Erratic Reading on Fuel Level, Oil Level and Oil Pressure - New senders?

[polizei]

Guys,

I just got my gauges rebuilt by NHS, and I'm wondering if I should replace some senders as well. Prior to having the gauges serviced, I saw erratic readings on the Fuel Level, Oil Level and Oil Pressure gauges. This sounds like an issue withe senders, but I wanted to check before spending $$.

Do the senders go bad over time or does everyone get erratic readings?

Thanks,

[gregwils]

You need to describe what you mean by "erratic" for anyone to understand the issues you were experiencing.

Oil level in my car is impacted by whether the car is level, uphill, downhill, etc. Fuel too. Oil pressure - no. Senders do go bad, but I am not sure I would replace until you verify they aren't working.

[gregwils]

You need to describe what you mean by "erratic" for anyone to understand the issues you were experiencing.

Oil level in my car is impacted by whether the car is level, uphill, downhill, etc. Fuel too. Oil pressure - no. Senders do go bad, but I am not sure I would replace until you verify they aren't working.

[polizei]

Originally Posted by gregwils

You need to describe what you mean by "erratic" for anyone to understand the issues you were experiencing.

Oil level in my car is impacted by whether the car is level, uphill, downhill, etc. Fuel too. Oil pressure - no. Senders do go bad, but I am not sure I would replace until you verify they aren't working.

Hi Greg - Here are some more details:

1. Fuel Level

The gauge is correct when the tank is full. As I take it on long trips, the gauge doesn't seem to move linearly with the amount of fuel used. For example, I've seen countless instances of being at 3/4 tank for about an hour, and then within 5 minutes, it drops to below 1/2 tank - with no significant change in elevation. This especially becomes an issue when you're under a 1/2 tank of fuel!

2. Oil Level

The oil level indicator is correct with a warm engine at idle. Once I start driving, the indicator drops. Often when I'm cruising on the highway, it looks like it's nearly empty. Under hard acceleration it does look empty. Braking does just the opposite - the gauge jumps to full.

3. Oil Pressure

Oil pressure is jumpy at idle. It stays constant at a cruising speed but seems to correspond to acceleration. For example, after a gear change, the indicator drops. As I get the revs up, the indicator starts to rise.

[Driver_X]

Your oil level & oil pressure gauges sound like they are working as designed. Oil level is only accurate when on level ground, @ idle, @ normal operating temp (180 +). Oil pressure will fluctuate depending on RPM.

As for the fuel level, mine sticks a bit when I start it (goes to full) and if I tap on the glass, the needle will drop and work normally. If you've had that gauge rebuilt, then I would probably check the operation of the fuel level sender.

[polizei]

Originally Posted by Driver_X

Your oil level & oil pressure gauges sound like they are working as designed. Oil level is only accurate when on level ground, @ idle, @ normal operating temp (180 +). Oil pressure will fluctuate depending on RPM.

As for the fuel level, mine sticks a bit when I start it (goes to full) and if I tap on the glass, the needle will drop and work normally. If you've had that gauge rebuilt, then I would probably check the operation of the fuel level sender.

Thanks for the reply. Two questions for you:

1. What's the acceptable range for oil pressure at a certain RPM?

2. How do you recommend checking the operation of the fuel level sender?

[moneymanager]

10-14 lbs per 1000 rpm when warm. Mine shows way more when cold.
If your gauge is good and the wires are firmly attached, there isn't anything else in the circuit except the sender. You might swap in a good sender. A search here could turn up a test procedure.

[JJ 911SC]

Originally Posted by Driver_X

Your oil level & oil pressure gauges sound like they are working as designed. Oil level is only accurate when on level ground, @ idle, @ normal operating temp (180 +). Oil pressure will fluctuate depending on RPM.

As for the fuel level, mine sticks a bit when I start it (goes to full) and if I tap on the glass, the needle will drop and work normally. If you've had that gauge rebuilt, then I would probably check the operation of the fuel level sender.

+1 and had the same problem with the fuel level sender until I switched to Shell Nitrogen Enriched Gasolines. The nitrogen act as a cleaner.