Alright guys, really looking for some help here. '97 3500 dually with 12v, 152k miles, all stock except im told it may have an aftermarket fueling plate. We've had this truck 3 years and never had a problem with emissions until now. Did get a suggestion to try adjusting the star wheel on the pump, it was set about in the middle. All the way one way produces lots of black smoke and its seems to choke a bit, all the way the other way produces moderate smoke (some white now also) when on the throttle hard but runs great. Im located in Phoenix (Mesa) AZ. The truck has always run great (and still does), but after 3 tries at the emissions test im begging for answers here - anyone????

 

What kind of test do they do in Arizona , is it a opacity test ?

 

Yes, opacity test. Pass is around the 40 mark, we keep registering in the low 50s. HELP!

 

slide the plate all the way toward the cab,move the starwheel all the way to toward the cab and block the wastegate. the truck will run very slow and have no power you will have a tough time just getting to 45mph but you will see no smoke at all. i don't even register on our emissions check when i take mine in. if that don't work propane will clear it right up

 

Maricopa county does a mash on it three times (in neutural) for the test. Do they let you drive it? They always have ours. Just don't mash it so hard. Push fairly hard up to 2400. They won't know the difference. It does sound like there might be an issue. Have you ran any injector cleaner through it?

Randy

 

can't you unhook the line going into the AFC housing from the side of the motor so you get no fueling off idle??? thought someone suggested this awhile back?? never really tried it, but I might just to see if it works?? should be the same as backing the AFC all the way off shouldn't it?? someone else chime in here & let me know if this is worth a shot or not??? Dusty

 

People are giving advice on how to pass the test by basically turning your truck into a dog.
Maybe better to address the real problem, low fuel pressure or slipped timing.

 

just failed mine too. check out these numbers:

60mph; 57% opacity
50mph: 68%
40mph; 87%

i've looked pretty thoroughly for a boost leak and don't really know how to test my timing or anything else, so it's off to Cummins and praying it doesn't cost beaucoup $$$ for me

 

Let me know what Cummins finds, looks like we are in the exact same situation.....

 

Forget about Cummins...save your money and follow Infidels advice (he knows these engines inside and out):

"People are giving advice on how to pass the test by basically turning your truck into a dog.
Maybe better to address the real problem, low fuel pressure or slipped timing."

Possibly replace the overflow valve, check the fuel pressure and have it timed properly. If that doesnt work, THEN take it to Cummins for "troubleshooting".

 

Can you provide details on this for us that are unfamiliar -- Thanks..

 

thanks Dr,
i just replaced my lift pump due to low power problems and that's when the smoking started. based on the power/acceleration i'm getting, fuel pressure doesn't seem to be a problem, but i don't know for sure. how does a faulty overflow valve cause smoking? i was taking it to cummins just b/c they are the closest diesel shop to me to get my timing checked out as that is something over my head.

 

I cant say for sure if you need an overflow valve....this valve regulates fuel pressure (provided the lift pump is working properly). If youve never replaced it, then its probably time to do it anyway.

You can get an overflow valve from Cummins or from:

Precision Diesel Injection and Turbo Inc.
888-734-7349


There is some good info here:

http://dodgeram.info/tsb/1996/14-07-96.htm

http://www.dodgeram.org/tech/dsl/tro...p.htm#Overflow

 

Just trying to save ya some hard earned $....up where I live the Cummins shop rate is $98 an hour..

 

woa, i had no idea. i better start calling around. sounds like it may be worth a longer drive.

i don't actually have any of these:

"For symptoms:

* low RPM miss/instability
* white smoke
* hard starting
* engine dies at idle
* low power
* fuel filter cracking"

so i guess for now i can rule out the overflow valve? anyone know of a trustworthy diesel mech near Boulder, CO where i can get my timing checked?