Engine/Transmission (1994 - 1998) AZ Emissions testing and 3k GSK?

[GrantP]

AZ (and a couple of other states I believe) require a diesel emissions test which basically amounts to flooring the throttle from idle while they check for smoke. I will be tightening up the star wheel prior to the test so I'm not concerned about the actual emissions output. What does scare me is the 3k GSK. How high will the engine rev in park and full throttle? If memory serves, you have to maintain full throttle for 15 seconds or so and do this multiple times all while someone is watching over your shoulder presumably to make sure that your actually flooring it and that the engine is not exceeding "redline" (as the tester put it). This test was not a problem when stock, the engine stayed right at 3k rpm, but where will it stop now with the 3k governor springs? Before I go out to the driveway and try it, I'd love to hear from anyone else that has to endure similarly retarded emissions testing with a 3k GSK. If it does rev much higher than 3k, any suggestions as to how to temporarily "limit" the RPM's during the test? Thanks in advance.

 

[Todd G]

Wood block under the go-peddle... ...

 

[JGK]

Wood block under the go-peddle... ...

Or can you twiddle with the throttle linkage on the side of the pump to do the same thing? Less obvious, perhaps!

 

[GrantP]

Any solutions/recommendations from anyone that has had similar testing would be appreciated... . before I rig up some sort of throttle stop... . Thanks.

 

[Mackie007]

Just do the test yourself, hold the throttle at 2700rpm or so. They will never know the difference. I always drive my vehicles through the emissions test. Down here in Tucson we have not had to do the diesel snap test your talking about, but its been 9 months since my last test so things could have changed. I'll find out in 3 months.



Best Regards,

Mac

 

[GrantP]

Well... decided to scare the neighbors today and see just where the engine would quit revving with a 3k gsk, in park, and full throttle. I suspect the engine would explode, I wasn't even at full throttle at 3500 rpm (stock valve springs too, yikes). There is no way this thing is going to pass the snap idle emissions test.

 

[GrantP]

Went to the inspection station today... rigged up some zip ties on the throttle linkage to prevent full throttle. Adjusted the ties so it stopped right at 3k, worked like a charm. Too bad I still blew too much smoke. 42% opacity, 40% max allowed. Star wheel is all the way back, looks like I'll be putting in the stock plate soon.

 

[Todd G]

Did you do the test or did the smoke monkey's? I have always passed even though I smoke like a train. Ease into the go-peddle and you'll pass every time.

 

[GrantP]

I did the test myself. I was pretty shocked that it failed considering what little I've done to the truck.

 

[Joe G.]

Disconnect the hose to the AFC and try it.

 

[MLee]

Joe;

I guess this cuts the fueling?? or reduces it?

Marv.

 

[Bob4x4]

It doesn't allow increased fueling with increased rpm,and or boost.



Bob

 

[JGK]

Also, if you haven't recently (like last 100 miles) go out and run it hard up a long hill if you have one near by. Put a load on if you need to. Get the system good and hot for several miles. It sort of burns things out, I guess. I did that after failing the first time and it helped a lot on the second try. Passed with no other changes by a conisderable margin. An old diesel mechanic told me about that trick.



-Jay

 

[Joe G.]

Marv,



The AFC is a throttle stop that revents increased fueling until boost comes up. The idea is to reduce smoke. The star wheel is just a fine adjustment for the AFC. If the hose is removed the AFC throttle stop does not move out of the way. I just helped a friend fix his '97 which was really sick. It ran fine. No smoke. When he was pulling his bass boat he was afraid he would be passed by kids on bicycles. His AFC was not working at all.

 

[JAmos]

add springs?

Thank God for country living-NO EMISIONS!!!!!!! Could it help to temporarily add springs to the throttle to make it harder to mash on it and get smoke if a smoke monkey has to run it? Maybe I could start a business renting my stock plate to people who unfortunately have to pass emissions? Jordan

 

[biggy238]

CHEATERS!!! I love this stuff. What exactly did you have to "Fix" Joe G?

 

[Joe G.]

My friend's '97 is a CA truck with an EGR valve. That thing caused the hose to the AFC to plug up with soot. He has an AFC from a '95 on there now. The affect of the soot was the same as if the hose have not been on there. If the AFC does not work any torque plate never gets into play. I doubt that the 3KGSK would have a lot to do with how the engine ran if the AFC was restricting fueling. It runs ok, just no power. That's how a valet switch works. It kills the AFC. No need to restrict the throttle linkage or anything like that.

 

[GrantP]

JAmos - I couldn't agree more. Failing the test with only a 6 plate and 3k gsk pretty much squashes the idea of throwing in some 370's... much less installing a nice 4" exhaust and losing the cat. Frustrating, very frustrating...

 

[Todd G]

I have 370's with a 11 plate full forward and the AFC housing full forward and I passed this year with 7% opacity. Do the test yourself and don't mash the peddle. Ease into it and they'll never know.

 

[GrantP]

I tightened the star wheel all the way and did a simulated test in my driveway, still blew lots of smoke (star wheel was in the middle during the first emissions test). Disconnected the AFC line, no change at all. Rather than risk another failure, I dropped the stock fuel plate back in. Almost no smoke with the stock plate. I passed this time with 20% opacity vs. 42% with the 6 plate (40 is max allowable). Looks like I'll be swapping fuel plates once a year. It sure was a dog with the stock plate, I dropped the 6 back in as soon as I got home!