Simple Testing Procedure for GTV6 Dual Relay

[shane wescott]

Hi Guys

Theres plenty of info around about the L-Jetronic FI system used on the GTV6. I couldn't find a simple testing procedure for the dual relay, so being a resourceful electronic dude I thought i would put one in the forum to help others in the future.

Here goes:

You will need:

1. The Dual Relay

2. A 12V source ,i used one of those car jump starters and a couple of small clip leads

3. A multimeter.

Test 1 - Check the relay coils

Refer to the picky and diag below

1. Connect your earth to pin 85 of the relay

2. Connect 12v to pin 86C

You should hear a click - cool one works :-)

Now

1. Leave your earth on pin 85

2. Connect 12v to pin 86B

You should hear another click :-)

Now connect 12v to pin 86 and you should hear another click.

So far so good both relays are working. You may notice that when you connect 12v to pin 86B the "click" is not as loud as the others, thats due to a current limiting resistor in the circuit so dont worry.

Test 2

Check the contacts.

1. Connect earth to pin 85 and 12v to pin 86, you should get a click so leave it connected.

2. Set multimeter to one of the OHMS ranges to check resistance and connect one lead on pin 88C and the other lead on pin 88D you should read 0 Ohms or a short here - those contacts are good :-)

1. Now leave the earth where it was and connect 12v to pin 86C, you should get another click so leave it connected.

2. Multimeter on OHMS again one lead on 88Z and the other on 88B and you should get another short - all good.

Right so if it's all good - congratulations, or maybe not because if the car isn't running that means something else is broken :-(

If your relay didn't pass all the tests, you have two choices 1. buy a new one, or 2. try and fix it.

As you may have seen from the other thread, I fixed mine failry cheaply, an external relay or maybe a diode or two should have the relay working again.

Find a friend who knows their way around a soldering iron, give em a slab of beer, and you will be miles in front $$ wise.

Hope this helps.

Catch ya

Shane

[john m]

Hi Shane,
thanks for the detailed description and the hard work thats gone into resolving this matter.
In the coming weeks I plain to do the full Greg Gordon procedure and will follow your advice as well for good measure.
I plan to keep a log of all the readings and values of all the sensors.
Due to this successful result I hope you will stick with the L-Jetronic and not go for the Megasquirt.
The more I read about this system, the more I have come to appriciate it. I wonder if Bosch hadn't invented it at the time, would the GTV6 have gone ahead? On carbs?
Thanks again.

[shane wescott]

Excellent Mate.

I also found this tech manual

http://bama.ua.edu/~darren/boschindex.html

which is from Bosch and explains a lot of things from a manufacturers point of view.
A  good read.

Have fun :-)

[AlfaACT]

Shane,

Some time ago one of our colleagues on this forum implemented a card system (a la euro football) for misdemeanors on the forum.

Well, I'd like to award you a Gold Star with Elephant stamp for the effort that you have gone to provide valuable information for the benefit of all.

Well done and keep up the good work.

Peter.