Vr sensor no signal

[louis123]

Hello
Iam finally getting close to hear this engine running, been working on it (on and off) for 5 years now!!!
It a megasquirt setup from the dub shop with relay board. Fuel pump is turning on, ecu has power but its does not received a signal from the vr sensor.
Tuner studio does not see the signal while cranking but tps signal comes in when the gas pedal is pressed.

Its connected to the tach connector on the relay board, sensor is grounded to a main ground direct to the battery with the rest of th ecu.

I moved the sensor a little closer and still nothing....

Anyideas of what i should test?

Thanks!!

Its a 2276 beast with megasquirt efi crank trigger in a camper bus. cant wait to drive it around!!!

[Clonebug]

How many wires does the sensor have???

Here is Thedubshop's wiring diagram.
Click on the VR signal diagram......

http://www.thedubshop.net/#!fuel-inject ... -tech/cizb

Mine is wired like this. If you have it wired like this and it doesn't work... you could try switching the ground and signal around to see if it works that way.
Maybe the wires are backward on the sensor.......

[Piledriver]

There was another very recent thread with ~same issue, turned out that the wrong settings were used as to the amp potentiometers.
This was due to using the B&G build docs for settings.
Those are only for basic assembly, and don't cover msextra hardware usage at all.
Make sure you are running current firmware, and ONLY use the fine msextra documentation.
Forget the B&G docs exist, especially the megamanual.

http://www.msextra.com/manuals/
http://www.msextra.com/downloads/

[louis123]

Hi Guys,

Sensor is a vr sensor with 3 wires, it is connected according to this schematic(black still not connected):
http://media.wix.com/ugd/9afa64_bebab1b ... aa128b.pdf


Mario suggested i tried with the tooth logger and still nothing while cranking (initial attemp i looked at the rpm gauge).

I read the other thread by gtmdriver, but i actually have no idea what are the trim pots that he turned to fully anti-clockwise.
What is the best way to test the sensor itself?

[Jadewombat]

viewtopic.php?f=66&t=148462

[louis123]

Thanks jadewombat, i actually just got it to work, initial installation was not carefully aligned with the tooth, i removed the sensor and reinstalled and now i got some readings and the engine tried to start. It does not fire up yet so i will have to investigate further more. But iam on the good path!

[andy198712]

plug wires in the right places on the coil?

[gtmdriver]

These are the two VR trim pots that need adjusting.



There is a small brass screw on each of them.

According to the manual they are 20 turns end to end but they have a slipping clutch so that you can't damage them by turning too far. Sometimes they click when they reach the end but not always. It depends on the brand used.

Just turn them both 20 turns anti-clockwise and try again. It worked perfectly on mine and I got a perfect signal and full sync lock.

[louis123]

Thanks for the info Gtmdriver, i actually got the signal in by replacing the sensor more carefully. But now i see the signal is not completely clear.

In the tooth logger i see imperfections (spikes) while cranking and the rpm signal sometimes drop to 0.

I cannot get it to start, it cranks and sometimes want to fire up for less then a couple seconds but it does not run.

Any ideas on what i should look into?

Thanks alot guys.

[gtmdriver]

You could still try adjusting the pots. They control the VR signal conditioner circuit.

There is also a noise reduction adjustment for the VR signal in the ignition settings.

[66brm]

It also sounds like you may need to tweak the ASE to get it to hold an idle after initial firing