Autronic SM4 Sync(Cam or reference) I/P sensor fault detected.

[Jamez 2147483647]

So my autronic SM4 is giving the following Error at just under 4500rpm and it cutting ignition when it hits ~4480rpm:

Sync(Cam or reference) I/P sensor fault detected.

Reason.

Sync I/P which is used to sync engine to 720 degree cycle is missing or has extra pulses. If not a mult-coil engine, engine will still run with out this signal.

Mult-coil engine will not run with this error.

Here is pic of the logger, you will see it sometimes will rev past 4500 fine, then when you go back under and up again it wont go past 4500. After a bit of playing round it seemed if I tapped the accelerator around 4400 it would rev past 4500 fine. I can't get it to rev past 4500 while driving around, only when revving in neutral or changing down to a gear that gives over 4500rpm.

Is this a faulty sensor or can I change the fault tolerances so it doesn't put a limiter at 4500rpm

[thorburn 121]

Can you get a scope on it?

Is it still running variable valve timing on both sides and factory cam sensors?

[Jamez 2147483647]

Can you get a scope on it?

Is it still running variable valve timing on both sides and factory cam sensors?

What do you mean by putting a scope on it?

It is still running variable valve timing on both sides with factory cam sensors. The ECU shows the cams as adjusting within tolerances so I don't think they are having any issues.

From what I can research on the web the engine should not work at all with this error so it baffles me why its only at a particular RPM it occurs. Will have to give Gavin a call on Monday and see if he can shed any light on it.

If its worth noting there are only 4 sensors:

-1 off the top of the block

-1 off the front of the crankshaft

-2 for the vanos

I'm guessing its either the one of the top or the crank that's gone faulty.

[thorburn 121]

Oscilloscope

Autronics might have a built in oscilloscope.

I'm guessing it's been running for a while so it shouldn't be a noise problem. But just to check are the sensor wires properly shielded? and is the ground cable from the shield connected to a good earth

The autronic forum seems pretty active. Surely they'll have some words of wisdom http://www.mrm-racing.se/forum/index.php

[hybrid 1043]

James, as I was saying the other day .. the only way youre going to know is running a ohm or voltage meter across it (depending on what output the hall effect sensor is putting out) An occiliscope will only show signal. Unless you have something you can compare it against, it wont mean too much to you.

Map it with something else first, the we can take mine for a run and map the same signal to see if its the same. (profile)

I would say that it is loosing count (for what ever reason) between the halleffect sensors and the cam timing teeth, the SM4 will then panic and call the safety program. Last time I read up for autronic you had to shave off several timing teeth to suit the SM4's counting algorythm.

Also need to determine what side its having the problem on. IC or EC.

What might be happening also is the cam postion (VANOS) may not be reaching its target.

The way MSS50-s52-S54 work is the DME has a target profile setting and the vanos adjusts its solenoids and therefor oil pressure to actuate the pistions.

Here is some profiling I have been doing on mine with this sh*t I've working on. It has RPM, Throttle postion, intake cam target, intake cam actual, exhuast cam target and exhuast cam actual.

Excuse the scale of these .. I have adjusted the formulas so they all fit on the graph .. otherwise RPM would dominate the scale @ nearly 8000rpm vs say the cam signals.

This is an on-ramp @ WOT (where TP = 100%)