need mustang help

RodneyWright · **Posted:** Thu May 14, 2015 9:37 am

All good points on using the hand held tuner. I'll try installing that today just to see if the fan works. I know it came on pretty much all the time w/ the race tune, so I'll throw that back on just to test. If no fan, I'll order the PCM.

RodneyWright · **Posted:** Thu May 14, 2015 10:45 am

Installed a 89 tune from the hand held as you guys suggested with no expectations of this working. Set the low speed fan to 180 and thought no way this is going to work. The freaking fan works! WHY??? Doesn't run w/ the stock tune, but works w/ the handheld. Makes no damn sense. Looks like I'm running a 89 tune for now.... I've reset the fan speeds to 190 and 210 for low and high. Not what I wanted to do, but this does save me some coin. This also removes 1 feature about this car and that was being able to run any octane, so now I'm stuck at 89 which is doable.

I appreciate all of the help and suggestions, great members!!

Vincent Keene · **Posted:** Thu May 14, 2015 10:54 am

RodneyWright wrote:

Installed a 89 tune from the hand held as you guys suggested with no expectations of this working. Set the low speed fan to 180 and thought no way this is going to work. The freaking fan works! WHY??? Doesn't run w/ the stock tune, but works w/ the handheld. Makes no damn sense. Looks like I'm running a 89 tune for now.... I've reset the fan speeds to 190 and 210 for low and high. Not what I wanted to do, but this does save me some coin. This also removes 1 feature about this car and that was being able to run any octane, so now I'm stuck at 89 which is doable.

I appreciate all of the help and suggestions, great members!!

From page one of this thread:

Vincent Keene wrote:

FYI, the hi/lo fans settings can be altered via your handheld tuner.

Glad we could help.

Richard Casto · **Posted:** Thu May 14, 2015 11:05 am

Thats good Rodney. I think a few of us was on the same page over the last few posts. Basically... if a custom tune can make the fan work, then it points strongly to a software issue and not hardware (fan, wiring, relay, PCM, sensor, etc).

I did a quick scan of the thread and others mentioned the potential for bad sensor and you also said you replaced the sensor. If this continues to be an issue for some reason (i.e. you just don't like the tune that make the fan work) I would look into verifying if the sensor is outputting the right values. I expect the factory manual has a test procedure for that. Something like suspend the sensor in water of known temperature and then measure output with a meter to see if it is in spec. Alternatively it could still be a PCM issue in that it might be measuring the output of the sensor correctly, but I would be surprised if that is the case.

As to why some tunes (software configuration) might work and others not? I assume there is a temp threshold for turning on/off the low and high speed fan. Each tune might have different thresholds. If the sensor is wonky (not giving linear output, or acting like an on/off switch) different tune configs might cover up that issue, but it might also turn fans on too early or even still let it get too hot before it kicks them on.

Lastly, I had asked to check on service bulletin just to see if the factory configuration you had might actually have a known issue. I know it is not uncommon to tweak these types of things over the life of a car. For example sometimes cars might have aggressive "out of bound" values for stuff that end up throwing a code and turning on the CEL, but in reality all is OK. They (manufacture) just adjust the range to be more realistic, flash the PCM and then the intermittent CEL goes away. I can envision something similar with respect to fan speeds and the output from the temp sensor.

Richard

RodneyWright · **Posted:** Thu May 14, 2015 12:02 pm

Vincent Keene wrote:

FYI, the hi/lo fans settings can be altered via your handheld tuner.

I couldn't access the stock fan settings w/ out installing one of the tunes which it not what I wanted to do, but it does provide a fix for now.

RodneyWright · **Posted:** Thu May 14, 2015 12:03 pm

Richard Casto wrote:

Lastly, I had asked to check on service bulletin just to see if the factory configuration you had might actually have a known issue. I know it is not uncommon to tweak these types of things over the life of a car. For example sometimes cars might have aggressive "out of bound" values for stuff that end up throwing a code and turning on the CEL, but in reality all is OK. They (manufacture) just adjust the range to be more realistic, flash the PCM and then the intermittent CEL goes away. I can envision something similar with respect to fan speeds and the output from the temp sensor.

Richard

I'll follow up w/ the dealer and ask if there is a service bulletin for the fan.

Edit: there are no TSB's for fan issues on the mustang according to the service department at CrossRoads. Service adviser said that's the first time he's heard of my issue.

DickRasmussen · **Posted:** Thu May 14, 2015 1:22 pm

Rodney - Did you use a Ford sensor?

RodneyWright · **Posted:** Thu May 14, 2015 2:00 pm

DickRasmussen wrote:

Rodney - Did you use a Ford sensor?

Yup.... all $29 dollars worth.... I purposely purchased a ford unit and not aftermarket. Seems that wasn't the fix. Still scratching my head over this one as to why one tune works over the other.

JamesMilko · **Posted:** Thu May 14, 2015 2:09 pm

A cheepo bluetooth OBD-II scanner should tell you if the coolant sensor is reading properly. If the water temp looks believable it's fine. Although, if it is reading I'm 100% confident you'd have a CEL since that would have a major impact on emissions and economy.

Jason Mauldin · **Posted:** Thu May 14, 2015 2:30 pm

RodneyWright wrote:

Installed a 89 tune from the hand held as you guys suggested with no expectations of this working. Set the low speed fan to 180 and thought no way this is going to work. The freaking fan works! WHY??? Doesn't run w/ the stock tune, but works w/ the handheld. Makes no damn sense. Looks like I'm running a 89 tune for now.... I've reset the fan speeds to 190 and 210 for low and high. Not what I wanted to do, but this does save me some coin. This also removes 1 feature about this car and that was being able to run any octane, so now I'm stuck at 89 which is doable.

I appreciate all of the help and suggestions, great members!!

Just request an 87 tune with the fan setting that you need, then you can run whatever octane that you like.

RodneyWright · **Posted:** Thu May 14, 2015 3:04 pm

Jason Mauldin wrote:

Just request an 87 tune with the fan setting that you need, then you can run whatever octane that you like.

That was one of the unique things about the bullitt, it would read the octane via the knock sensor and adjust the timing so you'd gain HP. I'm assuming the new tune is static. Bought it 2nd hand, so no purchase history or options to update.

RodneyWright · **Posted:** Thu May 14, 2015 3:05 pm

JamesMilko wrote:

A cheepo bluetooth OBD-II scanner should tell you if the coolant sensor is reading properly. If the water temp looks believable it's fine. Although, if it is reading I'm 100% confident you'd have a CEL since that would have a major impact on emissions and economy.

I scanned the car w/ my ODB II reader and found no codes. Also did not see any options to read temp parameters, but I can look again. This car has no coolant sensor, only the temp switch for the low speed fan mounted in the head. Not sure what triggers the high speed fan.

Chad Culbertson · **Posted:** Thu May 14, 2015 3:43 pm

Pretty much all cars adjust timing these days based on readings from the knock sensor.

The Camaros are kind of notorious for something causing the knock sensor to think it heard knock and moving to the 87 octane spark table and then not wanting to switch back. 87 isn't recommended for the LS3 anyway, so I had it tuned so that it just doesn't have the 87 octane table anymore to my knowledge, so hopefully nobody accidentally puts 87 in my tank haha.

I wonder if the dealer would simply just do a reflash of the PCM for you just to make sure it had a good stock flash.

Michael Westerfield · **Posted:** Thu May 14, 2015 4:22 pm

You could ask the dealer what the charge is for a reflash of the factory program as well.

Jason Mauldin · **Posted:** Thu May 14, 2015 4:58 pm

RodneyWright wrote:

Jason Mauldin wrote:

Just request an 87 tune with the fan setting that you need, then you can run whatever octane that you like.

That was one of the unique things about the bullitt, it would read the octane via the knock sensor and adjust the timing so you'd gain HP. I'm assuming the new tune is static. Bought it 2nd hand, so no purchase history or options to update.

Do a search for Lito on s197forum. I think he will be able to retain that functionality. His cost is $75 for a tune.

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