83 QV down on power and 5-8 light

I agree with Rifledriver here. Sounds like you have a bad crank sensor. They are no big deal. It's a coil of wire with a lead on it. They are about $100 from Ferrari UK, which is about 3 times what they should be, but not terrible. There are three on an '83. They are accessible through the left rear wheel opening. They are placed around the bell housing and read notches on the flywheel. They are a bit tricky to access, but they each have a two pin connector that is easy to reach and disconnect. Very easy to trouble shoot. Just disconnect the connector and measure the DC resistance across the pins with a ohm meter. They will read about 600-800 ohms if they are good, and very high to infinite resistance if one is bad. The good thing is they will tend to read bad when they are cold and may get flaky and intermittant as they get warm and they wire in them expands, so measure cold.

I had the exact problem you are having with the Mondial. I hear your pain, but once you find it, it will be an easy fix.

Birdman

 

Here are where the sensors go into the bell housing:

They are not completely visible in the pix, but at least gives you the idea. Just look for the white cables-
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if you can figure it out from the schem, measuring the resistance of the sensors at the ecu connector(s) is best. That will verify the sensor and a couple of plug connections along the way.

If the qv is the same as the gtsi, then the TDC sensors are connected to
pins 1 and 5 on each ecu. The 5-8 bank is a black wire on pin 1, and a yellow wire on pin 5. The 1-4 bank has a blue wire on pin 1, and a green wire on pin 5.
The tach sensor is connected to pins 2 (black/red) and 3 (red) on both ecu's.

Be a bit skeptical of the diagram for the round diagnostic connector. I seem to recall that the pin placement is wrong in either the owners manual or the separate schematics for at least one of the 3x8 series.

 

Wow, shades of the 'Wonderful One-Horse Shay'!!!

 

"The sensor was indeed bad. The wire had pulled out from the sensor head leaving just a little wire connecting"

I knew you could do it !!!!!! Great job.
(p.s. bad sensors were my guess- my PO had a similar problem, just dirty sensor connectors though)

Should run like new with all of those new parts.
Enjoy !
Steve

 

The new sensors will prob have the late style connectors so a little cutting and splicing may be in your future.

Good work.

 

Slightly off topic but relavent to the great picture from jwise. What is the white wire that is going "over" the oil pressure sender and down the other side. When I was replacing my oil pressure sender, this wire on mine was pinched underneath and made a simple swap much more diffucult. Just wonder where it goes. I pulled some slack out and ran it around the oil sender because it was preventing me from lining up the threads of the sender correctly. Hope I did not disconnect it on some other end by mistake.

Oleh

 

Heavier can't hurt...I'd use at least a 14ga, and 12ga would be best.

Here are the instructions:
http://www.***********.com/tech/view.php?id=20

 

You mentioned that 3 out of 4 plugs on the front bank are white while the rest are look good. White plugs indicate a lean condition. If you were not getting a good spark to those plugs, they would be carboned up i.e. sooty black. Your problem may be in the fuel delivery system. The cold start system probably has masked the lean condition until operating temps are reached. I'm running EFI so I have little experience with the CIF. Good hunting.

 

The new ones will be white cable with std Bosch connectors like in the picture. If you have those already it will just be plug and play. If not clip the black connectors off the old sensors and any type of reliable splice will work. You can use crimp connectors or solder and heat shrink tubing.

It will all be self explanatory when you have both in your hand.

 

Can you check that matteo?

The 1-4 and 5-8 sensors must be mounted 90 deg apart so isn't it the RPM sensor at the 3 o'clock position by the oil cooler?

 

Understood -- in your OM there is a figure in the ignition system section that gives the wire colors so you can reconfirm at the harness connectors (it also shows the 90 deg relationship for the 1-4 and 5-8 sensors).

 

Previously posted by Eugenio:
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