Throttle bodies interchangeable?

This is one of thoes, "if you gotta ask" questions.

When it stutters enough to throw a Check Engine light, then change something.

Techincally, it's one of THOSE ...

No CEL thrown. I've heard this stuttering is due to a bad IAC valve. I cleaned it, and the problem persists.

No CEL thrown. I've heard this stuttering is due to a bad IAC valve. I cleaned it, and the problem persists.

So? Wait until it throws a code, else you are chasing your tail. If you chcked and cleaned it, then the problem isn't what you want it to be. Wait, Grasshopper. Be patient.

Clean the entire throttle body with carb cleaner. Open the throttle plate and get rid of all the carbon. Keep the cleaner out of electronic sensors, plastic parts, and connectors. You might have to loosen the throttle body to get behind the throttle plate. Sometimes the throttle plate is dirty so that it leaks so much air, the IAC value is not really in control, so clean everything well.

Vito

No CEL thrown. I've heard this stuttering is due to a bad IAC valve. I cleaned it, and the problem persists.

The 1996 V6 was the 3VZ-FE engine, while the 1999 V6 was the 1MZ-FE so with different engine series, the throttle body almost definitely will not fit.

The 1996 and 1999 I4 engines were both 5S-FE engine but the 1999 produced slightly more horsepower and the body style was different so they are not likely to be interchangeable.

Some additional information would be helpful in diagnosing the condition, and fixing the condition is probably easier than swapping the throttle bodies.

What do you mean when you say that the engine "shudders a bit" when starting the engine while it is warm?

Is it difficult to start when warm?

Does it idle roughly when warm but not when cold?

Does the condition persist the whole time the engine is warmed up or only after it is first started?

When you cleaned the throttle body, did you check to see if the IAC valve moved freely when you were done? Was the inside of the throttle body oily or did it have a varnish-like coating?

Did you clean the edges and inside of the throttle plate?

What is the condition of the engine air filter?

Check the black plastic tube between the air filter housing and throttle body for holes, cracks, gaps, etc.

Yes that's exactly it. Engine gets about 100 RPM when starting while warm (never when cold). Sometimes stepping on the gas cures it; more often lately it stalls and my wife has to re-start the car. Then it's fine.

I cleaned by spraying throttle body cleaner and then with motorcycle chain teflon into the little rectangle in front of the throttle plate after removing the air intake hose.

This isn't an IAC problem? I thought the '99 was famous for faulty IACs, and this is one of the symptoms.

I'll clean the throttle body/plate when I get a spare moment

Michael

In message , Michael writes

If it's a carburettor car then it's possible for the choke to be slightly closed on starting a warm engine and this could cause mis-firing.

Carburetted Camry? Not even back in 1984, unless you're talking about one of the numerous Camry street rods. ;)

Both of my vehicles are giving me fits with rough and harsh running, but does not give me a check engine light. They both need fixing as soon as I can get some funds available. The check engine light finally came on for an out of spec MAF sensor after months of no power, severe hesitation (having to wait for a very big gap in traffic to trust merging without an accident), and backfiring. I tried a full tune-up and it did very little for the situation. I suspect the used MAF is also out of spec, but not enough to trigger a check engine light and I don't have the funds to put it on a machine to test it.

Yes that's exactly it. Engine gets about 100 RPM when starting while warm (never when cold). Sometimes stepping on the gas cures it; more often lately it stalls and my wife has to re-start the car. Then it's fine.

I cleaned by spraying throttle body cleaner and then with motorcycle chain teflon into the little rectangle in front of the throttle plate after removing the air intake hose.

This isn't an IAC problem? I thought the '99 was famous for faulty IACs, and this is one of the symptoms.

I'll clean the throttle body/plate when I get a spare moment

Michael

**************** The answers to all of my questions above would help determine whether or not the problem is caused by a sticking idle air control "IAC" valve. There are other things that can cause the symptoms you are describing, which is why I asked all of those questions. Depending on the answers to those questions, I may have some more.

How many miles are on the spark plugs, and what kind of spark plugs are installed, i.e., what brand?

Never apply any kind of lubricant inside the throttle body as it can damage seals and ruin the O2 sensor and gum up the IAC valve and throttle plate. It would be a good idea to use more carb cleaner to clean off the areas where you sprayed the motorcycle chain lubricant ASAP. It is possible that the lubricant re-gummed the IAC valve. When you clean the throttle plate, wipe the edges of the plate as it can stick to the interior bore of the throttle body, and also clean where the hinge rod enters the throttle body.

The IAC valve is technically not serviceable but it usually doesn't hurt to try cleaning it.

While you are at it, it wouldn't hurt to clean the MAF sensor with brake cleaner (do not use carburetor cleaner or anything else on the MAF sensor) by spraying the brake cleaner into the opening, letting the stuff drip out, and letting it air dry.

It is a good idea to always check a part's operation before replacing it to avoid unnecessary parts replacement.

Get some brake cleaner or electronics cleaner and spray a little in the opening for the MAF sensor, let the liquid drip out, let the part air dry, and re-install.

Use carburetor cleaner to clean the inside of the throttle body, throttle plate, and IAC valve.

Bosch spark plugs installed 30k miles ago.

I took a look at the Haynes and it appears that the IAC valve resistance deviates significantly in the '99 vs. the '96. Also it appears that three bolts hold the throttle body in the '99 vs. 4 bolts in the '96. So it appears I cannot simply swap the throttle bodies.

Michael

Bosch spark plugs installed 30k miles ago.

I took a look at the Haynes and it appears that the IAC valve resistance deviates significantly in the '99 vs. the '96. Also it appears that three bolts hold the throttle body in the '99 vs. 4 bolts in the '96. So it appears I cannot simply swap the throttle bodies.

Michael

******* While Bosch makes good products, I've run across driveability problems with Bosch ignition products installed in Toyotas. I would give some thought to installing Denso or NGK spark plugs.

In the meantime, use carb cleaner to remove all traces of the motorcycle chain lube

Already did that. It was bad and changing it out overcame the check engine light and most of the engine problems. The point is that if you have the funds to have it put on diagnostics that is better than waiting almost a year of extremely poor running before the check engine light came on to indicate the problem.

Yup, I agree that having the funds to diagnose a problem correctly immediately is better than waiting a long time and putting up with a vehicle that is running poorly.

Higher end OBD II scanners will provide real time data from each sensor. Having a trouble code point to a particular sensor does not necessarily mean that the sensor is bad. Just about every part can also be checked with a multi-meter, so with a detailed list of symptoms, a factory repair manual, and a decent multi-meter ($50+), it is possible to check stuff out before a check engine light is illuminated, and after the check engine light is illuminated, to see what the part is actually doing. Of course, depending on which part needs replacement, a free diagnosis is not as beneficial as a free part.

The part that has me confused is that in your original post, you said, "shudders a bit ..." This means a minor annoyance that you would prefer to not deal with, but not a big problem that makes you change your life. Now you tell us the problem has been going on for a long time and has driven you to the edge of buying a high-powered rifle and sitting in a church steeple outside of the Toyota Plant.

You started with, "shudders a bit," and now have been waiting the better part of a year with a piece of crap that makes you want to ride the bus. I don't get it.

...

Oh I see. You're confusing me with Michael Dobony.

I never had any intention of buying a high powered rifle and camping near any Toyota Plant. Ha ha ha.

Michael Darrett (not Michael Dobony)

..

Ok, will do. Thanks!

Michael Darrett