Idle Surge/Radiator Fan Issue

[sauminator]

I recently had an idle surge issue, which I thought I had gotten rid of. I replaced a broken biss screw and followed the steps in 1G BISS Adjustment After those steps, Car was idling at 800rpm even after I drove around for about an hour. This evening I go to start it and it started surging again from about 1200-1500 rpm.
I let it get to operating temp and turned on the cooling fans (these were wired up by previous owner, allowing to turn on/off with a switch). A few seconds after I did that, idle dropped down to 800rpm and stayed steady. I decided to turn the fans off to see if the surge continued again, and the lights flickered and the car died instantly.
I checked the switch and the wires on the back were not connected very well. I also checked the fuse box in the engine compartment and there was a damn DIME in place of the upper portion of the fuse!!!
My question is, could any of this radiator fan set up be a cause for my idle surge? I am in need of a new battery just in case that could possibly have any relation. Sorry for all the ramble, I really just want to fix the problem!

 

[undefined0000]

I recently had an idle surge issue, which I thought I had gotten rid of. I replaced a broken biss screw and followed the steps in 1G BISS Adjustment After those steps, Car was idling at 800rpm even after I drove around for about an hour. This evening I go to start it and it started surging again from about 1200-1500 rpm.
I let it get to operating temp and turned on the cooling fans (these were wired up by previous owner, allowing to turn on/off with a switch). A few seconds after I did that, idle dropped down to 800rpm and stayed steady. I decided to turn the fans off to see if the surge continued again, and the lights flickered and the car died instantly.
I checked the switch and the wires on the back were not connected very well. I also checked the fuse box in the engine compartment and there was a damn DIME in place of the upper portion of the fuse!!!
My question is, could any of this radiator fan set up be a cause for my idle surge? I am in need of a new battery just in case that could possibly have any relation. Sorry for all the ramble, I really just want to fix the problem!

Idle surge can be caused by a vacuum leak or bad ecu etc do a boost leak test to confirm its not being caused by leaks in the intake tract.

I'm honestly not even sure if your rad fan situation could cause the issue. That dime in place of a fuse. replace that. I'm assuming that there is no longer a relay in for the rad fans? If not, you can use the relay out of the A/C box for the A/C fan in its place. Your situation is a little backwards, the car should idle differently when the fans are ON and not die when OFF. The car dying when the fans are turned off just sounds like a short or something. Return it to the stock setup.

 

[sauminator]

It did seem like a short caused the car to just shut off completely. It wasnt caused by stalling or anything. Unfortunately I need a New battery so the car wouldnt start right away without a jump.
I have done a boost leak test and checked all lines. I will try and get everything back to stock tho as you suggested. I am certain there was a short caused by the fan switch because the wires were loosely connected.
Now, i had the surge in control just yesterday, keeping in mind I have a completely dead battery, would the ecu revert back to old settings even though I adjusted everything properly? Also why did surge go away when I turned on the fans?

 

[undefined0000]

It did seem like a short caused the car to just shut off completely. It wasnt caused by stalling or anything. Unfortunately I need a New battery so the car wouldnt start right away without a jump.
I have done a boost leak test and checked all lines. I will try and get everything back to stock tho as you suggested. I am certain there was a short caused by the fan switch because the wires were loosely connected.
Now, i had the surge in control just yesterday, keeping in mind I have a completely dead battery, would the ecu revert back to old settings even though I adjusted everything properly? Also why did surge go away when I turned on the fans?

I've never seen a change in my idle after having the ecu not powered for some amount of time, and its possible that the surge went away just because the was under load. I know personally that my car idles a good 200rpms less when the fans first kick on. The rad fans pull a good amount of electricity.

 

[sauminator]

I've never seen a change in my idle after having the ecu not powered for some amount of time, and its possible that the surge went away just because the was under load. I know personally that my car idles a good 200rpms less when the fans first kick on. The rad fans pull a good amount of electricity.

If the surge goes away after being under load and idle stays steady, is the car fine to drive, or is there still an underlying issue?

 

[undefined0000]

If the surge goes away after being under load and idle stays steady, is the car fine to drive, or is there still an underlying issue?

well you need to confirm your alt is not bad, it could die at the worst time. to return the fans to a stockish condition should take a minute literally. turn on the car and grab the voltage. come back when you do that.

 

[sauminator]

I am certain the alternator is good because it was just replaced, but I will take yor advice and return fans to stock setup. Thanks for your help and fast replys!!!

 

[Dillan45]

my car had the same problem and it ended up being the idler sensor. Just my two sense but it sure fixed my idle surge.

 

[preludeachris]

OP

Low coolant can cause idle surge check coolant levels make sure its full.

 

[tjohn23]

Thanks for the low coolant tip. I was freaking out because I just got rid of my idle surge with the FIAV bypass plate (after 3 year of having it ) and I thought it coming back , I have to say it's the most annoying thing ever.

Does it surge when cold, warm or both?

 

[gingerbredman00]

Mine only surges when warm, and is shifting pretty rough when decelerating..
G.D. dsm..