This is topic 1998 S2-trim Smog fail - any clues? in forum Tech Talk at Northern California Ford Owners  .


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Posted by Chris Tann (Member # 1444) on :
 
Hi all,

I have a 1998 S-281, with Vortec S2 supercharger installed about 2 1/2 years ago. It also has an aftercooler, basani, bigger Throttle Body, and a few other mods added by the previous owner. Dyno tune put her at 330HP at the wheels. It passed the last smog, but that was a non-rolling smog. I had to take it to a test-only station this time (in Milpitas), and she failed pretty dismally.

Here are the numbers:
code:
                              HC (PPM)        CO (%)       NO(PPM)
       RPM   %CO2  %O2      Max   Meas    Max    Meas    Max   Meas
15mph  1565  13.4  1.6      52    147     0.49   0.63    424   1178
25mph  2444  13.6  1.0      36     89     0.46   0.93    711   1191
The Engine was warm, but I had only driven a few miles - I know that can make a difference. Also, the tech marked it as "single exhaust", not sure if that has any effect. She is also due for a service. The tech said he thought she was running lean....

So, I'm scouting for suggestions. Am I going to have to get her re dyno-tuned to get her in line with smog? Do you think any of these "wonder" smog-passing products and a good long drive beforehand might work?

Thanks,
Chris.

[ February 09, 2005, 12:23 PM: Message edited by: Chris Tann ]
 
Posted by Chris Tann (Member # 1444) on :
 
Oh, another comment - this was the second smog-check station I took the car too - the first one couldn't get his machine to talk to the car's computer...
 
Posted by HungryHippo (Member # 537) on :
 
its hard to say if you're running rich or lean since you failed everything. bassani cats are known to go bad, so it could be the cats. also try a tune up with new plugs, o2 sensors, clean the egr, and make sure the tube for the cats is hooked up. who knows though, maybe you could have passed my letting the car warm up more
 
Posted by 94gt (Member # 3060) on :
 
i have a buddy that insists on driving to the smog shop in 2nd gear, he wont check in until the cats are almost red hot
 
Posted by 94Blackout (Member # 2541) on :
 
You should check the cats. Go to Michaels Mufflers off of Capitol Expressway. He'll check your cats to see if they are good or not for free, and is a real nice guy who runs the joint. I just had them checked on my Bassani X and they were completely shot.

With how you are failing, that wonder-smog stuff won't work. You also want to run it much hotter next time.
 
Posted by stangin' (Member # 514) on :
 
i suggest putting back your stock h-pipe back on and go do a test.
 
Posted by 92stangLX (Member # 3252) on :
 
Give it a good tune up and change the oil. Making sure it is above operating temp also helps.

I would contact the person who tuned your car and see if they did anything that would cause you not to pass smog (like turn off any smog equipment).

Also check the EGR to make sure it works.

After doing all of this you may want to get it re-tested and see how it does. If it still fails then move on to the more expensive stuff (ie new cats).
 
Posted by Jimbo (Member # 1456) on :
 
You didnt specify but I assume that dyno tune came with a chip? If so thats where I'd start make sure they didnt disable EGR function(that could cause the high NOx reading), any change in fuel/timing obviosly could effect your smog numbers. If it will run decent without the chip take it out when you smog it. It also looks like the cats might not be working (lot of 02 and CO leftover)or might not have lit off yet either, you can get a mechanic to check em for you before you go replacing them though. I would also recommend throwing a stock 4 cat H-pipe back on and see how it does(he should have failed you for non OBDII cats anyway but thats cool guess he didnt know)

[ February 10, 2005, 04:10 PM: Message edited by: Jimbo ]
 
Posted by Chris Tann (Member # 1444) on :
 
Hi,

The car did pass smog last time (at a referee),
and I haven't changed a thing since then, so
I assume that the chip/programming is not
too bad. But then again, they didn't have
rolling tests back then either...

Anyway, I'm waiting for the reply from CAP - they
should pay up to $500 for repairs, so I may get
a free CAT replacement out of it...

Chris.
 
Posted by vpr_klr (Member # 3353) on :
 
EGR. Older 4.6's have problems with not enough vacuum to the egr or too much. I mean. look at your NOx emissions. Cats aren't going to do a damn thing for that.
 
Posted by Jimbo (Member # 1456) on :
 
quote:
Originally posted by Chris Tann:
Hi,

The car did pass smog last time (at a referee),
and I haven't changed a thing since then, so
I assume that the chip/programming is not
too bad. But then again, they didn't have
rolling tests back then either...

Anyway, I'm waiting for the reply from CAP - they
should pay up to $500 for repairs, so I may get
a free CAT replacement out of it...

Chris.
The loaded dyno test is completely different than the old idle-2500rpm test. The EGR valve plays a big role in controlling NOx, NOx isnt even tested for on the old test and the EGR valve usually inst tested right on the old test.

CAP usually doesnt pay to fix your modified parts but good luck anyway.
 
Posted by andyman_2k01 (Member # 1448) on :
 
go to kragen and get that "guaranteed to pass" shit. follow the directions exactly and they almost guarantee any car to pass. i did it for the hell of it and i was at like .01 on everything. crazy
 
Posted by T-TopTerror (Member # 480) on :
 
High levels of Hydro Carbons (HC) is a "rich condition". Dark smoke coming out under excelleration? There are two things that can cause it to read the way it is and I am assuming that both are a benefactor. First off O2 sensors default to rich, replace them. 2nd either wait until those cats are red hot or replace them. The other guys are on the right track about your EGR though. But if you still have problems, I have a test only guy in Fairfield that won't fail your car. If it doesn't pass right away, he'll wait a little bit then try again so it won't get sent to the DMV with a fail.

Start with the 02's
 
Posted by jaybquick (Member # 4286) on :
 
Cats, FYI, some of this advice is way off too. Just my .02.
 
Posted by Maxoctane (Member # 1466) on :
 
I'd check egr valve 1st, stick your finger under the valve and rev the engine a bit, you should feel the diaphragm (sp?) move, also, if you have a FMU that could create an over rich condition, just my past experience. good luck!
 
Posted by Maxoctane (Member # 1466) on :
 
also if the tech guy is cool, you could pull the chip and bypass the blower just to see if it will pass like that. when you're done just hook it back up for another 2 years! [patriot]
 
Posted by 1988notchback (Member # 4498) on :
 
for my little experience what you want to look at is co2 if that is above 13% your car is running good and so I would just say your cats are bad. If you have a pyrometer you can test your own cat run your car at operating temp and get under with pyrometer and measure temp before cat and after it should be about 7 degrees hotter after cat
 




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