ibkevin

Suggestions from the Pros here? Looking at leaving timing and just add fuel; FQS #1 is a given or maybe #6.

Should I consider retarding any timing?

ibkevin

.. maybe a bit easier to read..

Just tested O2 again, correctly dithers up past .9v, pull the banjo bolt and zooms .1v and finally goes under.
Pulled the stock air filter - didn't look dirty to me, put I quadruple cleaned the K&N for the test.

Staying with the stock timing and not so sold on the acetone thing.

ibkevin

*UPDATE*

Todays numbers at +6% fuel, stock timing..

HC - 22 out of 86
CO - .02 out of .50
CO2 - 14.7
O2 - .1
NOX - 689 out of 697

Tech was cool, test was in manual mode.. he's on my side.

The 6% smoothed out idle and brought it up about idle 150 rpm and I noticed a new knocking sound.

ibkevin

* UPDATE 1*

Good gawd... that FQS #7 setting is the worst.

25mph -
HC - 201
CO - 1.66
CO2 - 13.3
O2 - 0.5
NOX - 2348

15 mph -
HC - 249
CO - 1.9
CO2 - 13.0
O2 - 0.6
NOX - 1591

ibkevin

I'm going back to my last cat and FQS #4.

Brantley

Very interesting...

I failed again with high NOx and I have been using FQS #7 as well... maybe I'll bump it down to #4 also.

I don't have my numbers right now but will post them up later.

I am going to try 100 Octane gas plus the FQS change for my next test.

ibkevin

#7 killed all my numbers from the start. If you only have bad NOX at #7, #4 should pull you through.

I enjoy posting this stuff for the 951 guys, it gives everyone an idea how to treat this situation. I think I'll dump a couple of $$ on the floor board AFTER my next passing test, the guy has been very kind with his time and I doubt I'll get many more check runs.

2.5" in the top of the pic, 3" in the bottom..

kev951

make sure they are 3 way cats,

Brantley

Failed my 4th Test

Previous work; New O2 Sensor, New Cat, New Cap / Rotor, Spark Plugs / Wires, Oil Change, 42 psi rear tires, FQS #7, stock chips

New for this test; replaced fuel filter, Witchhunter refurb'ed fuel injectors, replaced some vacuum lines.

15 MPH
HC: Max 81, Meas 28
CO: Max .52, Meas .04
NO: Max 689, Meas 1322 - Failed

25 MPH
HC: Max 63, Meas 15
CO: Max .43, Meas .03
NO: Max 730, Meas 877 - Failed

My results are worse than my 3rd try... Though, I think I may have introduced a vacuum leak which may explain the worse numbers for NO so will be triple checking for that again.

So, next steps, triple check for vacuum leaks using soapy water test, take a gamble with a different FQS setting, 100 Octane gas.

QUESTION: I have some hand written notes indicating one of the previous owners had the head rebuilt and ported. Would this contribute to high combustion chamber temps thus causing high NO?

Really a crap-shoot at this point...

ibkevin

^You should be at least passing 25mph, that tells me there is a distinct leak. Do you have a copy of the last test? Ported as in new seats or some kind of flow work? Thats why I ask about an earlier smog test, you have little to work with paper wise.

What was this FQS setting?
Did you test even the new O2 for dithering? Numbers looks like it is doing fine.


ANY leak upstream of the cat will easily jack your numbers, thats why I went to the tape vs. red RTV to seal the cat inlet. If you haven't verified its tightness, check that first. I even did the post cat stopper and pressed up the exh side to check for leaks. It's a bunch of work...

The 951 is a vac plumbing nightmare - have you considered pulling the intake to check hoses condition? Considering the thermal excursions of that turbo engine bay, old rubber takes a beating.

Quick tip - vac sucks, you won't see bubbles.

ibkevin

Loking back at my 2012 results, my notes say FQS #4 but I didn't note if that was the passing setting or just considering it... This would have been with the 3" cat. Diff was 39ppm NOX.

2012 was my smog from Hell, six months to pass and a couple of $$ later..

Brantley

Thanks for the suggestions Kevin.

Yes, would do a pressurized test with soapy water so I can see bubbles / leaks. I ended up doing the test this evening and found a substantial leak at the electrical connector to the ISV as well as a couple of other minor ones. I have a spare ISV so that will probably be going in...

Re: Head - the note says "Ported / Polished 3 angle valve job".

PEvans

Do you think that is more revealing of vacuum leaks than a traditional smoke test?

ibkevin

You bet! I've done an hour or two on these cars.. I was so glad to pull that ISV crap

Verified through Magnaflow, as Kev suggested, this cat is a three gasser.

Sometimes you have to start with the tools you have...

doabarrelroll

Try this:

http://www.arnnworx.com/catalog/inde...age=page&id=23