Taurus fan slows at idle

[awd92gsx]

Well, I'm about at my wits end with this car and I'm pretty much out of ideas at this point.

 

Awhile back I put in a taurus fan set (new aftermarket unit) with the JTR radiator. It really moves the air and seems to keep the car cool, with one exception...

 

Whenever I put it in drive and the rpm's drop a little (idles about 750 rpm in drive now) the fan slows way down and the car starts to heat up. Give it a little more gas to get up to around 825+ rpm, the fan speeds back up, and the car cools back down as a result. If I leave it in park/neutral it runs fine (gave it about a 900-1000 rpm idle)

 

Thinking it might be an alternator issue I put in a 140 amp summit unit in place of the 100 amp unit I had to no avail. Exact same symptoms.

 

Did some voltage drop tests and found that the 10g wiring was dropping quite a bit of voltage, so, I replaced/rewired the entire cooling system using 8g wire and a new 75a bosh style relay and also rewired the entire charging system using 4g and 8g wire along with new terminals, connectors, power distribution blocks, etc...

 

The lights do not dim, though, there is a noticeable heavy decrease in rpm when the fan comes on...probably around 200rpm or so.

 

Now, I realize the fan draws alot of amperage, but, has anybody else run into this problem of the car simply not being able to provide enough current at an idle to let this fan work properly?

 

I've done everything I can think of (including adjusting timing/fuel) to keep it cool...I'm seriously thinking the overheating issue is related to the fan cooling down since as long as I can keep the fan rpms higher it cools just fine and the fan cycles on and off as designed.

[Pop N Wood]

Shoot, man. You did everything I could think to do.

 

Do you have the fan on the low or high speed setting at idle?

 

Also do you have a 1 wire or 3 wire alternator? What is your voltmeter reading when all of this happens?

[Zmanco]

I think you already have determined that at idle with the fan on the alternator just can't put out enough current to run the fan fast enough. Modern cars deal with this by having the FI controller adjust the IAC by opening it up more so that the idle remains constant regardless of load.

 

On mine where I'm using megasquirt and a bosch 3 wire IAC, I can see the duty cycle for the IAC go from around 11 or 12% without the fan on up to as high as 30% when both 12" fans kick in. I'm running with a 90 amp Maxima alternator.

 

You didn't say if you are running with carb or FI, but a simple fix might be to just increase the idle so that even with the fans on, the alternator voltage stays above say 13.5 V. But of course this will generate more heat which will only make the fans come on more often.

 

A better method would be to increase the idle only when the fans are on. With an aftermarket FI system like MS you have choices on how to do this (like the bosch I'm using). With a carb, I believe a solenoid used to be used when the A/C compressor was active. Some used an electric one, others operated off of engine vacuum. I had tried to find one at the local pick n pull before converting to MS, but never found one that looked reasonable to install on the L6.

 

Hope that gives you some ideas.

[Dave]

Looks like you got the hot/positive side covered, but where does the negative/ground side go to? can you make the negative connection for the fan at the battery?

[Dragonfly]

Unless you drive close to red line all the time you could reduce the size of the alternator pully. That will cause the alternator to turn faster at idle than it does now. I does have the potential to work the voltage regulator harder under regular driving conditions though.

 

Dragonfly

[awd92gsx]

I installed the relay on the drivers side inner fender well, a little behind the headlight. The ground from the fan goes to the 75a relay (via 8g wire) and then to chassis ground; all in all, maybe a foot and a half of 8g wire for the ground.

 

Chassis ground from the battery consists of a single 4g wire from the battery to the chassis, though I do also have a 4g wire on the other side of the engine from the engine block to chassis ground.

 

I'm running a carbed setup.

 

It is possible for me to adjust the idle high enough, but, for me to get the fan to run high enough would require about an 850 idle while in drive which relates to about a 1100 rpm idle given everything else...which, to me, seems too high.

 

My original 100a was a 3 wire while my 140a summit unit is a single wire configuration. I noticed no change between the two alternators at all. Idle output from both was about 13.6v or so (at least in park/neutral)

 

I'd hate to go out and spend $200 or so on a fan that flows less but requires less current, especially when I see so many people using the Taurus fan setup successfully. That's why I'd just like to figure out what the problem is with mine. It's pretty much the only thing keeping me from driving the car for more than anything than just around the block.

[Pop N Wood]

There was another thread about this a while back. Temp guages can be voltage sensitive if the internal regulator is starting to age. Are you sure it is actually getting hotter? And how hot, really overheating or do you just not like it going up?

 

If you still had the 3 wire I would recommend putting the sensing wire right at the fan. That way you would have a constant voltage regardless of RPM.

[COZY Z COLE]

I have the 2-speed Taurus with a carbed/blower heat producing set-up. At idle I'm at 650 rpm and the low speed fan is on and the temp. is 192* which is normal for me so what is your guage reading that indicates running hot???

 

 

 

LARRY

[pparaska]

You can get a solenoid from Holley or off an old car in the junkyard to "idle up" the carb linkage (basically the plunger pushes on the throttle lever on the carb a bit). Runs on 12 volts. Hook it up to be energized when the A/C is on. I've meant to do this for a while, but not really needed it.

[getZ]

I have a 93 taurus fan with a summit 100 amp alternator. Later I switched to a 140 to take care of all the other electrical junk I added. In either case I never had any problems. My idle is set a little on the high side in "park" at around 900 rpm. Engaging the ac and putting the car in drive with the brake on never drops the engine below 700 rpm. This is also a carbed engine with one wire setups on both alternators.

 

One way to check if the wire guage is to small, is to feel if it is getting hot. If it's uncomfortable to touch you about due to fry a wire.

 

Is the voltage changing at idle? What size fuses are you running on the fan. I use a 50 amp on the high speed and 30 amp on the low speed. Are you taking out fuses? Are you using both high and low speeds of the fan. I never run the high speed although it works fine enough, but it does draw the voltage down, never measured it, but the lights were dimming with the 100 amp alternator.

[awd92gsx]

Pop: It's a mechanical temp guage, but, also the fan stop cycling as well. It will run all day long. It will get up to 225 on it's own (I shut it off at that point, so, it will probably get higher)

 

Cozy: In P/N the engine runs around 192 or so with the fan cycling on at about 210. In D it overcomes the 210 mark and will keep rising until I shut it off with the fan never cycling off.

 

PP: As of yet, the car is not equipped with A/C

 

Note: the fan is wired with the High side being the only side that is used. Before rewiring I did try the low side, but it actually made the problem worse.

 

I'm beginning to just wonder if maybe the Taurus fan I have is, in some way, defective; requiring more current than is necessary to turn the fan. When I say it's a slowdown, I can't stress enough how much it actually slows down. While it still moves air, with the hood shut and in Drive you can barely hear the fan running, while when it is in Park the fan is generally loud and pronounced.

 

[edit]

 

Am running a 40a circuit breaker...it doesn't appear to be blowing/resetting. Right now I have no other electrical components added (not even a radio)

[Zmanco]

Bill, it does sound like maybe there's an issue with your fan, although they usually don't fail by moving less air - they fail by moving NO air

 

I have a spare fan I pulled from a Sable (same as Taurus?) that I never used because it didn't fit with my L6 and the A/C. You're welcome to it for the cost of shipping. PM me with your address if you want it.

[awd92gsx]

PM Sent: Am willing to try anything at this point!

 

Ty!

[COZY Z COLE]

When you had low speed wired at what temp did it come on and what temp did your high speed come on . In my write up on this low at 180* and high at 210* works great . I only have seen high come on during power drives or freeway driving.

 

http://forums.hybridz.org/showthread.php?t=99700&highlight=FORD+TAURUS+FAN

 

 

LARRY

[getZ]

that is real strange. I'm not totaly conviced it's the fan yet.

 

Here is another point of attack. You can only try this when the car has cooled off a bit. Disconnect the fan and put a meter on the battery. Watch the voltage with the car running in park and drive.

 

The rpm drop in the engine should not be causing the problem unless it stumbling badly. The only thing I could think of that would be different in park vs drive is stepping on the brake pedal. A possible short somewhere?

[MikeJTR]

I have purchased a number of fans for various reasons.

 

I have found the percentage of defective used fans to be quite high. The defective fans draw a lot of current, and do not move much air. You would not know the fans are defective until you have the problems you are experiencing, and you can compare it to other fans.

 

The engine should run cool with the fan on low-speed, and the current draw should be about 15 amps.

On high-speed, the fan will draw about 25-30 amps, and it will move a lot of air. Again, normally, it is not necessary to run the fan on high-speed.

 

There are some inexpensive amp meters that simply lay over the wiring, and provide a direct reading. You can get these at most auto parts stores for under $20. I find these to be great for diagnosing problems.

I have seen the defective fans draw over 50 amps.

 

A better fitting fan for the Z with the JTR radiator is the fan from the 1992-1996 T-bird and Lincoln Mark 8. Just remember, these fans are fairly old, and about half of the used fans I have purchased off of ebay have been defective.

[Pop N Wood]

Let us know if you fixed the problem.

 

BTW, Taurus fans are under $20 at the local pick and pull.

 

They will even let you exchange bum fans.

[Tony D]

That honking Taurus fan pulls 30A+ when it kicks on!

JeffP was having similar problems relating to ECU power at idle because of all the electrical gadgets he has on his car as well, and he went to an external regulated alternator (some reworked GM unit from a late model car) that the company waranteed would give 90A delivery AT IDLE. This requires sufficient windings to cut magnetic fields--I think it was something like an 8" Stator housing---it's a big honker. It's not a matter of spinning it at a faster rpm, because that comes back to bite you when revving the engine up---what you want to look for is something like the Police Package Alternator---it's rated at something ridiculous like 140 or 200 Amps, but the key is what the thing puts out at idle speed---if you can get that information, I'm betting you are marginal for the actual load you have on the car when your accessories are running. Jeff monitored his and he was something like 50amps WITHOUT his fan running!!! (Electric Water Pump)

 

The better alternator reworking places can give you this kind of information. You may want to PM or E-Mail JeffP as he's done a lot of work in this area recently (making the alternator work at idle and live with a 7500 rpm redline). It may be on his webpage---don't know, haven't looked there in a while.

[pparaska]

I measured a static 35amps on high with my Mustang GT fan (I think the motor is the same as the Taurus fan). On start up, it has a transient that goes quite high - over 70 amps that I could read with a typical mechanical movement meter. I never got geeky enough to hook my oscilloscope up to see what the trace was .

 

Good point on the alternator thing. I'm running a CSI 130 GM alternator and I burned one up in 12K miles of use. I will be looking into a better option and will look at those Police Package Alternators.