cleaning throttle body

[roverman]

So I finally got around to cleaning the throttle body to fix my fluctuating idle issue. Worked like a charm. Engine went back to idling perfectly. Zero dollar fix, about 20 minutes.

24 hours later, solid engine light comes on - reduced emission performance or something.

What'd I do?

 

[Disco Mike]

No, what was the exact fault code number.

 

[roverman]

No what?
I don't have a fault reader so can't say. The manual says the engine light means reduced emissions performance, that's all I'm going by.
A hard reset extinguished the light, at least temporarily. I just cleaned the throttle body, didn't get near the oxygen sensor or anything else.

 

[RoverGuy7]

The check engine light will come on whenever a condition that is less then optimal for emissions. But that doesn't mean that it has anything to do with emissions...

How did you clean the throttle body? Procedure, not actual cleaning technique.

You probably have a vacuum leak at the intake tube, or a bad connection at the MAFS.

 

[roverman]

I didn't touch the MAF at all.
Removed the boot attached to the throttle body.
Disconnected whatever wiring is hooked up to the body.
Removed PCV valve.
Removed the 4 screws holding it on.
Did not remove the coolant lines (if that's what they are).
Scrubbed with some perclorethylene and a couple other petroleum distillates.
Reinstalled 3 screws, dropped one. grrr.
Found 4th screw resting on skid plate, installed. Gasket was intact and in place.
Reinstalled wiring harness.
Reinstalled PCV valve.
I can recheck the intake tube, or tighten clamps. But I think it's tight.
Maybe the hard reset cleared the code for good, maybe not. I'll report back tomorrow.

Thanks for the help.
RM

 

[whydahdvr]

Just a thought but the last time I had that light come on I asked my dealership mechanic about it. That light can be triggered by the gas cap too. So, if you filled up recently and the cap didn't get set back on there right, or had an air bubble or something that could be triggering the sensor. Check the cap. I also think my mechanic mentioned having to let it drive around for about 100 miles from start-up to reset that indicator.

 

[roverman]

Thanks for the tip. I actually did check the gas cap, even though I hadn't filled up for several days. But the timing with the throttle body cleaning leads me to believe that was the direct cause. That said, after doing the hard reset, I'm still warning light free. I think (hope) I'm in the clear.

It is amazing how much better the thing idles now though, wouldn't have believed it.

 

[Auburn92]

How do you clean the throttle body? My LR3 tach is beginning to fluctuate when I'm driving normally maintaining speed.

 

[tlt]

I paid the dealer some 500.00 to clean the throttle body a couple of years ago. As I drove home, the light came on. So I went and bought a can of sea foam, dumped in in the tank (full) and drove it. Eventually the light went off, it has been off ever since. I try to dump a can in every couple of months.

I recently went to the dealer and had them do a BG clean out of the valves, etc. -- I think that went ok... but the rest of what they did seems to have been a disaster.. more later on that..

It took 20 minutes to clean the oil and crud off my steering wheel...