Throttle Body

I have a '98 Camry, 4-cyl.

Sometimes it doesn't want to start. When it happens, if I have somebody start it while I lightly tap on the throttle body with a screwdriver handle, it starts. I clean the throttle body with air intake cleaner, and it works fine for a while (about a month or so), then it goes back to not starting.

I am a bit tiered of cleaning. Who makes replacement throttle bodies for this car, and where can I buy one.

Any other ideas?

Thanks!

Reply to
TObject
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If you would like genuine Toyota parts then consider

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found my local Toyota dealers to be more expensive.

Reply to
IceMan

Don't be so quick to replace the throttle body. I've had a very similar situation with my '97 camry, the car would start but die immediatly, or start and idle very slow. Hitting the throttle body lightly with a screwdriver handle cleared the problem temporarily. I suspected 2 systems:

1.) the EGR valve stuck open(Or part open). 2.) the Idle Air Control Valve. I was able to rule out the EGR valve. I posted the problem on
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followed the response-clean the Idle Air Control valve.To access the valve, Remove the air intake hose from the throttlebody, you will see a square opening(hole) in front of the throttleplate, Spray your intake cleaner into it, hopfully this will free itup. it worked for me.Hope this helps. JerryR
Reply to
JerryR

Try this: Let the engine idle when cold and the throttle body has not been tapped, so the idle is not right. This means the idle air control valve is sticking. Spray your cleaner into the rectangular hole near the bottom just right of center, while keeping the engine running by moving the butterfly valve at the throttle body. This should last a lot longer and prove satisfactory. If not, you want to replace the IAC valve, not the entire throttle body, but if it has not been harmed by "tapping" on it, cleaning should work. You also might want to check out:

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the part about helping clean emission control components, andmake sure the PCV valve is clear.Supposedly, oil fumes venting from the crankcase to the throttle body,help clog the idle control valve, so even if you replace it with new,the problem can return later.Mine was starting to need cleaning pretty regularly, too, but aftercleaning while idling, (so far) it had lasted a _ lot _ longer.

Reply to
Daniel M. Dreifus

I am curious about how a fuel additive would help clean the IAC or PCV? The IAC is located in the throttle body. The fuel is injected down stream from this, just before the intake valves. The PCV valve only sees stuff from the crankcase. I suppose some of a fuel system cleaner might work its way into the crankcase, but I can't see where an effective amount would every make it to the PCV valve.

My opinion (and it is only an opinion) is that IACs are clogged by contamination introduced into the intake tract by the PCV system. I can see where a better quality oil might have an effect (or it might not), but I have a hard time believing a fuel additive will have a significant effect on the IAC or the throttle body.

Regards,

Ed White

Reply to
C. E. White

IAC is located in the throttle body. The fuel is

only sees stuff from the crankcase.

-- entering into the realm of conjecture here -- All I know for sure, is that the IAC stays cleaner longer when sprayed with the engine idling. Since I also use the CFSC (Red Line), thought that may have been a contributing factor also. (By the way, Gave a bottle to a relative with a RAV4 for Christmas, and he commented yesterday he was slightly amazed he could actually feel an immediate improvement) From their site: "The detergents used survive the combustion process and clean the PCV valve and the EGR port as well as cleaning deposits in the combustion chamber." Once again, conjecture on my part: Isn't crankcase pressure vented by the PCV valve generated through "blowby" from the combustion chamber? If so, it seems the fuel cleaner surviving the combustion process is vented through the PCV valve into the throttle body.

Reply to
Daniel M. Dreifus

In news: snipped-for-privacy@mindspring.com, C. E. White being of bellicose mind posted:

Lets define "upstream" as the intake tract from the air filter to the throttle body.

Let's define "downstream" as the intake tract from the throttle body to the intake valves.

EGR introduces exhaust gases and fluffy carbon "downstream." So unless the EGR entrance is immediately underneath the throttle plate, you won't get deposits fouling the throttle body.

The PCV system has TWO connecting points to the intake tract. The downstream point (where the PCV valve is located) will introduce deposits "downstream" well below the throttle plate. The other PCV connecting point is locate "upstream." Now... under some conditions (full throttle and blocked PCV valve), all crankcase vapor will reverse normal flow and enter the intake tract "upstream." If this condition is prevalent, the throttle body and IAC circuit will get fouled by blowby gasses.

Nothing you put in the gasoline will affect the above. Fuel is injected after the throttle body and right before the intake valves. Not allowing engine oil to become excessively contaminated will minimize any deposits on the intake tract walls.

Cleaning a throttle body should NEVER be done on the car with a running engine. Both the aerosol cleaner and the deposits removed can foul the O2 sensor(s). BE sure to use a cleaner that is safe for throttle position sensors. Same thing goes for PCV valves. Remove it from the engine for proper cleaning.

Reply to
Philip®

You're probably right about not cleaning the throttle body with the engine running. There can be a lot of deposits in there, that would go right into the engine, perhaps potentially fouling the intake valves as well. This thread began with the original poster tapping on the throttle body to free up the idle air control valve. The suggestion was to use emission control safe spray carburetor cleaner directly into the air intake at the bottom of the throttle body, in front ("upstream") of the butterfly valve (closed position), with the engine completely cold. Hopefully, with the cold engine, where the oxygen sensor is not yet transmitting signals, and the slight amount of gum or varnish released from the IAC valve, the O2 sensor is still OK. Out of necessity, I've done this procedure twice, and, as mentioned, the idle operates correctly at cold start up for a very much longer time than if the IAC valve is cleaned cold with the engine off. I used to try turning the ignition key on and off, to try to cause the little pintel inside to move, but spraying with the engine stumbling from stuck IAC valve at cold idle until the mechanism frees up has been much more effective - perhaps because the cleaner flows through the IAC valve interior passages. Now, as it happens, I was wondering whether to replace the O2 sensor at 120,000 miles, when I change the timing belt, so I checked it recently with a digital multimeter, and the voltage fluctuations (OX1 at under hood DLC1) seemed normal and good, so apparently I haven't yet destroyed mine. The better procedure is to remove the Idle Air Control valve for cleaning, but that means removing the throttle body, and disconnecting water lines, versus a few seconds spraying cleaner after removing a single clamp at the air hose. Whole process can be completed in a few minutes, and so far, cold start up is still excellent - IAC opens immediately at cold start for high idle (1200 +/- for a few seconds, then progressively lower with engine warming).

Reply to
Daniel M. Dreifus

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