Autronic SM4 Error - Engine will only crank

[The Witzl]

yeah i dont know which is the full engine position signal, and which is the reference/home signal....

and yes i know that the full engine position signal is the one that is used to generate RPM.

[thechuckster]

crank (cyl pulse) would be rpm and crank positioning. Sync would be a home (to identify tdc #1) only.

any clues as to tooth count on the trigger wheel?

[The Witzl]

Yeah i couldnt see the trigger wheel mounted to the crank, so im unsure which sensors are being used for which signal.
There is the VR sensor on the camshaft, and the hall effect sensor on the crank trigger wheel.

In any case, the crank trigger wheel is working....


GLEN - perhaps try unplugging the cam sensor (the one i had to repin last night) and then crank the engine... see if the autronic gets an RPM signal then. If it does still, then maybe there is a problem with the wiring to the cam sensor.
It could be that we were looking at the wrong sensor?

[thechuckster]

The VR sensor will be more susceptible to noise - if you found one dodgy solder joint, there may be more.

[The Witzl]

yeah i realise all this in hindsight... but when its freezing cold, dark, and raining... you dont tend to think of all these things on the spot

I'd actually suggest that the VR signal wires from the cam sensor arent shielded all that well either (from memory).

Glen - take a pic of the wiring across the cam covers, and i'll see if there is still an issue there.

[BlackSupra]

I disagree, uncut shieded wire runs right up to within 1cm of the plug.

Only issue may be the solder joins on the pins of the plug.

What should the resistance of those wires be measured back to the ecu?

[CrUZida]

Resistance of all wires (except spark plug leads) should be near 0.

Touch the 2 leads together to give you a base reading, then any reading more than 1ohm higher is a bad joint.

[BlackSupra]

Resistance close to zero on cam and crank sensor

Definetly have fuel and spark

Replaced the spark plugs

Still just cranks and doesn't kick over.

Piss me off!

[RA35GT]

Are you sure your cranking map will start the engine? (i.e. is there sufficient fuel being sprayed and timing suitable, using same injectors/fuel pressure?

Timing light, see what the timing is?

Spray start ya bastard and see if it fires.

[BlackSupra]

Well with some help from wilbo, Cruzida and JCMO we managed to get it to actually start.

Moved the cam sensor and played with the wiring for the injectors.

It would appear all injectors are working, all spark plugs are firing, but an excessive amount of fuel is still smelt and emitted from the exhaust.

Also running very rough as if only running on 5 cylinders.

[The Witzl]

i think it needs a good drive to clear out the spark plugs dude - they are probably fouled up to hell.

Told you that everything seems to be working OK now - its just been sitting dorment for so bloody long!

[BlackSupra]

Put new plugs in, so they shouldn't be too folued, however the car stinks of fuel that isn't being burned, even a good flog won't sort it out i think.

Struggled to idle even once warmed up

[JP]

wouldn't have a stuck injector? how smooth is the idle?

[BlackSupra]

It's a possibility, but all injectors did have power and were 'clicking' open.

Might just be time to hand it over to the professionals.

[JP]

Ok,

Another test is to pull the plug lead to each cylinder one by one while it's idling to see if it makes a difference to the running. That's a fairly easy way it identify a cylinder that's not doing it's job.