Fan causing bucking in my LS2 FD
Thread Starter
On The Tree
Joined: Jul 2014
Posts: 128
Likes: 0
Ok guys , didn't want to leave this in limbo, battery, alternator and all associated wiring checked out good, come to fund out it was the fan! I couldn't believe it, brand new SPAL slim line fan. I swapped the plugs to my other fan and it runs beautiful with the fan on, I was finally able to warm the car up and make some full throttle pulls. Now I need a new diff and wider wheels lol, it's like driving on ice over 80% throttle 
Last edited by LS2FD3S; Dec 11, 2015 at 10:12 AM.
TECH Resident
Joined: Feb 2014
Posts: 954
Likes: 9
From: Encinitas CA
WOW - clean install!
Interesting - glad you closed the loop with us. Too often here folks resolve issues and never follow up.
There is a way to remove (filter) the inductive noise created by such devices, but perhaps it doesn't matter
I too have a SPAL fan, but don't have that issue. I wonder if it is something specific to that unit or inherent to the design?
Doug
Interesting - glad you closed the loop with us. Too often here folks resolve issues and never follow up.
There is a way to remove (filter) the inductive noise created by such devices, but perhaps it doesn't matter
I too have a SPAL fan, but don't have that issue. I wonder if it is something specific to that unit or inherent to the design?
Doug
Thread Starter
On The Tree
Joined: Jul 2014
Posts: 128
Likes: 0
WOW - clean install!
Interesting - glad you closed the loop with us. Too often here folks resolve issues and never follow up.
There is a way to remove (filter) the inductive noise created by such devices, but perhaps it doesn't matter
I too have a SPAL fan, but don't have that issue. I wonder if it is something specific to that unit or inherent to the design?
Doug
Interesting - glad you closed the loop with us. Too often here folks resolve issues and never follow up.
There is a way to remove (filter) the inductive noise created by such devices, but perhaps it doesn't matter
I too have a SPAL fan, but don't have that issue. I wonder if it is something specific to that unit or inherent to the design?
Doug
TECH Resident
Joined: Feb 2014
Posts: 954
Likes: 9
From: Encinitas CA
Can you feed the ECM from the battery directly positive and ground (on the 12V+ say using an ignition switched (and fused) relay but sourced directly from the battery post)? that might isolate it from the noise created by the fan?
I understand the battery itself is a great noise filter.
I might also suggest grounding the ECM case to a good ground.
Doug
I understand the battery itself is a great noise filter.
I might also suggest grounding the ECM case to a good ground.
Doug
Thread Starter
On The Tree
Joined: Jul 2014
Posts: 128
Likes: 0
Can you feed the ECM from the battery directly positive and ground (on the 12V+ say using an ignition switched (and fused) relay but sourced directly from the battery post)? that might isolate it from the noise created by the fan?
I understand the battery itself is a great noise filter.
I might also suggest grounding the ECM case to a good ground.
Doug
I understand the battery itself is a great noise filter.
I might also suggest grounding the ECM case to a good ground.
Doug
TECH Resident
Joined: Feb 2014
Posts: 954
Likes: 9
From: Encinitas CA
I hear you.
If you swap fans, are you sure the one by itself creates the bucking?
What size fan(s) do you have?
I use one 16" SPAL high performance fan (not slim). I have AC. Hottest I've seen is 205F indicated in 95F ambient with AC on and pretty high humidity, too.
Perhaps you don't need more fan?
OR
Maybe buy another of the same fan and then return the one creating the noise. Or perhaps both together create the noise?
Doug
If you swap fans, are you sure the one by itself creates the bucking?
What size fan(s) do you have?
I use one 16" SPAL high performance fan (not slim). I have AC. Hottest I've seen is 205F indicated in 95F ambient with AC on and pretty high humidity, too.
Perhaps you don't need more fan?
OR
Maybe buy another of the same fan and then return the one creating the noise. Or perhaps both together create the noise?
Doug
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