LQ9 Pulsed Cooling Fan output? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HzEmall · 06-12-2012, 01:31 AM

I have a LQ9 swapped in to my 79 C-10 with the Painless harness. It uses the OEM ECM and it sends out a cooling fan signal when it reaches temp and kicks on a 30 amp relay in the Painless Gen III fuse/relay box.

BUT, when it get to temp and kicks in the relay opens and closes none stop, sound like the turn signals are on.

Has anyone run into this? I can't see anything in the HP Tuner software that would make a difference with it.....

Thanks

ls1nova71 · 06-12-2012, 07:52 AM

Are your fan on and off temps set to the same temperature?
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mooseknuckles · 06-12-2012, 09:56 AM

I had a similar problem....the one fan relay was set to come on at 180* and it works, but number two fan relay would be clicking some times, so I thought it was the relay, so I switched it with another and now it doesn't do it anymore....not sure if the second fan is working, I've never had it come on....

BR3W CITY · 06-12-2012, 10:24 AM

You didn't somehow get a flasher instead of a relay...right? I'm mostly kidding.

I've seen both fans run off of one input, which works. If you run 2 fans, isn't the second fan only supposed to come on with the a/c loaded?

1BadAction · 06-12-2012, 10:34 AM

How fast is it pulsing? That sounds like how the electro-viscous clutch fan control works. What ECM and OS are you running? You should see a fan table (if HPT has it) that says something like 0% to 100% fan, my first thought would be to make that either 100% or 0% so it's not pulsing, but I'm not sure how the ECM would handle that...

mooseknuckles · 06-12-2012, 10:35 AM

lol..I have two separate wires for fans from the pcm, each one wired to a relay...from what I've been told, the second fan only comes on if the first one cant keep it cool?....and it's never come on, which is a good thing right?

HzEmall · 06-12-2012, 01:06 PM

i dont remember which ecm but its either the 89017733, 12576106 or the 12583560. Those are the ones Painless requires you to use with their harness. It's all based off of the 2002 4.8 parts I am told (ecm, tac, pedal etc)

It's clicking as fast as a turn signal flasher would. I swapped out the relay for another one and it still does it so it's something in the ECM I am guessing.

ls1nova71 · 06-12-2012, 01:50 PM

So do you have HPTuners? In your first post you stated that you didn't see anything in it that would make a didifference, which leads me to believe you do, so I would try lowering the fan off temp.
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HzEmall · 06-12-2012, 02:14 PM

The cut off temp was higher then the turn on temp so I lowered it to see how it will do now.

ls1nova71 · 06-12-2012, 03:55 PM

Quote:

Originally Posted by HzEmall

The cut off temp was higher then the turn on temp so I lowered it to see how it will do now.

The turn off temp should be lower than the turn on temp. For example if they come on at 210 if your off temp was 215 it would come on at 210 but since it sees the temp below 215 it would turn right back off, and so on and so on. If your on temp was 210 and your off was say 185., the fan would come on at 210 and continue to run until it cooled the temp down to 185.
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Shon · 06-13-2012, 09:48 AM

Could be that the PCM is not told correctly that there are 2 fans.
This happened to me recently. #1 fan come on as it supposed to, #2 would click the relay. Checked wiring and all was good. Went back into HPT and found that you have to tell it there are fans now, which if #1 is coming on that has been done. and for #2 to work there is a tab/section for #2 fan to come on, its something to do with A/C function, I do not have HPT here so I can not look at.
I did not notice this until I went to Beta HPT. Wondering if my 71 has this issue, but it never gets above 210; the one fan cools it down. I just happened to notice it in the stang b/c the relay/fuse block is going to be under the passenger seat.

DavidB · 06-25-2012, 05:29 PM

Yea I ran into this too. If you have the new beta hptuner. (if you have the old they will upgrade you for free) you have the option to turm off the ac signal and control the high fan output with that wire like Camaro PCM does.
Posted via Mobile Device

loweredd · 12-13-2013, 11:03 PM

I came across this in a search tonight for a primary fan relay clicking like a flasher while the fan was on. The OFF temperature WAS higher than the ON temperature. A few quick changes in HPTuners and the clicking was gone.

06-12-2012, 09:56 AM	#3
mooseknuckles Registered User Join Date: Sep 2009 Location: ottawa,canada Posts: 4,550	Re: LQ9 Pulsed Cooling Fan output? I had a similar problem....the one fan relay was set to come on at 180* and it works, but number two fan relay would be clicking some times, so I thought it was the relay, so I switched it with another and now it doesn't do it anymore....not sure if the second fan is working, I've never had it come on.... __________________ my build threads '86 C10 http://67-72chevytrucks.com/vboard/s...d.php?t=415628 '67 C10 http://67-72chevytrucks.com/vboard/s...d.php?t=635078 '63 GMC http://67-72chevytrucks.com/vboard/s...d.php?t=674682

06-12-2012, 10:24 AM	#4
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: LQ9 Pulsed Cooling Fan output? You didn't somehow get a flasher instead of a relay...right? I'm mostly kidding. I've seen both fans run off of one input, which works. If you run 2 fans, isn't the second fan only supposed to come on with the a/c loaded? __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

06-12-2012, 10:34 AM	#5
1BadAction Registered User Join Date: Dec 2010 Location: Dallas, TX Posts: 160	Re: LQ9 Pulsed Cooling Fan output? How fast is it pulsing? That sounds like how the electro-viscous clutch fan control works. What ECM and OS are you running? You should see a fan table (if HPT has it) that says something like 0% to 100% fan, my first thought would be to make that either 100% or 0% so it's not pulsing, but I'm not sure how the ECM would handle that... __________________ 2010 Basalt Black Porsche Cayenne GTS - Daily driver 1991 2500 Suburban, Black - 454/80E tow monster, soon to go under the knife... Again. 1979 16' Action Marine/"Johnny Cash" Merc Bridgeport Champ Motor - Metalflake Maniac

06-12-2012, 10:35 AM	#6
mooseknuckles Registered User Join Date: Sep 2009 Location: ottawa,canada Posts: 4,550	Re: LQ9 Pulsed Cooling Fan output? lol..I have two separate wires for fans from the pcm, each one wired to a relay...from what I've been told, the second fan only comes on if the first one cant keep it cool?....and it's never come on, which is a good thing right? __________________ my build threads '86 C10 http://67-72chevytrucks.com/vboard/s...d.php?t=415628 '67 C10 http://67-72chevytrucks.com/vboard/s...d.php?t=635078 '63 GMC http://67-72chevytrucks.com/vboard/s...d.php?t=674682

06-12-2012, 01:06 PM	#7
HzEmall Registered User Join Date: Sep 2009 Location: Sumas, WA Posts: 137	Re: LQ9 Pulsed Cooling Fan output? i dont remember which ecm but its either the 89017733, 12576106 or the 12583560. Those are the ones Painless requires you to use with their harness. It's all based off of the 2002 4.8 parts I am told (ecm, tac, pedal etc) It's clicking as fast as a turn signal flasher would. I swapped out the relay for another one and it still does it so it's something in the ECM I am guessing. __________________ Tim Baillie Installer/Designer/Fabricator Trick Factory Customs Company - www.trickfactory.com Personal - www.hzemall.com Instagram - @hzemall

06-12-2012, 01:31 AM	#1
HzEmall Registered User Join Date: Sep 2009 Location: Sumas, WA Posts: 137	LQ9 Pulsed Cooling Fan output? I have a LQ9 swapped in to my 79 C-10 with the Painless harness. It uses the OEM ECM and it sends out a cooling fan signal when it reaches temp and kicks on a 30 amp relay in the Painless Gen III fuse/relay box. BUT, when it get to temp and kicks in the relay opens and closes none stop, sound like the turn signals are on. Has anyone run into this? I can't see anything in the HP Tuner software that would make a difference with it..... Thanks __________________ Tim Baillie Installer/Designer/Fabricator Trick Factory Customs Company - www.trickfactory.com Personal - www.hzemall.com Instagram - @hzemall

06-12-2012, 07:52 AM	#2
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,119	Re: LQ9 Pulsed Cooling Fan output? Are your fan on and off temps set to the same temperature? Posted via Mobile Device __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

06-12-2012, 01:50 PM	#8
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,119	Re: LQ9 Pulsed Cooling Fan output? So do you have HPTuners? In your first post you stated that you didn't see anything in it that would make a didifference, which leads me to believe you do, so I would try lowering the fan off temp. Posted via Mobile Device __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

06-12-2012, 02:14 PM	#9
HzEmall Registered User Join Date: Sep 2009 Location: Sumas, WA Posts: 137	Re: LQ9 Pulsed Cooling Fan output? The cut off temp was higher then the turn on temp so I lowered it to see how it will do now. __________________ Tim Baillie Installer/Designer/Fabricator Trick Factory Customs Company - www.trickfactory.com Personal - www.hzemall.com Instagram - @hzemall

06-13-2012, 09:48 AM	#11
Shon Registered User Join Date: Sep 2005 Location: sc Posts: 1,203	Re: LQ9 Pulsed Cooling Fan output? Could be that the PCM is not told correctly that there are 2 fans. This happened to me recently. #1 fan come on as it supposed to, #2 would click the relay. Checked wiring and all was good. Went back into HPT and found that you have to tell it there are fans now, which if #1 is coming on that has been done. and for #2 to work there is a tab/section for #2 fan to come on, its something to do with A/C function, I do not have HPT here so I can not look at. I did not notice this until I went to Beta HPT. Wondering if my 71 has this issue, but it never gets above 210; the one fan cools it down. I just happened to notice it in the stang b/c the relay/fuse block is going to be under the passenger seat. __________________ 71 Cheyenne C10 LWB cam'd 6.0/T56 Swap

06-25-2012, 05:29 PM	#12
DavidB Registered User Join Date: Jun 2007 Location: South Carolina Posts: 106	Re: LQ9 Pulsed Cooling Fan output? Yea I ran into this too. If you have the new beta hptuner. (if you have the old they will upgrade you for free) you have the option to turm off the ac signal and control the high fan output with that wire like Camaro PCM does. Posted via Mobile Device

12-13-2013, 11:03 PM	#13
loweredd www.loweredd.com Join Date: Aug 2002 Location: Struble IA Posts: 808	Re: LQ9 Pulsed Cooling Fan output? I came across this in a search tonight for a primary fan relay clicking like a flasher while the fan was on. The OFF temperature WAS higher than the ON temperature. A few quick changes in HPTuners and the clicking was gone.



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