corrections I would like to make about cleaning it. First, it is not necessary to take the throttle body off the car to clean it. It can be cleaned right on the car and with the engine off. Second, do not use a scotch pad on it. That is simply too harsh and may scratch the area where the throttle valve seats, when it's in it's idle position. All you need is some spray throttle body cleaner or some O2 safe carb cleaner, along with a rag or a toothbrush for really stubborn buildup. Make sure you clean both the front and backside of the throttle valve along with the area around where it seats when it comes back to it's idle postion. Have someone hold the gas pedal to the floor (engine still off) to expose the backside of the throttle valve. If you are not familiar with how to clean it do a search. It has been covered numerous times.

Mike

[JH32552]

Thanks for the replies Guys.. but........

I cleaned the throttle body with carb spray when I lubricated all the cables.


Since the car performed beautifully yesterday, I took it for a drive about 35 miles, and guess what???? Yep, the damn thing stuck again!!!! I got out, pushed the accelerator lever back doan, sprayed it, and brought the car home. It behaved well on the way home!!!!

When I got home, I cleaned the throttle body again with carb spray and a soft toothbrush.....just in case I missed something before.
I then took the cables off and sprayed them liberally with PB spray. They are working smoothly with no sticking. I had someone keep pressing the gas pedal as it they were driving in traffic and as if on the open road. It never hung up once. In the area of the cruise control and lever type things, there is a spring. Should there be resistance on this lever that the cable fits into. This is hard to explain......please see picture at bottom of post... see the spring? It doesn't do anything!!!!!!!! Should it? (The bottom of the picture is the front of the car.) Oh, and the car has 149,100 miles.

Is is possible that there is some other reason that this is revving up? Computer.... Throttle positioning Sensor?? This is C R A Z Y!!!!

[JH32552]

No one has an answer about the spring on this lever in the cruise control area? C'mon guys, if I don't get help here, I have to take it to a mechanic, and I don't have the $ for that.....

H E L P!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Jackie

[jdmccright]

Contrary to popular belief, some of us gearheads DO remove our heads from under the hoods once in a while. And it is summertime, when vacations abound. I can understand your frustration at this, but diagnosis is much more difficult when we are limited to pics and typing versus real-time touch-and-feel. I simply haven't had time to pull the cover off and look at my set-up.

Honestly, the cruise control on the Camrys isn't one of the more trouble-prone systems, so the slow response kind of justifies that...we're just not that familiar with it. Bear with us. The spring does do SOMETHING, we just don't know yet. It appears to provide a resistance for the cruise control to measure the actual throttle position versus what the CC is requesting. OR it could be a CC throttle damper to smooth out small throttle changes....

Question #1: When it got stuck again and you said you pushed the accelerator lever down...do you mean the one on the TB or on the cruise control system? Sometimes you can feel it unsticking when you turn it or you can see the cable slacken when you turn one and it causes the other to unstick.

Question #2: Does the accelerator usually get stuck in the same position every time? 1/2 throttle? Wide-open throttle? Or does it vary?

I'd hate to suggest it, but frankly if all this spraying and brushing isn't cleaning out the crud that is causing it to stick, then I'd suspect that the TB needs to be disassembled and inspected for scoring where the butterfly valve shaft connects to the TB and/ or the cruise control actuator needs to be replaced. The only other thing I can think of is that the PB or whatever you are using is actually causing the sticking by gumming up and hardening as the engine heats up. Those lubricants are very low viscosity and will evaporate quickly when heated, leaving behind whatever else is in the oil formula as a gummy or solid residue.

[JH32552]

Originally Posted by jdmccright

Contrary to popular belief, some of us gearheads DO remove our heads from under the hoods once in a while. And it is summertime, when vacations abound. I can understand your frustration at this, but diagnosis is much more difficult when we are limited to pics and typing versus real-time touch-and-feel. I simply haven't had time to pull the cover off and look at my set-up.

Honestly, the cruise control on the Camrys isn't one of the more trouble-prone systems, so the slow response kind of justifies that...we're just not that familiar with it. Bear with us. The spring does do SOMETHING, we just don't know yet. It appears to provide a resistance for the cruise control to measure the actual throttle position versus what the CC is requesting. OR it could be a CC throttle damper to smooth out small throttle changes....

Question #1: When it got stuck again and you said you pushed the accelerator lever down...do you mean the one on the TB or on the cruise control system? Sometimes you can feel it unsticking when you turn it or you can see the cable slacken when you turn one and it causes the other to unstick.

Question #2: Does the accelerator usually get stuck in the same position every time? 1/2 throttle? Wide-open throttle? Or does it vary?

I'd hate to suggest it, but frankly if all this spraying and brushing isn't cleaning out the crud that is causing it to stick, then I'd suspect that the TB needs to be disassembled and inspected for scoring where the butterfly valve shaft connects to the TB and/ or the cruise control actuator needs to be replaced. The only other thing I can think of is that the PB or whatever you are using is actually causing the sticking by gumming up and hardening as the engine heats up. Those lubricants are very low viscosity and will evaporate quickly when heated, leaving behind whatever else is in the oil formula as a gummy or solid residue.

Answer to #1: When it stuck again, I pushed the lever down at the TB. When I push it down, it feels quite stiff.

Answer to #2: I would say it sticks at approx 1/3 throttle. When I am driving, and the tranny upshifts, it feels like full throttle, but that is only because I am in a higher gear. However, the 1st time it stuck, I gave the gas pedal a quick shot, and the rpms soared and stayed... I had to shut the car off!

There can't possibly be any crud left at either levers. I used a degreaser, a brush, and a jet spray of hot water to clean them.

I'm thinking you may be right about the TB having to be taken apart. Even though I have cleaned it numerous time, I may be missing something. It looks very clean, and feels very smooth, and I feel no grooves or scoring when I run my fingernail across the inside ot the TB. But, something certainly isn't right!

Sorry if I have come off as impatient or possibly demanding. But, I am just soooooo frustrated. I cannot/will not drive the car any more. It's just too dangerous like this.

I spoke with a mechanic, and he wants me to make an appt so he can use his test computer to diagnose the problem. He seems to think it's a computer or sensor problem. Is that possible?????

Thanks for your help and any more suggestions you may have.
Jackie

[pcushion]

Sorry if I have come off as impatient or possibly demanding. But, I am just soooooo frustrated. I cannot/will not drive the car any more. It's just too dangerous like this.

Don't worry about that ... We've all been there more times than not.

I spoke with a mechanic, and he wants me to make an appt so he can use his test computer to diagnose the problem. He seems to think it's a computer or sensor problem. Is that possible?????

He could be right ... It could be a throttle position sensor ... It seems that you have done everything a driveway mechanic could do. Good luck and keep us informed.

[jdmccright]

I'll stick with my diagnosis of a sticking TB...something somewhere in there, since you confirm that it is physically stuck. The TPS can only indirectly control it via vacuum. But I will concede that the TPS is a possiblity, too. I will note that hot water is not necessary to clean off the TB, and may cause corrosion formation where dissimilar metals are in contact. It doesn't take much to cause binding. Hopefully, the water wash was followed up by a shot of carb cleaner.

My only other revelation would be to check the throttle cable between the pedal and TB. It may have gunk in it too, have a kink, or need lubrication. Does the pedal stick too when it gest stuck or does it spring back when you lift off?

No worries about being frustrated, especially when safety comes into question. Hopefully, we'll find the problem!

Just read in the factory repair manual to not clean the TPS with carb cleaner as it may cause deterioration. Granted your problem started before you used it, but I'm wondering if the problem may have been exacerbated.

[JH32552]

Originally Posted by jdmccright

I'll stick with my diagnosis of a sticking TB...something somewhere in there, since you confirm that it is physically stuck. The TPS can only indirectly control it via vacuum. But I will concede that the TPS is a possiblity, too. I will note that hot water is not necessary to clean off the TB, and may cause corrosion formation where dissimilar metals are in contact. It doesn't take much to cause binding. Hopefully, the water wash was followed up by a shot of carb cleaner.

My only other revelation would be to check the throttle cable between the pedal and TB. It may have gunk in it too, have a kink, or need lubrication. Does the pedal stick too when it gest stuck or does it spring back when you lift off?

No worries about being frustrated, especially when safety comes into question. Hopefully, we'll find the problem!

Okay guys......

Here's the deal..... You all kept saying clean the TB, and I kept saying that I did clean it, in fact, MANY TIMES! Well, I decided today to take the TB off the car and take a look inside! Do I hear you all gasping? LOL! Well, I was going along fine getting the TB off until I hit a stumbling block. There were 2 hoses attached to the bottom and I couldn't get them off. However, I could get a good look at the inside/backside of the TB and I was shocked at what I found. Especially since I was so careful cleaning it. So, I would suggest anyone cleaning their TB should take it off to make sure BOTH sides are clean. Check this out!:




So, very carefully I cleaned the back side too, and now it looks like this:




So, Lets hope this problem is solved. I'll know better after the car is driven for a few miles. I will, however, stay out of high traffic areas and stick to the back roads for a while. LOL!

I would like to thank everyone who helped me with this problem.... lets just hope that is is solved!

You guys ROCK!!!!!

Jackie