Fan kicking on only when I turn the key off and back on - Third Generation F-Body Message Boards


Cooling Discuss all of the aspects of cooling that you can think of! Radiators, transmissions, electric fans, etc.

Fan kicking on only when I turn the key off and back on

Reply
 
Thread Tools Search this Thread
Old 11-20-2017, 05:41 PM   #1  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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.
Jp's camaro is offline   Reply With Quote
Old 11-20-2017, 08:09 PM   #2  
Sponsor
iTrader: (78)
 
Tuned Performance's Avatar
 
Join Date: Dec 2004
Location: Mile High Country !!!
Posts: 9,651
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt


Re: Fan kicking on only when I turn the key off and back on

Wonder if your resetting the ecm with the key on and back off again.
Could be a bad ecm like your other post about high idle.
Tuned Performance is offline   Reply With Quote
Old 11-20-2017, 08:23 PM   #3  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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
Jp's camaro is offline   Reply With Quote
Old 11-21-2017, 07:11 PM   #4  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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

Any other ideas ?
Jp's camaro is offline   Reply With Quote
Old 11-22-2017, 11:30 AM   #5  
Sponsor
iTrader: (78)
 
Tuned Performance's Avatar
 
Join Date: Dec 2004
Location: Mile High Country !!!
Posts: 9,651
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt


Re: Fan kicking on only when I turn the key off and back on

Any wiring issues, fan switch inside the car ? Someone tap the relay to the ignition switch.
On most years the ecm controls the fan relay ( might be located next to the radiator( with a green/white wire.
Tuned Performance is offline   Reply With Quote
Old 11-22-2017, 12:16 PM   #6  
Member
 
LiveIt!'s Avatar
 
Join Date: Nov 2016
Location: Florida
Posts: 341
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
LiveIt! is offline   Reply With Quote
Old 11-22-2017, 12:34 PM   #7  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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.
Jp's camaro is offline   Reply With Quote
Old 11-22-2017, 12:56 PM   #8  
Member
 
LiveIt!'s Avatar
 
Join Date: Nov 2016
Location: Florida
Posts: 341
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

Last edited by LiveIt!; 11-22-2017 at 01:04 PM.
LiveIt! is offline   Reply With Quote
Old 11-22-2017, 01:51 PM   #9  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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
Jp's camaro is offline   Reply With Quote
Old 11-22-2017, 01:52 PM   #10  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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
Jp's camaro is offline   Reply With Quote
Old 01-10-2018, 05:07 PM   #11  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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
Jp's camaro is offline   Reply With Quote
Old 01-10-2018, 07:01 PM   #12  
Sponsor
iTrader: (78)
 
Tuned Performance's Avatar
 
Join Date: Dec 2004
Location: Mile High Country !!!
Posts: 9,651
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt


Re: Fan kicking on only when I turn the key off and back on

Have you replaced the fan relay. Maybe the contacts are sticking. Not sure what else to tell you to try.
Tuned Performance is offline   Reply With Quote
Old 01-10-2018, 09:41 PM   #13  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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
Jp's camaro is offline   Reply With Quote
Old 01-11-2018, 01:20 PM   #14  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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.
Jp's camaro is offline   Reply With Quote
Old 01-14-2018, 06:26 PM   #15  
Moderator
iTrader: (1)
 
Join Date: Mar 2002
Location: Chasing Electrons
Posts: 16,849
Car: check
Engine: check
Transmission: check


Re: Fan kicking on only when I turn the key off and back on

How long are you keying off for? Maybe heat soak?

RBob.
RBob is offline   Reply With Quote
Old 01-14-2018, 07:25 PM   #16  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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:
Originally Posted by RBob View Post
How long are you keying off for? Maybe heat soak?

RBob.
I just cut it off for a second then start it back up and it comes on for a few seconds then cuts back off.
I just checked the relay wiring today and all seems good and fan fuse is good too
Jp's camaro is offline   Reply With Quote
Old 01-14-2018, 07:32 PM   #17  
Sponsor
iTrader: (78)
 
Tuned Performance's Avatar
 
Join Date: Dec 2004
Location: Mile High Country !!!
Posts: 9,651
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt


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 ?
Tuned Performance is offline   Reply With Quote
Old 01-14-2018, 07:45 PM   #18  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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:
Originally Posted by Tuned Performance View Post
I think d2 of the ecm is fan control to the relay. This should be a green and white stripe wire. Iím wondering if itís a bad coolant temp switch triggering the relay.Did you replace the one in front of the intake next to the cold start switch ?
Yes that's the one I replaced. Maybe the new one was bad ?
Jp's camaro is offline   Reply With Quote
Old 01-15-2018, 03:28 PM   #19  
Sponsor
iTrader: (78)
 
Tuned Performance's Avatar
 
Join Date: Dec 2004
Location: Mile High Country !!!
Posts: 9,651
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt


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.
Tuned Performance is offline   Reply With Quote
Old 01-15-2018, 04:52 PM   #20  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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 wouldnít 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 thatís the case. I canít 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
Jp's camaro is offline   Reply With Quote
Old 01-15-2018, 05:12 PM   #21  
Sponsor
iTrader: (78)
 
Tuned Performance's Avatar
 
Join Date: Dec 2004
Location: Mile High Country !!!
Posts: 9,651
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt


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.
Tuned Performance is offline   Reply With Quote
Old 01-15-2018, 05:29 PM   #22  
Sponsor
iTrader: (78)
 
Tuned Performance's Avatar
 
Join Date: Dec 2004
Location: Mile High Country !!!
Posts: 9,651
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt


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 [email protected]
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.
Tuned Performance is offline   Reply With Quote
Old 01-15-2018, 06:55 PM   #23  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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:
Originally Posted by Tuned Performance View Post
There should be a secondary fan switch in the cylinder head between cylinders [email protected]
I donít 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 donít see anything else that can trigger the fan other than the ecm and head switch.
I thought the 85 tpi didn't have the secondary fan switch
Jp's camaro is offline   Reply With Quote
Old 01-15-2018, 07:03 PM   #24  
Sponsor
iTrader: (78)
 
Tuned Performance's Avatar
 
Join Date: Dec 2004
Location: Mile High Country !!!
Posts: 9,651
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt


Re: Fan kicking on only when I turn the key off and back on

It says 5.7 only so it must apply to the corvette only.
Tuned Performance is offline   Reply With Quote
Old 01-15-2018, 07:06 PM   #25  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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:
Originally Posted by Tuned Performance View Post
It says 5.7 only so it must apply to the corvette only.
So its only the ecm that grounds it. I can't think of anything else it can be
Jp's camaro is offline   Reply With Quote
Old 01-20-2018, 07:02 PM   #26  
Junior Member
Thread Starter
 
Join Date: Jan 2017
Location: GA
Posts: 89
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
Jp's camaro is offline   Reply With Quote
Reply


Go Back   Third Generation F-Body Message Boards >

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Advertising
Featured Sponsors
Vendor Directory

1982 Camaro '82 || 1983 Camaro '83 || 1984 Camaro '84 || 1985 Camaro '85 || 1986 Camaro '86 || 1987 Camaro '87 || 1988 Camaro '88 || 1989 Camaro '89 || 1990 Camaro '90 || 1991 Camaro '91 || 1992 Camaro '92


All times are GMT -5. The time now is 06:19 AM.


All content copyright © 1997 - 2018 ThirdGen.org. All rights reserved. No part of this website may be reproduced without the expressed, documented, and written consent of ThirdGen.org's Administrators.
We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: