[headwerkn]

Hi all,

I'm just working through the usual laundry list of "things that need fixing" on my newly acquired Vitara. Both the temperature gauge and tachometer needles don't move when motoring... the previous owner reckons the temperature gauge HAS worked in the near-past but it definitely hasn't for the past 24 hours of driving (almost 300km worth). The tacho occasionally moves (slowly) from 0 to about 400 rpm.

Is this a common issue? I'm assuming it is either a sensor or wiring issue... or possibly even a connection that has come away, though I've not seen anything obviously disconnected under the bonnet yet. I've never really ever heard of gauges going bung in an instrument cluster (they tend to be quite reliable) though I suppose that is a possibility.

Anyway - questions are:

1. Where is the temperature sensor located on the 1.6?

2. Where does the tacho take its reading from? Hall sensor on crank? Actually thinking about it a bit more now... wouldn't the signal go from a sensor to the ECU which then in turn would send a signal to the instrument cluster... which would mean if the sensor itself was stuffed, the ECU wouldn't be getting RPM input and thus would drive horribly (which it isn't)? Sorry, still getting familiar with what's under the hood... give me a service manual and a couple of nights

3. Is there a Service Manual for the early 90s Vitaras available online (other than the one in Russian)? If not, which of the books is considered to be worth the money?

4. What's the secret to taking apart the dash without it ending in tears? Question 3 would probably provide the answer there.

Many thanks - keep zookin.

Cheers, Ben.

[shandy92]

Hey mate,

1- sensor is located on the thermostat housing on the front right hand corner of the motor(next to the top rad hose) should have 1 wire coming from it. if you place another wire going from that single wire to the chassis (or another earth) the gauge should move to max (full hot). if the gauge moves then its a faulty sensor, if it doesnt move it all or not enough then you have a wiring issue.

2- pretty sure its from the dizzy, is yours carby or EFI? (assuming efi, since ur talking ecu's) pretty sure the ecm doesnt receive anything to control the tacho. just done by a wire or 2 from the dissy.

3- yes there is, have a look in here http://www.suzukiinfo.com/ there should be something to sort you out. other wise a haynes manual is always handy.

4- not sure, im keen to find out my self ahah

hope that helps a little
Mitch

[headwerkn]

Thanks mate, will check them out tonight and see how I go. Hopefully it is just a bung sensor - I imagine they take a pretty standard probe? Yes, EFI engine; will have to go through the adjacent wiring and see if anything's come off.

Couldn't find an english Gen 1 Vitara manual there - the Haynes manual has been removed. Did find some electrical/wiring info though, will keep me busy for the interim.

Cheers, Ben.

[shandy92]

yeah the sensor is pretty cheap, but genuine is $80 or so. ok i thought there was one on there but maybe not, ill have a look for you.

how many wires do you have going to your dizzy?

[headwerkn]

An update:

Good news - when grounded out at the temp sensor, the gauge went full-scale.
Bad news - when I put a new sensor, it made no difference... it's been bloody cold here in Tassie the past few days, but after 35 mins of driving this morning I would have expected the needle to move a bit.

The sensor was whatever the book at Supercheap Auto said was the right one - something, something 001. Looked and fitted exactly the same as the original one, minus the rust on the submerged end. Weird.

I'm assuming these probes work as a temperature-dependant resistor, with ohmage dropping as the temperature increases (hence full scale with zero resistance). In theory I should be able to hook up a potentiometer (variable resistor) between the sensor lead and ground, and test the gauge for a varying response to ensure the dash unit is working properly?

There are 2 wires coming from the body of the distributor - I'll put up some pics tonight when I'm back home. Gave everything a wiggle to test for dodgy connections, but everything looks tight. Might a dodgy sensor or contact within the distributor itself?

Cheers, Ben.

[shandy92]

Ben,

Do you know what kind of condition the thermostat is in? i would be checking that the wires are making good contact with the spade terminal its self, or just cut it off and crimp on a new one.

pretty sure you can put a multi meter on the sensor and read the resistance and then compare it to a temp in a manual (think it been covered here tho) that would give you a good range scale.

Mitch

[headwerkn]

Another update:

Ran a variable resistor in place of the temp. sensor. With a small amount of resistance applied (measured ~37 ohms on my meter) the temperature gauge was showing approximately 'half'. I think we can definitely say the gauge in the cluster is working fine.

Attachment:

temp-tach-3.jpg

The old probe (shown above) measures around 500-700 ohm at room/cold garage temperatures - if I breathe on it (warm it up slightly) it comes down to around 450 ohm. If I dunk it in just-boiled water I get single-double digit readings briefly before it climbs back up to a few hundred ohms. Seems as if the old sensor was just fine... I wonder if it is a grounding issue on the engine block? The previous tests I did grounding out the sensor wire straight back to the battery terminal - if the engine isn't receiving a good ground then that would prevent the sensor circuit being complete. Have finished up in the garage for the night, will check tomorrow evening.

What doesn't make sense is that numerous other sensors and the like would require a good engine block ground too, and nothing else is playing up. Well, other than the tacho. Here's the distributor setup:

Attachment:

temp-tach-2.jpg

The two wires indicated go right into the distributor body. Have not measured them for voltage, etc. as I have no idea what I'm supposed to be testing for. Open to ideas here.

Cheers, Ben.

[shandy92]

well mate, im not to sure. ill have a think and get back to you. ill let someone else chime in if they can.

sorry im not much help with the tacho,

[ozhummer]

I had both these issues in my recent vitara rebuild.

I swapped the g16a for the g16b and in order to get the speed sensor i needed to replace the instrument cluster. After it was replaced neither the tac or temp worked ... Actually the tac tac moved to a few hundred rpm after a blip of throttle.

Temp gauge.
These are counter weighted - if you remove the fascia and carefully remove the clear plastic and carefully pry off the temp needle then run your car to temp, feel the top hose and make sure the thermostat has opened, then replace the temp needle to point half (keep the car running), then turn off the car. The needle should settle to 0. There, calibrated.

As for the tac, the efi tac I got didnt work, I put the carb tach mechanism (which is different) in and it is now fine..

[Reubs]

Have you checked the car even has a thermostat fitted and if it does it isn't stuffed/jammed open causing the coolant to never get hot?

The guage in my SWB vit always read cold until I re-fitted a thermostat - could have had overheating problems in the past and someone removed it but no-one put one back in!

[headwerkn]

I popped the thermostat housing earlier this evening - it is definitely there. It also works too - after 5 minutes of idling the water in the radiator was circulating and very warm.

Definitely no ground issue on the engine block... measured resistance was less than 0.5ohm from the sensor body to the negative battery terminal.

Might have to try a genuine Suzuki sensor... anywhere they can be had online, etc. in Australia, or is it down to the local dealership with a mortgage deed?

Cheers, Ben.

[headwerkn]

Ok, some developments... well, observations.

Yesterday, I noticed the tacho moving a bit more than usual. I managed to get it to show ~1400rpm by revving the tits off it... basically I could see it rising and falling with the revs, but at a mere 20-25% of the usual rev range. Strangly, today I was seeing the same thing but 'reduced' - redlining (or what sounded close it it) would show about 1000rpm. So clearly the gauge is working; either its pickup is dying, or some bit of electronics in the gauge itself is having trouble.

Also, on the temp sensor front.... driving up to Devil's Gullet early today, mostly 2nd gear at high revs on the steep, tight and rather muddy initial decent, the gauge actually crept up off the left hand side bump stop about 10mm. I'm thinking the sensor isn't calibrated to whatever resistance range the gauge expects to see.

Oh, the fun continues...

Cheers, Ben.

[shandy92]

are you sure they gave you the correct sensor?

[shandy92]

check these out, should help you out:


its all on that suzukiinfo site i said earlier