In working through problems with JBravo's ProCharger setup, there are some things that have come to my attention that need to be addressed. Things that apply to ALL blowers, so this is not just another ProCharger thread. It even applies to N/A guys with rich or lean codes.
In this case, the original complaint was the truck was lacking power. Then we noticed the boost level on the gauge did not coincide with the specifications as noted by the manufacturer. Low boost level was one problem. A rich A/F ratio was a problem (9:1 A/F ratio, which is VERY rich). And it lacked power, obviously. So, we considered an improper tune and belt slip, assuming the blower was installed correctly. In directing John to look at specific problems, belt slip with a 3.0" pulley made sense, but the A/F ratio was still rich. Inspection revealed this...
The oil separator was connected to the 3/8" vacuum port at the rear of the intake and the other end was OPEN to atmosphere, and tucked away behind the intake. That eliminated the belt because slip issue (Most of it), because boost was being forced straight out through that port! The original PCV valve should be connected in the stock location. This separator should be routed from the driver side valve cover vent to the inlet of the blower to scavenge blow-by under boost, but AFTER the MAF in the blower inlet to ensure the air was metered only ONCE! The tuner tried and failed after at least 15 dyno runs, because a huge boost leak was driving the system rich, at a higher rate than the PCM could compensate for and probably outside the capability of the system!
When a member comes to me and purchases a new supercharger, (Even if fuel system upgrades have been purchased and are to be installed) when the system is tuned, we MUST verify the system is installed correctly. I always install the system as it comes out of the box, with the FMU and stock injectors and MAF FIRST. Then I fire it up and test drive it to verify everything is connected the way it should be and we don't have any problems, not even a belt alignment issue.
Once the installation is verified to be correct, THEN you can install the fuel system upgrades and go to the tuning step. Otherwise, if you do it all at once and run into problems, you know for sure the fuel system mods are not a factor. A process of elimination is next, and walking through the installation manual for potential problems is the place to start, then verify there are no connectors damaged or disconnected or make sure there are no boost / vacuum leaks. If you install the blower and fuel system upgrades, this creates many more factors to eliminate. It has proven to be well worth the additional time to verify the install first. Some might try to save by doing it all at once, and it may cause headaches and wasted time and money!
This article will address several issues, beginning with layouts and will touch on tuning. In this case, the truck is blown, so we are going to approach this problem for the supercharged guys out there. In fact, it applies to turbocharged engines as well. The theory is the same for all blown engines, and diagnostic processes are much the same for the N/A guys too, but the method of testing will be a little different.
If you are having problems on your normally aspirated engine, you will learn how to deal with vacuum leaks. This is important because nearly EVERY diagnostic routine in the Ford Manuals will have the tech looking for vacuum leaks FIRST.
To begin with, let's start with the MAF. This is an absolute. Blow through or Draw through, it doesn't matter. In simple terms, in order to maintain calibration in closed loop operation air it to be metered ONLY ONCE and all of that air must make it to the combustion chamber to be mixed with fuel. If an "X" amount of air is metered, the PCM will calculate how much fuel is to be added to maintain the programmed A/F ratio. It will always try to maintain the ratio, no matter how big a leak occurs (Unless a hard fault sets a code and you are in limp home mode with the SES light on). If you meter "X" amount of air, the PCM will adjust IPW to inject "Y" amount of fuel, based on the programming (Factory calibration or tuner supplied). The O2s are used to make calculations and algorithms tell the PCM what the O2s should read under any given load or condition. Again, this is a ratio, so if you measure the air and then don't use it, you are out of calibration.
On a draw through MAF setup you cannot...
Poor integrity of an installation (Tubing blowing off) or improper installation can cause metered air to leak, and if you are leaking boost or vacuum, no tuner in the world can get the fuel curves right, even though it appears to be tuned correctly. In other words, a boost leak will cause poor performance, low boost level readings, poor drivability, poor fuel economy, and difficulty in tuning, if it can be tuned at all. It just got tuned for an engine that had a boost leak.
So, if you meter air once, the PCM makes a decision, and boost leaks out, you have altered the ratio because part of the metered air just leaked out. To keep it simple here, the ratio is no longer correct. The ratio is no longer controlled by the PCM because the PCM would need to see short term fuel trim (A recording or table of the adding or subtracting fuel) change. It needs to see this compensation (Adding or subtracting fuel) outside of a set parameter for a programmed period of time before it ever flags it and sets a lean or rich code (Depending on the circumstance and programming). Then it starts updating the long term fuel trim. You will not see a vacuum leak immediately or within 3 dyno passes a tuner normally needs to write the new code. A scan tool will show it but a drive cycle needs to be completed prior to the system throwing a code.
Short and long term fuel trim outlined...
A blow-through MAF generally flows more air, used for racing, and you CAN vent the bypass to atmosphere because the air is vented before it enters the MAF for metering. This also applies on the new cartridge type MAF (2004-present) because the MAF is relocated to the intercooler discharge tube just before the throttle body. Venting the valve covers can be tuned for, but the filters must be installed at the time you are writing the code. This was true last time I checked.
The drive cycle... This is the process the PCM must verify the driver completes for the PCM to complete the self diagnostic process and identify failures. If nothing is wrong, you will get a P1000 code when scanned (No faults detected). So if the engine is running and you pull off a vacuum hose, it will not immediately trip the light and set a code. Pull off a sensor connector, and it WILL trip the light and set an open circuit code immediately. This is known as a hard failure.
Ford OBD II Drive Cycle
Visual inspection is the first step. This is how John found the hose disconnected. Finding boost leaks becomes more difficult. Vacuum leaks can be heard by a trained ear, sometimes. Boost leaks do not occur until you go WOT, so testing is required. The COMPRESSOR side of the system is pressurized, and then simply trace the system looking for an air leak.
Here are some helpful videos that demonstrate what I am talking about.
Finding a boost leak- The test. This video was the most informative and thorough. On a turbo car, but he does demonstrate the many places boost can leak from. This varies by application.
Building the tool-
Boost Leak Testing 101: Building the tool. - YouTube
Using the tool-
Boost Leak Testing 201: Using the tool. - YouTube
This works on all forced induction setups. On a centrifugal supercharger or turbocharger, clamp the tool to the inlet of the inducer. On a Roots/Screw, clamp it to the throttle body.
I chose this video instead of others because he checks all areas that actually see boost. The intake, intercooler, bypass, blow-off, vacuum manifold, and the fuel rail. You will also want to spray down the hoses to your vacuum gauge and as shown, don't forget the IAC and EGR mounting flanges. Check anywhere there is a vacuum port that could potentially see boost, and you're done!
Most leaks you will hear, as is the case with Jbravo, but the spray will blow bubbles where you may never have known there was a leak!
BTW- NEVER use sealant on an injector "O" ring. If replacing injectors or "O" rings, clean sockets perfectly, and use WD-40 to lube them. They are self sealing! Rock the fuel rail in a circle and the fuel rail will seat the assembly, and when the rail mounting bolts are aligned, you're home.
Vacuum leaks for the N/A guys... I like this guy. He's good, and he also gives a quick explanation on how a vacuum leak affects fuel trim.
How To Find A Vacuum Leak - EricTheCarGuy - YouTube
The use of soapy water will cause NO problems whatsoever. Not even an issue. When checking for boost leaks, it will blow it outward and make bubbles.
When checking for vacuum leaks, we are introducing a fuel that alters the idle speed (Propane or carburetor cleaner). In the case of the video, the leak was large enough to kill the engine by overfueling it.
If there is a vacuum leak, there is no possibility of damage by introducing soapy water, unless you stick a vacuum hose in a bottle of water and suck LIQUID into the engine. This is NOT advisable... LOL!
Crash!
In this case, the original complaint was the truck was lacking power. Then we noticed the boost level on the gauge did not coincide with the specifications as noted by the manufacturer. Low boost level was one problem. A rich A/F ratio was a problem (9:1 A/F ratio, which is VERY rich). And it lacked power, obviously. So, we considered an improper tune and belt slip, assuming the blower was installed correctly. In directing John to look at specific problems, belt slip with a 3.0" pulley made sense, but the A/F ratio was still rich. Inspection revealed this...
The oil separator was connected to the 3/8" vacuum port at the rear of the intake and the other end was OPEN to atmosphere, and tucked away behind the intake. That eliminated the belt because slip issue (Most of it), because boost was being forced straight out through that port! The original PCV valve should be connected in the stock location. This separator should be routed from the driver side valve cover vent to the inlet of the blower to scavenge blow-by under boost, but AFTER the MAF in the blower inlet to ensure the air was metered only ONCE! The tuner tried and failed after at least 15 dyno runs, because a huge boost leak was driving the system rich, at a higher rate than the PCM could compensate for and probably outside the capability of the system!
When a member comes to me and purchases a new supercharger, (Even if fuel system upgrades have been purchased and are to be installed) when the system is tuned, we MUST verify the system is installed correctly. I always install the system as it comes out of the box, with the FMU and stock injectors and MAF FIRST. Then I fire it up and test drive it to verify everything is connected the way it should be and we don't have any problems, not even a belt alignment issue.
Once the installation is verified to be correct, THEN you can install the fuel system upgrades and go to the tuning step. Otherwise, if you do it all at once and run into problems, you know for sure the fuel system mods are not a factor. A process of elimination is next, and walking through the installation manual for potential problems is the place to start, then verify there are no connectors damaged or disconnected or make sure there are no boost / vacuum leaks. If you install the blower and fuel system upgrades, this creates many more factors to eliminate. It has proven to be well worth the additional time to verify the install first. Some might try to save by doing it all at once, and it may cause headaches and wasted time and money!
This article will address several issues, beginning with layouts and will touch on tuning. In this case, the truck is blown, so we are going to approach this problem for the supercharged guys out there. In fact, it applies to turbocharged engines as well. The theory is the same for all blown engines, and diagnostic processes are much the same for the N/A guys too, but the method of testing will be a little different.
If you are having problems on your normally aspirated engine, you will learn how to deal with vacuum leaks. This is important because nearly EVERY diagnostic routine in the Ford Manuals will have the tech looking for vacuum leaks FIRST.
To begin with, let's start with the MAF. This is an absolute. Blow through or Draw through, it doesn't matter. In simple terms, in order to maintain calibration in closed loop operation air it to be metered ONLY ONCE and all of that air must make it to the combustion chamber to be mixed with fuel. If an "X" amount of air is metered, the PCM will calculate how much fuel is to be added to maintain the programmed A/F ratio. It will always try to maintain the ratio, no matter how big a leak occurs (Unless a hard fault sets a code and you are in limp home mode with the SES light on). If you meter "X" amount of air, the PCM will adjust IPW to inject "Y" amount of fuel, based on the programming (Factory calibration or tuner supplied). The O2s are used to make calculations and algorithms tell the PCM what the O2s should read under any given load or condition. Again, this is a ratio, so if you measure the air and then don't use it, you are out of calibration.
On a draw through MAF setup you cannot...
- Vent the bypass to atmosphere.
- Run breathers on the valve covers.
- Have any vacuum/boost leaks.
Poor integrity of an installation (Tubing blowing off) or improper installation can cause metered air to leak, and if you are leaking boost or vacuum, no tuner in the world can get the fuel curves right, even though it appears to be tuned correctly. In other words, a boost leak will cause poor performance, low boost level readings, poor drivability, poor fuel economy, and difficulty in tuning, if it can be tuned at all. It just got tuned for an engine that had a boost leak.
So, if you meter air once, the PCM makes a decision, and boost leaks out, you have altered the ratio because part of the metered air just leaked out. To keep it simple here, the ratio is no longer correct. The ratio is no longer controlled by the PCM because the PCM would need to see short term fuel trim (A recording or table of the adding or subtracting fuel) change. It needs to see this compensation (Adding or subtracting fuel) outside of a set parameter for a programmed period of time before it ever flags it and sets a lean or rich code (Depending on the circumstance and programming). Then it starts updating the long term fuel trim. You will not see a vacuum leak immediately or within 3 dyno passes a tuner normally needs to write the new code. A scan tool will show it but a drive cycle needs to be completed prior to the system throwing a code.
Short and long term fuel trim outlined...
A blow-through MAF generally flows more air, used for racing, and you CAN vent the bypass to atmosphere because the air is vented before it enters the MAF for metering. This also applies on the new cartridge type MAF (2004-present) because the MAF is relocated to the intercooler discharge tube just before the throttle body. Venting the valve covers can be tuned for, but the filters must be installed at the time you are writing the code. This was true last time I checked.
The drive cycle... This is the process the PCM must verify the driver completes for the PCM to complete the self diagnostic process and identify failures. If nothing is wrong, you will get a P1000 code when scanned (No faults detected). So if the engine is running and you pull off a vacuum hose, it will not immediately trip the light and set a code. Pull off a sensor connector, and it WILL trip the light and set an open circuit code immediately. This is known as a hard failure.
Ford OBD II Drive Cycle
Visual inspection is the first step. This is how John found the hose disconnected. Finding boost leaks becomes more difficult. Vacuum leaks can be heard by a trained ear, sometimes. Boost leaks do not occur until you go WOT, so testing is required. The COMPRESSOR side of the system is pressurized, and then simply trace the system looking for an air leak.
Here are some helpful videos that demonstrate what I am talking about.
Finding a boost leak- The test. This video was the most informative and thorough. On a turbo car, but he does demonstrate the many places boost can leak from. This varies by application.
Building the tool-
Boost Leak Testing 101: Building the tool. - YouTube
Using the tool-
Boost Leak Testing 201: Using the tool. - YouTube
This works on all forced induction setups. On a centrifugal supercharger or turbocharger, clamp the tool to the inlet of the inducer. On a Roots/Screw, clamp it to the throttle body.
I chose this video instead of others because he checks all areas that actually see boost. The intake, intercooler, bypass, blow-off, vacuum manifold, and the fuel rail. You will also want to spray down the hoses to your vacuum gauge and as shown, don't forget the IAC and EGR mounting flanges. Check anywhere there is a vacuum port that could potentially see boost, and you're done!
Most leaks you will hear, as is the case with Jbravo, but the spray will blow bubbles where you may never have known there was a leak!
BTW- NEVER use sealant on an injector "O" ring. If replacing injectors or "O" rings, clean sockets perfectly, and use WD-40 to lube them. They are self sealing! Rock the fuel rail in a circle and the fuel rail will seat the assembly, and when the rail mounting bolts are aligned, you're home.
Vacuum leaks for the N/A guys... I like this guy. He's good, and he also gives a quick explanation on how a vacuum leak affects fuel trim.
How To Find A Vacuum Leak - EricTheCarGuy - YouTube
The use of soapy water will cause NO problems whatsoever. Not even an issue. When checking for boost leaks, it will blow it outward and make bubbles.
When checking for vacuum leaks, we are introducing a fuel that alters the idle speed (Propane or carburetor cleaner). In the case of the video, the leak was large enough to kill the engine by overfueling it.
If there is a vacuum leak, there is no possibility of damage by introducing soapy water, unless you stick a vacuum hose in a bottle of water and suck LIQUID into the engine. This is NOT advisable... LOL!
Crash!
