Vehicle & Technical > Suzuki

WANTED: Vitara throttle position sensor

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Evilgoat:

--- Quote from: "StuartL" ---!Expletive Deleted!.

Found a proportional signal varying between 500 ohms and 1.5k ohms (for my limited test range).  It's not the TPS.  Scratch that idea.

Maybe the injector itself is !Expletive Deleted!?

I'd give my left arm for an oscilloscope.
--- End quote ---


Mine came from a bootsale for £5, just needs the pots cleaning. Works as is, just not much use fo rthe tiny signals I'm using in its current state. More than adequate for car stuff though.

Meter out the injector then make sure you are getting a pulse to it. If you are, check for fuel pressure/flow. Pressure and no reaing over it = injector o/c and dead. other way round and time to look at the fuel pump.

Given what suzukis are like for electrical niggles, you might just need to clean things up.

*drags wiring diagram out*

Injector is driven direct by the ecu so check fuses and control relay. Not sure that a dead sensor would cause no injection.

StuartL:
There's definitely fuel pressure (see all that petrol all over the engine!) so the oscilloscope I borrowed last night from my Dad (120 mile round trip for a darn oscilloscope!) should give a simple binary diagnosys.  Electrical signals mean broken injector, no signals mean broken or confused ECU.

Evilgoat:

--- Quote from: "StuartL" ---There's definitely fuel pressure (see all that petrol all over the engine!) so the oscilloscope I borrowed last night from my Dad (120 mile round trip for a darn oscilloscope!) should give a simple binary diagnosys.  Electrical signals mean broken injector, no signals mean broken or confused ECU.
--- End quote ---


or Nadgered wiring, pick the inector signal up at the ECU if its not at the connector on the throttle body. If you have a stable trace iirc the width of the injector pulse should vary with throttle position and engine speed.

As a thought, have you got a correctly timed spark and tacho?

StuartL:
Oscilloscope is refusing to work (completely dead, no traces), so that's an awkward conversation with the father yet to happen.

A second attempt at the DVM across the injector terminals shows zero voltage.

That can't be right.

Guy on difflock reckons that the ECU output drive for the injector can go, which would correspond perfectly with the symptoms.  I'm toying with the idea of putting 12v across the injector (if I can figure out the polarity) to see if it works.

If the injector works (which I guess it might) and the oscilloscope remains dead I have to assume that the ECU is dead.  This means either locating another ECU (argh), checking the wiring (bit of a PITA) or just ditching the TBI system and resorting to traditional carb.  That'll mean basically rewiring the whole Vit not to use an ECU...

MMmmm.   Projects...

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