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Truck blows white smoke when first starting up need to pass emissions what can i do

When i first start up the truck it smokes bad with white smoke then stops but the rear differential is going out as well it was fixed but nit properly what can i do to pass

Please tell us the model year and engine

Because you only have a 1/2 ton truck, the model year dictates whether the truck gets a dyno smog test, or only a plug-in test

I believe the engine is a 5.7 l

95 suburban lt

Since your truck is 1995, your truck goes on the dyno, gets a tailpipe test and a visual inspection

The white smoke could be due to coolant getting into the crankcase. Cracked block and/or heads, head gaskets, lower intake gaskets, etc.

Because of your truck’s model year, I believe the inspector does not hook up his tool to check for codes

If the check engine light doesn’t remain on at idle, that part of the inspection should be okay

As for getting it to pass, I suggest driving the heck out of it before heading over to the inspection station. Drive the truck in a lower gear for several miles on the freeway. The idea is to get the catalytic converter REALLY hot, because I suspect it’s in marginal shape, due to age. A hot cat might make the difference between pass and fail

Once the cat is hot, but before you head over to the inspection station, make sure there’s no visible smoke coming from the tailpipe at idle. Also rev the engine to make sure no smoke is visible under load

The inspector is supposed to make sure your idle speed and ignition timing are correct, so make sure that’s okay

Make sure the egr works, the inspector is also supposed to check that

Make sure there’s no smoke from the crankcase ventilation system. No visibly split hoses

The inspector is supposed to test your evap system, and he’ll visibly inspect your cap and hook it up to the tester as well. If the cap’s seal is rotten, replace it now.

But if your truck is also belching smoke because of a pig rich condition or super high engine oil consumption, there’s no way it’ll pass . . .

Good luck, and please let us know what happens :smiley:


Thank u very much

1 Like

This is a link to an old thread that detailed what I did to get a 1993 Caprice to pass emissions testing in NJ.

DB is correct, you have to get the cat good and hot to pass. The Caprice failed once because the wait at the Inspection station was too long.

Good luck,

Ed B.