Thread: Electrical draw interfering with operation

Originally Posted by StuRR80

After a few months off the road, I've started driving the Rangie to work most days and when I have the lights on (low beam) I've noticed the difference in the way the vehicle runs.

There's a slight but noticable change in the "effort" it take to maintain speed over 80kms and after idling for a while, the vehicle will stall or have a cough and flat spot on accelerating from a giveway or stop.

Obviously the energy is being diverted but I wouldn't expect a significant impact on performance? It seems to run ok (although still feels woefully underpowered) when the lights are off.

Any ideas on what to start looking for to remedy this?

Thanks

Stu

What kind of Rangie? If its a '80 RR are you running the Lucas ignition amp? Or points? What is your ignition advance? Which plugs/plug gaps? Where is the gas system getting 12V from? Hopefully not off the ignition coil. What kind of gas system? Have your headlamps had relays fitted yet?

Hi Bee-Utey - always to the rescue!

Originally Posted by bee utey

What kind of Rangie?
If its a '80 RR are you running the Lucas ignition amp? Or points? Crane Fireball electronic (is that what you're asking for?)
What is your ignition advance? No idea?! How can I tell?
Which plugs/plug gaps? Bosch WR7DC - set at 6mm
Where is the gas system getting 12V from? Which part of the system?
What kind of gas system? Rheem tank, converter is Reg by OMVL R90/E. Runs with the twin Zenith carb setup.
Have your headlamps had relays fitted yet? Yep

This was the last lot of work I did on it.

http://www.aulro.com/afvb/lpg/120105-3-5-v8-rough-running-80kms-lpg-replacement.html

I tried adjusting the idle speed on the converter yesterday but that didn't really do much. It took the idle to a point but then ended up making no difference.

Also, I'd like to hook the tank gauge up to a Smiths fuel gauge of a similar vintage to the other gauges in the car. Any ideas how to get it reading the tank?

Thanks

Stu

Crane Fireball is good, providing the coil is good and the voltage is correct.
Idle timing by timing light should be around 6 degrees BTDC.

Plugs are good

The gas system gets power into the gas/petrol selector switch. From the switch the power flows either to the gas solenoids or the petrol solenoid. You are looking for where the gas/petrol switch gets its power from. Run a volt meter at the ignition coil (+) terminal (relative to battery(-) ) and see how low the voltage dips with the lights on, the gas on. If the voltage here is substantially below battery (+) voltage at the same moment your accessories are dragging down the voltage. This will definitely make your ignition weak. You can easily use your existing 12V feed to the coil to run a relay, to provide battery voltage to the coil. Make sure the coil you use then is rated to run at a full 12 volts.

You don't adjust idle speed with the converter. You adjust the mixture with the converter which then makes the idle speed change. You want the maximum idle speed with the least mixture, THEN you play with the idle speed setting on the carbies. IE richen the idle until the idle speed starts to slow down, stop turning the screw, reverse screw direction, the speed will rise, then lean off to the point just before the idle speed drops again, no further.

Wire up your Smiths gauge with a 500 ohm variable resistor or old fuel float as a sender. Measure the resistance of the sender at "full" and "empty" gauge readings. Ask your local gas fitter to look for the closest LPG fuel sender to that pair of values. They are made in various ohm ranges for that purpose. Something will come close.

Thanks I'll check out the voltage, etc when I get a minute.

FYI - The coil is a Bosch GT-R is new since January.

Originally Posted by StuRR80

Thanks I'll check out the voltage, etc when I get a minute.

FYI - The coil is a Bosch GT-R is new since January.

GT40R? If so it might be that the Crane box is wired up to the ignition positive connection on the coil. What happens is the Crane box then gets low voltage while running. Try simply running the Crane box positive off its own ignition feed, straight from the key or a fuse box connection for ign accessories. Leave the coil connected as it was. Negative side of the coil remains connected to the Crane box of course.

GT40-R, that's the one! Sorry...

Will check. Thanks again

Originally Posted by StuRR80

GT40-R, that's the one! Sorry...

Will check. Thanks again

Yep - it is joined to the coil. I'll try and sort it over the weekend. Any other benefits which might come from fixing this?


Would it still be worth hooking up a relay to the coil with a direct power source?

Thanks again.

Originally Posted by StuRR80

Yep - it is joined to the coil. I'll try and sort it over the weekend. Any other benefits which might come from fixing this?


Would it still be worth hooking up a relay to the coil with a direct power source?

Thanks again.

As the coil is a resistor type it is designed to be run with some loss in the supply wire. Direct wiring it would cause the coil to overheat. To connect it direct via relay you would need to get a GT40 without the "R" suffix. Not that I would recommend that, as then you don't get full remaining power during cranking, as is normal for points wiring. I would just try the crane to 12V first.

If all this fails I would get a Disco dissy and a remote Bosch amp + electronic coil instead. The basic crane kit was good in its heyday but a well sorted constant energy electronic system will run rings around it.

All the ignition runs from the brown power feed to the ignition key, then to the accessories. That is why I suggest you double check the headlamps are drawing their power from the battery not the original harness somewhere. Sometimes you also see a voltage drop at the connector at the back of the alternator, the insulation goes all crispy and black. If the wires are in good condition and the battery is being charged at around 14 volts with the headlamps on it should be all OK.