SPF Electricals -
 

OK – winter is in full swing and I’m getting restless…
So lets here about some electrical gremlins or oddities on your SPF…
Maybe someone has an electrical modification they have been thinking about doing…Now’s the time…I’m in the mood to do some detective work…

I have 1, my amp metter keeps jumping unless you cut the lights on an the fan. the parking lights pulse when they are on. Its charging but annoying watching the hand jump all the time.

I had a bad short which caused the starter, lights and such all work in tandom. Ended up being a bad light bulb of all things. But in the adventure to track it down, I pulled the wiring down under the dash and to tell you the truth, my six year old could have done a better job. There was pinched wires due to the zip ties being clamped down to about 6,000ft.lbs, others were bent to the breaking point. So, I spent a few hours re-doing it for the simple hope to stop future problems.

One of my cooling fans keeps blowing the 20 amp fuse. This happens only while driving the car. I have the extra manual fan switch set up. Replaced the relay to no avail. Then I noticed that the fan was turning the wrong way. Switched the wires, now it turns the proper way. I pulled the fuse. One fan does a great job by itself. I'm afraid to put the fuse back in. Don't want a fire. Is it possible that the fan turning the wrong way while driving at speed would cause a fuse to blow?

Goopie_18
I have seen this once before.
Check the connections at the 2 relays on your drop down fuse panel - are they all tight? Does the wiring looks ok?
Check the wiring connections at the 2 fans, and on the temp switch (lower left side of the radiator - it's just a ground)
A loose wire or bad crimp can cause havoc with these fuses.
I would now suggest you reconnect the fuse - after the wiring inspection and fixing the fan rotation and see if it still pops a fuse.
The fuses will protect the fan circuits.
Now the fun begins:
If it still blows the fuse, the next step would be to switch the relays on the fuse panel and see what happens.
If it then blows the other circuit you know the problem is in the relay - replace it.
If the same fuse blows, you know the relays are both ok, and have narrowed it to wiring in that circuit or that fan motor.
BTW: Which way is the good fan moving the air? They both should pull air into the engine compartment.
So now remove the power supply wires from both fans and use temporary jumpers to switch the power supplies to them.
Retest and see what happens. If the same fuse blows it's the wiring, if the other fuse blows, it's the motor.
Hope this makes sence, you are just switching power flows to find a bad component - a process of elimination.
Send me a message to my email address listed below and I'll send you my home number to call.
Let me know what the result is.

what dir should the fan be going? should it be pushing the air towards the rad, or pulling the air through the rad,

flipscobra
Tell me this:
First - So I can determine how your AMP gauge is wired - What is your SPF car #?
Which way is the needle jumping? + or - ?
Now:
Car running - no lights or fans - what is the meter doing?
Car running - lights on - no fans - what is the meter doing?
Car running - lights on - fans on - what is the meter doing?
Check the wire connections on the back of the AMP meter visually - look clean & secure?
Check the wire connections on the starter solenoid on the firewall (that's the power source for the AMP meter) - look clean & secure?
Check the wire connections on the alternator - look tight, clean & secure?
REMEMBER - We are talking wiring that is always "HOT" so do your inspect ions with CAUTION.
Send me a message to my email address listed below and I'll send you my home number to call.
Let me know what the result is.

cobras
Both of the Superformance fans should be "pulling" air into the engine compartment.

Goopie 18,

Having the fan wired backwards so it blows the wrong way could certainly cause the fuse to blow while driving at speed. Motors have a huge in-rush current. Depending upon the motor it can be up to 6 times the normal full load current. While driving at speed, the motor is trying to turn one direction while the air rushing across the fan blades would be trying to turn it the opposite direction. That's going to significantly increase the current that the motor draws as it fights to try and turn the "right" direction. The result will be significantly higher current draw until the fuse blows.

Chris

Right - The fans will turn when the car is moving from the air coming thru the radiator. They will actually create a small current flow, and if one is wired backwards could pop the fuse.

CJ428CJ and Blas: my thoughts exactly. I suspect the cause might be the reversed fan. I check it out this weekend. If not, I'll follow Blas's steps. Thanks guys!

OK Blas here's one
 

I noticed that my anmeter jumps. So, at idle it's steady and reads just on the positive side. But at highway speeds (and only at highway speeds) it has a rythemic bounce in the positive. Normal?
No performance symptoms - is it a short? Loose belt? A symptom of something else?

Goopie:
A cold beer says it's the reversed fan...hahahaha

STL_Mark...
First, Like I mentioned below:
Check the wire connections on the back of the AMP meter visually - look clean & secure?
Check the wire connections on the starter solenoid on the firewall (that's the power source for the AMP meter) - look clean & secure?
Check the wire connections on back of the alternator - look tight, clean & secure?
REMEMBER - We are talking wiring that is always "HOT" so do your inspect ions with CAUTION.
Send me a message to my email address listed below and I'll send you my home number to call.
Let me know what the result is.

One other thing regarding the AMP bouncing issue, we'll do the cheap stuff first.
There are two main grounds on these cars. One back by the battery and one on the chassis, passenger side, below the starter. Hi-Tech put a fantastic layer of black paint on these chassis's - And they paint the grounding lug just as nice...I would suggest that you get under there, remove the grounding cable (up front) wire brush that grounding lug to a metal finish, reinstall the cable using a star locking washer, and then a little di-electric grease to prevent corrosion. You can usually get a little packet of the grease at the parts stores. This takes a little time and effort, but has cured many ill's with the cars...try it....

Follow-up to fan problem:
 

Anyone with cars #2600 and above: If you get a chance, check the fuses for your cooling fan motors for me....Drop-down fusepanel - fusebox towards drivers side - 5 & 6 slots down Anyone NOT have 20amp fuses in these both locations?

Okay Blas-
I hope you can help me with this one.
Chassis no. spo-2571, the tach will follow the engine rpm to about 3000 then will drop to 0 as the motor gains rpm. Tach will pick rpm back up at about 3000 again as the rpm falls. It seems to function normally at 3000 and under.
Back ground on the car is, Accel dfi Thruster controlling the timing thru the new MSD digital 6a. The tach signal is sent out via the tach output on the MSD box.
Any thoughts would be appreciated.
Thanks in advance.

Don,
I'm not well versed in fuel injection control systems...
Lets check a couple easy things first.
I'm assuming there is no drop-off in power when the tach goes weird...
Check to be sure you have a good, clean, tight ground and power wires to the MSD box...(These are the red & black heavy wires to the box)
Check all the wire connection crimps in and out of the MSD box too. FYI: It's usually a white wire feeding the tach from the side of the MSD box.
Can you check the connection on the back of the tach to be sure it's seated properly? Carefully thread your hand up there and lightly push.
Pop open your distributor and look at the center carbon electrode...does it look like all the rest? Not worn down or burned looking? That would be because the connection to the rotor is arching if it was not touching the carbon button, or because it's bent up too much rubbing the button off.
Let me know...we'll go from there....

Don , I am assuming this is the Smiths Repro tach.

Question ; Does the tachometer track at other RPMs >? (idle -3000 )

I am wondering if you are having AC voltage feedback at high revs with the Alternator.

my other idea would be the tach feeding off of the same positive circuit as the MSD.

Do you have a another tach that you can test with >?

Dan Bevers ---------- years ago when I switched my old Ford ignition systsem to MSD, my tach did the same thing -----went up to 3k and then to zero while engine revs were still going up .

My mechanic called the MSD hot line tech support guys and we were told to add a MSD Tach Adapter ( I can't recall the MSD part number at the moment , #8910 comes to mind but i will continue to look thru records) .......a diode also had to be added after the Tach Adapter to smooth the tach out.

I recall in other experiences such as mine discussed some time ago that some folks with newer SPF's
had slightly different tach wiring and different alternator wiring which also affected Smith tachs differently on newer cars vs older cars like mine . Blas is the expert on what/when electrically . Bill

Bill