Rough idling issue
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Rough idling issue
So, I recently installed an electric radiator fan, and whenever it is on, my engine idles very rough, like it's almost about to die. I know if my alternator can't keep up, it would just take the power from the battery, so that leaves me with the conclusion that a sensor might be the cause of this?? Also, it doesn't do it all the time, it acts rough sometimes, and good other times. Any of you know which sensor could be responsible for this, so that I can start troubleshooting?? It also seems to run a little rich, the exhaust pipe tends to be very smelly, and it didn't use to smell like it does now.
Thanks for the help!
Thanks for the help!
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From: Denver Metro Area, CO
Originally Posted by bedmondo
whenever it is on, my engine idles very rough, like it's almost about to die. I know if my alternator can't keep up, it would just take the power from the battery
-Chris
Colorado, USA
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From: Virginia
I would check the battery voltage with the fan on, and the fan off, with the engine idling. You should have around 14 volts with the fan off, and hopefully stil have at least 12v with it running.
If this looks ok, then I would try moving the ground for the fan directly to the battery neg terminal. If the problem goes away by doing this, I would look at the battery neg terminal, and see if there is a small ground wire coming off this terminal, going to a connector and then to the efi ground. Sometimes there is a connector on this ground that can get corroded. Also if the moving the ground around seems to affect or cure the problem, you may want to permanently mount a decent sized wire from the neg terminal of the battery, to the same bolt on the body that your fan ground is bolted to.
If this looks ok, then I would try moving the ground for the fan directly to the battery neg terminal. If the problem goes away by doing this, I would look at the battery neg terminal, and see if there is a small ground wire coming off this terminal, going to a connector and then to the efi ground. Sometimes there is a connector on this ground that can get corroded. Also if the moving the ground around seems to affect or cure the problem, you may want to permanently mount a decent sized wire from the neg terminal of the battery, to the same bolt on the body that your fan ground is bolted to.
Last edited by Franklin2; Jan 1, 2008 at 09:14 PM.
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ctubutis, as said in my previous post i'm using a hayden fan controller to turn the fan on/off. thanks for the suggestions, i will try them out. Any ideas as to why it only happens occasionally, and not all the time?
i will also try and check the ignition wire that i'm hooked up to. It might be possible that it is not a constant hot wire, and so maybe the fan is drawing lots of current because it is never at its full speed...ie always trying to speed up. I don't think this is very likely though.
i will also try and check the ignition wire that i'm hooked up to. It might be possible that it is not a constant hot wire, and so maybe the fan is drawing lots of current because it is never at its full speed...ie always trying to speed up. I don't think this is very likely though.
Last edited by bedmondo; Jan 1, 2008 at 09:46 PM.
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From: Denver Metro Area, CO
Another possibility is a defective motor or controller switch. What I would be inclined to do: Disconnect the motor from the controller switch and hook it up directly to the battery (both + & -) and see if your engine misbehaves in such a situation. If so, the motor is to blame, perhaps it has an internal short or bad brushes or something similar. If not, that leaves only the controller switch and the wiring (and associated ground connections). While the engine is misbehaving, disconnect the motor from the controller switch and hook it up directly to the battery. Still misbehaving? That points to the motor. Not misbehaving when hooked directly to the battery but does misbehave when connected to that switch? Then it's the switch or associated wiring grounding. Just try to isolate the components from each other and see if you can cause the problem on demand, that should help you figure out where the origin of the problem lies. Might take some testing over time as intermittent problems are usually difficult to figure out.
-ct
-ct
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From: Virginia
will also try and check the ignition wire that i'm hooked up to. It might be possible that it is not a constant hot wire,
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I dont know how much this helps as i am referencing a ford escort to a truck, but i had the same problem with an escort after changing out the main ecu wiring, now your saying to yourself i never changed wiring, but you changed the fan, and the fan hooks into that wiring and you see there is a little black box under your dash on the escort it was on the passenger side just behind the glovebox, not sure where on a truck, but it controlls all that stuff, when the fan turns on/off, when the a/c if option is there/ turns compressor on/off. so i would check to see if you have one of these, it may be your new fan has shorted this out, that caused my escort to just about die, after i changed it, it never fluttered again when the fan kicked on. hope this helps
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the wire is yellow and it leads into one of the relays on the passenger side fenderwell. fordman, i'm using a hayden fan controller to do all that business, my truck cannot control fans through the ecu like your escort.
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From: Denver Metro Area, CO
Originally Posted by bedmondo
the wire is yellow and it leads into one of the relays on the passenger side fenderwell
-ct
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From: Virginia
The yellow wire is a constant hot. What does the controller need this for? I thought maybe it needed a key-on hot so the fans would not run with the key off.
You have another heavier wire connected to the battery + correct?
You have another heavier wire connected to the battery + correct?
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ya, I tested the wire its on and it was +12 with the key on, but not with it off. However i dont know if the wire fluctuates voltage with the engine running. Yes there is another wire connected directly to the + of the battery, the hayden fan controller uses a temp sender to open a relay, and it also has an ac override. it uses the ignition wire so that the fans aren't running with the engine off.
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From: Denver Metro Area, CO
If it were me and my truck was behaving this way after doing what you've done, I'd get away from those yellow wires and go someplace else. To me, it just doesn't seem kosher to add additional draw into a circuit containing a voltage regulator used to control the output of the alternator (and here I'm assuming you've tapped into that circuit but don't really know for certain, I could be wrong and you've got yellow wires used for something additional than what I'm used to). I have no scientific evidence proving my point or anything, it's just a feeling I get from having worked with electronics as a hobby. I suppose there's always the chance that there's some cause of your engine misbehaving that's totally unrelated to what you've changed on the vehicle but the chances of that are fairly remote.
Wouldn't rhe sensor *close* the relay, thereby completing a circuit and supplying power to the fan?
-ct
Originally Posted by bedmondo
the hayden fan controller uses a temp sender to open a relay
-ct
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From: Virginia
I am not exactly sure what yellow wire he is using. Ford always used yellow for the main bat + feed for the hot all the time ignition switch wire and the hot all the time part of the fuse box. Since his is fuel injected, they also use it for hot all the time to the fuel pump relay and the PCM power relay. He must have some other wire if it's turning on and off with the key.