Formula vs. Smog Check: cleaning up the combustion chambers with some B12 ( not the vitamin )

In the continuing saga of trying to get my beloved Formula to pass emissions this year I bring you my latest adventure.

Just to catch you up, the story is this.

My registration came up and when I dutifully reported to my local emissions testing station I was sadly informed that my car had failed...badly.

The only thing I passed was the gas cap test.  HC and CO were twice the acceptable values and NOx was even worse at 3 times the standard.

So I attacked the problem by switching back to Premium fuel, dealing with a bad EGR and Fuel Pressure Regulator and chasing down vacuum leaks.

Which is an excellent segue to my current project.  During my "leak" hunt I discovered that my PCV valve appeared to be the original piece.  Meaning it was time for replacement along with its associated vacuum line which after 20 years was as brittle as a potato chip.

I'd been doing some research on emissions failures and happened across a few videos about the benefits of combustion chamber cleaning.  I'm not talking about sticking a bottle in your gas tank at the next fill up.  Rather this is a process targeted specifically at cleaning up the combustion chambers and upper cylinders.  Some may call it snake oil but there is something to be said about trying to get rid of some of that built up carbon that inevitably bakes itself onto the tops of your pistons.  The cause?  Poor quality fuel, neglected maintenance and issues with the ignition system just to name a few. 

LT1's have a compression ratio of 10.5 to 1 right out of the factory, a bunch of crap on top of a piston after 100,000 miles decreases cylinder area and increases compression.  That leads to pre-ignition which is an uncontrolled explosion that happens sometime other than when the spark plug fires.  Uncontrolled explosions are ok for diesel engines, not LT1's.  It's a bad thing unless of course you like the idea of hammering the tops of your pistons and potentially bending a connecting rod.

There are a number of products out there to clean up the combustion chamber with some more snake oil than others but the two most popular are Seafoam and B12.

I chose the B12 Combustion Chamber Cleaner Part # 2610 after seeing a few YouTube videos and reading up on it.  I'd been running lower octane fuel for the past year to save a few bucks.  The car could tolerate it for awhile but not indefinitely and there would be a price to pay.

Call it a penance for the few bucks I'd saved by not giving the car the quality of fuel it really needed.

The procedure was fairly simple once I figured out what vacuum port to use.  Access to anything under the hood of a 4th generation Firebird is difficult.  Finding the right vacuum port without breaking parts that have been cooking under it for 20 years even more so.

I found a suitable port in the driver's side of the LT1 intake manifold right above the PCV valve I was fighting with earlier.  

I popped off the vacuum tee that was attached to it and connected the hose from the can of B12 making sure it wasn't in danger of contacting anything that could ruin my day.

One thing to be careful with here is to make sure to use the included hoses that come in the B12 kit.  There's an inline tee that functions to vent the line to keep the flow constant.

Once connected, it's pretty simple.  Start the car and let it run until the can is empty.  In my case it took about 15 minutes. 

I noticed some white smoke and water vapor coming out of the exhausts during the process as well as a slight chemical smell.  Nothing of note really aside from the wet spots immediately under the exhaust tips that seemed to stain the concrete a bit. 

If there was anything that alarmed me it was the sounds my catalytic converter made while the B12 made its way to the exhaust system.  A steady rattle that sounded like ball bearings in a metal coffee can.  Happily, a sound that went away once the can was emptied.

Recall that the catalytic converter is likely on its way out anyway.  In fact the whole point of this  emissions adventure is to see if I can get the car to pass without investing $250 in a new one. 

After the process completed and everything underhood was returned to normal I took the car out for a few runs up and down the freeway to burn off whatever B12 was left.  Some have reported dramatic smoking akin to all those SeaFoam videos but I didn't see much of anything. 

What I did notice was a bit smoother power delivery and a lessening of a slight miss at idle that I've had since I bought the car.  The instructions mention that using B12 may set a trouble code that can be safely reset without concern.   I saw no such code get set.  Apparently in some cases the amount of contaminants being sent out the exhaust can give a false positive to O2 sensors. 

Will this finally get me through emissions?  I don't know.  The only thing left to do now is an oil change immediately before taking it in again.  I'll wait a week to make sure all the B12 solvents are completely burned off to ensure I don't contaminate the new oil.  Not a big deal since I don't have that much oil blow-by anyway so I don't expect much of the B12 got into the crankcase.

Whatever the outcome of the test, none of these activities were a waste of time even if the car fails again.  The EGR and Fuel Pressure Regulator weren't working, the PCV valve and its grommet was overdue for replacement, vacuum lines needed to be checked, the car needed to be running the right grade of fuel and the combustion chamber was overdue for a cleaning. 

I'm just hoping I can put off the bill for a new Cat!

Formula Vs. Smog Check: EGR sadness

Last time I pretty much laid out my dilemma.   20 year old car, Emissions testing Nazis, questioning my life choices...

So I won't rehash it here.  It's a problem anyone with a car roughly the same vintage as their parent's high school diploma knows well.

This time we're going to attack the root cause of our NOx failure at the emissions testing station.  If you recall, the standard for a 95 Formula in Arizona is 2.00 and I managed to crush the scales at 5.99.

There are two primary emissions systems that contribute to this failure.  The first is the EGR or Exhaust Gas Recirculation valve and the second is the Catalytic Converter.

As I see it, the Catalytic converter is a secondary emissions component.  Meant to clean up whatever the other primary systems left behind.  There are exceptions such as certain vehicles that eliminate the EGR altogether and incorporate similar functionality within the intake system of the engine itself. 

But most of us with older cars will still have to deal with the tried and true EGR valve.  Considering it's exposed to constant exhaust heat, depends on a seal made of rubber and failure of said seal negates its function you're going to have to deal with it at some point.

The good news is that at least on mid 90's GM F Body cars ( 93-97 Firebird/Camaro) with an LT1 V8 the diagnosis and replacement is straightforward.

I should clarify here.  Diagnosis is easy, replacement would be easy if you could somehow wrest the engine out of the car in under 5 minutes.

That's not going to happen in a 4th generation F Body.

But enough of that...

The EGR's function is to circulate exhaust gases back into the combustion chamber to cool it down.  

Combustion temperatures above 2500F cause NOx, a noxious gas that creates excess ozone and irritates respiratory ailments among other things.

So the emissions Nazis are gunning for you if your car exceeds their standards.

On the 4th Gen F body LT1 (V8) cars the EGR is located on the back of the intake manifold in pretty much the most inaccessible location GM could come up with. 

Now if Camaros or Firebirds had hoods that tilted forward ( like the same vintage Corvettes do) it would be no big deal.  Thing is, these cars are cursed with about a foot of bodywork hanging over the engine.  Thank that 60 degree windshield for that one.

Still, you can deal with the EGR and the Fuel pressure regulator as well ( since it's in the same location) so long as you're willing to lay across the front of the car to get to them.

Which is what I had to do to replace mine. 

But we're jumping ahead here. 

Before we start turning wrenches we need to figure out if we need to.

Assuming the rest of your emissions components are working within specification, high NOx generally only comes from the aforementioned high combustion temperatures caused by a bad CAT or EGR valve.

The simplest test for a bad EGR is to stick a vacuum pump on the vacuum port on top of the EGR and give a few pumps.  If it doesn't hold vacuum it's junk, no exceptions.  The EGR relies on a flexible diaphragm that moves in and out as vacuum is applied to it. 

That diaphragm operates a rod ( pintle ) that allows a measured amount of exhaust gas to recirculate in the combustion chamber which helps cool it down and decrease NOx emissions.

If that pintle doesn't move then NOx can run rampant.

The other reason the EGR system can fail is if the EGR passages in the manifold become clogged up.   If the exhaust gas can't get to the combustion chamber it can't cool it down.

It can also cause the engine to run too lean ( too much air not enough fuel ) which can increase HC emissions as well.

Vacuum leaks can contribute to high HC and NOx as well and a torn diaphragm in a 3 inch disk is a pretty big leak.

So now we know the problem, the solution is pretty simple. 

Replace the valve...

While you're at it, check out the EGR passages and clean them out if they're full of crud( as best you can considering where the EGR is.)

Removal is easy, 2 (1/2 inch) nuts on a couple of studs.  Of course getting to them requires draping yourself across the front of the car but once you get positioned, it's not so bad.  I'd also recommend the use of an offset boxed end wrench since the bolts are partially shrouded by the EGR "disc."

Pop it off, remove the gasket, clean up the mating surfaces ( there's likely to be a sticky film left by the old gasket) and clean out the EGR passage of any carbon build up.  Then just bolt the new one on, torque the bolts down and reconnect the EGR vacuum line and you're done!

Really not much more to it. 

Below is a video that outlines the diagnosis and testing procedures.

Formula vs. Smog check: Feeling the (Fuel) Pressure!

You know the drill...

You get your registration renewal and in big block letters you see, "EMISSIONS TEST REQUIRED."

So you dutifully prepare to waste half a day sitting in your car inhaling exhaust fumes from the 30 other people ahead of you similarly afflicted. 

So it was with my Formula.

If you've kept up with this blog you already know the car's been an adventure having suffered more breakdowns in the 2 years I've had it than the last 5 cars I've owned combined.  Not that I'm surprised.  It's led a long life of commuting and road trips that have ticked off over 165,000 miles in its 20 years.

So things are gonna break.  I've been down this road before and the truth is that you're either in it for the long haul or destined to wave goodbye as it's dragged off to the scrap yard.

I was pondering the latter after suffering the indignity of the car failing almost every emissions standard except the gas cap.

Things are still tight and the last thing I needed was another dip into my wallet.  As it is I'm living on ramen noodles!

So armed with my failing report card I began my latest adventure.

The car failed on all the readings, CO, HC and NOx.  I've been suspecting the catalytic converter was failing but these readings went far beyond anything a single emissions component could cause.

The CO readings were slightly above the acceptable standard but HC was almost 2x.  HC means unburned fuel is leaving the exhaust pipe (rich.)  CO is also considered to be a condition of an overly rich fuel mixture but usually caused by weak spark not completely burning the fuel.  Remember we're dealing with chemistry here.  While CO and HC being high both indicate an engine being over-fueled (rich) they aren't the same thing.  

HC is unburned gasoline showing up in the exhaust stream.  It hasn't been chemically changed by the combustion process.  

CO is an overly rich condition as well but the difference is that it has been partially changed by the combustion process.  A weak ignition, compression loss in a cylinder, anything that interferes with the combustion process can cause this reading to go high.  

If HC is a raw steak, CO is that same steak but partially cooked.  Neither is edible.

I've had carbureted vehicles that ran lean but produced a high CO reading.  That seems contradictory but taken with the accompanying Low HC it made some sense.  The other component I failed to mention was that the reading only went high at high speed but was normal at idle.  That meant there was a problem with my ignition system not keeping up with the fuel being delivered.  

It's an example of the value of looking past initial readings and the importance of collecting all the information.  If I'd just taken the high CO at face value I'd be led to believe I had a fuel problem instead of an ignition problem.  Which ultimately turned out to be the case.

When computer controls get involved things get even more interesting.  The output from the O2, MAP, MAF and other sensors play an important role in keeping that ideal fuel ratio of 14.7 to 1.  Any failure of those measurements could effectively lie to the engine management computer and cause a response that makes it run inefficiently.  For example, a rich running engine with sensors telling it it's lean could literately flood the engine with even more fuel. 

HC and CO aside, however, the worst failure was the NOx readings.

It was almost 3x the standard.  NOx readings indicate how efficiently the engine is at using fuel.  High readings usually mean the engine is running too lean and heating up the combustion chamber.  But even a rich running engine (like mine) can make this reading go high if upstream sensors are getting bad information.  
It's kind of the canary in the coal mine since it's more of an overall indicator of the combustion process than just the HC or CO readings alone.  

Causes could be an overheating engine (which can happen from idling too long in that damned line) and/or a failing EGR ( Exhaust Gas Recirculation) valve.  The EGR is designed to force some spent exhaust back through the combustion chamber to cool it down thus removing the conditions for the gas to form.  If your EGR fails you lose that effect.

The other component that can affect NOx is the catalytic converter whose primary job is to clean up any leftover NOx before it leaves the tailpipe. 

So now we have some idea of the problem, time for the solution.

The Formula has always had a slightly rough idle which I attributed to mileage and age.  Thing is, with a completely new ignition system and no evidence of a compression problem on the cylinders, something else had to be in play.

Looking at the test results and noting that the car has been experiencing long starts intermittently it was time to dig deeper. 

I looked at the 2 most likely culprits that could cause both an excess of fuel and high combustion chamber temps.

That led me to checks for vacuum leaks (which can make high NOx worse) and fuel pressure.   I began by hooking up a fuel pressure gauge to the port on the fuel rail and watched the pressure over time.  What I noticed was a slow drop just barely noticeable but it was there.  

I then pulled the vacuum line off the fuel pressure regulator (FPR) and connected a vacuum pump to the fitting on the regulator.  It mimicked the result I saw with the Fuel pressure gauge, a slow bleed off but of vacuum not fuel.  The final test was to take a whiff of the vacuum line that connected to the regulator. 

Damning evidence, the telltale smell of gas where there should be none.  Gas fumes present in the FPR vacuum line indicate a ruptured internal diaphragm which compromises fuel metering and allows fuel into places it shouldn't be.

So I needed a new FPR.  That should help with the high HC readings but what about the NOx and CO?

The EGR valve on the Formula (and the FPR for that matter) is in an almost inaccessible area under the foot or so of bodywork that supports the windshield above.  Still I have my tricks and I was able to do some preliminary testing of the EGR valve itself.

Testing an EGR without the car running is pretty straightforward.  The first test is to try to move the internal EGR diaphragm assembly by hand.  If it moves freely then you know the EGR valve itself isn't frozen. 

This first test it passed.  On to the next test...

I connected my vacuum pump again and proceeded to give a few pumps. 

Nothing, absolutely nothing...

It was like attaching the vacuum pump to a straw which told me the internal diaphragm was ruptured.  Being a vacuum controlled valve no vacuum means it's broke.

The final test required the engine to be running.

With the engine idling I again moved the internal EGR assembly and the engine sputtered and died.  That's exactly what it should do and told me that the internal passages were clear enough to work with a properly functioning valve.

OK, so now I know I have 2 problems that are causing me all this grief with the emissions Nazis.  A bit of research and some shopping found me a deal on both parts ( thanks Amazon.com )

Thing is, even with a deal I was going to be out a C-note I couldn't really afford but I couldn't afford to be without the car either. 

Once more we fast forward to today and the first of my parts showed up.  The FPR.  I did a little more research to see how much of a pain it was going to be and if I was going to need more parts.

I made the decision that I had what I needed and if I didn't... Well, I was going to need more parts anyway so there was really nothing to lose. 

Instead of recounting the whole process of replacing the FPR I made a video.  I'll just touch on the major points you need to know.

Safety is always a primary concern so make sure you do the following before attempting the repair.

• Disconnect the negative battery cable - Sparks and gas are meant for combustion chambers, not garages.
• Depressurize the fuel system - A faceful of gasoline or worse spread all over the engine is not only annoying but dangerous.
• The minute you open the fuel system gas is going to come out - make sure you've got rags or something handy to catch the fuel that's going to leak out the minute you pop off the fuel line and/or FPR

Once you've done all that keep the following in mind while you perform the repair...

• Take your time - Better to do the job right the first time than wonder because you rushed through it.
• Be organized - keep track of all the bits and pieces that you take off.  Nothing's worse than a 45 minute job taking 3 hours because you lost a screw you can't replace.
• Follow directions - Use a manual or do some research on the Internet before you do anything.  You're not inventing the wheel here and chances are someone's done it before and wrote it down or posted it somewhere.
• Use the right tools - For instance the retainer bolt for the fuel line clip that you must remove is a T-25 (Torx) the FPR retaining bolt is a T-27.  The T-25 kind of fits but you risk stripping the head of the bolt and ruining your day
• Check your work - make sure you've got everything back where it needs to be.  #2 makes this a whole lot easier

So with that I'm going to close Part 1 and invite you to come along with me as I replace the FPR on my Formula in the video below.

Next time, we'll cover the EGR and see how that goes..