SD2 AC and radiator fan

[dyermullet]

I just switched to SD2 chip.

I noticed that when I turn on the AC the radiator fan does not come on. I get the check mark for the AC on the power logger but it does not check the box for the fan. The fan does not run.

The fan will run when the coolant temp reaches the set point. Once the coolant temp goes down the fan will turn back off even if the AC is on.

Before the conversion both the 5.7 and 6.0 chip, the computer will turn the fan on when the AC is turned on.

 

[dank GN]

The fan doesn't need to run when the AC is on . Is there a reason u think it needs to ?as long as it turns on when it has hit its set point u r good .

 

[dyermullet]

You are incorrect the radiator fan running is mandatory for ac running. It cools the condenser. Without the fan the system preasure gets too high.
On every ac system im the world mobil or stationary the condenser is actively cooled either by a fan or water cooled.

Are you running sd2? Does your fan check box get checked as soon as ac comes on?

 

[TurboDave]

I think we've just discovered a serious bug in the SD2 system. I just checked, and my fans don't kick on with A/C either!

Bob and Eric need to look into this.


Sent from my iPhone 6+ using Tapatalk.[emoji252]

 

[STF420@comcast.]

The fan may be controlled by pressure switch on the AC line? Low freon low pressure no fan?

 

[TurboDave]

The fan may be controlled by pressure switch on the AC line? Low freon low pressure no fan?

Not in my case, a/c is working fine except for the fan thing.

Are you running sd2?

 

[STF420@comcast.]

Just fired up SD2 in the driveway switched back to my 6.1. Still need to move my IAT. I will give it a try when can to see if fan works with SD2

 

[dyermullet]

I think we've just discovered a serious bug in the SD2 system. I just checked, and my fans don't kick on with A/C either!

Bob and Eric need to look into this.


Sent from my iPhone 6+ using Tapatalk.[emoji252]

Yes it is a problem. I already lost most of the refrigerant it started leaking from the seals on back side of the compressor.

Dissapointing development on the second time driving the car on sd2.

Most days this car is my dd.

 

[dyermullet]

The fan may be controlled by pressure switch on the AC line? Low freon low pressure no fan?

Low pressure switch just inhibits compressor. It is all in the wiring diagrams.

 

[STF420@comcast.]

You Guys are correct NO AC cooling fan with SD2 chip.
I switched back and forth,
With 6.1 chip. Fans would cycle on and off with AC compressor.
With SD2 chip fans would cycle with coolant temp only!

 

[dyermullet]

You Guys are correct NO AC cooling fan with SD2 chip.
I switched back and forth,
With 6.1 chip. Fans would cycle on and off with AC compressor.
With SD2 chip fans would cycle with coolant temp only!

disappointed right now.

 

[Eric Stage I]

We will make a tweak to the Powerlogger software to fix that.

I never ran across it since I run my fan all the time to keep hot air out of the engine compartment (I have the fan set to 140*).

For now, you guys might want to lower the fan coolant setting to help out, until we get the fix worked out. For now you could set it to something like 80* to keep it running all the time.

 

[dyermullet]

Eric,

How long do you think it will take to complete the change?

 

[TurboBob]

Will have something done this weekend.

Sorry for the oversight.

Bob

 

[dyermullet]

Thanks Bob. I will start repairing my ac tonight then.

 

[Eric Stage I]

Just a note, the A/C has a high pressure cutoff switch on the compressor, so you should never see any damage.
If the pressure cutoff switch is faulty, there is a backup pressure blowoff valve on the compressor also, so again, no damage.
What you thought was leaking seals could possibly be from the blowoff valve.

 

[dyermullet]

You are correct. If i remember correctly that high pressure switch also turns on the fan as a backup/failsafe . I will check the diagram tonight.

I dont have that high pressure switch anymore. Havn't had it for years. Never had a problem because computer commanded the fan with no problems.

This is probably why no one noticed this issue sooner. Everyone with sd2 and working ac, the radiator fan comes on when the high pressure switch was made.

I don't remember if my compressor has a relief vakve that will reseal or if it is a rupture disk of some kind. But i will take your word on it being a relief valve. I still have some charge left so i didnt loose it all. I will probably just try to charge it using beer can method. If i have problem i will change seals equate and charge again.

 

[Eric Stage I]

Hopefully you can just recharge it. Sorry for the troubles!

 

[dyermullet]

Besides the ac problem. The car is running real good on the sd2. Fired right up first try. Drives very nice.

 

[TurboBob]

Yes it is a problem. I already lost most of the refrigerant it started leaking from the seals on back side of the compressor.

Dissapointing development on the second time driving the car on sd2.

Most days this car is my dd.

the refrigerant high pressure switch has 2 sections. 1 for the low speed fan at 280 psi, the other for the high speed fan at 300 psi.

in any case, we will have an update ready shortly.

Bob