On this page are a couple of videos showing you the results of my Fuel Pressure Leak-down test and how to test a MAP sensor on an LT1 V8. These are two important tests when you've got an emissions problem especially if the car is running rich. The fuel rail will bleed off some pressure over time but not all of it in a few minutes! Anything more than a couple of PSI drop after a few hours means there's a leak in the system somewhere. It's important to mention that if at all possible, you really want to isolate the individual components of the fuel system when troubleshooting. If you're testing the fuel rail and you don't know the condition of the fuel pressure regulator, for example, then ideally you'd want to block off any return lines to the tank so you don't confuse a bad fuel pressure regulator with say a stuck check ball in the fuel pump. If that's not possible then you're only going to get a general idea that there's a problem. In which case you'll have to take into account other factors. In my case I know the Fuel Pressure regulator is good ( brand new ) so I'm fairly confident that any pressure loss seen at the rail is going to be isolated to a component of that rail. Note that all of this testing is done with the engine off. With the engine running other factors like the Fuel Pump, Injector pulse time and engine vacuum come into play which can mask a basic fuel pressure problem. Incidentally, you won't see it in the video but the way to isolate the fuel system to check for what part is causing you the headaches involves either pinching off the return lines or installing a shutoff valve. I don't have the valve and I'm not about to start pinching anything made of plastic that's been baking under the hood of a car for 20 years. So I didn't do that test but a rich mixture is more likely to be a fuel injector than a check ball in a fuel pump at the back of the car. I was more interested in seeing if there was a drop in pressure in general. Once I can afford a new set of Injector O-rings I'll be pulling the injectors out, priming the rail and seeing which one(s) are leaking. As for the MAP sensor testing, well, it's always the first thing blamed right behind the O2 sensor when an engine is running to rich or lean. That makes sense since those sensors as well as the MAF (Mass Air Flow) provide critical data to the engine's PCM to adjust the mixture rate. There are others like the Coolant Temperature sensor, Throttle Position Sensor and others but basic emissions troubleshooting will have us starting at the MAP sensor since it's usually the easiest one to access and check. The MAP sensor's job is basically to read engine vacuum and send a signal back to the PCM. With an LT1 the PCM takes that vacuum value and compares it with the Air flow data from the MAF to see if the two values complement each other. That allows the PCM to make more minute adjustments to the fuel mixture for performance and emissions. It's also a sanity check for each sensor since the failure of one can be compensated for by the other. Either one can provide enough data to allow the engine to continue to run but not as efficiently. Some cars only have a MAP sensor but LT1's are a bit of a wild animal when it comes to tailpipe emissions. Getting the engine into emissions compliance takes a lot more data points than your average grocery-getter especially with high compression that lends itself to problems with NOx and CO issues. So if you ever wondered why there's so many wires under your hood, now you know.... For me this is all kind of a reference exercise but for you it might be instructional. Enjoy! Fuel Pressure testing...
Checking the Manifold Absolute Pressure Sensor (MAP)
The saga continues... The story so far. My 1995 Formula failed it's emissions test. We did some diagnostics and found out that the EGR, PCV, and Fuel Pressure regulator were all bad. We also knew from the first test that the major problem with the car was it was running too rich. There was also a suspicious rattling under the car which upon inspection showed a problem with the catalytic converter. It's the original and a couple of soft taps with a rubber mallet confirmed it. So after more diagnostics that involved chasing down vacuum leaks, replacing any crispy hoses I could find that were causing them, checking the EGR solenoid and changing the oil it was finally time to try again. The first test a month earlier gave us readings of:
HC 1.57 .8 is the max
CO 13.7712.0 is the max
NOx 5.992.0 is the max
Today's second pass at it:
HC 1.57 .8 is the max
CO 15.5712.0 is the max
NOx 4.592.0 is the max
So we've taken a chunk out of our high NOx reading, done nothing for the HC but what's this? The CO went up! That's actually a good thing because it means we've got better fuel control. Instead of gas leaking past the regulator it's staying in the combustion chamber. In effect the gas is where it should be but there's too much of it! It's also another indication (in addition to reduced NOx) that the EGR is working since it's recirculating exhaust vapor back into the combustion process. It's taking that raw and partially burned gas and adding it back in just as the EGR system is designed to do. The problem is that the exhaust is so rich with fuel that it adds to the CO problem. HC stays the same because we're not adding any more raw fuel into the exhaust stream. That any reading stayed the same across 2 tests a month apart also indicates that the catalytic converter is doing virtually nothing to help us. It's also indicative that our rich mixture is being caused by something other than what's been fixed. I'll cut to the chase. We've still got an over-fueling problem and it's likely related to a leaky fuel injector. Admittedly, all I have to back up my diagnosis is some fuel injection tools, a multi-meter and a code scanner that works with OBD1. And a bit of experience... Before I changed the Fuel Pressure Regulator I'd have intermittent long starts when the car was cold. With some of the fuel pressure bypassing the rail for places less useful it wasn't a surprise. What was a surprise had to do with warm starts. I thought my fuel pressure problems were over but noticed longer starts (more cranking) after the car sat for a short period of time (15 minutes to an hour). That has everything to do with the fuel rail bleeding off pressure when the car was warm. Remember that when the engine's cold the fuel pump will prime the rail but when it's warm it shouldn't need to. So when it does it has to build up pressure again. I also noticed that during these longer warm starts I'd sometimes see a bit of grey smoke out of the exhausts. That told me there was un-burned fuel in the cylinders. With the engine off the only way that can happen is if something is dripping fuel into them. Something like a leaky fuel injector. Which is the likely cause of my over-fueling issue. Of course without a scan tool that can read fuel trim or at least the state of the O2 sensors it's still a guess. The only way to know for sure without one is to pull the injectors out of the manifold while still attached to the fuel rail. Then turn the key on and prime them to see if they leak. That's a story for the next installment. Yes, I can put my fuel pressure gauge on the rail but that only tells me there's a problem on the rail not where it is. So that's the story up to now. I'm convinced I have a leaky injector and a bad catalytic converter even given my limited resources to diagnose the problem. But when I got the results for the second test which I half expected to be a disappointment anyway something struck me. Those results I showed you earlier? They're absolutely useless for diagnosis. All I know is that the car failed. For all that time and trouble I have no indication what the conditions of the failure were. In Arizona it's always been that way as I'm sure it is in other parts of the country. But like everything else that's supposed to be "progressive" in the state Arizona's managed to turn it into a profit center. Which is a great segue to the video below. It's a bit of rant but for me it was a bit of an epiphany as well. Stay tuned!
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!
There's no denying it, when most people think muscle cars
it's likely the first image they think of is a Mustang. That is, if they're under 40 and don't know
any better.
Oh yeah, the hallowed names
of GTO, Chevelle and Challenger eventually show up in there somewhere but Ford's
marketing department has done a bang up job of obscuring history with the
Mustang.
So is today's car the best engineered example of the breed
in its 50+ year history? Of
course it is.
The question is, can it really be called a Mustang? In Ford's rush to globalize its offerings it
seems the Mustang is destined to join the ranks of other fine examples of
Ford's "world cars." [sic] An
"honor" bestowed on such legendary models like the Escort and Fiesta. [even more sic-kening]
So is it any surprise that the 2015 redesign was so
"sophisticated?"
It saw the first appearance of an independent rear
suspension as standard equipment in a Mustang (except for 99-04 Cobras) which until now was a feature left to those "copycats"
over at GM and Chrysler. Coincidentally,
both the Camaro and Challenger owe much of their engineering to "them civilized" folk in Australia and Europe. European tastes won't tolerate a car with a live axle unless it's 100 years old and requires a crank handle to start it.
Don't get me wrong, I've got nothing against IRS ( the suspension not the tax guys) but
if your buyers don't care about carving corners at the Nürburgringthen who are
you really trying to impress with an American coupe?
Let's not forget such "must-haves" like that center mounted touch
display with GPS and smart phone integration.
A feature no self-respecting BMW or Mercedes owner would be caught dead
without.
Or the price. This one's a sin all 3
current pony cars suffer from. Instead
of being within reach of "Joe Six Pack" the entry point of these cars
is more in the realm of "Joe Six Figures." Considering the average price of a pony car with a decent V8 hovered
around 3 grand in 1969, you'd come up about 10 grand short (around 25%) in today's money when you adjust for
inflation.
I'm not even going to get into the very "euro" trend of sticking
a damned turbocharged 4 banger in everything.
An option now available on the Mustang! Yeah, Ford's done it before but nobody looks on those days with nostalgia.
Finally the look.
Sorry, but the new Mustang isn't a Mustang at all. It's a squished ripoff of an Aston Martin Vanquish. Think I'm nuts? Forget the goofy stripes or hood scoops and
take a close look at the two photos below then tell me who the Mustang is really
being aimed at. It sure as hell isn't
the traditional pony car buyer!
Nobody should be buying a Mustang thinking they're getting a cheap Aston
Martin!
I've been screaming this from the rooftops since the first photos of the
redesign leaked and nobody was listening. I'm sure it has something to do with most buyers not getting past the engine compartment and 7" touch screen in the dash.
Ford is trying to upscale Mustang's market which is a mistake for a car as
iconic to middle-class America as the VW Golf is to Europe.
Get real, nobody looking at a Bimmer is going
to consider a Mustang folks. America's population
is aging meaning the people with the cash to afford the gouging won't want it
for much longer. They'll go buy a 5 series BMW sporting big puffy seats with built in butt massagers. That leaves the target demographic
populated by debt-burdened millennials enamored more with smart phones and public
transportation than an overpriced European wannabe. Offering up a 4 banger
won't help either, especially when it costs 2 grand more than the base V6!
The idiocy of it is stunning.
In short, the 2015 Mustang is all wrong.
It's only tenuous link to the mark's heritage is a throaty sounding powerplant wrapped in the bodywork of a cheap European knockoff. It's more
Ford Focus than Ford Mustang. In fact, side by side it's hard to tell which one's styling is influencing the other. My money is on the Focus... Bottom line...It's a
sellout with no redeeming features outside of its power train. Not that it's all bad. Take that power train and stick it in an '08 Mustang GT and you might have something! Even the 2010-2014's retained more heritage than this car. Those were cars I wasn't wild about either but at least they weren't trying to be a Ford Ka!
Hopefully the Camaro and Challenger will stay true to their heritage and their
market.
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.
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..
If that's not possible then you're only going to get a general idea that there's a problem. In which case you'll have to take into account other factors. In my case I know the Fuel Pressure regulator is good ( brand new ) so I'm fairly confident that any pressure loss seen at the rail is going to be isolated to a component of that rail. Note that all of this testing is done with the engine off. With the engine running other factors like the Fuel Pump, Injector pulse time and engine vacuum come into play which can mask a basic fuel pressure problem. 
The MAP sensor's job is basically to read engine vacuum and send a signal back to the PCM. With an LT1 the PCM takes that vacuum value and compares it with the Air flow data from the MAF to see if the two values complement each other. That allows the PCM to make more minute adjustments to the fuel mixture for performance and emissions. It's also a sanity check for each sensor since the failure of one can be compensated for by the other. Either one can provide enough data to allow the engine to continue to run but not as efficiently.
