So..I have a quick question and asking for help to figure out how my measurements are so much different from 15MPH to 25MPH on my California Emissions Test...

I have a 93 Del Sol Si, D16Z6 that is completely Stock..

Here are ratings in numbers if you can not see the attached image..

I measured 83 compared to 36, .21 to .08, and 716 to 158 on the 15 to 25 MPH range...these numbers are about 3x across the board.
15MPH(1860RPM) 14.7 0.2 92 23 83 .55 .08 .21 716 194 716

25MPH(2029RPM) 14.9 0.1 57 14 36 .54 .06 .08 764 166 158


I tried to bold, and italicize the numbers that "matter".

Where should I start?

 

Have you checked the ignition timing with a timing gun?

 

The ignition timing was told to be 16 by one technician, and 19 by another. Both between spec.

 

Did they do the test correctly? See diagram in FAQs sticky.

 

They are smog technicians, I would assume they tested it correctly.

The car runs excellent, just really bizarred by the difference in numbers.

 

Also, I recently just replaced the distributor, and the timing was set correctly 16 BTDC.

 

Set by whom?

 

"A professional".

 

Given the problem, why assume?

 

Not assuming, the timing is set correctly at 16 BTDC, I am sure.

 

Some pros don't get it right.

You can either check things out yourself or pay the pros more money.
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Also, how old are plugs and plug wires?

Are you using properly gapped NGK plugs?

Any CEL codes?

 

From what you said previously, this is what you assume not know as you have no direct knowledge that the timing is set to spec.

 

I am just saying, I'm positive the timing is set correctly.

Not sure the age of the plugs/wires, planning to replace plugs/wires soon, and no CEL.

I passed the test, but barely. Really curious in the differences in the measured numbers from 15MPH to 25MPH.

 

The plugs look good, but I am going to replace with new wires too soon, as I stated above.

 

As I have said, start here:

Hook up a timing gun and actually check the timing yourself. Follow the service manual instructions to the tee.

Install basic, properly gapped NGK plugs and replace the old plug wires with OEM.

Check for CEL codes.

Did you install an aftermarket distributor?

 

Well, with no timing gun in my possession, I am still 99.9% sure my timing is set correctly, because it was checked/adjusted/set when the distributor was replaced.

NGK plugs and wires will be replaced soon.

Nope, an OEM distributor. No CEL codes.

 

Let us know how it turns out.

Does the CEL work?

 

Yes, it works.

 

Okeedokee

 

So your only answer is plugs/wires/ignition timing?

 

Getting new post till number 5/1

 

That's where to start. Not enough for you?

 

I definitely appreciate the suggestions sir, and will be taking care of all three tomorrow, not like I'm going to be able to run another test..

Like I stated before, not that big of a deal because obviously I didn't fail, so I am able to go on with the transfer of ownership.

Just really bizarre on the differences in numbers between the two ranges..

 

For problems like yours, ignition system problems always must be ruled out first.

 

Will do, might also replace the cap/rotor while I'm doing all other components.