sunbitz

Hi,
Car is failing yet again.

Here are the results....
HC at 15mph is 114 allowable is 110 FAIL
At 25mph is 84 allowable is 85 PASS

CO at 15 is 0.04 allowable is 0.71 PASS
At 25mph is 0.02 allowable is 0.59 PASS

NO at 15mph is 326 allowable is 772 PASS
At 25mph is 219 allowable is 711 PASS

The guy at the smog shop told me my timing might be off, or I have a bad cat.
He told me I could advance the timing a few degrees and maybe that will be enough to get me to pass.

I do have a timing gun which will allow me to advance the timing. Question is... how much can I advance it and still be able to pass the sniffer?

Second question is....
I have a 140 degree stat in the car right now and with all the cold temps up here in Lancaster... the car doesn't reach the first mark on the guage. I'm wondering if it's not going into closed loop?
I bought a 195 degree stat today and will install it if it will get me to pass.

Any help will be greatly appreciated.
Thanks.

It's a stock 305, all emmisions stuff was replaced new 2 years ago including the cat and since that time... the car has only been driven maybe 8 months out of the past 24 months.

Guest

I am not totally sure about the timing. Timing is probably not the case, but wait for someone more experience chime in Like Kevin or Don. Check your timing and let us know where it is o.k.

Your cats seem like there doing a real good job because those numbers are really low.

This should be an easy thing to resolve because you almost passed.

sunbitz

Timing is around 4 to 5 degrees advanced at approx 600 to 650RPM with the engine temp about 120 to 150max degrees.
I'm thinking the car is in open loop at this time.

Side note...
Anyone got any good tips on how to get at the distributor bolt?
I'm sure the car is too advanced at this point and I can't turn the Distrib no matter how hard I try.

leo037

You need a distributor bolt tool. Kind of an odd looking, Sears has them.

Kevin91Z

iTrader: (1)

Zero degrees is the factory setting for a TBI engine. The state allows you a tolerance of plus or minus 3 degrees, so 3 degrees advanced is the most you can go and still pass the test.

I have never heard of a 140 degree thermostat. 160 is the lowest I have seen. Since you are so close on passing, I would say you need to get the car hotter before you test. Drive the car around a bit more, or just leave it in park and rev it up to 3000 rpms for a minute right before you do the test.

Guest

So is he better off with the timing where it's at now? or should he set it at factory specs?

Kevin91Z

iTrader: (1)

He has to change the timing down a couple degrees. The smog guy should reject it at 4 or 5 degrees as being too high.

sunbitz

Passed!!!! Big

The only thing I did was toss in a 195 degree T-stat, biught a new air filter, pcv valve and blow by filter.

Now get this.....
Drove the car around to get it hot enough for the stat to open and then went to the smog station.
Asked for a pre-test.
Here are the numbers of the pretest.
HC was 110 @ 15mph
83 @ 25mph

CO was 0.03 @ 15mph
0.03 @ 25mph

NO was 528 @ 15mph
446 @ 25mph

So it passed on the pre-test and went ahead for the real test.
A new guy hopped in the car and ran the test.
He screwed up when going to 25mph and we had to run it again.

Here are the results of the second test with a different guy behind the wheel.

HC was 69 @15mph
59 @ 25mph

CO was 0.06 @15mph
0.01 @ 25mph

NO was 278 @ 15mph
293 @ 25mph.

WTF??

The only difference between the two drivers was... one was running at 15.5 and 24.7mph and the second one was running at 15.2 and 24.1mph.

Can it make that much of a difference on a smog check??

So all in all Kevin is correct in many ways...
I don't have a 140 t-stat. It's a 160 with holes drilled in it.
My temp just stays in that range of 140 to 150.

As for the timing... I think I was reading the wrong mark.
At the smog station It idled from 575 to 600 rmp. So I'must have been in the correct range.

I'm just glad I passed.
Now time to go put all my non-stock parts back on.

Thanks for all the input.
Sorry about the misinformation I posted.
I only work on my car when it breaks.
Thankfully it doesn't break that much. (knock on wood)

sunbitz

Edit.. link did not work.

Guest

Glad to hear that you passed. I figured you be able to do it.

injdinjn

Ambient air temp/pressure, vehicle running temp and how it was driven prior to the test and how long it idled before the test, how long it sat turned off while the tech inspected the smog equip and how long he let it run before starting the actual test will effect the outcome of your test.
Helen Keller was better at darts than anyone can predict the outcome of a smog test.

BretD 88GTA

Same comment I got from the tech when my car failed the 25mph NO number. EGR was also suggested.

Ran the car around the block at higher RPM and then re-ran the test shifting the trans manually. The car passed the NO number.

Russ-So Cal

You need a higher temp t'stat for the benefit of your engine. I would try 180 degree instead of 195. Running the engine at temps below 150 degrees is not as bad as overheating, but it isn't getting hot enough to remove water vapor. Keep running it like that and expect to create a bunch of internal engine problems.