BPT cleaning - was New Owner of a 92 SE-R

[Tim Rogers]

Peter Serwe <peter@easytree.net> wrote:
> I'm having those stupid EGR problems.  (Low rpm stalling, etc) The BPT
> passage (is that what it's called?) - the approx 3/4" tube that runs
> from the exhaust manifold to the intake manifold,

That's the EGR tube, FWIW

> and has the approx 9" multi-bent tube that feeds the BPT valve,

_That's_ the BPT tube.

> I've tried de-carbonizer, throttlebody/intake cleaner, waiting for 10-60
> minutes, and reaming it out with the biggest wire I can snake through
> there ... nothing frees the passage.  The BPT is probably dead, the EGR
> valve may be dead, but like the BPT, I'm not getting any exhaust
> pressure to make the BPT valve give vacuum to the EGR (this is what
> triggers the EGR valve, right? :P) I don't have any exhaust pressure to
> speak of, so I can't really tell.

Yep, its blocked if you can't feel any exhaust pulses out of the BPT tube
while the engine is running.  The clog usually happens right where the BPT
tube meets the EGR, since the orifice there is literally of pinhole size. You
can see it by removing the bolt at the top of the junction.  I think if you
have CA emissions, there is an EGR temperature sensor in place of the bolt.
I tried drilling the orifice out (had to take the EGR tube off the car, which
was a major PITA) and it did free the hole, but it caused the hose to collapse
due to the extra heat.
The tubes are pretty sturdy, but I would not risk bending the BPT tube around
and cracking it.  OTOH, you can stick just about anything in the tube without
fear of harming it, and if it frees the clog, TELL US!
You can also work at it through the bolt hole that is above the junction.  I
would like to use a set of dental picks, but I don't want to bend the ones I
have.....

Tim Rogers
-'93 NX2000 T-top
-'91 NX2000 SCCA ITS racer-to-be (won't need EGR...)
-'75 Silverado tow vehicle