Lucas Electrics in my Hilux?

[Diesel Damo]

My dashboard has started displaying some interesting things.

Often, especially in between gear shifts, the lights on my dash will
flicker on/off/on/off/on/off really fast for a fraction of a second,
and also the temp guage goes nuts as if it's getting too much "juice"
(I don't know a great deal about electrics). And the rev tacho can
float about a bit too (in time with the temp guage) +/-400RPM.

The headlights and indicators (if they're on) will dim and flicker in
time with the dash lights too.

My guess is a loose wire(s) somewhere which is why it tends to happen
in between gear shifts (car loses momentum and then gets a kick in the
pants when the next gear comes in).

The temp guage will dance all over the place during steady cruising
too, so I don't think it can *solely* be put down to a loose wire that
occasionally makes contact with something that it shouldn't.

And I can't stand not being able to trust the temp guage - it's the
most important guage on my whole dashboard.

Any ideas? Is my alternator about to die or something?

[Josh]

Diesel Damo wrote:
> My dashboard has started displaying some interesting things.
>
> Often, especially in between gear shifts, the lights on my dash will
> flicker on/off/on/off/on/off really fast for a fraction of a second,
> and also the temp guage goes nuts as if it's getting too much "juice"
> (I don't know a great deal about electrics). And the rev tacho can
> float about a bit too (in time with the temp guage) +/-400RPM.
>
>
> Any ideas? Is my alternator about to die or something?
>

It's not a loose wire/plug behind your clutch pedal is it? My radio used
to turn off everytime I changed gears, turned out that the clutch pedal
was pressing on a part of the loom that was causing a plug to make/break
contact.

josh

[John_H]

Diesel Damo wrote:

>My dashboard has started displaying some interesting things.
>
>Often, especially in between gear shifts, the lights on my dash will
>flicker on/off/on/off/on/off really fast for a fraction of a second,
>and also the temp guage goes nuts as if it's getting too much "juice"
>(I don't know a great deal about electrics). And the rev tacho can
>float about a bit too (in time with the temp guage) +/-400RPM.
>
>The headlights and indicators (if they're on) will dim and flicker in
>time with the dash lights too.
>
>My guess is a loose wire(s) somewhere which is why it tends to happen
>in between gear shifts (car loses momentum and then gets a kick in the
>pants when the next gear comes in).
>
>The temp guage will dance all over the place during steady cruising
>too, so I don't think it can *solely* be put down to a loose wire that
>occasionally makes contact with something that it shouldn't.
>
>And I can't stand not being able to trust the temp guage - it's the
>most important guage on my whole dashboard.
>
>Any ideas? Is my alternator about to die or something?

The fact that the headlamps are also affected suggests it may be
charging system related, though not necessarily the alternator itself.

First up I'd try to take voltage readings with the electrical system
under load (ie headlamps on) while the fault is showing. Set the
throttle to 2000 rpm or so.

Take a reading across the battery terminals which should be steady at
somewhere between 13.8 and 14.2 volt if the charging system is OK.

If you _don't_ get a steady reading at the battery shift the meter
leads to the alternator (output terminal and case) -- if it still
isn't a steady reading you've got an alternator problem.

Tell us what you find.

--
John H

[Diesel Damo]

Josh wrote:
> It's not a loose wire/plug behind your clutch pedal is it?

While that's possible, it doesn't explain the bulk of the problems. The
same dash light display can be had by simply lifting off the throttle
too.

[Patrick Young]

Diesel Damo wrote:
> My dashboard has started displaying some interesting things.
>
> Often, especially in between gear shifts, the lights on my dash will
> flicker on/off/on/off/on/off really fast for a fraction of a second,
> and also the temp guage goes nuts as if it's getting too much "juice"
> (I don't know a great deal about electrics). And the rev tacho can
> float about a bit too (in time with the temp guage) +/-400RPM.
>
> The headlights and indicators (if they're on) will dim and flicker in
> time with the dash lights too.

Your battery connection is stuffed. What you are seeing is the car
running on the alternator without any capacative (or smoothing)
effect from the battery. The engine will run fine this way, as
being a diesel only requires power to hold the fuel cut solenoid
open enough - AC would prolly work for all it cares.

Close to 400,000 I'd check the alternator brushes (you will need
to remove the A/C compressor to do this).

On the pre 1992 or so models the alternator has the vacuum pump
on the back and the brush assby on the top held by two bolts.

The spec for the brushes new are 20mm. They wear at 8 to 9 mm
per 100,000 km. If you near 400,000 time for their 2nd
replacement.

> My guess is a loose wire(s) somewhere which is why it tends to happen
> in between gear shifts (car loses momentum and then gets a kick in the
> pants when the next gear comes in).

The speed at which the alternator turns is decreased hence giving a
somewhat fluctuating voltage than if it were being turned faster.

[Patrick Young]

Patrick Young wrote:

> Your battery connection is stuffed. What you are seeing is the car
> running on the alternator without any capacative (or smoothing)

Note, there are two cables going to the battery so this condition
may not affect starting (as long as the larger starter motor cable
is making contact) where there is enough current flow to operate
the starter solenoid.

Was there slightly harder starting due to no glow plug functionality?

[Diesel Damo]

Patrick Young wrote:
> Was there slightly harder starting due to no glow plug functionality?

Indeed there is!

I think you've nailed it with the battery connection idea too, because
your other post made me remember some dodginess that was employed to
wire up my new battery after the other one got stolen. I meant to get
around to fixing the bandaid solution, but obviously forgot about it.
Shame shame shame! =(

[Diesel Damo]

Thanks John. Yeah I think I'll give my car a good going over with the
voltage meter this weekend (if it stops snowing) =)

[atec]

Diesel Damo wrote:
> Patrick Young wrote:
>
>>Was there slightly harder starting due to no glow plug functionality?
>
>
> Indeed there is!
>
> I think you've nailed it with the battery connection idea too, because
> your other post made me remember some dodginess that was employed to
> wire up my new battery after the other one got stolen. I meant to get
> around to fixing the bandaid solution, but obviously forgot about it.
> Shame shame shame! =(
>
I suspect as well as what appears to be an answer just make sure the
engine block is well bonded to the body .