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Mq electrical problems???urgent

Posted: Sun Sep 17, 2006 8:27 pm
by Turbo Tonka
have just done a build up with dad and his MQ patrol.We have fitted a sd33 turbo motor replacing the n/a motor.everything hooked up to the same spots,the parts that had to change were changed.e.g : the starter motor,alternator,glowplugs all from the old 24v motor.all the old 24v wiring loom and relays were used.Our problem is it wont fire when you turn the key,also the headlights,tail lights etc wont work but the glow plug light in the dash works and so does the heater and cd player.All earths seem right.If you run a wire from battery to headlights,tail lights etc they all work.Any ideas would be great people.thankyou.

Posted: Sun Sep 17, 2006 10:02 pm
by ausoops
a 24v relay wont operate with 12v. also you should uprate all your looms as by halving the voltage you will double the current draw.

ok

Posted: Mon Sep 18, 2006 9:49 pm
by Turbo Tonka
it is a 24 v loom,out of this same truck when it had the non turbo motor.Its still 24 v now,just the parts off the new 12v turbo motor were changed to 24 v parts...????

Posted: Mon Sep 18, 2006 11:21 pm
by chimpboy
Well, there are only a very few steps between the battery and the starter motor, so if you can track the problem down that pathway, you will probably solve your whole problem.

Battery -> starter motor solenoid -> starter motor -> ground for the heavy work.

Battery -> ignition key -> relay -> starter motor solenoid -> ground for the switching.

Basically you should be able to check for 24V all along those two pathways when you are turning the key to "start". At the point where you don't have 24V, you'll have narrowed the problem down a lot.

Do you have a multimeter? Put the -ve side at the -ve battery terminal. Then test for +24V at:

- the +ve terminal
- the +ve post on the starter motor

etc

If that all seems to work, you do the same thing the opposite way checking that all the grounds are okay.

I am guessing you have missed something really simple, like earthing the block or something.