Anyone by chance have a list of the ground connections on a 960 wagon? Seems like a good thing to check on a '96 with 200k...

 

Unless you have electrical problems, I wouldn't worry...

 

I agree, don't fiddle if not broken.

But you should have the factory wiring diagram, most years can be downloaded at volvowiringdiagrams.com. Most grounds in the electrical system are illustrated within along with all kinds of other nerdy details about wires and connectors.

 

Thank you ...

Curious to know, do you guys always wait for something to break before learning more about your engine?

 

See above...

 

No! Absolutely not! In fact I would prefer to have read the factory manuals before I buy the car For the way I deal with things, the time and brain cells spent are worth it, but this may not be the case for everyone. These materials are difficult to read because they are worded sparsely and translated from another language.

You should also understand that the factory service documents and training materials assume the audience has a general mechanics competency. For example, I have not seen a page in the Volvo materials I have that explain how the knock sensor works or what it really is.

 

A lot more problems are caused by overly eager owners fiddling with things unbroken, than failure to address problems that aren't there... It's fascinating the kind of problems that pop up!

A common type of post: "I was going down the freeway and I felt my Volvo stumble a little. I got home and I changed the fuel pumps, the fuel relay, the idle valve, the FPR, the pulgs, the wires, the cap, the rotor, the timing belt, the air in the muffler, and the Johnson rod. Now, the car won't start! Help!"

So, yeah, if it ain't broke, don't mess with it!

 

Yeah well that's not me. I work as an electrician in a yacht yard, and I wire and repair and maintain all sorts of private boats and their systems including navigation electronic, lighting, pumps of all sorts, and - oh yes - engines with bad grounds.

And one of the most common problems across the spectrum of electrical failures is the ubiquitious "bad ground." In case you didn't know.

So no, this is not "if it ain't broke, don't fix it." This is a request for information about a troubleshooting procedure that I will no doubt need to perform on my Volvo some time.

If you can't help with the information, why bother to post?

 

I have this in my Green Volvo Fault Tracing Guide, the best money ever spent on a factory manual. It would even be a better guide with the Volvo factory scan tool.

Here is what is says about knock sensors, maybe you have seen this but in case you haven't it is from the design and function section, input signals;

"The function of the knock sensors is to provide the ECM with information of the onset of engine knock.

The signals from the KS and CMP (cam shaft) sensor allow the ECM to determine which cylinder is knocking.

The engine management system has two KS, which incorporate the following:
Housing
Sleeve
Piezoelectric crystal
Contact strip
Damping weight
Washer
Nut

Engine knock generates vibrations which are transmitted through the engine block. The piezoelectric crystal detects these vibrations and sends a signal proportional to frequency and amplitude to the ECM.

The front KS detects knock in cylinders 1,2 and 3, and the rear 4,5 and 6.

KS are mounted on the engine block."

In another section, fuel injection: "If knock occurs and is not suppressed by ignition retardation, additional fuel is injected to reduce the temperature of the combustion chamber." This sounds like it can do this function to an individual cylinder.

This last statement is why when someone uses lower octane fuel, gas mileage falls. I did an experiment several years ago regarding fuel octane and kept meticulous records. Did about 4,000 miles on low octane and 4,000 miles on the required octane. The added mileage with the correct fuel nearly paid for the use of the required octane, I believe at the time is came to with in 2-3 cents per gallon. The car ran so much better when using the correct octane too. So the actual cost of the higher octane came to under a buck for a tank. At the time I was driving about 35k miles a year so figuring that out was important.

DanR '94 964 387,000 miles (153,000 on the new engine)

 

OK, this convinces me to buy the Technical Publications DVD. I hope it's not too difficult to use the books on DVD.

I have not yet found a way besides the volvo scan tool to get some of the functionality mentioned in the books. The vadis package can read fault codes but refers "activation" and some status checking to the scan tool, seemingly because it does not have a way to do these things.

Being stuck with obd2 or nothing makes it harder, so I wonder if a thirdparty tool like bosch esi/tronic or launch x431 can do these things?

 

Check the Resource sticky for a 250-page Wiring Diagram book, along with 1-line (abbreviated) 20-page diagrams that can be found at volvowiringdiagrams.com.

There is also a file or link there to Bosch Motronic files, about ECU, sensors, etc. that even Volvo books don't have. It explains the logical / conditions / sequence of operations.