A friend is helping me get this car up and running after sitting in a guy's front yard for around 10 years, only briefly driven to move houses once or twice. 199,701km on the clock when I bought it, engine sounds to be happy once it warms up.

Now that it's with me, it's first getting all it's fluids changed and fresh tyres and battery. Poor bugger is still home bound until we can get it blue slipped and road legal again but we've come across a mystery to solve.

At the moment we are having trouble with what we thought was the alternator, got another matching part and installed that but the engine still cuts out when you disconnect the battery. **Check the comments, because my mate is likely to jump in with the technical info**.

We checked the alternator and "the exciter wire seems to be giving 3v which is lower than it should be". Next up he is going to check the cluster behind the dashboard to make sure that isn't.. uh.. doing something circuit related.

Not going to add photos until I can get it to a carwash, it's still covered in leaves temporarily. ?

The alternator isn't outputting anything (I think). The exciter wire, which is more like an input to the alternator that tells it exciting news to motivate it to start alternating, is reading a low voltage, which may point to an issue with the instrument cluster, which is at the other end of the exciter, and according to @Spac is a known issue in 940s.

There’s apparently a couple of potential sources, but the one I have experienced more than once is the flexible circuit board fatigues the solder joints around the inflexible components soldered to it.

Easy fix.

@Spac bang on, reflowed every joint, car runs nice now!

As a side note if you try to drive with no cluster fitted the alternator won't work. Don't ask me how I found out

Driving without the cluster also sets codes for lack of speed signal to the ECU, meaning you get fast idle and backfire on the over-run.

Also on clusters - there are some good notes on exchangability in the 700/900 FAQ.

And the old guys whine how complicated modern cars are.....

There is a significant difference between a modern car and an 80s 740 or 90s 940

    ramrod

    There is a significant difference between a modern car and an 80s 740 or 90s 940

    Pretty sure the 940 is more complicated than the new 2019 fully redesigned bajaj auto rickshaw

      We slapped five new tyres on it, bled the brakes, flushed the coolant, flushed the oil, and flushed the power steering. It's driving nice, has a low idle and keeps throwing a faulty AMM code. I cleaned the AMM but that didn't solve it so I suppose we'll need to swap it out.

      Not pictured: an ant colony we killed. RIP

      Also, I totally forgot about these sweet EQs. The stereo sounds great too - bonus!

      Cleaned out the pcv? and have you done the rear diff and checked the front suspension bushings?

      Haven't done PCV yet or diff oil. I've looked over the front bushings, the sway bar endlinks are pretty toast but everything else is okay-ish

        jamesinc

        Haven't done PCV yet or diff oil. I've looked over the front bushings, the sway bar endlinks are pretty toast but everything else is okay-ish

        Even if they look ok they are most likely rooted

        Replace the bits between the 2 arms with poly and then the others with normal rubber

          @DecimalDuck that is ATF from the power steering rack. I'll have to have a look and see if it's the rack or just a hose. That amount of leaking will stop it passing blue slip though.

          Looks like rack to me, it's leaking from the passenger side dust boot

          Oh yeah, these were the old tyres:

          Seller was like yeah they'll be fine to drive to Eastwood from Dee Why. Hahahahaha

          • Spac replied to this.
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