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1986 Alfa Romeo GTV6
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Discussion Starter #1
I have a 86 3.0 swap and the senders are not working.
From reading too many posts on replacing with new and drilling and whatever I was wondering what would you guys personally would do.
So the 3.0 has 3 senders
One next to the dip stick for the low oil. A big one facing up at the back of the motor for the gauge sender and the last one on the back of the engine facing the fire wall for the oil light.
The oil sender gage has no movement at all. Not cold, not hot, idling or whatever situation. The oil light never turns on. I have no idea if it works or not.
According to what I read, some of these wiring and stock gtv6 are not compatible with the 3.0 from the milano QV. That said I only have one wire to connect these 3 sensors. Even when I change the wire between the sender and the oil light, nothing happens.
Related (I think) to the situation.
I may have a ground/electrical problem.
Every 4 seconds, like a Swiss watch the idle goes down for a second. At exactly the same time you hear an electric buzz comming from the radio/speakers. If I signal with the turn lights, the sound does not "follow" the blinker rythum. It continues its own rythum but gets a bit louder. If I turn headlights and/or wipers they take like 3 pizzas time to do a full wipe on the windshield. Window motors take same time to go up or down.
This is the situation.
Now the questions
I want to take this electrical/ground problem but don't know where to start.
Assuming electrical gets fixed, how would you guys solve the sender problem?
I love gages and want them working.
Aslo bought a voltmeter to install. Just don't know where. No damaging/drilling of all that's stock is considered, so need opinions.
Thanks in advance and sorry for repeating this post. I tryed but I think my situation is distinct from what I found.
 

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Hi there, as far as I know, GTV6's didn't come with a low oil pressure light, you could add one I guess, there is an unused light position in the instrument cluster by the fuel gauge.
The oil pressure sender, the wire to it should be a red/black. If you ground the end of the wire that would go in the sender, you should get a full scale reading on the gauge. If not you will have to trace the wire, see where the break is.
I don't have ideas about your 4 second problem.
 

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1986 Alfa Romeo GTV6
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215 Posts
Discussion Starter #3
Hi there, as far as I know, GTV6's didn't come with a low oil pressure light, you could add one I guess, there is an unused light position in the instrument cluster by the fuel gauge.
The oil pressure sender, the wire to it should be a red/black. If you ground the end of the wire that would go in the sender, you should get a full scale reading on the gauge. If not you will have to trace the wire, see where the break is.
I don't have ideas about your 4 second problem.
Yep, no low oil light. That is the least of my worries. If that light comes on on any Alfa you are already in deep trouble. Lol.
The wire, if I recall it is red with a terminal. Now, when you say ground the wire. How?
 

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If the starter motor works, the engine should be properly grounded. But, it can't hurt to check the ground cable from the battery to the chassis, and the chassis to the engine. Are you certain that the 2.5 didn't have a low oil pressure sensor? Do you have proper wiring diagrams? To test the oil pressure (gauge and/or low pressure) circuits, touch the chassis wires to a good ground source. The gauge should peg maximum, and the low oil pressure light should illuminate (if equipped).
 

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Don't remember now, but if the GTV6, like the Milano, comes with a low oil quantity sensor and light, it most likely does not work, the sensor having failed. They almost always fail. Don't worry about it. Just go old fashioned and check the stick.

The sensor doesn't work in either our 164S or Milano. Don't know about the LS. At least in the 91S, I was able to put a 12 ohm resistor in line and that put the light out. That trick didn't work for some reason in the Milano, but I put a tiny piece of black electrical tape over the light and that took care of that. Can't see the tape.
 

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The wire, if I recall it is red with a terminal. Now, when you say ground the wire. How?
Take the wire off the sender, switch on the ignition and touch the metal of the connector that was on the sender to clean, bare metal (aka ground; 12V negative). The gauge needle should go to maximum. If it does, this confirms the gauge works and the wire from the sender to the gauge is intact.
 

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The oil pressure gauge is the only one to be concerned with. As others have said, the GTV6 has no warning lights for low oil level or low oil pressure. Identify the wire for the gauge and test as described in the previous post.
 

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Yep, no low oil light. That is the least of my worries. If that light comes on on any Alfa you are already in deep trouble. Lol.
The wire, if I recall it is red with a terminal. Now, when you say ground the wire. How?

The wiring diagram I have that came on with my Cardisc says the wire to the oil pressure gauge sender is red/black, not straight red.
 

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1986 Alfa Romeo GTV6
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Discussion Starter #9
If the starter motor works, the engine should be properly grounded. But, it can't hurt to check the ground cable from the battery to the chassis, and the chassis to the engine. Are you certain that the 2.5 didn't have a low oil pressure sensor? Do you have proper wiring diagrams? To test the oil pressure (gauge and/or low pressure) circuits, touch the chassis wires to a good ground source. The gauge should peg maximum, and the low oil pressure light should illuminate (if equipped).
The starter works and the car runs marvelously except for what I described above. Checking the grounds. Thought about replacing the bat groung cable but am not sure which is the engine ground cable. For what It looks like, there is a few. Not sure about the 2.5 sensor. The 3.0 has and I have nowhere to connect it. But not bothered at all. Like I said above. What would you recommend as a good ground source to test that?
 

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1986 Alfa Romeo GTV6
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Discussion Starter #10
Don't remember now, but if the GTV6, like the Milano, comes with a low oil quantity sensor and light, it most likely does not work, the sensor having failed. They almost always fail. Don't worry about it. Just go old fashioned and check the stick.

The sensor doesn't work in either our 164S or Milano. Don't know about the LS. At least in the 91S, I was able to put a 12 ohm resistor in line and that put the light out. That trick didn't work for some reason in the Milano, but I put a tiny piece of black electrical tape over the light and that took care of that. Can't see the tape.
Yep, that's what I always do. Dip stick an a walk around the car before I start it.
 

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1986 Alfa Romeo GTV6
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Discussion Starter #11
The oil pressure gauge is the only one to be concerned with. As others have said, the GTV6 has no warning lights for low oil level or low oil pressure. Identify the wire for the gauge and test as described in the previous post.
But isn't there a light on the top of the oil gage? That should light up at leas on the key 1st position.
 

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GTV6's and Alfetta's do not have a low oil pressure switch
 

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Re Grounding the wire...after disconnecting, just touch the metal terminal to the metal engine block or cam cover somewhere near near where you detached it From the sender. You’ll need a helper to watch the gauge, or do the wire bit. Ignition will need to be ‘on‘, of course.
 

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1986 Alfa Romeo GTV6
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Discussion Starter #14
The wiring diagram I have that came on with my Cardisc says the wire to the oil pressure gauge sender is red/black, not straight red.
That could be true. I am not close to the car. will confirm if its red/black.
 

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1986 Alfa Romeo GTV6
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Discussion Starter #15
What about the other electrical problem. No ideas?
Bought a tester and am willing to put it to work guys. lol
 

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No other ideas about your 4 second buzzing electrical problem other than getting the usual stuff out of the way. Engine bay grounds, which there are several, both ends of the big wire, the bundle down on the fender by the alternator, the bundle in about the same place on the other fender, the bundle on the rear of the right valve cover. There is also a bundle of grounds above the hood release pull handle. You might want to tackle putting a relay in the brown wire of the fuse box which may help your slow wipers.
Does the four seconds thing happen hot or cold, all the time or only at idle, what if the radio is turned off, what have you done to isolate it already?
 

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1986 Alfa Romeo GTV6
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Discussion Starter #17
No other ideas about your 4 second buzzing electrical problem other than getting the usual stuff out of the way. Engine bay grounds, which there are several, both ends of the big wire, the bundle down on the fender by the alternator, the bundle in about the same place on the other fender, the bundle on the rear of the right valve cover. There is also a bundle of grounds above the hood release pull handle. You might want to tackle putting a relay in the brown wire of the fuse box which may help your slow wipers.
Does the four seconds thing happen hot or cold, all the time or only at idle, what if the radio is turned off, what have you done to isolate it already?
Everytime its idling. hot or cold.
When moving, it starts as soon as i let go from the gas and brake, or when i signal.
Radio was installed by a pro shop, so i assume it's right.
My first idea was alternator not compensating enough. Here's another symptom i forgot about.
When starting, i have to rev up to above 3k rpm so the idling stables out and the bat light goes out. That's why i thought about alternator, or voltage regulator.
But the battery charges good.
The ground bundles, that's why it threw me off when i was looking for it.
I saw too many and wasn't sure all were grounds.
So, i will follow your recommendations and everyone else's here.
Will keep you guys posted.
Lets see if we get the rona out of this gtv6. lol
 

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But Mad North-Northwest
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L-Jetronic controls the mixture by steadily oscillating back and forth across stoichiometric. If you listen carefully at idle you can often hear the engine sound / RPMs varying as this happens, and I suspect this may be what you're hearing. As your oxygen sensor ages its response time slows down and this becomes more noticeable.

You can watch this happening in real time by monitoring the oxygen sensor output with a digital voltmeter. If the voltage oscillations correspond to your noise then you've found the issue. You can also usually see it with a digital tachometer, but the sensor output is easier to see.

It's possible your idle may be set too low, and at the low point in the oscillation it may be affecting alternator output. It's also possible your oxygen sensor is just worn out. I would start by verifying warm idle with a digital tachometer and setting to spec.
 

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So every time you signal your idle drops?... You know what they say about assumptions.....
I would recommend that you go through the Ljet troubleshooting guide, and work on getting your car to start and idle hot or cold without having to compensate for anything. I find over time, in some cases, that we compensate and compensate that it becomes harder to troubleshoot with more than one thing throwing out curveballs.


Batt light should go out just after a start or by 1000 rpm, at least in my experience. Easy enough to do some basic tests, see what voltage is car off, just after start and with red light out. Would be interesting to see where voltage goes during an idle cycle.
 

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1986 Alfa Romeo GTV6
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Discussion Starter #20
So, looks like everyone is pointing to the same.
ordering this from amazon.
Cheap and to use once or twice
1626480

Already have a digital multimeter
and will be checking those ground connections. Although, to check, mind as well disconnect them and clean to improve contact correct?
Going back, it had the same symptoms before the new radio.
VintageMilano. You are correct. I'm all about doing it right the first time, but i have the car for a year and do not know what it was done to it before.
I can imagine.
When i went to install the radio i gave up. There was so many wires in the back of it that i decided to take it to a pro.
Don't get me wrong, the installation was well done and neet. but it was passed my auto tinkering capabilities. and if there's one thing i don't go on discovery mode is car electric/electronics. I've seen how bad and fast things go.
 
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