California smog analysis, ask a smog tech

[85Ram50]

That hasn't changed 85ram50. But the truck had been sitting unregistered for a few years and the deal was, if I could get the truck up and running, then I could have it.
So I'm trying to figure it out, one part/fix at a time. I'm capable,but not a mechanic so the learning curve is pretty steep!

OK I was wondering about that. Good luck then.

[camoit]

If it sat for a long time it could be it has stuck rings and leaking valve seals. Run the piss out of it and check again.

[85Ram50]

I wonder if that oil flush that Geezer101 suggests would work?
I've done it but I don't need smog where I live. Anyway He says to drain the oil and the filter. Put the old filter back on add 1/2 the the amount of new oil suggested (2 qrts) and 1/2 qrt of diesel. Then drive it as normal for a day or so. Then drain it while its warm and put on the new filter and add full amount of oil. He says it fixes valve seals and stuck rings and removes a lot of gunk. I've done it on my Ram50 and my Dakota no harmful effects.

[geezer101]

He says it fixes valve seals and stuck rings and removes a lot of gunk. I've done it on my Ram50 and my Dakota no harmful effects.

It will break down old oil residue inside the engine but it won't fix valve seals. It may 'clean' them out a little and take some of the old oil that has laminated onto the valve stems which might be enough to get them seal better, but when a seal is dead - it's dead. The oil flush is primarily to freshen up the hydraulics first, and then to prolong the life of the new oil by decontaminating the engine as much as possible.

[Sampson]

I definitely appreciate the ideas on how to clean out old crud and oil residue from the engine, and I figure I'll try it, but how likely is that to be the culprit for such high NOx emissions?

[geezer101]

If your piston rings are carbon'd up they will drag contaminated oil up and down the cylinder walls. It affects compression and traces of it will end up in the combustion chambers. Also with the hydraulic lifters/lash adjusters being gummed up this also affects performance/fuel economy (it will reduce valve lift, I am pretty certain of this). I would advise you to do everything practical to clean up the internals of your engine - even run an additive to de-carbon the combustion chambers (but make sure ALL the fuel additive is cleared from the fuel system before taking it in for inspection). Hell, take the air cleaner box off, run the engine with the throttle open and use a water sprayer pump bottle to atomise water into the carb throats and scour carbon out of the engine (this won't wreck your engine - it will be unlikely you can squeeze the trigger fast enough to stall the engine out but even then it will only be temporary) You'll hear the exhaust crackling as flakes of carbon are getting burnt off if the engine is particularly fouled up. Run brand spanking new plugs when you take it in as well. Oh, and install a new coil - a weak spark will prevent a clean combustion burn and this will also have an affect on emissions. Some people have recommended using E10 fuel to lower emissions but I haven't read up on it enough to say if this is legit or a snake oil remedy. We have enough members who have faced the terror of emissions testing and passed so there will be some good advice available.

[camoit]

Seeing you have such high HC tells us it's mechanical. Put a vacuum gauge on the engine and tell us what it's doing. Should be a rock steady needle. If it's whipping around there is a big problem. But I'm 95% sure its a valve seal problem, and, or, a MCA jet problem.
The high NOx is a vacuum leek / lean run. Could be any line and or the booster and MCA jets. It happens when the combustion temp is to high. Clean out the EGR system ports. Also the carb float might be stuck or other ports internally clogged.
You should get the Jet valve delete kit.

[85Ram50]

Thanks for correcting my mistake Geez. I don't want to misinform anyone.

[hutch]

Waiting for California to extend this smog exempt to 1980.

[geezer101]

Thanks for correcting my mistake Geez. I don't want to misinform anyone.

That's o.k. Neither of us like to have a fan club with torches and pitch forks I should have added to also check the plug gaps and their heat rating. Have you attempted another emissions test yet Sampson?

[Indigo]

Im glad I found this post what Noah says a few posts back is good advice, break up that carbon and put a new coil in to prevent it from building up again. I have an 89 ram that I have struggled with and been unable to get smog legal even with some help from my local ref.
I thought it was Carb related but after reading this I want to try a new coil, do a compression test and clean out the cylinder walls then see if that passes.

[zacatiz]

I have an '85 Dodge Ram 50 with 2.0 G63B engine. I failed Smog today, it passed in every area except for carbon emissions at 25 mph. I needed to get STAR certified smog. I believe the limit is 1.4 units and I came in at a little over 2.

Do you have any recommendations as to a fix? There is a smell of fuel when the car is running that I cannot seem to trace. Should I try and run one of those pass smog additives? Or is carb tuning the wiser option?

[geezer101]

Are all of your ignition components in good shape (leads, plugs, coil etc)? You're getting an incomplete fuel charge burn, that is what is causing high CO readings. Also make sure your engine tune is right, and check for vacuum leaks. Next you can try purging your carb (the jets may be clogged or dirty, causing poor fuel atomisation). Take off the air cleaner, start the engine and try to starve it of air by placing your hand over the throats of the carb. Sometimes it's enough to pull a large volume of fuel up in one hit to clear the jets.

[claych]

???
Pic of the V.I.R. ?(with Noah wins Grace).

[Careyes84]

I failed smog the other day. Here's the cert. Any help would be greatly appreciated.Smog Cert FAIL.jpg
I failed at 15mph but passed at 25mph.

[geezer101]

One or possibly a combo of the following - EGR is clogged up, engine is out of tune, a vacuum leak, O2 sensor isn't functioning properly, CAT converter is bad or the engine isn't cooling properly. High NOx is as of a result of high combustion temps - high HC readings either a vacuum leak or something directly related to fuel mixture control like the O2 sensor or even possibly a clogged primary jet.

[Careyes84]

Thanks Geezer! So, before i smogged the truck and posted this, i had already re-timed the engine (cam was off by two teeth and so was the distro), cleaned and and tested EGR for functionality and it passed, replaced all vacuum lines, replaced O2 sensor with new OEM sensor, and had the Carb tuned by Carburetor Exchange.

Took it to a test and repair facility and they said it was my CAT, Thermostat, and Carbon build up in the cylinders on the pistons. Checked the CAT out, it was deteriorated inside so i had it replaced. Since i have 3 other vehicles, this one is sitting for a little while. Gonna replace the thermostat and use my borescope to check out the cylinders. If they appear to be all carboned up, i'll run a leak down test to see if it affecting the valves seating.

Appreciate all the help fellas!

[mitsubishikid]

another tip for you guys change your oil a day or 2 in advance, before the smog test it will help not having junk in your oil...

[SubGothius]

So my '87 w/ the 2.6 just failed emissions here in Arizona, where they do an idle and 25 mph loaded dyno test. The standard to beat is max. 220 ppm HC and 1.20% CO for both loaded and idle tests. My loaded HC reading of 211 ppm passes, but loaded CO fails at 7.92%, idle HC fails at 1250 ppm, and Idle CO fails at 11.43%.

I'd already replaced the coil and ballast, dizzy cap and rotor, ignition wires, and plugs due to poor running covered in another thread here. I set the static ignition advance at the low end of the stock spec range (5-7 degrees), as I've read less advance can improve emissions at a tradeoff vs. performance. Spark plugs are NGK BPR6EY gapped at the minimum 0.039" (1mm); would expanding this to the maximum spec .043" (1.1mm) help emissions? What else could I try?

[geezer101]

Don't expand the plug gaps, close them. The plugs are gapped from factory to allow a worst case scenario cold start. Try decreasing it 0.5-0.15mm. It will allow a more aggressive/cleaner burn. There a bunch of other recommendations in the smog posts here that should help drop your figures.

[SubGothius]

Hm, what I've read elsewhere indicates there's in inverse relationship between tuning the spark for HC/CO emissions vs. for performance, so what's good for HC/CO emissions is bad for performance and vice-versa, which corresponds to heat being wasted combustion energy that isn't going towards useful work (explosive pressure) -- i.e., a large gap and less advanced ign. timing produces a longer, softer, later burn that produces more total heat to more fully consume the HC in the intake charge, but less explosive pressure and later in the cycle when it's less useful, whereas a small gap and more advanced timing produces a more abrupt, explosive, earlier burn that produces more useful pressure earlier but less heat and thus consumes less of the HC.

NOx is different, as that's a byproduct of heat fusing the oxygen and nitrogen in the air, so more heat produces more NOx. Fortunately, they don't test for NOx around here.

Why retarding spark advance reduces HC emissions

"With the maximum spark plug gap, the engine produces minimum hydrocarbon emissions..."

"Decreasing the gap can make it vulnerable to incomplete burn or misfire."

[geezer101]

True about decreasing the gap, but that relates equal and opposite of increasing the gap. Gap is too close, not enough ignition area. Gap is too wide, spark is not hot enough. The idea is to find the engine vs sparks' happy place (I have to amend my gap dimensions - it's 0.05 to 0.15 mm less gap )

[Careyes84]

So a follow to my failed smog...Sorry it took so long.
I replaced my CAT and Thermostat and she's passing with flying colors again. As soon as i find the Smog Cert, i'll post up the new numbers! Thanks again to everyone for their help!

[amsoiltek]

This may be getting a bit off topic but has anyone compared before and after emission test results of switching to a Weber carb from a FBC on Gen 1 Montero?

[pennyman1]

it will fail the visual, and they won't run the tailpipe test in California...