Idle fluctuation and fan always on high speed

[Tiny99]

Hello everyone!

300c 2009 AWD Hemi 5.7
Predator 9r23
93 perf cai tune

I recently noticed that my engine temp would rise quite a bit on the highway and plumet down while stopped on a street corner. Also, idle seems to fluctuate about 300 RPM in a sporadic pattern.

I tried to find the issue and noticed that the HS fan are always on. I tried ajusting the fan settings and tried every possible combination(190/200-195/205- stock). I even tried changing the thermostat for a 185 Motorad 4128.

I tried to make sense out of my fuse box... I noticed that I have a relay labelled as rad fan low/high speed another one as rad fan med/high speed and also one labelled rad fan parrallel.I tried taking off the 3 fan relays one by one and depending on the relay, I can get one fan or the other working but always in high speed. Also, the AC will work at idle if the engine is cold. As soon as the engine gets to operating temperature the AC will stop working at idle. It will work slightly when going on the highway.




Does anyone have an idea?

[brandy16]

Put it back to stock and see if you have the same problem.

[Tiny99]

Ok, will try and report back!

Thanks!

[Tiny99]

Ok same thing with the stock programming... it must be a faulty relay or something. I'll send it to the dealer.

Thanks for the help!

[Tiny99]

Ok, I made a mistake while validating...
The problem doesn't occur with the original stock map.

Once the HS fan kicks in it doesn't go down until I stop the car and wait a good while.

Currently the fan settings are the usual one for the 93 perf cai tune.
I will try to raise them to 205/215 and see if that helps.

Anyone has an idea?
Sorry about the confusion about the original map... I don't know a great deal about the predator and I thought the stock tune was the backup...
Thanks!

[rodneyiii]

I don't know what menu options you have for the '09 fans but the 7135 menu for my '06 has 9 different settings that can be adjusted. There are fan setting for high MPH (above 15mph) and for low MPH (below 15mph). It sounds like your high mph HS fan is set for a low temperature value so as soon as you get above 15mph, the fan turns on HIGH trying to cool down the engine. As you mentioned, when you stop the car (below 15mph) the HS fan shuts off because it has a higher temperature setting for the low mph value.

[DGatzby1]

I keep the low and high MPH speed fan settings the same. I personally don't need any other variables and confusion.

[Tiny99]

Thanks for the feedback!

Turns out I have a defective AC compressor. My fan problems might be related to that. That should be repaired this week. I'll try to upload a tune after that and see how it goes.

So far, what I have established is that any diablo tunes will cause the same behavior and the OEM tune doesn't do that. The problem is the high speed fans kick in sooner than what I set and they don't go off untill I shut the car off and let it cool down.

This wouldn't be too bad if the fans were sucking in instead of pushing out. When the HS fans kick in and stay stuck, the engine temp can rise up to 245 on the highway. The fans are blocking the airflow to the rad by pushing against the wind. When they are stuck in traffic, the engine temp stays low, no surprises here...

I'll get the AC compressor replaced and I'll wait for the next crom update. I think 9r24 is due out soon right?
That should hopefully fix the issue.

I'll report back after all that to let you guys know how it went.

Thanks everyone! BTW, even if I have a small issue, I would still recommend the Predator. This thing kicks ass!!