Hi guys,

 

This is how the story goes:

 

I was driving along quite happily and the engine cuts out, IIRC the speed and revs dropped to 0 instantly, I might be wrong about that though, it might have just been wishful thinking - I was busy trying to get the bloody thing to a safe place with no vacuum assist on the brakes, no power steering, and no power!

 

It wouldn't start up again until after 15 mins of cooling with the bonnet up. Suspected PTU; but I opened that up to fix it - all the connections seemed fine, I gave them all quite a good pull/wiggle.

 

Where do I go from here? Could it be the CAS? The TPS seems okay, it was giving the correct voltage during the failure. It was a pretty instant cut out so I don't think it was the fuel pump, besides, would the fuel pump start up again within 15 minutes?

 

Can any other sensors cause this? It seems to be a heat related failure of some sort, broken connection somewhere. Will doing an ECU diagnostic when it fails again shed any light on the problem?

 

All suggestions gratefully recieved!#!

 

Thanks,

John

The PTU could still be at fault. There is more to 'blow' on these than just the connections... Suppose it could be the CAS failing intermittently - if the ecu receives no rpm signal it turns off the fuel pump, also it won't fire the plugs. I doubt it is the CAS though. I would try a known good PTU first tbh...

 

HTH

 

CheerZ,

 

Andy

Bah! Just been out and put the PTU back on. Won't start. The check engine light keeps popping on and off, and there is a horrible grating/arcing sound coming from the back of the car. Touching the throttle slightly with the engine off causes this sound too.

 

Fuel pump?

 

Cheers,

John

After messing about a bit more, we have ignition, and also that funny sound is gone.

 

Can the fuel pump have an intermittent failure? Or could it be the circuit that supplies the fuel pump, the relay, etc?

 

The symptoms I'm seeing now are:

 

Touch the throttle slightly with the engine switched on but not running, and I hear what sounds like very slight arcing, or something switching on and off very quick. Occasionly what sounds like the fuel pump will pipe up in the backgroung with a bit of grating/whirring, when this happens the check engine light goes out, then back on when it stops. The engine will not run when I try to start it if I hear this noise.

 

Then, when it feels like it it will start up, and I wont hear the noise.

 

Cheers,

John

I think the fuel pump thing must be a red herring - took a plug out and it's not sparking.

 

Does anyone have a spare PTU for testing?

 

Cheers,

John

John - CAS can also cause a lack of spark, as the ECU won't fire the PTU unless it knows where the crank (well, cam) is.

 

A test for that - and ONLY do this if you are SURE you know what you are doing - is this;

 

Mark the position of the CAS against the cylinder head (actually it's mounting bracket) with a scribe, carefully and accurately so that you can put it back on in EXACTLY the same position. This is VERY important - if you get that wrong, at best you screw up the timing, at worst you detonate and kill an engine.

 

Take the CAS off (three small bolts), but leave it attached to the loom.

 

Switch the ignition on but don't try and start the car (to the position before crank).

 

Turn the CAS spindle by hand - if you can hear injectors clicking, the ECU is receiving a signal. If they aren't, the CAS is dead or there's a wiring fault etc.

 

Put the CAS back on carefully and line up the marks you made earlier exactly.

 

Oh yeah - if the ECU loses the CAS signal while you are driving, the tacho will drop *immediately* to zero. If the PTU fails, the tacho will still show a reading.

 

Been there, done that

 

HTH

 

------------------

GZ.

 

[This message has been edited by greyzed (edited 30-09-2002).]

greyzed - thanks for the info.

 

I'm going to try RobH's PTU if I can sort out getting it before Friday before messing with the CAS.

 

Just a thought, but if my engine isn't firing at all due to a CAS failure, then would the RPM signal from the ECU be 0? If that's the case then I can probably rule out the CAS being at fault if I try starting it in the morning and it doesn't start with the odometer showing 0 RPM.

 

Unless of course there is a fault on the other side of the wiring, not a pleasant thought, heh.

 

JPH

Yaay!

 

Found out what the problem is, all the clues fit into place now :-)

 

It is the CAS connector that is playing up. I had the engine running then touched the top of the connector and the engine cut instantly. Pressing it again caused the noise I heard from inside (Injectors firing), and the fuel pump starting up.

 

Now all I need to do is find where the fault in the connector is and patch that up. I hope this is it and I can finally give my Z a proper drive! (I've only driven it at 7psi before! This time it's going to be 15!!) Even though the thing still isn't running now I'm still getting excited :-)

 

If anyones fixed a CAS connector before or anyone has any things to watch out for I'd appreciate if you share them :-)

 

Many thanks,

John

 

Sounds like it is just full of crap tbh m8. Remove the metal clip holding it on then remove the connector. Check for any green sh1t in there and give it a good does of electrical contact cleaner, using the connector to scrape the cas end clean if that makes sense - slide the connector on and off without the metal clip a few times basically lol.

 

HTH

 

CheerZ,

 

Andy