Car won't start checklist....

[Semnoz]

All of a sudden, car won't start

Last Sunday, I noticed it was slightly slower to start, but ran perfectly for 100 miles (as always). Yesterday (Tuesday) started fine during the day (2 times) and then took about 3 seconds to start later that evening. And then once home, it wouldn't start at all (glad I got it home then), and then tried a couple of times this morning and it still won't start.

I'm aware of numerous info out on the web, and have trawled through it, but would like some advice on a logical order in which to eliminate the cause.

Symptom: Engine turns well (battery is in good condition) but doesn't ever fire. No error messages. No leaks or any visible issues around engine bay.

I don't want to start replacing parts in desperation, in case it introduces another problem, e.g. if I replace fuel filter, I could create air-block, or if I change glow plugs, I might damage an electrical cable.

What would be my first check ? As the engine has always run perfectly, can I rule out the fuel pump, or can that suddenly fail ? If so, is a valid test to disconnect the fuel line, crank the engine and see if fuel spurts out ?

Is there a single component that can prevent the engine starting ? I'm aware that for each cylinder, parts such as inject heads/glow plugs can fail, but I'm assuming they would only lead to a very rough/spluttering engine, and not one that fails to fire up at all.

Sorry for all the questions on what is probably a common occurrence. I need car this weekend, and it's currently stuck on driveway, so I must fix this myself A.S.A.P.

[Splodger]

Good luck....mine got stuck in a field on Sunday and on top of a canal lift bridge on monday night....much to the annoyance of the boaters but stuff them.

[Semnoz]

Originally Posted by Splodger

Good luck....mine got stuck in a field on Sunday and on top of a canal lift bridge on monday night....much to the annoyance of the boaters but stuff them.

I thought barge owners were respectful to other barge owners

[Splodger]

One did me a comment about Volvo drivers!

[cheshired5]

Back to the starting problem, get data, follow where the data leads.

https://youtu.be/awMkm4AwLs4

[Semnoz]

.

Thanks - I'd not thought of that at this stage as I assumed more specialist ECU reading equipment was necessary (e.g. VIDA).

However, I do have a similar ODBC bluetooth connector that I've used on my Focus (although the Focus ECU didn't like Torque and only seemed to give full info with FORScan).

I've just tried this on the V70 and it really struggled to connect with the ECU. The Torque app constantly cycles through different connection protocols, so it could be that my ODBC connector isn't fully compatible with the D5. It did connect once, and I did a scan of error codes and it said none were stored in the ECU (possible I guess). I tried cranking the engine, but it seemed to get stuck turning over (still not firing) and bizarrely didn't stop trying until, I think, the ECU rebooted (which I think happens if the battery voltage suddenly gets really low). Torque did at least record some info, such as battery voltage getting to about 12.2V, but fuel rail pressure didn't go up, although as per your video, that might be expected if other parts of the engine don't get moving quick enough. I've put the ODBC to one side for now.

My main voltmeter is also saying 12.2V. When I cranked the engine it dropped right down to about 6V for a split second, and gradually back up to about 11.7V after a couple of seconds, and then it hovered around 12.15V. The battery is old, but I can't tell how old. I've got the CTEK MX5 doing a deep charge at the moment, but maybe the battery is getting a bit tired, despite voltage resting at 12.2V.....

thanks again

[Semnoz]

Had more luck with the OBD/Torque connection after charging the car battery - and getting a good night's sleep

Engine RPM gets up to 161 and fuel rail pressure to 6023psi. ECU voltage does then drop from 12.43 to 7.17V and then straight back up to 12.12V but I don't know if that's an issue or not.

I'm not sure if the Torque app (Pro) can reveal anything specific to the electronic fuel pump. I think for now I'll take a chance at replacing the fuel filter in case there is restricted flow (presumably there's still enough fuel at the mechanical pump to allow sufficient pressure there ?)

[cheshired5]

Not sure I agree with your fuel filter suggestion.

If you follow the logic and guidance in the video, your fuel pressure is fine.
Your rpm however, is not ok neither is your cranking voltage.

The most obvious cause is a battery past its best but you could also run some simple multimeter tests on your starter motor to confirm its good operation.
There's a starter testing video on my YouTube channel too.

[Semnoz]

I'm buying a Bosch S4 battery at the same time....so will start by replacing that this evening.

The fuel filter has probably not been changed in many thousands of miles, so will need doing, but I won't touch it yet.

[cheshired5]

There are several Bosch S4 so make sure you at least match the CCA rating required in your handbook (around 800) and if you haven't checked already, genuine Volvo batteries from the main dealer can be very competitively priced.