EJ22 1991 crank angle sensor

[Auz23]

Hey team

I am just wondering how I would go about testing my crank angle sensor and my wiring - I've been having stalling issues and starting issues since i checked the sensor last night and reconnected it, with a check engine code for crank angle sensor

I have a multimeter, checked the wiring connector and it had continuity, but with the key in the on position I could not find any voltage running through - it had 0.05v running through all the connectors which obviously is nothing - but in the workshop manual, it says voltage should be zero as well. This is different from what I've  learnt that usually there should be voltage running through it when the key is in the 'on' position. I have attached the page of the manual where that is found

Thanks in advance!

 

[GeneralDisorder]

It's an inductive pickup. It doesn't require any input power. You need an oscilloscope to monitor the waveform and also the cam angle sensor and then check for correlation. A multimeter is useless for testing this sensor. 

GD

Edited October 24, 2019 by GeneralDisorder

[Rampage]

10 hours ago, Auz23 said:

This is different from what I've  learnt that usually there should be voltage running through it

As GD said, inductive.

It basically works like a coil reacting to a magnet. The output will be a sinewave, the frequency of it will increase with rpms. When doing a timing belt, if you look at the timing mark on the crankshaft you will see multiple tabs sticking out of that ring with different spacing. This is how the ECU knows when number 1 cylinder is top dead center and when to fire that plug and each one after that.

Pull the sensor out and see if there is any crud built up on the end of it.

Most service manuals recommend NOT probing certain wires going into the ECU with an ohm meter because the output voltage of an ohm meter may be high enough to damage the ECU. You should unplug the ECU connector and probe from the pin of the connector to the plug you are working with. You can however unplug the connector from the sensor and probe the sensor for ohms.

You mentioned it acting worse after plugging it back in. Did you probe the wires with the ohm meter?

It could be as simple as a partially broken wire near the plug, or dirty contacts. Between that connector and the ECU the wires are shielded like in a coax cable.

[Auz23]

6 minutes ago, Rampage said:

As GD said, inductive.

It basically works like a coil reacting to a magnet. The output will be a sinewave, the frequency of it will increase with rpms. When doing a timing belt, if you look at the timing mark on the crankshaft you will see multiple tabs sticking out of that ring with different spacing. This is how the ECU knows when number 1 cylinder is top dead center and when to fire that plug and each one after that.

Pull the sensor out and see if there is any crud built up on the end of it.

Most service manuals recommend NOT probing certain wires going into the ECU with an ohm meter because the output voltage of an ohm meter may be high enough to damage the ECU. You should unplug the ECU connector and probe from the pin of the connector to the plug you are working with. You can however unplug the connector from the sensor and probe the sensor for ohms.

You mentioned it acting worse after plugging it back in. Did you probe the wires with the ohm meter?

It could be as simple as a partially broken wire near the plug, or dirty contacts. Between that connector and the ECU the wires are shielded like in a coax cable.

I used a DC volt setting on my multimeter as that is what I was Instructed to do, the reading hasn't changed at all since the first test

I unplugged it and then plugged it back in again and my no-start condition turned into a starting condition last night, and it has cranked fine ever since - does that mean that it is most likely a dodgy wire near the connection? 

It is worth mentioning that it is a 3 pin crank angle sensor, like this one here. I'm not entirely sure about them but usually, don't they require voltage?

[Auz23]

15 minutes ago, Rampage said:

As GD said, inductive.

i was under the impression that this was how the sensor worked, but correct me if i'm wrong

[Auz23]

5 hours ago, GeneralDisorder said:

A multimeter is useless for testing this sensor

See above image, or am i wrong in assuming that is the layout of the connection

[Rampage]

On the wire from the harness of the car to the sensor connector one of the outside pins is the shield and ground (on a 92 it is yellow) and the other two are signal (black and white).

I checked rock-auto and 91 and 92 use the same sensor. The colors on the sensor plug could differ.

24 minutes ago, Auz23 said:

does that mean that it is most likely a dodgy wire near the connection? 

Sure does...or a loose or corroded or broken pin.

[Auz23]

 

 

 

 

9 minutes ago, Rampage said:

 

Sure does...or a loose or corroded or broken pin.

 

I just got off the phone to the mechanic, he said to wiggle around the wiring and see if the car stalls out when it's running. sure enough, it did

That all but confirms for me that there is a dodgy wire near the connector? should I get a professional to change that out? I'm pretty confident with wiring and soldering, and my old man is pretty good at it too

[Rampage]

Now to find out which wire or the plug.

Repairing the break depends on where it is and how much wire you have to work with.

Soldering is ok, but it will melt the insulation on the wire. What I do is use a heat sink on the wire to protect the insulation. A pair of needle nose plyers works good. I have several spring loaded aluminum clips that work like a cloths pin. They are from my electronics days.

Normally I poke the stripped end of the wire into silicon grease and use crimp connectors.

This might be useful, they make a liquid tape that is applied with a brush on the lid. Even hardware stores carry it around here.

[Auz23]

12 minutes ago, Rampage said:

Repairing the break depends on where it is and how much wire you have to work with.

since it is near the connector, I was thinking of splicing in a new connector maybe 6 inches back from the wiring; i have one available. I would strip the wires first of the insulation then use heat shrink insulation to reinsulate the wires. I'm no auto electrics expert but do you think that would work fine?

[Rampage]

That will work, but you will run into the shield around the two signal wires. In the picture above the dotted lines are the shield around the signal wires.

All you can do is experiment. Gently cut the outer insulation and see what you have to work with. The exposed wires you splice in must be as short as possible because they will pick up noise from ignition wires and other things.

You could splice in an extra wire with the shield wire crimp on each of the new connectors and then when you're done splicing and have it taped wrap it with aluminum foil and strip that extra wire and lay it on the foil and wrap it one or two more times then tape over it. That will work good as a shield.

[Auz23]

 

 

 

 

 

3

5 hours ago, Rampage said:

You could splice in an extra wire with the shield wire crimp on each of the new connectors and then when you're done splicing and have it taped wrap it with aluminum foil and strip that extra wire and lay it on the foil and wrap it one or two more times then tape over it. That will work good as a shield.

Thanks for that suggestion!

I will probably give that a go. just for reference, would this work? http://www.aeroelectric.com/articles/Shielded_Wire_Splicing/S_Wire_Splice.html

thanks for all your help, you've been a lifesaver

[Rampage]

You're welcome.

Tried that link, but all I saw was a page with three links to click on.

I try to do a repair as good as I can do it. I have done that same thing with foil on signal wires in electronics and it does work.

Good luck.

[Auz23]

On 10/25/2019 at 3:45 PM, Rampage said:

Good luck.

Update! Today I soldered in a used connector I got from the wreckers. I did a test of wiggling the wires near the connector when the car was running and sure enough it was near the connector - the engine shut off

I soldered in new cable and connector, and my car runs like a dream now. The idle is no longer as rough and there is no stalling. More power and response from the engine which is great! Thanks so much for all your help and expertise. 

Project successful! (So far)

I will post an image later 

Edit: Not sure if i didnt notice before, but now on a warm start the revs of the car go straight to 650-800/ the revs that the car usually has when running. its very smooth, but I'm used to the 1200 revs on startup that slows to 650-800 after 20-30 secs. Im guessing its something to do with a proper connection now? unsure as to why the crank angle sensor would change the idle speed but anywho... Feels great

Edited October 26, 2019 by Auz23
addition

[Rampage]

Great. Makes you feel good when you find the problem and fix it.