Help diagnosing a non starter

[Casheye]

Hey peeps, so first off the Car in question;

Volvo 940 1997 Classic Auto 2.3 b230 LPT

For a while the car has been having trouble starting. By this I mean that when I turn the key, the starter motor engages but the engine doesn't fire up. After a couple of tries, the car will usually start and will run fine for the rest of the day and wouldn't have an issue restarting if I park up somewhere for an hour or two.

Recently though, starting the car has been a fair bit more miss than hit, and on some days I can't get it started at all (although a fair few choice words and the threat of going to the crusher has sometimes resulted in it coming to life). And when it has started and I've given in a blast down some A roads, after parking it up for a while, it will struggle and sometimes completely fail to come back to life.

I'll list some points below, some will probably be irrelevant but the combination of a few may give a clue as to where I can start looking as to the problem.


1. So first off, the angle of the car when trying to start it doesn't seem to have a bearing on the success. Although most of the time it's parked on flat ground, when it's been facing up a hill is when I have had the least amount of sucess.

2. When the weather is warm, and the sun has been on the car for a while in the morning, the rate of first time startups has been higher than when it is damp and cold.

3. On occasion, when I have turned the key, there has been absolutely no responce from the car at all. Not even the starter motor. All the dash lights come on first then here's an audible click and it goes dead. To remedy this I have disconnected and reconnected the battery and usually the car will start first time. However on maybe 2 or 3 occasions this hasn't solved the problem and after a day or two, I'll try again with more success. (I fear this may be a unrelated and quite possibly an undiagnosable electrical gremlin).

4. The battery is charged and holds at roughly 12v and when the car is running, the battery measures around 14v. After trying to start it a few times, I have previously connected one of those jumpstarter batteries to make sure there is enough juice (although 10v has been enough to start one of these cars in the past) but it made no difference.

5. Fuel level doesn't seem to affect this issue either. Whether the tank is almost empty, half full or brimming, the problem will be just as intermittent.

6. When i started it on Sunday, I left it idling as it felt like it was running a bit lumpy (it's always felt like it's had a bit of a missfire, but it's had new leads, plugs, cap and rotor in the last 14 months) and after i returned within 3 minutes, it had died. Turning the key, it started first time again after this initial cut out.

7. The fuelpump relay does click when the key is turned.

OK, so what I'm basically asking for is advice on where to start looking first. I do have breakdown cover, but the local garage that the company send out probably have my face on some kind of "avoid at all cost" board as when I've had them out before the effort to get it going again has been, well pretty diabolical. While I await your sage advice, I'm going to see if there's any fuel pressure which might narrow things down a little.

Kudos in advance.

Mike.

[BorderVolvo]

Regards points 3 and 6, might you have the start of an ignition switch fault?

[Casheye]

Originally Posted by BorderVolvo

Regards points 3 and 6, might you have the start of an ignition switch fault?

Noted. Thanks.

[Casheye]

So the bloody thing is only running sweet as a flippin nut right now.

I went out and turned the key. Nothing. So I disconnected the fuel line where it joins the rail above the intake manifold and wrapped an old shirt around the hose and gave the key a turn.

The car started right up, ran for about a second and then died. Obviously. Checked the shirt and it had definitely soaked up something. I turned the key again just to make sure it was fuel from the hose and not anything that had dripped out of the fuel rail and it was soppin.

I reconnected the hose and turned the key and it came to life straight away. let it idle until the car came up to temp and it didn't burble, gurgle or missfire once.

Anyone care to throw a guess as to what might have happened? I'm going to let it cool back down again now and then go out and try it again in a few hours and see if the original problem persists.

[Laird Scooby]

Originally Posted by Casheye

So the bloody thing is only running sweet as a flippin nut right now.

I went out and turned the key. Nothing. So I disconnected the fuel line where it joins the rail above the intake manifold and wrapped an old shirt around the hose and gave the key a turn.

The car started right up, ran for about a second and then died. Obviously. Checked the shirt and it had definitely soaked up something. I turned the key again just to make sure it was fuel from the hose and not anything that had dripped out of the fuel rail and it was soppin.

I reconnected the hose and turned the key and it came to life straight away. let it idle until the car came up to temp and it didn't burble, gurgle or missfire once.

Anyone care to throw a guess as to what might have happened? I'm going to let it cool back down again now and then go out and try it again in a few hours and see if the original problem persists.

Reading through the description Mike, i was thinking condensation in the tank. This will always settle at the lowest point of the tank (it's water after all, petrol floats on water) and if the car is facing uphill, with the sender and pump at the back of the tank (which will also be the lowest point then), more condensation will be around the pick up point.

Purging the fuel rail with your shirt will have purged watery fuel and the fact the return line will also have shot petrol into the tank and mixed up the contents is probably what meant it fired easily afterwards.

The other thing that crossed my mind was the beginning of a starter switch (as Volvo call the igntion switch) problem. I have a good 940 starter switch here but whether it's suitable for yours is another matter.

That said, remove the ash tray, pull out the cover behind it so you can slide the central electrical board out aka fusebox and relay box.

Firstly, push each fuse in turn to ensure they are all fully in. Second do the same with all the relays.
Third, check around fuses 11, 12 and 13 for any signs of heat. It's not unknown for the fuses to go high resistance with age, on a high consumer that is constantly on when running such as the fuel pumps, this translates into heat on the fuse blades which goes even higher resistance, causes more heat and eventually stops the pumps running.

If all that checks out, pull each fuse, one at a time, clean the blades with some emery paper and hold each up to the light to ensure there are no hairline cracks in the fuse link itself - any doubts, renew it! Refit it and then then remove/refit several times to clean the fusebox contacts as well.

Something else to also consider is the CPS - Crankshaft Position Sensor mounted on top of the bellhousing. THe cable is in a very hot place and doesn't endure well so the cable can become brittle and break with age. Worth checking out at least.

Unfortunately with this being an intermittent problem it could take time to track down, try the basics as i've described and see where you go from there.

If condensation is looking like the primary cause, 2L of meths in NO MORE than 4 gallons of fuel (already in the tank DO NOT ADD 4 gallons! ) will usually eliminate the condensation. Toolstation are usually the best price for a 2L bottle of meths :

https://www.toolstation.com/methylated-spirit/p99550

Don't try and skimp or add more, the first won't work and the second is a waste - a concentration of 10% meths in petrol is the best ratio.

[Volvo_Utrecht]

Did you read the codes?
Both the ‘red light’ codes as well as the codes using vol-fcr?
Mine for example had an immobilizer fault recently
This prevented a proper start

[Casheye]

Originally Posted by Laird Scooby

.

Many thanks. I'll give those things a whirl and see what happens. It started fine this morning and also last last night. With regards to the 4 gallons and meths, the broken fuel guage isn't going to help with matters but I'll give it a shot when I've run it down enough.

[Casheye]

Originally Posted by Volvo_Utrecht

Did you read the codes?
Both the ‘red light’ codes as well as the codes using vol-fcr?
Mine for example had an immobilizer fault recently
This prevented a proper start

I don't have a code reader and it's a MKII model so it's not got the flashing light box in the engine bay, just the OBD port in the centre console.

[TonyS9]

Standard tests (assuming the starter is turning but engine not starting)

Listen for a high pitch whine from the pump when the key is turned. Open the tank inspection hatch in the back if necessary. It won't prime every time if you redo it quickly. You will hear a click in the dash when it is ready to go again.
If its anyway gratey or grindy it needs changed.

Next turn the engine over and see if you get the rpm needle flickering while its turning, it will take 1s or so before it starts moving. Normally this is when it should start.

[Casheye]

Originally Posted by Laird Scooby

Something else to also consider is the CPS - Crankshaft Position Sensor mounted on top of the bellhousing. THe cable is in a very hot place and doesn't endure well so the cable can become brittle and break with age. Worth checking out at least.

So with the quote above in mind, I think I may have solved the problem but some clarification would be appreciated.

I haven't had much success with getting this solved but yesterday I took a drive up to Dartmoor and on the way home, the temp guage went into the red. So I pulled over and the radiator was empty. Unfortunately (and because I'm such a good samaritan ) I'd given the 5 litre bottle of water I usually carry to someone I spotted with radiator problems the other day. So I didn't have nearly enough to top up. Phoned my breakdown company and ended up getting towed home.

This morning I went out and topped up the system and I could hear water gushing out from near the bellhousing. A quick peek and I could see that one of the necks for the heater water valve had snapped off. I've removed the old valve and dug out the old neck which was more like picking and old damp cigar out of the hose than a piece of plastic and poured some more water though the system to flush out any bits I missed.

Now am I right in assuming that the CPS has to pick up a signal before fuel is sent to the engine? If that's the case, then the likely cause of my problems has been this degrading plastic meaning that water has been leaking onto the top of the bell housing and getting the CPS wet, causing it to not work?

It would definitely explain why I'd have varying degrees of success starting it when the car was parked at different angles as the water wouldn't drip straight down onto the sensor.

I'll need to order a new valve, but the only place I can find one for sale is on the eurocarparts ebay site. I can't find it on their main website and delivery is a week away. So if anyone has a spare for sale, let me know.

What do you guys think as to this being the sole cause of my starting issue?

Also, on a side note... what's the danger in bypassing this valve temporarily with a straight bit of pipe?

Thanks in advance.