Autronic SM4 Error - Engine will only crank

[The Witzl]

do you need to borrow an oscilliscope to check that the crank sensor is providing a signal?
It could be fuddged? (as unlikely as that seems)

[thechuckster]

assuming that the ECU is getting the right trigger signals, have you checked the configuration to make sure Cyl Pulse is a Hall Effect and Sync is VR/reluctor.

I only suggest in case it's gone back to some kind of default configuration.

When you were trying to start it, was the laptop showing any cranking revs at all? It should show ~250rpm. If you're getting that, then the ECU is getting Cyl Pules - if not, then that's where I'd be looking.

[BlackSupra]

do you need to borrow an oscilliscope to check that the crank sensor is providing a signal?
It could be fuddged? (as unlikely as that seems)

Probably would need to borrow one, if i knew what that was!

And chuck, no revs are displayed when cranking, can't access the setup as it is password protected to check what the settings are.

Here is a screen shot after i tried cranking, lots of red!

[BlackSupra]

well according to an autonic forum member, the 99.9% inputs for TPS, coolant and air temp mean that the ground isn't earthed properly.

I think i may have bent one of the pins when continuity testing the loom, so i need to check that, but that won't be the end of this i beleive.

[thechuckster]

the earth for pulse, TPS, CLT & AIT all go to BK22 (sensor earth) - the 99.9% suggests it's open circuit probably between where they join up and the ECU pin.


no rpm when cranking does point to no signal for cyl pulse (the Hall Effect sesnor at the crank).

[gearb0x]

I have tested a hall effect sensor on my crank using a pullup resistor on the output wire to the (+) feed

I was able to then test on a normal multimeter that the hall effect sensor was working (it was showing 5v as a gap passed, and 0v as a tooth passed, using 5v as the sensor reference)

The following diagram shows a 1-2k resistor used as the pullup on either a 12v or 5v supply

[gearb0x]

for the record this is the spec sheet on the sensor i was using

http://www.pe-ltd.com/Downloads%5Chall_effect_GT1.pdf

I am unsure if the nissan hall effect sensor has the same "Digital current sinking output" output

[The Witzl]

yep im going to agree with Chuckie here.
BK-22 sounds like your culprit. Put the car into ignition, and test the sensor earth at intake temp sensor and at your crank trigger sensor, and maybe also at TPS and shit.

It might be that you accidentally fudged up this wire when shortening the loom somehow.


If you are struggling to sort this out, and you really want to get it to Toyotafest, then give me a call. I might be able to drop in and attempt to save you from fudging it any further.


P.S. why was there not a wiring diagram like the one posted above when i first wired up your SM4??? Life wouldve been a LOT easier if there was....

[BlackSupra]

yep im going to agree with Chuckie here.
BK-22 sounds like your culprit. Put the car into ignition, and test the sensor earth at intake temp sensor and at your crank trigger sensor, and maybe also at TPS and shit.

It might be that you accidentally fudged up this wire when shortening the loom somehow.


If you are struggling to sort this out, and you really want to get it to Toyotafest, then give me a call. I might be able to drop in and attempt to save you from fudging it any further.


P.S. why was there not a wiring diagram like the one posted above when i first wired up your SM4??? Life wouldve been a LOT easier if there was....

Diagram is from a tuner in sweeden who clearly didn't rate the factory one.

Yes the aim is toyotafest and yes I'm struggling with this, the witzls help would be greatly appreciated.

[cambelt]

You could plug all the HKS mess back in.
Dave

[The Witzl]

You could plug all the HKS mess back in.
Dave

That web of aids was napalmed. There is no going back there!


Yes the original factory SM4 wiring diagram was quite lacklustre, as was the user manual (ie. no user manual). I guess that's what you get for installing one before proper release!

Hopefully we can fix it before sunday for you BVD

[BlackSupra]

As expected i had damaged the pin on the plug at the ecu. This affected the ground for PIN 22 and explained all sensors.

Resistance was very high on the crank sensor earth as a result of a poor solder join. New solder on the join and this solved the issue with the sensor. We now have RPM when cranking approx 200rpm. Checked the signal from the crank and it is sending back pulses.

However, still can't get the engine to crank over, but this may be due to fouled plugs from all the cranking.

I have attached another screen shot if there is anything here that needs to be addressed that you can see.

[thechuckster]

curious to see it shows a Sync/Cyl error yet both inputs have an duration (since last trigger?) showing - maybe it didn't crank long enough to get two sync pulses?

Pull a plug and look for fuel on it - i doubt it may have been heavily fouled as it hasn't been injectingg fuel until you got the rpm/cam triggers sorted? ... actually, fuel-used says it's had total commanded injection time of 2500 m/s so maybe they are wet.

[The Witzl]

Chuck - plugs were definitely wet. I told Glenny to wait for a sunny day, pull them out and let the cylinders evaporate a bit, and maybe chuck in some fresh copper plugs to try and kick the engine into life.

I also recommended some start ya bastard.


With regards to the Sync/Cyl % value... when cranking the engine this value hovers around 50-70%, and then falls to 0% when you stop cranking.
The problem seemed to originally be with the CRANK (home/ref) signal, which is now definitely working properly, providing a healthy 5V pulse (hall effect sensor) on my scope.

As for RPM signal - i wouldve thought that comes from the cam sensor?


Hopefully now its just foulled plugs. Im pretty sure it is...There is definitely spark as we took a plug out and rested it on the engine, and saw it sparking during cranking.... but it smelt of fuel pretty bad.

[thechuckster]

ECU's use the crank trigger for rpm - a single pulse per 720 degrees would be a shit way to determine rpm