Fan kicking on only when I turn the key off and back on
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Fan kicking on only when I turn the key off and back on
I have a 85 z28 with the 305 tpi. I let it get to 3 quarters then cut it off and start it back up then the fan kicks on. I replaced the coolant temp sensor but didn't change anything
Last edited by Jp's camaro; 11-20-2017 at 06:22 PM.
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
Yah this is the other reason I was thinking something is up with the computer
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Car: 1988 Camaro Sport Coupe
Engine: The All-Powerful 2.8l!! :P
Re: Fan kicking on only when I turn the key off and back on
His ECM flashes 12 codes fine and even stored trouble codes for stuff we know is wrong (EGR delete), and grounding the green/white wire on relay by rad kicks fans on no problem. Just FYI
We think there was a fan switch hooked up in the car but flipping it does nothing lol
We think there was a fan switch hooked up in the car but flipping it does nothing lol
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
There is a relay wired to the neutral safety switch for some reason. There is also a switch in the center console it is ran to the relay on the firewall, its spliced in between the thick orange wire running to that relay.
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Car: 1988 Camaro Sport Coupe
Engine: The All-Powerful 2.8l!! :P
Re: Fan kicking on only when I turn the key off and back on
That sounds like the Orange +12V constant line for the fuel pump relay, so now the question is what was he trying to power with the switch
EDIT: might be red neck kill switch
EDIT: might be red neck kill switch
Last edited by LiveIt!; 11-22-2017 at 01:04 PM.
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
Yup kill switch to keep the pump from priming
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
I looked over the fan relay it appears to be fine. The connections had a bunch of old grease on them so I cleaned them up
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
Bump, tried a new ecm and the fan is still doing the same thing
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
Actually just picked up one today but haven't tested it yet. Will do tomorrow
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
Welp tested it with new relay and still doing the same thing of only coming on for a few seconds when I let it get to about 3 quarters and cut the car off and start it again. I'm stumped.
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Re: Fan kicking on only when I turn the key off and back on
I think d2 of the ecm is fan control to the relay. This should be a green and white stripe wire. I’m wondering if it’s a bad coolant temp switch triggering the relay.Did you replace the one in front of the intake next to the cold start switch ?
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
Yes that's the one I replaced. Maybe the new one was bad ?
#19
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Re: Fan kicking on only when I turn the key off and back on
I wouldn’t think the cts is bad in the same manor as the first one. Is the wire from the ecm to the relay spliced . The other possibility might be a bad prom. You might have a code 41 or 51 if that’s the case. I can’t think of any other possibilities maybe rbob can suggest something.
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
[QUOTE=Tuned Performance;6194984]I wouldn’t think the cts is bad in the same manor as the first one. Is the wire from the ecm to the relay spliced . The other possibility might be a bad prom. You might have a code 41 or 51 if that’s the case. I can’t think of any other possibilities maybe rbob can suggest something.[/QUOTE
I couldn't find any splices in it when I looked it over and only code I get is for egr. Maybe it is the prom, I need to have a new one burned anyway to delete the emissions
I couldn't find any splices in it when I looked it over and only code I get is for egr. Maybe it is the prom, I need to have a new one burned anyway to delete the emissions
#21
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Re: Fan kicking on only when I turn the key off and back on
The code 32 can be programmed out of the prom. The fan on should be set to 222f in the stock programming but can be changed too.
You might consider the 870 to 165 swap instead of investing in a prom.
It sounds like your prom is working if you can retrieve codes.
You might consider the 870 to 165 swap instead of investing in a prom.
It sounds like your prom is working if you can retrieve codes.
#22
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Re: Fan kicking on only when I turn the key off and back on
There should be a secondary fan switch in the cylinder head between cylinders 6@8.
I don’t see how this could cause the intermittent fan operation but the switch grounds the relays green/white wire like the ecm does for fan request.
Here is the schematic for the 870 ecm. I don’t see anything else that can trigger the fan other than the ecm and head switch.
I don’t see how this could cause the intermittent fan operation but the switch grounds the relays green/white wire like the ecm does for fan request.
Here is the schematic for the 870 ecm. I don’t see anything else that can trigger the fan other than the ecm and head switch.
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
There should be a secondary fan switch in the cylinder head between cylinders 6@8.
I don’t see how this could cause the intermittent fan operation but the switch grounds the relays green/white wire like the ecm does for fan request.
Here is the schematic for the 870 ecm. I don’t see anything else that can trigger the fan other than the ecm and head switch.
I don’t see how this could cause the intermittent fan operation but the switch grounds the relays green/white wire like the ecm does for fan request.
Here is the schematic for the 870 ecm. I don’t see anything else that can trigger the fan other than the ecm and head switch.
#26
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Car: 1991 rs, 1985 z28
Engine: 3.1 v6, 305 tpi
Transmission: 700r4, 700r4
Axle/Gears: 3.23, 3.23
Re: Fan kicking on only when I turn the key off and back on
I found the coolant temp sensor connector was a bit broken and I think it wasn't making a good connection. I messed with it a bit and it fixed my high idle issue but the fan is still doing about the same thing. I did notice when I cut it off and back on the fan stayed on a little longer than before until it cut off