89magic98

I did my California emissions today - "Test Only" center in Rancho Bernardo (really nice guy BTW, if anyone in San Diego needs to do a test at a "Test Only" facility).

Here are my results:

"Limit" means the max allowed.
"Average" is the average value seen for all cars measured (?)
"Meas" is what was measured on my car.

-------------------
15 MPH (2899RPM)

HC (PPM)
Limit: 121
Avg: 31
Meas: 22

CO (%)
Limit: 0.76
Avg: 0.10
Meas: 0.11

NO (PPM)
Limit: 807
Avg: 237
Meas: 593

-------------------
25 MPH (2899RPM)

HC (PPM)
Limit: 96
Avg: 20
Meas: 17

CO (%)
Limit: 0.65
Avg: 0.09
Meas: 0.14

NO (PPM)
Limit: 746
Avg: 199
Meas: 655

-------------------

I'm pretty satisfied with the results, somewhat worried about the NO number for future emissions tests (2 years from now)

Some facts on the car's condition:

- 49-state model (from FL/GA)
- original catalytic converter
- 4 year old oxygen sensor
- recent plugs / wires / coil / air filter
- original vacuum lines
- original injectors
- intake manifold gaskets changed ~11 years ago
- no other fuel injection / engine management parts changed
- car does stumble a bit when cold at idle
- intake manifold boot changed ~4 years ago
- small idle ajustment made ~4 years ago
- car idles at 950 or so - sometimes it wanders a little

Any comments on the NO result? I read that it is related to combustion chamber temperatures from prior posts, but I don't remember anyone posting some concrete diagnosis techniques or repairs that can be made to improve them.

Thanks for your feedback everyone!

Kevin

SoCal Driver

Here is mine from last month.

83 944 with 86 engine and new O2 sensor, original CAT.

Car is a 48 state delivery -- doesn't have a heated O2 sensor.

I find the difference in rpms to mph intersting. Guess it depends on what gear it's in.


-------------------
15 MPH (1773 RPM)

HC (PPM)
Limit: 138
Avg: 45
Meas: 95

CO (%)
Limit: 0.98
Avg: 0.16
Meas: 0.32

NOx (PPM)
Limit: 1136
Avg: 434
Meas: 523

-------------------
25 MPH (1975 RPM)

HC (PPM)
Limit: 110
Avg: 33
Meas: 75

CO (%)
Limit: 0.98
Avg: 0.14
Meas: 0.29

NOx (PPM)
Limit: 966
Avg: 357
Meas: 471

-------------------

SoCal Driver

Check you rpms. Can't both be the same?

I wonder about the constantly lowered thresholds myself.

How can you get a car to have "better" emmissions than it would as a new car?

89magic98

The RPMs are the same on the printout - so no typo.

On the pretest printout, they were:

15MPH 2898
25MPH 2920

He was in 1st gear for one part, the 2nd gear for the other part.

SoCal Driver

Interesting. Read somewhere that if the rpms are not in a certain range for the mph they have to use another gear.

Think the software adjusts the Max for the mph and rpms.

Flight_951

Your HC and CO are on the low side compared to what I have seen. The higher NOx with these could mean slightly lean. Vacuum leaks could cause this lean condition (with the funky idle). You can check the operation of the air temp sensor in the afm too.

SoCal Driver

He is burning a bit lean. High NOx.

Bryan

Flight_951's got it right.

You've probably got a couple small air leaks in an otherwise tip-top condition engine. You can probably track them down and fix them for about $0.

You might maybe want to consider possibly having your injectors cleaned by a company that does that sort of thing. When all 4 injectors are spraying the exact same amount of fuel with a perfect pattern, your NOx might go down. A cruddy spray pattern might be restricting how much fuel gets injected in one cylinder. Although since your HC and CO are so low, I doubt it. So on reconsideration, I'd just check for air leaks.

Your HC and CO will probably come up a little when your NOx goes down. But you have plenty of room there.

Bryan

89magic98

Tip-top? Wow, you know how to make someone's day.

Well, at least all the oil consumption is because of leaks from the cam tower and the oil pan, as opposed to burning oil One of these days I'll meet SoCal or Legoland and learn that trick for doing the cam tower gasket in a hurry.

I thought of sending the injectors out for a rebuild. I have 4 injectors I got from an 88 944 on ebay that I was going to send for cleaning/balancing, so I could do the swap without any down time at the same time I did the cam tower gasket.

One more hint on the stumbling. It does tend to come and go. The severity of it generally is less (in other words, car can idle perfectly sometimes) when it gets warmed up.

I would like to "kill" the vacuum line issue in one step. Is there anyone who sells a kit which would have everything needed to replace 100% of the hoses and fittings? I suspect that I could buy vacuum hose by the foot somewhere, I would just like to spend a little more and save the hassle, and know that I changed all the hoses.

Thanks everyone!

Kevin

89magic98

Bump.

Flight_951

Lindsey sells a kit to replace the small diameter plastic lines with puricil hose (IIRC) and includes brass t-fittings for about $40. I recently purchased all the OE fittings for my 951 from a mail order dealer for less than $20 with shipping. The hard lines are also available in different lengths and the dealer told me they were $4 per section (he wasn't sure how long each section was though...) My car's hard lines still seem bendable and strong. The original rubber fittings were falling apart.

Bryan

What usually happens is that the hard black plastic vacuum lines get holes worn in them where they contact the metal parts of the engine. I just had a parts place send me a bunch of used line from some random Porsche (they all use the same line) along with a parts order. I think they even threw it in for free. Figure it'll take about another 15 years to wear through again, so I should be OK for a while.

Bryan

Ben Z.

Wierd, all my hard lines were brittle as hell, but the rubber fittings seemed to be in pretty good shape.