REALLY REALLY bad day today.

[RICH MUISE]

There is continuity between the block and neg post on the battery. Looking at my wiring instructions, the other sensor coming off the coolant pipe is labeled engine coolant sensor. It is 2 wires, green and grey. This is where I may lose you guys, because both those wires feed back to the Televork panel (engine>computer patch panel). There is continuity between that sensor body and the block.
Any guess as to how that 2 wire "sensor" works. Could it be the sensor is just closing the loop between the two wires when it gets "too hot"? I'm  wondering if I could make a jumper to do the same to see if it turns the fan on......

[oldave57]

Rich,

Now you have lost me.  Your wiring harness and engine connections are completely different than what I had on my car and my advice is like trying to apply a 1957 fix to a 1990 era wiring harness. 

Apparently your trinary switch is working like we think it should (providing a ground to the cooling fan relay), and the wire from one of your engine switches to that switch seems to be related to providing a ground.  If that temperature switch has a single wire connection, then it would seem that it should be grounding when the temperature reaches its preset limit.  I sure don't know what the 2 wire temperature switch going to your control device would be doing or how to troubleshoot it.

Sorry for the misdirection,
Dave

[RICH MUISE]

Not a misdirection at all.....you got me thinking and the basics are still there. You're input is greatly appreciated. I did add a last question to my previous post. I've rarely had to call Ron Francis, but this seems like a good time. They made my engine harness, chassis harness, and a number of small (but expensive) things like the fan relay kit, battery cables, etc etc.
That one wire to the trinary switch is a Vintage Air thing, btw, notthing to do with the engine harness. The two wire is part of the engine harness, so it would make sense that is the one that controls the fan on at engine temp. The engine harness has no way of knowing that a A/C unit is going to be added, so the engine harness would have to take care of the fan........not as I had thought earlier.
Am I making sense? I'll find out the purpose of the two wire as opposed to just the single wire closing ground.

[oldave57]

Rich,

I'm thinking that the 2 wire temperature switch might part of your engine controls (I had completely forgotten that you have a more modern engine when I was sending all of my suggestions).  If you have 2 temperature switches, I would guess that the switch with the single wire connection (especially if that is the one that connects to the terminal on the trinary switch wire) that would be the switch related to the cooling fan.  I don't think there would be a need for more than one switch for the cooling fan, so I'm supposing that the 2 wire switch "talks" to your engine  controller regarding fuel/air mixture or fuel injection modifications relative to engine temperature.

Would it be possible to jump from the single wire switch to engine block just to see if the fan would start up?  That's about the only suggestion I would try first. 

Best of Luck,
Dave

[RICH MUISE]

I did try that (key on, but not in run?)....nothing happened.....unless there is a delayed start I didn't compensate for.

[oldave57]

Would it be worth a try to do the same jumper test with the engine running?  The controls on that newer engine might be smart enough to not work unless the engine is actually running.  If that fails, I am running out of suggestions.  It sure seems like it should work.

[RICH MUISE]

We're thinking alike.............That's exactly the case.....earlier I checked the fan on A/C request, and would not turn on in either on or run key positions. Has to have engine running, and there is about a 15 second delay.......I'll keep that in mind when I try grounding a sender wire.. I'll try again tomorrow grounding the single pole wire to the block with the engine running.....

I keep coming up with new issues. Tonight the engine started howling at me more so than it had a few times earlier this week. Not sure where it's coming from, but if it does it again tomorrow, I'll pull the serpentine belt to at least determine if it's something belt driven. I'm suspecting the new water pump I put on.  It goes away if I hit the gas.
I'm gonna watch a ball game.

[Ford Blue blood]

Rich that sensor with the two wires is for the computer.  The gray wire is reference V from the computer, the green is the signal from the sensor to tell the computer the status of engine temperature.  Don't ground either of them!

My earlier reference to the computer providing grounds was with respect to commands it gives to the injectors, solenoids for EGR, gas tank venting, compressor on/off, fuel pump control, all that stuff. 

All the inputs to the computer to tell it the status of cam timing, crank position, barometric pressure, RPM, throttle position, air temperature into the engine, air flow into the engine, exhaust gas O2 levels are all fed a reference voltage, pretty sure it is 5V in your system, irrespective, that reference voltage is the basis for all the measurements that input the computer and there by control the engine.

If I remember correctly in the MKVIII the computer tells a fan control box to turn on one or both of the fans.  I do know the computer turns off the A/C when at wide open throttle and RPMs above 3500 (I think).  It also turns on one fan when the A/C is on and head pressure gets to a preset level. 

I am not sure how RF modifies the fan controls but I am 100% positive that the computer does not provide power to the fans, it controls a relay to power the fan/s.  It could well be that there are separate relays for the A/C and engine temperature control?

Just went to his instruction manual for the system.  Did not see any instructions for wiring up a fan control circuit.  Did see all the fan control failure codes.  How are your fans wired?  Off the control panel or a separate sub system?

Lastly are there any codes dealing with engine temperature or fan control?

[RICH MUISE]

Thanks Bill........First, let me say after Thursday's 60 mile run and the car never getting over 195, I'm not sure how long I've been without a fan! Maybe never had one operational. Apparently the car can run at length (probably all winter) without a fan as long as there aren't other circumstances involved. It was 2 years before the car ever got over 200, and that was sitting in traffic over an hour on a hot day last September in Fort Worth.
Ron Francis supplied the connector to the Mark VIII fan. I'll check the wiring imprints and instructions to see if it fed the Chassis wiring harness or the engine harness. Some of that stuff intermingled between harnesses. The Express chassis harness did have a built in fan relay and fuses, but only 30 amps, so I had to add a 60 amp relay kit. I'm 95% sure the fan connector was supplied with the Express chassis harness. Those are custom made to fit a specific build whereas the MK-93 engine harness is pretty much unaltered from one kit to another.

The fan control box you mentioned. One of the codes thrown, OBD 1 code 587, now and before,  "no communication problem between pcm and vcrm(variable control relay module). That code and an egr code have always been thrown. I'm pretty sure the VCRM is the "fan control box" you mentioned. You probably just hit the nail on the head, and was one of the main reasons I was going to call Ron Francis today. The VCRM is not part of the controls transferred from the donor car. There was no "Bag 78..VCRM" in my kit, and the instructions were ambiquous in stating "........and other functions not used in a aftermarket application".
Way back when I was wiring the car I called to confirm/inquire about that, and they said it was not needed for my application. I'll follow up on that again.

[RICH MUISE]

I haven't called them yet, but just to add...........the VCRM was never on my list of needed things to remove from the donor car. I believe the conversation with Ron Francis tech went something like....the VCRM controls many things on the Mark VIII that are not used in a conversion, and if the VCRM were  installed, the computer would would start throwing codes for many missing signals/systems requiring the computer to be reprogrammed.
195 degrees is below the normal operating temp, I believe somewhere I read that some functions are not turned on by the computer until the car reaches it's normal operating temp of 204(?). I'm not sure at what temperature the system would want to turn the fans on, I'm guessing not before it reached it's "norm". Could it be possible it wouldn't even want to turn it on at my high point of 225?
BTW, my fan is just a single fan, but I believe 2 speed.

[RICH MUISE]

I called Ron Francis. They confirmed the VCRM has been deleted from their kit and the only way to delete the code is to have the computer reprogrammed. Second, they confirmed their harness controls the engine temp request, it's the vintage air wiring that controls the A/C.
The front 2 wire coolant temp sensor is for fuel injection control info...nothing to do with the fan. The other front sensor is vintage air. What I'm looking for is a single wire sensor that has a green wire marked sensor ground. He told me to find it and provide a ground to see if the fan turns on. depending on what happens, he may have me check the sensor by testing to see at what temp it opens up.

[RICH MUISE]

While out running errands, I stopped by to talk with my transmission guy. Have a new theory now. He said if I hadn't installed the front seal correctly, it would leak steadily, not intermittently, and most probably from the first time I started the engine. I asked about an overfill. The bleed valve for my tranny is on the back topside of the tranny..no way it would leak at the front from an overfill. His theory: a possible cracked torque convertor. If I stopped the car with  the crack at the bottom, it would leak, with the crack at the top..no leak. He suggests to keep driving it and if it leaks again, mark the crankcase pulley, then get it rotated 180 to see if it stops. Makes sense, I hope his theory is not correct.

[Ford Blue blood]

Rich the sight I looked at had the low speed fan coming on a 205 and the high speed at 220.  Not sure if that applies to the MK VIII, the t-stat in my MK was a 205.

[RICH MUISE]

Good info, thanks.......I'll add the two speed to my questions for the Ron Francis tech guy when he comes back from lunch. Mine just seems to go right to lift-off stage, lol.
Found the sensor ground wire/sensor he had me look for, made a ground jumper wire. as soon as I turned the key on the fan came on! I shouldn't be assuming things, but I can't help but think that's saying whatever problem it is, it's in that sensor....either not functioning or not operating at a low enough "turn-on" speed.
With everything that's happened, I have to revisit my thoughts about having a switch for the fan, as Dave does. I'm obviously not aware when or if my fan is running when on "automatic", So, if it stopped working, how would I know? Yeah, my deaf ears can hear it running in the garage, but on a highway in traffic?? not.
I'm more likely to be aware of a potential heat problem due to ambient temps or traffic, etc, and manually turn the fan on, so I don't think forgetting to turn it on would be an issue due to the fact I apparently don't need it most the time. It would be ideal of course to get the intended system working and have the manual turn-on as an option. I'm thinking that would be easy as splicing in a switched ground wire to their "sensor ground"

[RICH MUISE]

OK......apparently I have a bad sensor or connector. I'm having them send new ones. That should take care of the fan issue, other than adding the switch.
I have to get into the cooling system to replace a leaking (too-small) o-ring on a coolant pipe, so I'll wait for the new sensor from RF before I drain the system. He was going to have me pull the old sensor and do a boilng water test, but if I did that, I'd have to wait for the replacement to come in. I'd rather just replace the old with the new while I'm doing it and be finished with it.
My fan is 2 speed, but the way it's wired is high speed only. To use both speeds I'd have to rewire the connector and wiring and add a second relay. The sensor is set to ground out/turn the fan on at 205*, which my engine under normal conditions never gets to. I could order a lower temp sensor that starts the fan at 176*, but that would keep the fan running all the time.
Keith @ RF oddly enough suggested I may want to put in a toggle switch exactly the way I had thought above. Gonna do it. My only question there is..............I'll be switching ground, I'd like an indicator light, so I'm guessing it would have to be a separate light with the ground wire the same wire I'm switching with the toggle?