Michael56

iTrader: (1)

My '92 SC300 5-spd failed on NOX numbers (3X the maximum allowed). The HC and CO were low, so I'm suspecting the modulator.

WTB--Anyone have one laying around for cheap? -- I want to try it before digging deeper.

I live in the Concord/Pleasant Hill area (East Bay-NorCal). After the test failing I dumped a bottle of that CRC product in the tank that says it will help you pass, and was thinking about pouring a gallon of Acetone in the tank before my free re-rest (read about that here on the forum). Is that move considered by you guys an effective one to get this through?

The car has 196K on it now, but I rebuilt the engine from the Crankshaft- up-- about 15K miles ago. The last smog test right after that rebuild was super clean.

I had bought, and rebuilt a used JDM engine, and remember the cross drilling from the #6 cylinder exhaust port-to the rear face of the cylinder head was of a much smaller diameter than the original cylinder head (of course-the JDM engine had a EGR blanking plate there). I had just transferred over the EGR plate from my old US spec engine, and not thought much about it. But-- it did throw the CEL light at anything over 4000 rpm, right after the rebuild. I jumped the test port connectors to get the flash code, which was a EGR fault. But-- the engine had always run great, and I just took off the negative battery terminal for a re-set, and drove it to the test station under 4000 rpm and it passed 2 years ago with great numbers.

I assumed that would be the case today-- but....no dice.

Any advice is welcome.

Thanks,
Mike

Michael56

iTrader: (1)

I'm looking for opinions here. Today I used a pistol-style vacuum pump -- attached to the EGR dashpot with the engine idling. When I pulled even a little vacuum with the pump the engine started stumbling. As I released the vacuum and watched the gage -- when it returned to zero the idle returned to a very smooth condition.

So-- I'm thinking it is the EGR VM with the three hoses running to it.

Any opinions one way or another?

I'm hoping there are not electrical components (as I see the EGR valve has a two-wire lead going to it) that are the real cause for why it's not opening as designed.

Michael56

iTrader: (1)

Well -- a very helpful Club member sold me a good EGR Vacuum Module, as mine failed a test with my vacuum pump. I dumped in a bottle of CRC- guaranteed to pass- product, and drove about a half tank of fuel thru it.

Before this--the first failed test had me at 3600/3300 on Nox, against a max allowed of approx. 700. (A flagged "Gross Polluter" in CA) --I should have remembered that number, though.

So I took it back for the free re-test today even though I hadn't burned thru all the fuel with the treatment in it and then re-filled with premium as recommended.

This time--I barely failed on the low (15mph on the dyno) Nox at 654 -- even though it was a huge reduction from the previous number. Hc and CO were all well below the max allowed.

So-- I'm thinking that I just should have waited and followed thru with the CRC deal..... until I started thinking about the 2nd test value -- and pulled out the paperwork for a side-by-side look.

That's when I saw that he had entered my car as a auto trans model (with lower max numbers allowed) instead of a 5-spd. It would have passed!

So one more trip, I explained his error and he re-ran it. And -- it passed!

Lesson learned? -- read the fine print before leaving the Counter.

I'm confident that the Nox values will continue to drop now, and that the Cat's are still fairly healthy.