Car stalled on coasting

[91SS]

How do I load photos?

Says to file to big.

 

[grey_hawk]

Try cropping them and save.

 

[91SS]

Photo loaded with description.

Check post #30.

 

[MikeC]

Photo loaded with description.

Check post #30.

Bet you're glad you found the cause.

Dry joints caused by age, heat and vibration, are the bane of the electrics on our cars now. I take of any suspect component joints on my phone then blow them up for examination as a matter of course. Same with any second hand parts I buy now - blow photos of the circuit boards up and look for dry joints before installation

 

[Immortality]

Update;

Solved.

Was the module , and more specifically dry joints on module PCB.

Trying to load photos.

Took it of car and access to PCB is by simply lifting plate off rear..

At this point the way I repaired it is.

1) Unsolder terminals off transistor in cut out on PCB x 3, and unsolder 2 x terminals off resistor/noise filter.

2) Remove 4 x screws ( 2 go through brass eyelet as mentioned by @the5819 which must be cleaned). Lift off wire loom from 4 pin plug from main body.

View attachment 258515
This is the rear of PCB.

Note 2 x brass screw holes at bottom. These act as a earth for PCB and must be cleaned.

Note on enlargement of photo halo marks and solder deteriorating can be clearly seen.

Note in centre of PCB the cavity with 3 x unsoldered terminals ( from main transistor which can be seen from outside module)which must be unsoldered prior to removal of PCB from module housing.

2 x resistor terminals on top of photo must be unsoldered from other side prior to PCB removal.

Note deteriorating solder on 6 pin plug terminals.

Notet IC terminals right of cavity.

At this point if problems are intermittent it's very unlikely there is any component failure, more likely numerous dry solder joints as was the case with mine. On closer inspection under magnification I found nearly all solder joints oxidised and or with minor cracks or visibly deteriorating joints.

In the end I reflowed all solder joints taking special care on ICs.....not to overheat them. Go with a hot iron and plenty of flux. If one isn't confident and wants to address main trouble spots reflow the 6 pins which hold main connector and 3 pins on main transistor (which is available if faulty I.e a hard fault).

On reinstall into car take care to make sure battery negative is disconnected and 4 pin module plug doesn't get caught on top of main plug when air cleaner assembly is installed because it will strain solder joints in module pertaining to 6 pin plug.

Also noticed a slight barely discernible hesitation/miss occasionally at idle has also disappeared.....so all connected.

Like to add picked up Jaycar Hall effect sensor for $27 for the parts bin. If anyone goes this ŕoute they wiil need to solder the 3 wires on original connector, and will need a little heat shrink..

Thanks to all who helped me on this thread especially @the5819 .

Definitely looking a little tired.

There seems to be a heap of cheap (or not so cheap) knock off units on ebay now. I wonder what they look like inside.

 

[91SS]

Definitely looking a little tired.

There seems to be a heap of cheap (or not so cheap) knock off units on ebay now. I wonder what they look like inside.

That's why I reconditioned this one, and passed on info. Some of the knock off's are poor but at least they exist. Remember late 80s ,90s it was hard to get parts for older cars and non genuine items were woeful.

Was considering a nuclear powered module reconditioned unit from ebay, seems good and obviously a tech for many years. He talks about performance upgrade with them .

Anyone had any experience with them?

 

[91SS]

Bet you're glad you found the cause.

Dry joints caused by age, heat and vibration, are the bane of the electrics on our cars now. I take of any suspect component joints on my phone then blow them up for examination as a matter of course. Same with any second hand parts I buy now - blow photos of the circuit boards up and look for dry joints before installation

Certainly am.

One wonders what these newer cars and electric vehicles will be like in the future.......probably unfixable.

Now I have to get around to the cruise control unit.

Mild winter in Sydney and obviously dry joints didn't play up much. Maybe 2 or 3 times and I ironically saw cruise light on after this repair coincidentally.

I suppose that's the trick now for our cars. If intermittent suspect dry joints/connections. Even with hard faults.

 

[Skylarking]

Certainly am.

One wonders what these newer cars and electric vehicles will be like in the future.......probably unfixable.
...
I suppose that's the trick now for our cars. If intermittent suspect dry joints/connections. Even with hard faults.

Thanks for sharing the solution

Supposedly lead free solder causes issues with the longevity of solder joints as used in modern electronics. Not sure when this environmental lead free movement started, may be warly, mid 1990's?

So the interesting question is whether the VN was built during the pre or post lead free solder movement. If it was pre lead free, the question obviously becaomes whether our more modern cars will have even more (very complex) intermittent issues occuring considering the number of modules (using lead free solder) we now have in our cars

 

[91SS]

Thanks for sharing the solution

Supposedly lead free solder causes issues with the longevity of solder joints as used in modern electronics. Not sure when this environmental lead free movement started, may be warly, mid 1990's?

So the interesting question is whether the VN was built during the pre or post lead free solder movement. If it was pre lead free, the question obviously becaomes whether our more modern cars will have even more (very complex) intermittent issues occuring considering the number of modules (using lead free solder) we now have in our cars

Good point.

Certainly, when I started in the technical industry late 80s it was talked about....but everyone was using leaded solder, so I don't have definite proof but I would say the VN had leaded solder PCBs..

Note that later model cars used more dampers like our cruise control units and thought of adding some rubber on module mount but yeah there could be more issues with solder on late model cars not to mention far more electronic componentry.

 

[MikeC]

Certainly am.

One wonders what these newer cars and electric vehicles will be like in the future.......probably unfixable.

Now I have to get around to the cruise control unit.

Mild winter in Sydney and obviously dry joints didn't play up much. Maybe 2 or 3 times and I ironically saw cruise light on after this repair coincidentally.

I suppose that's the trick now for our cars. If intermittent suspect dry joints/connections. Even with hard faults.

It took years to solve the dry joint problems in my cruise control compounded by problems with the VSS. You will be lucky if you fix all the dry joints on the first pass.