Hi all,

Recently my alternator went out while driving down the highway. Radio quit working and dash lights and gauges started acting funny. Eventually the truck died and I was stranded on the side of the road. The next day I replaced the alternator and everything seemed to be back to normal.

However, now my temp gauge (ECT) always reads in the middle. When I turn the truck off the needle drops. When I turn the truck on the needle goes to the middle regardless of the actual temp of the engine.

I did the "gauge test" where you push and hold the odometer button. The temp gauge needle does not sweep across the full range like the other gauges.

Did running my truck on low voltage cause this? And how can I fix it

I plan to buy a monitor of some kind so I can read temps more accurately but I would still like the stock gauge to work properly.

Thanks in advance.

 

No idea the year of the truck or if it's not a F-150.

Once you get one of the monitoring setups you can see if the temp sensor is tracking correctly. If not, replace the sensor. If it is then you may have cluster or PCM issues.

If it's a Superduty, you need to view this for next time.

 

Thank you. The truck in a 2004 f359 6.0L diesel.

I'm afraid running the truck on low voltage may have caused some larger issues.

 

If your dash coolant gauge ever goes to red, then you have a problem. It will go from normal to red VERY quickly.

What is your coolant level in the degas bottle?

Get that monitor ASAP. Waiting for the dash to work is not the right choice.

 

Thank. Coolant level is normal. I doubt there is an real mechanical problem. I'm sure the gauge is malfunctioning die to the alternator dying and running on low voltage.

Any recommendations for a monitor system???. It's work truck and I'd rather not spend too dollar unless it's necessary.

 

ForScan Lite download to a smartphone and an ELM327 OBDII adapter (WiFi for iOS and Bluetooth for Android).

 

My take on Russian software is the THUG-GOON running the country has his slimey mitts on all their companies. FORSCAN is on my personal AVOID list.

https://www.reuters.com/article/us-u...-idUSKBN1E62V4

 

Jack, I never get more than 13,9V in my system, not even with a new generator. Driving dowm the highway, I have ~13,3V on the system. I don't have any obvious electric problems, but I notice that again and again.
What have you changed in your system to come to 14.5 V?

 

If you get numbers that seem more like they should when using one of the OBD2 tools.
I would be inclined to point my finger at the stepper or the driver for that gauge.
Give the people over at >>> https://circuitboardmedics.com
They can help you diagnose the issue and also do the repair for you.
They support FTE as a sponsor.

 

You have to convert EU volts to US volts.


Sorry, I could not resist typing that. It's early in the am with a lack of sleep.

It depends on several factors. With the 110a and 140a alternators, both achieve 14.4v without high loads post 5 minutes of starting cold. By design, the thermistors in the voltage regulators will bring that down to 13.6 - 13.8v once the underhood temperatures are elevated. The Leese-Neville 230a alternator has an excessively high voltage regulator that does not meet SAE norms, so under the cool operation will output 14.5v to 14.6v, then also lower when hot. All of these values are at the alternator post or passenger battery post.

The voltages inside the cabin and from the OBD2 port are lower. The PCM in our trucks reports a slightly lowered voltage than with any other Ford product I have checked, in my case 0.1v to 0.2v. More than that, when I have worked on my truck the issue has been the accumulation of the resistance in the connections. Both the ground or negative connections and positive connections.

Most of the time I look at circuitry in terms of electron flow, not conventional current flow, so I concentrate on the grounding or negative side which I find is often poorly addressed in the design and in maintenance. So the electrical videos are concentrated on reducing any resistance, by cleaning those connections or adding reducency. With all the repeat grounding connections of all electronics to the ground plane (body tub) can cause a voltage differential.

To address that the primary connections from the sources (battery and generator) we can lower the resistance by half by installing redundant connections. That's what I do with the main battery cables, battery to battery and driver's battery to the engine block, and the added negative cable from the driver's battery to the FICM and PCM grounding points, adding redundancy - reducing resistance in the connections. I try to do it in the simplest and most cost-effective way. But the battery to battery connection is not optimal due to the terminal connection, which I will leave alone for now.

Some have responded here, but I just had a response from another site. It's not much of a voltage change. But unseen is when we increase the current demand, the response in these connections with higher than ideal resistance is to lower voltage even more. You can't get around V = I x R.






It is as simple as making sure the connections are as best as they can be within reason if that's the problem.