EJ1 wilcox

I can usually figure things like this out but I am kind of stumped on this one. I have a hypothesis but I want to hear what you guys think before I move forward with messing with more stuff.

Okay, so I installed an autometer oil pressure gauge in my console a few days ago. It's a short sweep electric gauge by the way. I tapped the backlighting into the stereo harness, which works fine. Then for the sender, I tapped the switched 12v ignition into the stereo harness, and ran the sender wire and engine ground through the firewall.

I installed the electronic pressure sender in an oil filter sandwich adapter, and connected the ground to a random bolt on the back of the intake manifold.

When I first installed it, everything worked perfectly. It zeroed out when I turned the ignition on, and was perfectly responsive to changes in oil pressure.

Now here's where it gets weird. The next morning I go out to my car, turn the key, and the gauge doesn't zero out, it does nothing at all. I turn the car on and it starts fine, but still, the gauge doesn't move. The needle is still below the zero.

The gauge doesn't move, but the car is running fine. I get out and check for leaks and there are none. I figure it's a problem with the sender and drive to work. About 2 miles down the road the gauge randomly starts working. And working perfectly. Fluctuating with engine speed just like it should.

When I get to work I turn the car off and turn the ignition on just to see if the gauge will zero out, and it does. It's working fine.

When I get off work it's dead again. It doesn't zero out and doesn't work for the first few minutes the car is on. Then it randomly starts working.

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That night I took the sender back off to see if it was clogged. I cleaned it out and there was nothing clogging it at all. So I reinstalled it and tried the key again, this time it zeros out right away. I'm thinking I fixed it.

But I didn't!

The morning after that (this morning) when I went to start the car the same thing happened! Damn it! The gauge didn't budge, didn't zero out when I turned the key, and didn't read the pressure when I started the car... nothing. But sure enough, a few minutes later it started working randomly.


Hmmmmm.... so what do you think is the problem?? I know it's wired correctly because when it works it works fine. The sender isn't clogged, and my grounds are clean.

What else could it be??

What would cause it to not work at startup and randomly start working a few minutes later??

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Here's what I think (the only thing I can think of). I think it's either a ground, or has to do with the wire I used. The ground is about as perfect as I can get. I checked the ground and it appears to be clean (but if it were a ground wouldn't it NEVER work correctly?)

I did verify that I'm getting a full 12 volts to the gauge, and when I measured the voltage at the sender it was 9.6 volts. So 12 v into the gauge, and 9.6 v to the sender. Normal?

I also used just regular 14 gauge "primary wire" that I had in my tool box. I did notice that the autometer instructions call for 18 gauge. But could that small of difference in diameter wire really cause this unusual behavior??


What are your thoughts? Any guesses you have are greatly appreciated!

Here are some pics... not that it really helps, but we all love pics!

The gauge... this is where the needle sits w/ out a key in the ignition. And when it's acting funny it doesn't move from here.


My engine ground location for the sender ground. The screwdriver is pointing to it.


The sender and ground wires running through the firewall. You can see the gauge is 14, which doesn't look that much larger to me than 18 but then again, I don't know that much about electricity and wiring.

vtecb18c

could be a bad ground or you have a faulty guage

EJ1 wilcox

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecb18c &raquo;</TD></TR><TR><TD CLASS="quote">could be a bad ground or you have a faulty guage</TD></TR></TABLE>

Yeah, I've checked the ground and placed it different places on the engine with the same result. I'm really starting to think to think the gauge is bunk.

Is there any way to tell for sure if the gauge is defective?

vtecb18c

well by the way its acting up i think its just faulty....my boost guage did the same thing so after troubleshooting i decided to get a new one and it worked great...did you just buy it? i would send it back and get a new one

vlang29

if the gague won't zero out, it is definitely a power connection problem and NOT the sender.

Do you have 12v at the gauge when it isn't zeroing out? I would check your hot wire connection.. Did you use butt-splice connectors? those things suck, even when they seem tight, they can still give **** poor connection. soldering connections is much better, and worth the extra time.

EJ1 wilcox

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vlang29 &raquo;</TD></TR><TR><TD CLASS="quote">if the gague won't zero out, it is definitely a power connection problem and NOT the sender.

Do you have 12v at the gauge when it isn't zeroing out? I would check your hot wire connection.. Did you use butt-splice connectors? those things suck, even when they seem tight, they can still give **** poor connection. soldering connections is much better, and worth the extra time.</TD></TR></TABLE>

I've checked and I do have 12v at the gauge when it's not zeroing out. It's like 12.36 volts or something like that. All my connections are soldered and I've double checked the joints, they are clean and solid.

I think I'm just going to buy a new gauge. I've had this one for about 5 years and in 4 different cars. It's worked fine until now. Oh well, I suppose it's served its purpose.

EJ1 wilcox

I'm going to just go ahead and buy a new gauge, and see if it works properly. I'm almost 100% sure the gauge is just bunk.

boostatic

autometer is basically an industry standard but sometimes its a bad standard..their stuff goes bad all the time..and its so random..even new gauges..most likely it is just the gauge..

SpoolD16

Take the ground off the back off the intake manifold and actually ground it to the chasis

MightyG

Hello, I have a little question...

When we install a new oil cooler into my brother Del Sol , i broken one of his AutoGauge oil pressure sender connector, the sender working, but i want to change it before makes a trouble.... I have a new sender but different than the old one . The new one have only one connector.... What is your opinion, can I use the new one, and if yes how do I make?

Thanks for any help...