Gauges - 1977 spider 2000 V

[jeremyburnan]

Help please.

Having restored my electrical system from basket case to almost 100% efficiency, my attention turns to the gauges.

First of all, the coolant temperature gauge: at rest, ignition off, power down etc, the gauge needle is mid way along the dial. Turn on ignition and the needle flicks to zero. Should this happen? If anyone can tell me where the coolant temperature sensor is, I'll make progress. Clearly there is current into the gauge but where from? I ask myself.

Secondly, Oil Pressure gauge: This is connected to the sensor on the left side of the block, midway down. The power lead to the gauge is red/black. With igniton off etc, the gauge needle is at zero. When ignition is turned on, the needle flicks to max. Again, should this happen? When I start the engine, the needle goes back to zero, and stays there. This may be a sensor problem.

Powering up the spider has an apollo 11 quality about it - the two gauges flicking in the opposite direction!

If you could advise, I'd be eternally grateful.

Lastly, according to the wiring diagrams, there are two separate oil pressure sensors - one for the gauge, one for the warning light. Where is the second sensor?

Your advice gratefully received.

Jerry
1977 Spider 2000 Vel
1989 75 2.0L TS Vel

[John M]

Hey Jerry:

Welcome to the board. Be sure to post some pics up of your Spider.

The coolant temp sensor is up on the intake manifold next to the thermostat housing. It sounds like that gauge might be working correctly....especially if she is coming up to operating temp and the gauge shows it.

The oil pressure sensor is on the passenger/right side of the block under the intake manifold, near the firewall, and above the starter. Its a cannister type spin on sender. The sender on the left side of the block near the exhaust and oil filter is the oil low pressure warning light. It sounds like your oil pressure gauge sender wire is disconnected and grounding out....hence the full scale.

Best Regards,
John M

[BeigeAlfa]

Hi Jerry,

My temp guage does exactly the same thing. I've being eyeing it suspiciously for years, but it seems to be accurate.

From what you say, sounds like your oil pressure guage is connected to the low oil pressure light sender. Look for the correct sender where John descibes, and also look for your low oil pressure light!

Dan.

[Roadtrip]

Agree with Dan, it's obvious that you've connected the oil pressure gauge to the oil pressure warning light sensor. The warning light sensor is strictly an ON-OFF switch (at 5 psi) and not a variable grounding rheostat like the pressure gauge sending unit is.

Hence, when you turn on the ignition (no oil pressure) the sender unit is completely grounded and allows full voltage to the guage (full scale deflection high) since it's trying to turn the low pressure warning light on. Then once the engine is started, the sender unit goes OFF (denys a ground) and the gauge goes to zero.

[jeremyburnan]

Hi Dan, hi John,

Yup, took on board John's very quick reply. You're right - light sensor was connected to gauge. Gauges now work. I need to look at fuel level gauge now. It's dark, so have to begin that tomorrow.

Many thanks for your input.

Jerry