Throttle Body Cleaning and EGR Port

[Garry]

I took my throttle body off and gave it a spruce up yesterday. I got rid of my bodgy silastic repair on the throttle plate seal and used paint as the seal like the guys at Flying Miata suggested. It seems to be working fine so far.

I also removed the air bypass screw and cleaned the passage. It was fairly gunked up as expected. I took the opportunity to modify the adjusting screw so I can now extract it quite easily for regular maintenance.

I removed the idle speed controller and gave that a good clean out. It was nicely gunked up. But the biggest surprise was the EGR port. It was totally blocked up with carbon. The guys on Miatanet are always going on about this, now I know why.

I took it for a drive afterwards and it is so much smoother coming on and off the throttle now.

If you have a couple of hours to spare and feel like doing some bonding with your car I highly recommend it, just be careful not to disolve the throttle plate seal with your cleaner.

[Uncle Arthur]

Garry - got the time to post a 'how to'?

[Garry]

I didn't take any pics UA and the NA6/NA8/NB's are all a little bit different. For example NA's dont have an EGR system to worry about. But the job is pretty straight forward. On an NB 2 nuts, 2 bolts, 2 water pipes, the air inlet, 2 electrical plugs and throttle cable are all you need to remove to get the throttle body out. The ISC is held on by 2 Phillips head screws.

The mod I did on the air bypass screw was to drill a 3mm hole in the end (along it's axis) about 5 mm deep so that I could stick something in it to extract it when needed. I used a 3mm allen key as the extraction tool. Works great.

To use paint as the throttle plate seal I closed the throttle then used some Mazda touchup paint (because it comes with it's own little brush) to paint around the throttle plate and body on each side that seals against the throttle body. So that the trottle moves away from the painted surface as it opens. If that makes sense. As the paint dried I opened the throttle occassionally so that it wouldn't stick shut and to make sure it still went back to the stop correctly when it was shut.

Hope that helps.