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Failed Cali Smog Evap

David_Bricker

PSR Fire Marshall
NAXJA Member
I'm sure it's been discussed before, but Gomer just failed CA smog evap inspection. Don't know what failed; shop couldn't/wouldn't say. I've got only a couple of days to fix before I head home, so may end up taking to a shop tomorrow. The emissions part passed so clean I'm not sure the engine was even running.

Any quick ideas of things to check before forking over big bucks to a shop.

David Bricker / SYR - PSR
 
They're required to tell you what failed. If their machine failed you, it will say. If the tech failed you and won't tell you he's got his head up his backside.

If the emissions passed then the rest is a visual inspection. So the smog tech failed it.

Go back to the shop.
 
They're required to tell you what failed. If their machine failed you, it will say. If the tech failed you and won't tell you he's got his head up his backside.

If the emissions passed then the rest is a visual inspection. So the smog tech failed it.

Go back to the shop.

It failed for the evap part of the test.

Gas cap, cracked vacuum lines are common causes.
 
Good to hear that stroker runs so clean.

You might have to drop the tank to check the vent lines and the grommets, but I would start with all the relatively accessible bits: Gas cap, fuel fill and vent hoses between the tank and the filler, the vent lines coming from the tank, the "T" connection at the tank, and then follow that hard line forward.

If heading for a shop I would want to make sure their smoke machine is up and running. That is probably the quickest way to diagnose this situation.
 
If heading for a shop I would want to make sure their smoke machine is up and running. That is probably the quickest way to diagnose this situation.

A smoke machine is the fastest way to find a emission leak.

Two years ago, my 01 wouldn't clear the emission's systems diagnostic self check.
Not owning a smoke machine, I used a air-brush pressure regulator to pressurize the emission system port to 2-3psi and then listened for the leak, using soapy water to pinpoint the exact spot.
There was a crack in a rubber coupling, on the large tube going to the carbon canister, that was barely visible, once found.
 
For future reference. 2-3 psi is probably a touch too high. All the smoke machines I've ever used stay below 1 psi. Other than that, good advice!
 
Sorry for the delayed response. We dropped the tank, as the shop said the problem was somewhere on top of the tank. They wanted more $$ for diagnostics, and didn't have availability of parts anyway, so I took it back to PSR.

We dropped the straps to the tank, and the tank wouldn't come down! That's when we realized the likely issue. Got the tank down, and there was a nice rivet hole in the top. Last year, put in some steel plate to reinforce the rusted floor. Unfortunately, one of the rivets went through the top of the tank.

Thanks to Dumptruck for dropping everything, and running up to PSR with a spare tank he had. We swapped the tank, verified the evap valves worked and the grommets were decent, gooped them up with sealant, and put them back together.

A few days later, and back to Ridgecrest for the test. Gomer passed both emissions and evap with flying colors.

Just for reference, here are the numbers:

1st pass - after driving 78 highway miles, and then 2 hour cool down
Idle - %CO2: 13.88 %O2: 0.9, HC (ppm) Max 100, Aver. 17, meas 7
2500rpm - %CO2: 14.06 %O2: 0.6, HC (ppm) Max 170, Aver. 13, meas 14
%CO in both cases was 0.00

2nd pass - after driving 78 highway miles, and pulling in immediately:
Idle - %CO2: 14.40 %O2: 0.2, HC (ppm) Max 100, Aver. 17, meas 11
2500rpm - %CO2: 14.30 %O2: 0.4, HC (ppm) Max 170, Aver. 13, meas 12
%CO in both cases was 0.00

So, a stroker can burn quite clean. In addition, if you have a marginal test result, you may get some improvement getting on the tester immediately after an extended drive and at full operating temperature.

David Bricker / SYR
 
Definitely on the extended drive when you have any doubt.
 
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