Full Size Ford Bronco Forum banner

1 - 20 of 57 Posts

·
Premium Member
Joined
·
3,984 Posts
Discussion Starter #1
Many know that I have just completed a 408 Stroker build with MAF Upgrade. Seattle FSB 408 Stroker Build

What an experience! After hours and hours of research and many questions it has all finally come together. Although challenging at the time, the fun part was problem solving. Check this out, my tuner believes that I have reached my goal of 500+ Ft/Lbs Torque at the flywheel. He estimates a 30% loss of HP & TQ through the drivetrain to the rear wheels. I more conservatively estimate a 25% loss. The best part is a smooth running engine and no codes!!!

I wanted to share some issues that crept up which created significant learning opportunities. I hope that this can provide some clarification to others that are contemplating a MAF Upgrade. If I am mistaken in any area, please correct me. If you have some personal Lessons Learned with your MAF Upgrade, please post them here for all to see.

A MAF Upgrade is something that requires a lot of research, preparation and problem solving. In my case, my 1990 EFI 5.8L Speed Density E4OD Bronco required a EEC-IV/OBD-I/E4OD/MAF Powertrain Control Module (PCM) which can only come from a 1995 Ford Truck PCM, unless I chose an older non E4OD Ford Mustang PCM which would require a separate Transmission Control Unit (TCU).

No matter which computer you use, a proper "tune", or reprogramming of the PCM, is in order for your specific build. Many will attempt to do a MAF Upgrade on the cheap with a closely matched PCM, such as the 5.8L BIO0, attempting to end up efficient. But unless you provide a custom tune, or install a on-board tuner, you will be settling for "good enough" which may never become efficient.

How did I ever become convinced that I had to have a 5.8L "BIO0 PCM" or a "AKCO Lightning PCM"? With a knowledgeable, experienced custom tuner all can be made near perfect for your application even using a 5.0L MAF PCM. Mail order tune? Blah!!! Get on the Dyno and get the most out of your build!!! A tune can even benefit an aging EFI vehicle, with or without upgrades, to create a much more efficient system (i.e. more power and better mpg).


Here is what I ended up with:

MAF Upgrade

1995 Ford F150 5.0L PCM - WAY1 (F5TF-12A650-JB)
Pro-M Racing 75mm Mass Air Meter
RJM Injection Technologies Truck MAF Conversion Harness
Distributor Mount Gray "Push Start" TFI-IV Ignition Control Module
Single Narrow Band Oxygen Sensor
DynoJet Performance Tune w/Custom Chip

287.85 - Peak Rear Wheel Horsepower
392.11 - Peak Rear Wheel Torque :twotu:
13.00 - Air/Fuel Ratio (Flat @ WOT)


Air/Fuel Ratio - 14.7 Idle, 13.0 WOT
Fuel Pressure - 42 psi with 40 lbs/hr Fuel Injectors
Base Timing - 12.5 BTC
Compression Ratio - 9.546:1




MAF Upgrade - Lessons Learned

HEGO - The Oxygen Sensor (O2 Sensor) assists the PCM in determining if the Air/Fuel Ratio is rich or lean by measuring the percentage of Oxygen in the exhaust. In Closed Loop, (idle/ low load cruising), the PCM continuously adjusts the Air/Fuel Ratio according to input from the Oxygen Sensor. In Open Loop, (acceleration/high load), the PCM ignores the Oxygen Sensor and relies on a programmed Fuel Map to provide a more rich Air/Fuel Ratio. This is how EFI provides economy (Closed Loop) and performance (Open Loop).

Modern Oxygen Sensors are typically Heated Exhaust Gas Oxygen (HEGO) Sensors, having a heating element to quickly bring the Lambda (Oxygen) Sensor into operating range instead of slowly waiting for exhaust gases to heat the sensor. There are 4-wire and 3-wire HEGOs. The only difference is the 3-wire HEGO uses a common ground for both the internal lambda sensor and heater element. Older non-heated Oxygen Sensors have only 2 or 1 wire.

I got caught up in the "you have to install 2 HEGOs with your MAF Upgrade" threads. Furthermore, my Ford Fuel Injection Truck Computer Pin-out Chart indicates a Left and Right HEGO on Pins #43 & #44. So I had 2 new bungs welded in the appropriate locations on my Bassani Y-Pipe and I was ready to go. Then I saw a post on FSB where someone stated that they only needed one HEGO with their WAY1 PCM MAF Upgrade. Totally confused, I decided that it just wasn't clear from all the threads and builds that I have read. So after hours more of researching, I determined the following:

Bronco MAF w/OBD-I (WAY1/VEX1/AKC0) only requires 1 HEGO.
Bronco MAF w/OBD-I (BIO0) requires 2 HEGOs.
Bronco MAF w/Mustang PCM (A9L/A9P) requires 2 HEGOs
Bronco MAF w/OBD-II (1996) requires 3 HEGOs


Look at the wiring schematics in your Chilton or Haynes manual. I have finally figured out that the Ford Fuel Injection schematic only says for a "1994-95 Mass Air V8 Truck". It doesn't say what kind of PCM, I'm left guessing. Clearly a A9L or A9P. If you install a second HEGO with a WAY1/VEX1/AKC0 PCM, the right passenger side HEGO will be in the incorrect location and the left drivers side HEGO will not function at all.


ACT/IAT - This is the Air Charge Temperature Sensor (ACT) or Intake Air Temperature Sensor (IAT). It provides Intake Air Temperature for the PCM to determine proper air/fuel mixture considering the density (temperature) of the air. On Speed Density systems, this sensor is located on the driver's side lower intake manifold. On Factory MAF, it is located in the air intake tube after the filter and before the MAF Sensor. In either location, the same sensor is used.

With a MAF Upgrade, we have been advised to relocate this sensor to the factory MAF location. I believe this is due to the new MAF PCM being programmed to look for different temperature parameters due to the sensors expected location. Clearly the intake manifold will have warmer air than the air filter box.

I did not relocate my ACT/IAT Sensor and left it in the intake manifold. With my custom tune, we programmed the PCM for the specific ACT/IAT Sensor temperature parameters for the intake manifold location. Heh, if you have an on-board tuner or are getting a custom tune, why not? My tuner insists that this will work fine.


TFI - The Thick Film Ignition (TFI) Module, aka Ignition Control Module (ICM), works electronically with the PCM to control ignition timing and dwell. There are two types of distributor mounted TFI ICMs used in Broncos, the gray "Push Start" TFI-IV Module and the black "Computer Controlled Dwell" TFI-CCD Module. These are not interchangeable unless harness wiring modifications are made. Due to the TFI ICMs propensity for heat related failure, Ford relocated a redesigned module in the 1996 Bronco to a remote location. The remote mounted TFI-CCD Module is not interchangeable with either distributor mounted modules.

I was prepared to upgrade my Distributor Mounted TFI Ignition Module from TFI-IV Push Start (Gray) to TFI-CCD Computer Controlled Dwell (Black), but I have stayed with my original "Push Start" TFI Ignition Module. Even though my new WAY1 MAF PCM was designed to be used with a TFI-CCD, I have had no CEL or dwell issues. My PCM receives proper signals and adjust timing perfectly. I currently don't see a problem. What are the differences between the two? Well, lets review...

Both TFI-IV and TFI-CCD send a Profile Ignition Pickup (PIP) Signal to Pin #56 of both Speed Density and MAF Computers.

Both TFI-IV and TFI-CCD send a Ignition Diagnostic Monitor (IDM) Signal to Pin #4 of the PCM - the TFI-IV from the negative terminal of the ignition coil (filtered through a 22k ohm resister) and the TFI-CCD from Pin #4 of the TFI (internally filtered).

Both TFI-IV and TFI-CCD use the ECM Spout Signal from the PCM to control the ignition timing.

The main difference between these two Ignition Modules is that TFI-IV Ignition Dwell is controlled by the TFI in relation to engine RPM and 12v Start Relay Signal. The TFI-CCD Ignition Dwell is controlled by the PCM through the Spout Input. I still don't see a difference, same input just a different way of getting it. Heh, my computer is happy and efficient.

Edit: My engine eventually developed a ping when warm and under load. This was remedied by a distributor upgrade to a remote mount CCD TFI ICM. I am not sure whether this is due to the increased heat from the performance engine or the content of the signal. I would now recommend this upgrade to anyone who is using a PCM that was originally designed to use a Black CCD TFI ICM.


VSS - I was initially confused regarding the Rear Anti-lock Brake System (RABS) Sensor located on the rear differential and the Vehicle Speed Sensor (VSS) located on the Transfer Case. This was largely due to terminology where the RABS Sensor is also commonly called a VSS. This caused significant E4OD shifting problems until I figured it out.

The VSS is critical to the electronic E4OD. It sends an AC Frequency Wave to both the Cruise Control Module, and more importantly to the PCM indicating vehicle speed. In relation to the E4OD, this signal allows the PCM to determine shift points. Additionally the VSS Signal provides input to the Anti-Lock Braking System (ABS) on 1992 and newer Broncos.

1990-1991 Broncos have mechanical speedometers connected to the Transfer Case Tailhousing by cable and gears. The VSS is part of this system and sends a usable AC Frequency separately to the Cruise Control and PCM which controls both engine and E4OD functions. It is important to note that electrical schematics show one VSS wire going to PCM Pin #3 (VSS+) and the other wire going to PCM Pin #6 (VSS-) and what I believed to be a Chassis Ground. Also note that there is a separate ABS Sensor on the Rear Differential solely for RABS Module Input, which also measures vehicle speed.

1992 and later Broncos upgraded to an electronic speedometer connected to a Programmable Speedometer/Odometer Module (PSOM). The speedometer cable and VSS were removed from the transfer case and the ABS Sensor on the rear differential became both the VSS and ABS Sensor. The signal goes through the ABS Module to the PSOM, for speedometer/odometer functions, and is then sent to the Cruise Control and PCM. It is important to note that electrical schematics show one VSS wire going to PCM Pin #3 (VSS+) and the other wire going to PCM Pin #6 (VSS-) with No Chassis Ground.

This is where my dilemma occurred following the Ford Fuel Injection 1994-1995 MAF V8 Truck EFI Harness schematic. The FFI schematic clearly shows (what I believed to be) a VSS Chassis Ground on both Speed Density and 1994-1995 MAF PCMs. Knowing this, we left the 1990 VSS in place during re-pinning as the schematic and instructions indicated and installed a chassis ground on the VSS-. Subsequently, the E4OD would not shift correctly at all. After a week of searching, I finally found that a Chilton's wiring schematic showed no Chasis Ground for 1995 PCM Pin #6 (VSS-). We removed it and it worked! Clearly this was my mistake in not recognizing that the VSS- on PCM Pin #6 was a reference ground which does not include a chassis ground. The schematic ground symbol on VSS- threw me off.

The point is that there is a difference between the 1991 & 1992 Bronco VSS and without it being correct your E4OD will be very unhappy.

--------------------------------------------------------

Finally, I would like to say that the information on this site has been invaluable. The informative and entertaining dialogue from those experienced and knowledgeable is exceptional. I hope that I can return the favor to someone else. :thumbup
 

·
Registered
Joined
·
36 Posts
that is awesome info and nice job

That is a ton of real world info. Thanks a load for posting that. Sounds like that truck rocks !!!!!!!!!!!!!
 

·
Satyr of the Midwest
Joined
·
17,741 Posts
You should be getting an IDM fault with the gray ignition module. At least, I did with mine, before rewiring to a CCD-TFI setup. Theoretically, if you have the ability to change the binary, you can change this as well. I've even thrown around going to EDIS and eliminating the inaccuracies of a distributor setup. Time and money, that's all it takes. :cry

BIO0 PCMs need both left and right bank HO2S.

Have fun with your newly-tuned setup. You're right about the acceleration not stopping! :thumbup :rofl:
 

·
Registered
Joined
·
373 Posts
Thanks for posting your experience SeattleFSB!

Sig, what did you have to rewire for the Black CCD modules on a truck that originally had the grey? Was yours dist or firewall mounted?
 

·
Satyr of the Midwest
Joined
·
17,741 Posts
It was on the fender. :toothless You'll see remote-mounted in most documentation.

IIRC, the line coming from the coil negative terminal with the 22kΩ resistor should be clipped out, as should the line providing the "START" signal to the TFI (pin #3 on the TFI connector). Then, that same "START" pin needs to be connected to the PCM's IDM input, that same IDM line previously discussed, except withOUT the resistor, i.e. a direct connection between the old "START" terminal and the PCM's IDM input line.


Ryan made a couple of nice schematics that better illustrate the small differences (nevermind the INGition vs. IGNition):




 

·
Registered
Joined
·
373 Posts
Thanks!!

Did you have to rewire anything to get your speedo working trans shifting correctly?

Wondering if you maybe have any insight on this:

Signal path is as follows:

VS --> 4WABS --> PSOM --> PCM
monkei said:
Can the 4WABS module be bypassed on a truck with an EEC that is meant to have that module in the truck, to send the signal straight from VSS to PSOM?

I'm converting to MAF using a BIO0 EEC that came from a truck with 4WABS but I'm not going to have 4WABS.

If you have the module in place and wired up but no front brake sensors or front ABS lines, will the RWABS still work? If not, will the incomplete 4WABS throw a code resulting in a CEL?
 

·
Premium Member
Joined
·
3,984 Posts
Discussion Starter #8
You should be getting an IDM fault with the gray ignition module. At least, I did with mine, before rewiring to a CCD-TFI setup.
I can't see where the two IDM Signals are different enough to cause a code. Both are filtered versions of the ignition primary waveform and both go to Pin #4 of the PCM.

Additionally, I have seen posts from others who have also successfully retained their Push Start TFI post MAF Upgrade. The main problem I have seen is when people mistakenly replace a Distributor Mount TFI Module with a Remote Mount Ignition Module and can no longer send a PIP Signal to the PCM.

See this article quote regarding TFI IDM differences:

Ford TFI modules: Gray or Black?
Article by David Sill, IDENTIFIX Ford Team Leader

The Ignition Diagnostic Monitor (IDM) signal on a Push Start TFI system comes from the coil negative circuit and is filtered through a 22k ohm resistor to pin #4 on the EEC-IV computer. The computer monitors this circuit to verify a coil firing for each PIP signal, and sets codes if it sees missing or erratic signals.

Pin #4 on the CCD TFI module, which was the start circuit input on the Push Start TFI module, is now the IDM signal, sent directly from the TFL module to pin #4 on the EEC-IV computer. This signal is still a filtered (low voltage) version of the ignition primary waveform, but is filtered internally in the TFI module rather than through an external resistor.
 

·
Satyr of the Midwest
Joined
·
17,741 Posts
The signals are different in content, and that's where the code will come from. The PCM will command a shorter dwell time in a CCD setup, and when that signal isn't replicated on the IDM line (the only feedback the PCM gets about the ignition system working), a trouble code is tripped. The PCM compares the signals, and if they're not identical, something is amiss in the ignition module or downstream from there.
 

·
Premium Member
Joined
·
3,984 Posts
Discussion Starter #10
Originally Posted by monkei
Can the 4WABS module be bypassed on a truck with an EEC that is meant to have that module in the truck, to send the signal straight from VSS to PSOM?

I'm converting to MAF using a BIO0 EEC that came from a truck with 4WABS but I'm not going to have 4WABS.

If you have the module in place and wired up but no front brake sensors or front ABS lines, will the RWABS still work? If not, will the incomplete 4WABS throw a code resulting in a CEL?
According to my Chilton Manual, Broncos had rear wheel only anti-lock system (RABS-I) through 1992. In 1993, all F-series trucks incorporated a slightly improved rear wheel only anti-lock system (RABS-II) and Broncos converted to the new 4-wheel anti-lock brake system (ABS). Considering this, I am guessing that you have RABS-I and no front wheel brake sensors.

Here is a quote from Steve83:
A failed 4WABS module can interfere with the PSOM & everything on the Gy/Bk circuit, but the RABS module won't. If the 4WABS module is suspected of interfering with the PSOM, bypass the 4WABS module & feed the ABS signal directly to the PSOM by installing jumper wires from LG/Bk to LG/Y, and from R/Pk to O/LB. If the RABS module is suspect, simply unplug it.
PSOM

Considering that the RABS Module is what will send a RABS Warning Light signal to the PSOM, I think the fact that you do not have front brake sensors is irrelevant because they are not applicable to RABS, only to a 4WABS System.

Why do you not want your RABS?
 

·
Registered
Joined
·
373 Posts
I am guessing that you have RABS-I and no front wheel brake sensors
Why do you not want your RABS?
Correct, I have rwabs on my 92, (no front wheels sensors/lines) which hasn't worked since I put on the superlift speed calibrator. The calibrator will be removed and Ill be keeping all the RWABS hardware, but I will be using the BIO0 pcm which came in trucks with 4wabs.

In those trucks the VSS passes through the 4wabs computer before going to the PSOM and PCM. I'm wondering if I can have the VSS signal bypass the 4wabs computer and be fine as far as transmission and speedo are concerned.

If that won't work, will I just get an ABS light if I run (wire in) the 4WABS computer without the accompanying 4WABS front sensors and lines, or will my RWABS also not work. I can live without RWABS just fine, but I do need to be sure my PSOM/PCM gets the right speed signal.
 

·
Premium Member
Joined
·
3,984 Posts
Discussion Starter #12
Here is a quote from Steve83:
A failed 4WABS module can interfere with the PSOM & everything on the Gy/Bk circuit, but the RABS module won't. If the 4WABS module is suspected of interfering with the PSOM, bypass the 4WABS module & feed the ABS signal directly to the PSOM by installing jumper wires from LG/Bk to LG/Y, and from R/Pk to O/LB. If the RABS module is suspect, simply unplug it.
See this link and scroll down to PSOM and ABS Sensor:

PSOM
 

·
Premium Member
Joined
·
3,984 Posts
Discussion Starter #15
So...at 14.XXX at idle and 13.XX at throttle, what MPG do you get with over 400"?

SWS
Air/Fuel Ratio - 14.7 Idle, 13.0 WOT

14.7 AFR would be the most efficient, correct?
A flat 13.0 AFR at WOT is good, right?

I haven't a clue of the MPG. Yet.

The tune was done on January 6. I am still getting used to how fun this truck is. Probably very poor gas milage until I calm down and ease off the gas. ;)
 

·
Registered
Joined
·
1,639 Posts
Air/Fuel Ratio - 14.7 Idle, 13.0 WOT

14.7 AFR would be the most efficient, correct?
A flat 13.0 AFR at WOT is good, right?

I haven't a clue of the MPG. Yet.

The tune was done on January 6. I am still getting used to how fun this truck is. Probably very poor gas milage until I calm down and ease off the gas. ;)
yes better to be rich than lean ;)

13.0 is right on the marker at WOT.
 

·
aka: kemicalburns
Joined
·
7,605 Posts
Great Thread seattleFSB. I have a question why you didnt use a factory 95 5.0/MAF/E4OD harness. I know RJM makes good stuff and if one could afford there product i can see it being newer and potentially less problematic.
 

·
Registered
Joined
·
1,224 Posts
yes better to be rich than lean ;)

13.0 is right on the marker at WOT.
What does this mean? The lower the number, the richer the AFR. I was thinking it was a tad on the lean side, but if there is no ping and the EGTs are good, run with it.

SWS
 

·
Premium Member
Joined
·
3,984 Posts
Discussion Starter #19
What does this mean? The lower the number, the richer the AFR. I was thinking it was a tad on the lean side, but if there is no ping and the EGTs are good, run with it.

SWS
Quote from Wikipedia: Air-Fuel Ratio - Wikipedia

For gasoline fuel, the stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel. Any mixture less than 14.7 to 1 is considered to be a rich mixture, any more than 14.7 to 1 is a lean mixture...

A stoichiometric mixture unfortunately burns very hot and can damage engine components if the engine is placed under high load at this fuel air mixture. Due to the high temperatures at this mixture, detonation of the fuel air mix shortly after maximum cylinder pressure is possible under high load (referred to as knocking or pinging). Detonation can cause serious engine damage as the uncontrolled burning of the fuel air mix can create very high pressures in the cylinder. As a consequence stoichiometric mixtures are only used under light load conditions. For acceleration and high load conditions, a richer mixture (lower air-fuel ratio) is used to produce cooler combustion products and thereby prevent detonation and overheating of the cylinder head.
I should right on target, according to my tuner, for idle and WOT. A flat 13.0 AFR at WOT shows that my upgraded fuel system is adequate for my 40 lbs/hr Fuel Injectors as the AFR does not migrate to lean. :thumbup
 

·
Premium Member
Joined
·
3,984 Posts
Discussion Starter #20
Great Thread seattleFSB. I have a question why you didnt use a factory 95 5.0/MAF/E4OD harness. I know RJM makes good stuff and if one could afford there product i can see it being newer and potentially less problematic.
I used the RJM MAF Truck Harness because I was looking for a clean install with minimal problems and serviceablilty down the road. This is a well made harness and each wire is well marked for ease of repinning. You just have to be patient with Ryan and order this harness well in advance of your build.

Keeping my stock factory harness, along with the RJM MAF Truck Harness addition, allowed me to keep my ACT/IAT in the stock Intake Manifold location which is currently used on my existing Edelbrock Performer Intake Manifold. Otherwise, I would have had to plug the Intake Manifold sensor port and relocate the sensor to the air box, requiring a new enclosed MAF Air Box and the 1995 5.0L/MAF/E4OD harness for the correct harness length to the sensor.

This made the upgrade much simpler as I am using an open K&N filter with no air box.
 
1 - 20 of 57 Posts
Top