CAS, Crank Angle Sensor trouble. Need help!

[NismoFunZ]

Hi all!

My first post.. =)

I replaced my timing belt on my 300ZX 90 NA, and stupid as i was, i took of the CAS sensor 3x12mm bolts and unplugged the contact.

When new gates belt was on, and the cas mounted in place, the car starts very easy like it used to, but sounds like it doesnt get any fuel at all.
The sound of engine is like what it used to be the first 2 seconds, but then rpm falls to 500-600 and the engine is dying.

Im sure the belt is 100% correctly on aligned with white marks. All contacts has been cleaned, and wires are in great condition.
The car was working perfect until this sensor came off.

Probably a stupid thing to do, but i tried to start the engine with the new belt in place, without the CAS sensor.

Have i ruined everything? What should i do?

No Nissan dealers here in Norway dont even want to look at my car...

All help will be greatfull. Got videos and pics if some kind person will help me out..

Emailadress: [email protected]

[BigTDogg (MA)]

Welcome.

This should be in technical.

Does moving the CAS while the engine is running have an affect on the way the engine runs?

[NismoFunZ]

When the key in position 2, I tested the CAS by turning the cylinder, and each injector sprays as it should.

I have not tested that yet.. You mean turning the cylinder by hand, while the engine runs ?
Better be quick because the engine shuts down within 10 seconds after startup.

Really need my car back on the road, and this "major" problem is the only thing from driving it..

[nissanfreak12]

BigTdogg is talking about having the CAS connected and in the engine. Then start it up and run it, then turn it in with the bolts loose enough so it can turn. Your car needs to have its timing checked since you did do a new timing belt and have taken the CAS off and changed the timing.

I honestly would connect everything back together, run the car till it warms up to operating temp, then set the timing to 15btdc with a timing light. Then take it for a drive and see if that helps out. Pretty sure the belt is connected properly, but you have to get the engine correctly timed to get it to run properly.

[GerryO]

Is all of the intake ducting on the car, properly sealed up, with the MAF connected?

Moving the CAS while the engine is running will change the ignition timing and how the engine runs.

[NismoFunZ]

I have not moved the CAS while the engine was running, I took it of with the hole bracket and leaved the 3 adjustable bolts alone. Took of 3x12mm bolts. Turned the key on pos 2, and tested the CAS. It works fine.

That was it, mounted the bracket with sensor back on, and fired her up with timing belt properly on, it just sputters and humps for 10 seconds, and dies.

I did not adjust the CAS, just took it of with the hole bracket itself.. Is this alone enough to mess the timing up ?

Yes, all intake, hoses and MAF is connected.

[nissanfreak12]

Some how something is not connected, just go through and double check the wiring.

[NismoFunZ]

Can a faulty temp sensor or anything like that cause the engine to die like that ? Im confused, the car ran absolutely great right before we took of belt and bracket with CAS sensor on.

I will try to soak everything with electric cleaner.

[sexyfatkid21]

have u timed the engine using a timing light and adjusting the cas till the crank pully lines up 15* befor top dead center?

[GerryO]

I have not moved the CAS while the engine was running, I took it of with the hole bracket and leaved the 3 adjustable bolts alone. Took of 3x12mm bolts. Turned the key on pos 2, and tested the CAS. It works fine.

That was it, mounted the bracket with sensor back on, and fired her up with timing belt properly on, it just sputters and humps for 10 seconds, and dies.

I did not adjust the CAS, just took it of with the hole bracket itself.. Is this alone enough to mess the timing up ?

Yes, all intake, hoses and MAF is connected.

Got antsy and started my engine after replacing the WP/Front Oil Seals/Timing and Accessory Belts/Tensioner/etc with the ducting and MAF off of the car. It actually started and ran for a short while, before it sputtered and died.

Also had replaced both sealed bearings inside the CAS, bending the slotted wheel inside pretty badly, while learning and devising a way to pull things apart and press them back together again without doing any damage, and once I'd flattened the wheel as much as I could.

Air/Fuel/Spark is all you need. Sounds like the Air Regulator might not be handling its' cold start responsibilities?

http://www.mdsmarthome.com/z/Z%20Tech/Z ... 20Idle.pdf

[NismoFunZ]

Allright, its running! Finally!

Adjusted the CAS, and double checked the rubberducts that go to the throttebody.

Vacuumleak. Probably the MAF sensor sent wrong signals to ECU since it was leaking.

Thanks for all help guys Just mount everything back on now =) Yihaa!

Btw, I want to share some pictures of my Z32, where do I post them ?

[es.biggs]

general forum. glad you got it sorted out!

[Gumpuck]

Crank Angle Sensors (CAS), essentially the distributor on your Nissan or Infinity or any VG style engine, can go bad. The part sells for $300+ from the Dealer, $170 as refurbished unit. If you have a high mileage engine, this unit should be addressed.

The Service Manual indicates two tests to determine if the CAS is working properly. The first is to remove the three retaining bolts and manually spin the shaft with the Key in the "on" position. With this test you should hear fuel injectors clicking. This test also will indicate if there is a wiring problem or faulty injector.
The second test is to measure the voltage with the plug disconnected. There is one ground. One 12 volt line. Two wires will alternate 5 volts.
While spinning the CAS unit, it should feel notchy. I have not taken one apart, however there are definite magnetic pickups or a bearing determining a position within the sensor.

The CAS unit in my car failed at 187,000 miles while replacing a leaky water pump.
Corrosion at the connectors removed during this procedure lead me to believe that a connector or wiring was related to a non start issue.
Both tests dictated in the service manual failed, however I was hesitant in replacing the unit due to unit cost and the fact that the car was running before water pump replacement was performed.

In other electrical component testing for the Nissan, Ohm tests are provided. In the case of the CAS a voltage variant is measured. Typical solenoid components including fuel injectors and transformers such as coils, have a measurable resistance and is typically a good indicator of the electrical components' service ability. Any small or large component of this nature should have some resistance such as 2 ohms, 7 ohms or 15 ohms. Anything in a sigma outstanding from these values such as thousands (000's) of Ohms or slight resistance such as .02 ohms indicates a electrical component that is close to failure, failed or faulty.

Charles WL Pearson.