Low Speed Fan Turns on right away

[striker754]

I have a 3 bar OS on an ls1. When I start the car, the low speed fan comes on even if the car is not up to temp. My fan 1 on temp is 165, off temp is 160. Fan 2 is 180 and shut off at 170.

I haven't been with my car for awhile, but if I remember right the high speed fan doesn't turn on at 180. I think it comes on before that. I do not fully remember with regards to this though. I know for sure the low speed fan is always on from the get go.

I believe it to be an os problem or something because I can turn both fans on and off through the controls in the hp tuners scanner. And I can also control both fans through my manual fan switch.

It's not that big of a deal, but if there is a fix for it or if a fix can be created, I would like to do it.

[Russ K]

I assume that you have the A/C turned off?

Russ Kemp

[striker754]

Fan 1 Enable Speed and Fan 1 Disable Speed?

I believe I tried messing around with those because I am logging fuel pressure through the A/C so I wasn't sure if the PCM was doing it because of that.

I don't think messing with those values did anything IIRC. They are set at 0 right now

[WS6FirebirdTA00]

No, he is asking if the AC was on, that runs the low speed fan IIRC. How is the ECT sensor? There are more things that run the fan than just the on/off temps.

[striker754]

No because I don't have a/c. But like I said the fuel pressure is logged through a/c

[WS6FirebirdTA00]

OK, so your air controls were not on at the time. Post a scan showing ECT and your tune.

[striker754]

Finally got to get a log on this. Attached are my current tune and a log I made today.

As I said before I am logging fuel pressure through the A/C pressure. I don't believe the PCM thinks the A/C is on though if you look at the status bits in the log.

The low speed fan turns on as soon as the car comes on. The high speed fan doesn't come on at the right temperature.

I have a manual fan switch that controls both fans just fine. The HP tuners controls for the fans control them just fine. I have the 3 bar OS

Frame 4640 is a place where you can see the high fan comes on for no reason.

My tune settings are as follows:

Fan 1 On Temp: 165
Fan 1 Off Temp: 160
Fan 1 Enable Speed: 0
Fan 1 Disable Speed: 0

Fan 2 On Temp: 180
Fan 2 Off Temp: 170

[WS6HUMMER]

I have seen the high speed relay stick in the on positon once, changed it out with the sam relay from another car and it was fine. May not be your problem but just another thing to think about.

[striker754]

If the relay was stuck, the fan would stay on and never go off. The wiring is fine. Everything operates as it should. The pcm can operate both fans and I can operate them both manually. The pcm just doesn't operate them at the correct times...either something with my settings or an OS problem.

[striker754]

HP tuners? Any idea on this?

[NTIMID8]

Its more than likely the 2.5v the A/C pressure is seeing and where you have your pressure a/c pressure controls set. Unhook the fuel pressure voltage and check it.

[striker754]

Its more than likely the 2.5v the A/C pressure is seeing and where you have your pressure a/c pressure controls set. Unhook the fuel pressure voltage and check it.

I thought about that before and then looking at the status bits from the log the computer thinks the a/c is off. Either way I have the enable and disable speeds set to 0. And I don't think the fuel pressure explains the reasoning for the high fan turning on at the wrong temperature.

I just realized that the high fan thing isn't even simply an issue of a wrong temperature. It just comes on randomly. If you look at frame 3870 the high fan turns on for no reason. Shuts off for no reason at 4214 and back on at 4640. Temperature is a consistent 165 at these points. No change in temperature that should be accompanied with a fan change.

[NTIMID8]

I thought about that before and then looking at the status bits from the log the computer thinks the a/c is off. Either way I have the enable and disable speeds set to 0. And I don't think the fuel pressure explains the reasoning for the high fan turning on at the wrong temperature.

I just realized that the high fan thing isn't even simply an issue of a wrong temperature. It just comes on randomly. If you look at frame 3870 the high fan turns on for no reason. Shuts off for no reason at 4214 and back on at 4640. Temperature is a consistent 165 at these points. No change in temperature that should be accompanied with a fan change.

Those are separate independent functions and you have not disabled the fans VS A/C pressure. The high speed fan turn on also coincides with the increase in A/C voltage (fuel pressure).

[striker754]

Where do you disable the fans vs a/c pressure?

[NTIMID8]

Where do you disable the fans vs a/c pressure?

Try this, the new version should have the ability to edit these functions and then some.

[striker754]

Try this, the new version should have the ability to edit these functions and then some.

I don't see these functions at all. Can you lead me?

I've read that the PCM will turn the high speed fan on when the a/c pressure is high here: http://ls1tech.com/forums/conversion...am-here-2.html

High Speed Cooling Fans
The High Speed Cooling Fans are controlled by the PCM based on the following inputs:

The A/C system.
The Engine Coolant Temperature (ECT) sensor.
The Vehicle Speed Sensor (VSS).
The PCM will enable both fans on high speed when any of the following conditions exist:

Certain PCM Diagnostic Trouble Codes (DTCs) set.
The ECT above 112°C (234°F).
The A/C high side pressure above 248 psi.
Once the high speed cooling fans are turned ON by the Engine coolant temperature, the PCM will turn the fans OFF when that temperature has dropped about 4°C (7°F). If the high speed cooling fans are turned ON by high A/C head pressure, the PCM will turn the fans OFF when the pressure has dropped to 208 psi. The minimum ON time for the high speed cooling fans is 30 seconds.

I am unsure about this because at frame 3129 it turns the fan ON at 2.82V. Frame 3278 it shuts the fan off at 2.60V. Frame 3870 it turns back on at 2.47V. Frame 4215 its off again at 2.73V.

EDIT: The interval from 3129 to 3278 is exactly 30 seconds so the pcm must be using the minimum on time of 30 seconds. Frame 3870 to 4215 is longer.

[NTIMID8]

I don't see these functions at all. Can you lead me?

I've read that the PCM will turn the high speed fan on when the a/c pressure is high here: http://ls1tech.com/forums/conversion...am-here-2.html



I am unsure about this because at frame 3129 it turns the fan ON at 2.82V. Frame 3278 it shuts the fan off at 2.60V. Frame 3870 it turns back on at 2.47V. Frame 4215 its off again at 2.73V.

It will be in the new release of HP(assumed) which is why you cant see it. I modified it in the file I attached.
Much like the Fan on/off vs temp, there is a high/low psi to turn on/off each and time intervals for hysteresis.

[striker754]

It will be in the new release of HP(assumed) which is why you cant see it. I modified it in the file I attached.
Much like the Fan on/off vs temp, there is a high/low psi to turn on/off each.

Where do I get the new release of HP tuners?

And do you have any ideas on why the low fan turns on right away?

[NTIMID8]

Where do I get the new release of HP tuners?

And do you have any ideas on why the low fan turns on right away?

Because 2.5v is above the low fan turnon threshold and barely below the high speed turn on point.

[striker754]

Because 2.5v is above the low fan turnon threshold and barely below the high speed turn on point.

Excellent thanks. Do you know where or when I can get the new version of HPT? I would be fine with a beta even