The TSB for routine cleaning of the Part Load Breather (600-03) states that the Throttle Body which carries the label "JJM ** 30 99" should not be cleaned as damage will result.




As you can see, I have that label on my '98 XJ8L Throttle Body. The butterfly plate looks a little dirty. However, TSB 310-06, which describes how to clean the throttle body has no such warning.

Is it simply the case that they are warning you to be careful of the MolyKote layer around the rim of the butterfly - which TSB 310-06 states that the cleaning agent must be silicon free.

OR am I missing something more fundamental?

 

It's a very high precision part with special coatings. Clean gently with care at your own risk. Some think they need cleaning, others disagree. Your car, your call.

I _guess_ warnings are to stop ham-fisted harsh attempts. And to prevent warranty claims. Note: _guess_.

 

Is there a particular reason you want/need to clean it? Cleaners have changed since the production of these cars. The old "brake cleaner" users were the ones whom these warnings were directed at.
The area specific cleaners available today are less harsh (and don't remove the coatings) and will do the job. Be sure to read the labels and ask an indy if you have one nearby. Heck, I've found my dealer to be fairly informative.

 

+1 Buy throttle body cleaner and clean it and the throttle plate; from the photo, it clearly needs to be cleaned -- be gentle, be patient.

 

I have cleaned my throttle plate with no ill effects whatsoever. And I was "less than gentle" with it, using cleaner and a flathead screwdriver to scrape the crud off (I do not recommend or condone that, btw).

 

I appreciate the comments -

I have a loss of power, so typically that's an air restriction. I cleaned out the part load breather and got most of it back, but she's not quite as "lively" as she was, so going through the list of diagnostics in another thread, the throttle body is another easy target. It looks dirty to me, and I figure i'll give it a go - just waiting on a new gasket being delivered and I'll get her done.

 

When I took off my throttle body the butterfly valve looked like yours as did the upper body itself. However on the other side below the valve it was a heck of a lot worse.

I used carb cleaner to clean mine with no ill effects.

Also my MAP sensor was pretty dirty.

 

I'd guess this has to do with the air flow sensors permanently mounted into the throttle body, if they get damaged the whole throttle body needs replacement (unless someone knows a way to swap the sensors out.)

 

It's same advice for S-Type TB and no such sensors are mounted there. (I think they're not for this forum's cars, too.)

 

Well, after getting a hold of a gasket, I took the throttle body off, gave it a good clean using CRC Throttle Body Cleaner. The underside was fairly clean.

However, after re-assembly i'm still not a whole lot better off. I'm leaning back towards the MAF Sensor. Got a OBD Reader (ELM327 WiFi) and an iPhone app that can access the MAF output (OBD Fusion). I can now see the air flow is over-reported.

I've had the MAF unit out, since it's a '98, the hotwire and temperature sensor don't just pull out for cleaning like I've seen on a few posts.

Is there any way to expose the hot wire? I'm not convinced spraying the MAF Cleaner into the hole in the center of the unit, where the hot wire lives is effective.




The Hot Wire is below the cross in the center




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