Rev counter gone bad in Terrano

[danielbeek]

Hi,
Anyone had this happen before?
Today while driving, revs suddenly dropped to zero, then randomly would spike to max rpm, and occassionally settle on actual rpm. Mainly sitting on zero rpm now.
Just wondering if there's a weak spot I should check first?
I read on an old post that possibly the pickup is off the camshaft? Can anyone confirm that?

Its a 1995 Terrano WD21 TD27T, with facelift dashboard. 235,000km.

[Dirtydog]

mine did something similar, when trucks turned on its nomal, but when truck gets turned off drops to zero, then sits at 4k.

gets anoing but ya get use to it.

id say its to do with the rev counter in the dash, check wires arnt pinched somewhere, and that its earthed properly

[CLUMZ1]

Safari one does the same, just ignore it and listen to the beast...

[Budore]

Mine does exactly the same totally unpredictable. Unfortunately for me, I have to get mine fixed as the yearly test here (MOT) expects all instruments & lamps to be working or it is a fail.

[Gardengnome]

Had similar in a Hiace and identical in the inlaws 1996 Terrano 2.7TD. Had both fixed by E.Parrott and Son Ltd in Chch.
http://www.eparrott.co.nz/

Took the dash(s) in and they resoldered all the joints on the circuit board. $65.
Can't remember if it was + or inc GST. Anyway, worked a treat and still going.

The terrano only took 10min to get the dash cluster out!

[kiwipete]

If it is a case of dry solder joints, I can do that for you for a box of beer, got to be way cheaper than a shop.

[sibainmud]

If it is a case of dry solder joints, I can do that for you for a box of beer, got to be way cheaper than a shop.

^^^^^^^like^^^^^^^

[new2zukes]

my 1995 terrano has similar problem but it doesnt go at all, i hasnt gone for the past 4 years that ive owned it every now and then like once a year it will jump into life for 2 seconds then back to sleep again. not really in too much of a need for a rev gauge but is a bit annoying.

[danielbeek]

If it is a case of dry solder joints, I can do that for you for a box of beer, got to be way cheaper than a shop.

I'm an electronics technician, so thanks for the offer, but I should manage ok!
Glad to hear this is a likely cause - beats engine work or pulling a new pickup cable.
Thanks everyone. I'll update with the fix once it's done.

[icekayak]

Fixed mine a while back, has been going fine for a few months now. Was doing exactely the same thing.

Have a look at http://www.gtr.co.uk/forum/151359-crazy-rev-counter-fixed-guide.html, mine was quite different in construction (facelift D21 TD27), but gives an idea of what you are looking for.

I only resoldered the big joints, 1 of the legs of the ic, and one of the legs of the resistor, basically anything that looked possibly slightly dodgy.

The one catch is I had to pull the needle off to get to the circuit board with the soldering iron, so lost the calibration. I just put it back on at 750 with the truck idling so is roughly about right.

[icekayak]

Also this site

http://www.gtr.co.uk/forum/67592-r33-rev-conter-problem-fix.html

This i.c. has a slightly smaller than 'normal' pin-pitch, it appears Nissan left to much 'solder-resist' on the p.c.b. around the holes through the board for it's legs to go through, I strongly recomend desoldering this i.c. completely and then cleaning the solder-resist back around where the pins exit, then re-fit the i.c. and resolder carefully, remember to use ESD precautions at all times.

It's not like 'normal' dry joints, the failiure is NOT visable there just is not enough copper p.c.b track for the solder to make a perfect joint, once the green solder resist is cleaned away it is fine.

I didn't bother unsoldering it, just basically held the iron on anything that looked dodgy.