How To: Install Electric Fan WITHOUT going aftermarket (Let the PCM do the cooling!)

[masospaghetti]

Having an electric fan driven solely off of coolant temp, IMO, wouldn't perform that poorly. The mechanical fan moves very little air when the fan clutch is disengaged (ie, coolant is relatively cold) in the stock configuration and the air conditioner has no problems with it.

Obviously it would do better with the fan directly controlled by head pressure, but having it controlled by coolant temp should do fine as well.

 

[NICE59FORDF100]

Found this on a lincoln forum:

Fuel pressure is controlled by the fuel pressure regulator and is adjusted by vacuum. You should have around 30-32 psi at idle. Under low vacuum conditions, (WOT) it will adjust to 40-42 psi. The fuel injector pulse width is set by the MAF, and adjusted by the o2 sensor. The MKVIII uses Pulse Width Modulation, to reduce fuel pump speed. This intern reduces the amount of fuel being returned to the fuel tank, thus reducing fuel heating, thus reducing fuel vapors. This is your "low speed fuel pump relay". The high speed fuel pump relay is located in your engine compartment fuse box. IT is grounded inside the VCRM upon command from the PCM. It is only used during WOT and when heavy loads are placed on the engine. If your codes 542 and 543 were current faults, the engine would not be running, as there would be no power to the fuel pump circuit.

Fuel System Description for Taurus Flex Fuel and 4.6L-4V Mark VIII

The Mark VIII has a DUAL FUEL PUMP VOLTAGE system ( «Figure 11» and «Figure 12») to aid in fuel system noise concerns. The fuel pump operates in the high voltage mode (12-14 volts) during crank (for 5 to 60 seconds depending upon engine temperature), after start-up, at engine speeds in excess of 3300 rpm, and during periods of Wide Open Throttle when maximum fuel delivery may be required. The normal operating mode calls for low voltage (7-10 volts) to the fuel pump. This minimizes operating noise. Fuel pump operation is controlled by the PCM. The fuel pump operates in the same manner as all other systems except for the two speed feature.

NOTE:
Maximum fuel pressure is obtainable at WOT or the vacuum hose removed from the fuel pressure regulator. If fuel lines/systems have been drained or evacuated, it may take up to 15 seconds to obtain the pressure specified.

 

[2000StreetRod]

Prefer non-return fuel system

I think I prefer the non-return fuel system over the MKVIII PWM return fuel system since neither system has the capability to monitor the actual fuel pressure. The non-return fuel system has a fairly constant fuel pressure as long as the fuel pump has adequate capacity at max engine load and max RPM. That should make the injector pulse width calculation simpler and more accurate. With the return fuel system engine vacuum (not monitored) changes the fuel pressure via the fuel pressure regulator complicating the pulse width calculation. Also, vaccum leaks introduce inaccuracies in the calculation. When the PCM is in closed loop at light to moderate engine load the O2 sensors can allow the PCM to compensate for inaccuracies (except for the O2 sensor) by adjusting the short term fuel trims so both systems should have comparable performance.

I saw no mechanical relays in the VLCM photo. With the exception of the power transistor in the middle of the circuit board it looks like the power transistors (7) are mounted on the right side between a commom heat sink and individual clips/sinks. The schematic (023-7) indicates that the VLCM fuel pump output can be bypassed with the energizing of the high speed fuel pump relay. When the relay is energized the full (uninterrupted) battery voltage is directly applied to the fuel pump allowing it to run at max speed. This could be for redundancy, or because the VLCM does not support 100% on duty cycle, or because the VLCM overheats at max on duty cycle. Schematic (033-1) shows two cooling fan power inputs to the VLCM and two cooling fan outputs from the VLCM. I suspect the VLCM has multiple applications with different PWM loads and different solid state relay functions.

The VLCM interests me as a fan controller but it would not solve the main problem I have with an electric cooling fan implementation. I have replaced my single row (one inch thick) radiator with a double row (two inch thick) and there is not enough room between the water pump and the radiator for an appropriate electric motor fan.

 

[BrooklynBay]

I was thinking about connecting the fuel pump switching circuit into your vehicle, but I'm not sure if it will throw a lean mixture code when the pump runs on low voltage & slow PWM. On a side note, Ford should have eliminated the external fuel pump relays if they have a control module sending a PWM signal to the pump. I don't know why Ford has to reduce voltage if they are already reducing PWM. They didn't do this on the 2 wire fan circuit (they could do it on the 3 wire fan circuit).

 

[2000StreetRod]

Vlcm pn?

In the first post you stated that you found a VLCM on a 1996 MK VIII and there is a photo of a VLCM dated 14 Apr 1997 with part number F7LF-14B239-AB. Then you mention that the VLCM is found on 94-96 MK VIIIs. I searched eBay for VLCMs and found PN F7LF-14B239-AB listed for 1997 & 1998 models. I searched the Tasca and Tousley Ford database for F7LF-14B239-AB and it was not found. Do you know what year VLCM would be compatible with my 2000 Sport? OBDII was supposed to be implemented in all vehicles sold in the United States in 1996.

 

[NICE59FORDF100]

The first picture I posted was just an example of what the vlcm looks like. It was used on all 93-98 mk viii's (I've learned through my research). You're best bet for a 2000 explorer would be use of the later 97-98 style since that is when ford made the switch to multiplexing instead of the older SCP style network.

 

[GETDATSTUFF]

Not sure if this helps but I found this on an eBay listing that ended,

" Up for sale is the VLCM or Variable Load Control Module (also known as Engine Cooling Fan Module or CCRM) from a 1996 Lincoln Mark VIII. This module fits all 1993 through 1996 Mark VIII's.

This module controls the operation of the engine (radiator) 2-speed cooling fan, based on inputs from the PCM and coolant temperature sensors.

This was removed from a running vehicle and worked perfectly before removal.

The Ford engineering number of this is #F4LF-12B577-AA, which was sold as Ford service #F4LZ-12B577-AA. This unit also replaces #F3LF-12B577-AG, #F3LF-12B577-AH and #F3LZ-12B577-A.

As with most MarkVIII parts, this part is considered obsolete and no longer produced or sold by Ford"

 

[BrooklynBay]

Check WWW.GreenSalesCompany.Com.

 

[NICE59FORDF100]

So today I went to salvage yard to get a new motor for shade, and while out there, I managed to get two VLCM's out of a 95 and 96 mk viii. So testing should commence soon

 

[2000StreetRod]

connector with pigtails?

From the photos and wiring diagrams you've posted it appears there is only one VLCM connector (C106). Did you purchase a VLCM with mating connector and pigtails? I checked eBay and the going rate for a 1997-1998 VLCM with mating connector and pigtails is around $90 with free shipping.

One thing I've never favored on the aftermarket fan controllers is the radiator temperature probe. I learned with my remote reading temperature sensor that the radiator temperature varies significantly vertically and horizontally. However, I think there is an advantage of monitoring the radiator temperature instead of the engine coolant temperature (ECT). The ECT sensor is located on the block side of the thermostat instead of the radiator side. The purpose of the ECT sensor is to allow the PCM to determine the engine temperature and adjust the air/fuel ratio accordingly. The ECT sensor also allows the PCM to determine when the engine is overheating. A good thermostat will allow the engine to reach operating temperature as soon as possible and then maintain that temperature. According to my data logs my ECT only varies a few degrees F under normal driving conditions. It is only when the heat generated under load exceeds the cooling capacity of the radiator that the ECT increases. If the VLCM monitors the ECT, the cooling fan may only be activated when the ECT exceeds the specified value for a stock thermostat by a certain amount. It could compare the difference between the ECT and the stock value and make the fan speed directly proportional to the difference. It will be very interesting to find out how the VLCM actually works.

For engine cooling I'm inclined to prefer a system that monitors the radiator temperature and keeps it at least a certain number of degrees cooler than the thermostat setting if the cooling fan at max speed can't keep up with the engine heat generated at max load.

 

[NICE59FORDF100]

2000Streetrod, you never cease to amaze me with your knowledge of EEC. We need to have lunch one day!

nd yes, i bought both modules with wiring pigtails for 12 dollars each. One was from a 95, the other a 96. And i believe that yes, they operate based off the ECT reference value and compare it to the temp mapping tables and decides on cooling fan strategy if/when the ECT starts getting to a certain temp (let's say 200 degrees). When I begin testing this, i can monitor and record the ect via datalogging on my WDS and compare it to the PWM controlled voltage output of the VLCM and see how proportional they really are.

 

[delexploder]

Subscribing

 

[2000StreetRod]

Electro-drive fan strategy

I've started reviewing the electro-drive fan strategy module of the 1997 Ford Powertrain Electronic Control Strategy source code. It appears that this version has direct control of either a one speed fan, a two speed dual wound fan, a two speed fan with a series resistor or two separate fans. So far I haven't found any reference to a variable load control module. It looks like the PCM performs the entire control function but the logic used may provide some insight into the VLCM logic. Apparently the MK VIII is not considered to have the electro-drive fan and all of the "smarts" are in the VLCM.

"Electro-drive fan refers to an electric motor driven fan used to provide forced air circulation through the engine coolant radiator when natural air flow is inadequate; i.e., low vehicle speed or high engine coolant temperature. The fan is always turned off during CRANK mode to minimize the accessory load. Fan control is accomplished through the use of EEC controlled relays in the fan power supply circuit. . .

When the WOT EDF cutout feature is invoked, the low speed fan (LSF) is turned off only if not required to be on for some other reason, primarily high ECT. Therefore, if the LSF is on only because AC is requested and the vehicle speed is low, then, when AC request is cleared because AC throttle position flag is set, LSF request is cleared by AC throttle position flag being equal to 1. . .

The High speed fan can be requested by any of the following conditions:
- Very high ECT.
- ECT sensor failure.
- High A/C head pressure (transducer).
- Medium A/C head pressure switch tripped.
- High RPM and Load with low Vehicle speed (Grade load).
- Output state control forces ON state
The high speed fan request will be cleared when none of the above request conditions are true and also:
- Low ECT and Low A/C head pressure for a sufficient time.
However the fan will be forced off by any of the following:
- Output state control forces it off.
- Held off for a calibrateable time after start. . ."

A software timer is utilized to:
"1. To provide a delay to enable idle speed compensation before turning on the Low Speed Fan.
2. To ensure that once the Low Speed Fan is turned on, it stays on for a minimum period, to ensure that the relay is not required to open while passing the high surge currents that are associated with the first couple of seconds of EDF operation.
3. To delay the turn on of the High Speed Fan in order that the Engine may have stabilised and the LSF reached its minimum electrical loading. . .

Failure modes:
If the low speed fan fails the relevant malfunction code is set (P1474) but no action is taken as it is presumed that eventually the high speed fan will run. If a high speed fan failure is detected (P1479) then control reverts to the low speed fan to provide at least some cooling. The high speed status remains the same until either the fault is cleared or the temperature drops."

 

[NICE59FORDF100]

If I get time tomorrow, Im going to go ahead and hookup my breakout box and WDS to Blue, and see if i cant test wire the VLCM and see if it will output fan control. So Hopefully Ill have an answer tomorrow...

 

[2000StreetRod]

ECT sensor test

It would be interesting to disconnect the ECT sensor connection and see if the VLCM energizes the fan when it would not run under normal conditions.

 

[NICE59FORDF100]

OK, so since I was home alone all day today, I decided to start test this. So i hooked up the bare needed wires and went for a quick test. Mind you, i have not disabled the factory cooling fan or anything, just wanted to see what the VLCM would do.


Here is the VLCM kinda wired in on the core support of Blue

My breakout box that I was using for some inputs into the VLCM

And my multimeter as a stand-in for the electric fan itself

On the first test, nothing happened. I warmed the engine up to operating temp (Monitored via a second multimeter on the breakout box) and nada, no voltage output to the VLCM. At this time, all i had hooked up was power and grounds, fan output, DATA link, and fuel pump monitor circuit. Then i remembered reading the fans will not operate unless the engine is running. How does it know it's running? By monitoring the EEC relay. So i disconnected the explorer EEC relay under the power distribution box, and ran some more wires to make the VLCM the new EEC relay for the truck. I started it again.

This time I had full voltage (13.6v) being output to the fan. Problem now is that the fan is on High speed only and will not turn off no matter what. So now i am in the process of making the VLCM take over fuel pump relay duties and see if this changes things. Standby

 

[92exp4x4]

Where do you get your knowledge of the Ford systems? You must be a Ford engineer or something. I have the factory service manuals, EVTMs, wiring schematics and some other literature for my vehicles, but I never have been able to find anything that really describes the basic operation of the system.

Like when you referenced the network protocol of the OBD-1 system; I didn't know they used anything that complicated in these older systems. It seems similar to the CAN BUS networking in newer machines and the forklifts I work on. I have always wanted to know the inner workings of the computers and what they are capable of.

Good work and good luck in your project, I will be reading along. I like trying to keep stuff factory looking myself. It's interesting to see you make the machine work for you and build it like Ford would have.

 

[NICE59FORDF100]

Where do you get your knowledge of the Ford systems? You must be a Ford engineer or something. I have the factory service manuals, EVTMs, wiring schematics and some other literature for my vehicles, but I never have been able to find anything that really describes the basic operation of the system.

Like when you referenced the network protocol of the OBD-1 system; I didn't know they used anything that complicated in these older systems. It seems similar to the CAN BUS networking in newer machines and the forklifts I work on. I have always wanted to know the inner workings of the computers and what they are capable of.

Good work and good luck in your project, I will be reading along. I like trying to keep stuff factory looking myself. It's interesting to see you make the machine work for you and build it like Ford would have.

LOL, thank you for the compliment! But I can assure you, I am in no way a ford engineer, lol. I gathered my understanding of Ford electrical systems just by studying electrical diagrams and reading service manuals. Luckily, a lot of the older ford stuff is compatible when it comes to the programing language and sensor values (see my message center install and 5R55E swap). It just takes time to learn all of it, but the basics of it all is simply 12 volts

As far as the networking goes, the early ford networks (in this case, SCP) is very basic. Granted, not even I know exactly how it works per se, but it's the network that allows the more sophisticated scanners to read and interpret the PID values. Hence why I think this VLCM will work on an explorer. It's very possible I am completely wrong, and in today's tests, that may be the case. But ill keep working at it till I figure it out!

 

[2000StreetRod]

independent fuel pump control?

I see from the schematic 033-2 that the VLCM is looking for EEC voltage on C106 pin 15, and a fuel pump input (C106 pin 12) from the PCM but I'm going to predict that the fuel pump and the fan control functions are indepenent. However, the PCM does monitor the fuel pump output voltage (C106 pin 7) for diagnostic purposes.

 

[BrooklynBay]

Do you have any updates at this time?