finally!

ARRGGGH! Failed emissions again...



HELP!!!
Here are the readings and background..

Within last 2,000 miles or so:
- New spark plugs
- New distributor caps
- New Oxygen sensor
- New Water temp sensor
- New oil and filter (today)
- Filled up 1/2 tank of fuel and a bottle of Guaranteed to Pass

Drove for around 30 minutes to get good and warmed up. Have had ZERO issues in driveablity, in fact is running GREAT!

Do have high-flow cats which I bought around 1.5 years ago from Roger, X-Pipe

Here are the readings

HIGH SPEED EMISSIONS RESULTS (25 MPH)

HC (ppm)
Standard: 148
Reading: 128 (PASS)

CO (%)
Standard: 0.94
Reading: 0.53 (PASS)

Nox (ppm)
Standard: 1047
Reading: 140 (PASS)

Dilution
Standard: >6.0
Reading: 9.33 (PASS)

LOW SPEED EMISSIONS RESULTS (15 MPH)

HC (ppm)
Standard: 152
Reading: 190 (FAIL)

CO (%)
Standard: 0.86
Reading: 1.05 (FAIL)

Nox (ppm)
Standard: 1146
Reading: 298 (PASS)

Dilution
Standard: >6.0
Reading: 9.45 (PASS)

Tom in Austin

Air pump connected?

76FJ55

Appears rich in the low speed test. Is the idle switch opening as it should? If it is staying closed at partial throttle it could be leaving you on the idle map during the test. How about FPR and FPdampers? If you have a diaphragm going bad the extra fuel could be causing the rich mixture at low rpm but could be diluted by the additional air at the higher rpm.

finally!

No air pump (Sean removed when he did tb wp last year)

How do I test the FPR and FP damper and idle switch?

finally!

Also, I have a fuel pressure gauge on the passenger side rail, what should it be reading? At idle, engined warmed up, it is displaying around 38, needle bounces a bit +/- 1-2 from the 38 hash mark. Should the needle hold rock steady?

xschop

Acetone 4 0z. per 10 gal. petro with NO ETHANOL. never fails.

WallyP

First thing to check is the Temp II sensor. Two independent sensors (ignition and injection) in one housing on the top front of the engine. Check resistance from each pin to engine ground - never pin-to-pin.

59 - 86 deg F S/B 1.4 to 3.6 kOhms
104 deg F S/B 0.9 to 1.3 kOhms
140 deg F S/B 480 to 720 Ohms
176 deg F S/B 250 to 390 Ohms

Next thing to check - pull the small vacuum line from each of the fuel pressure dampeners and the fuel pressure regulator and check for any trace of fuel in the vacuum lines. Any leaking unit must be replaced.

victor25

I would guess that your just running too fat in the lower rpms caused by the x-pipe and high flow cats breathing better. The computer probably just cant adjust enough to compensate. Do you have your stock cats around? Maybe you could throw them on and retake the test, otherwise adjusting the fuel could get a little complicated without a shark tuner.

SeanR

That's exactly what is happening and I"m sure if we ST'd it things would be fine. I'm having Kenny bring it up to the inspection station we use and I don't foresee a problem.

Lizard928

Too rich and it's not getting burnt.
Check can timing too. That said, your cats appear to not be working well

Speedtoys

Ya..you gots problems in cat land I think.

Here are my results from about 2mo ago, big intake, big exhaust, X pipe...generic non-airpump cats about 4yrs old.

terry gt

try incressing the idle speed a couple hundred rpm , by tighting the throtle cable .

Speedtoys

The computer might catch that as "Dave..this isnt Idle...Dave...."

terry gt

here is my emisions report . stock idle . colins stage 2 cams / headers / X / twin 200 cats / 2.5 " exhaust /no air pump 353 RWHP

finally!

Barring something indicating a fuel issue, which I doubt as the car is running EXCELLENT, no stumbles, starts up first try instantly, settles to idle uber fast, etc. I agree it is most likely the cats.

They are hi-flow ones I got from Roger about a year and a half ago. Worked fine last year at inspection time..