940 LPT not starting after new PCV box and heater valve.

[Vintoni]

Hi all

I've just replaced the PCV box and heater control valve on my 1997 940 LPT estate. I was getting some oil blow-by so I replaced the PCV box and cleaned out all of the breather pipes.

I was also getting a coolant leak which turned out to be the heater control valve. I have just replaced both items and now the car won't start!? It cranks strongly (new battery recently) but won't turn over. What on earth have I done?

The only thing I removed which I thought could cause an issue was the coil lead but I've just replaced this with a brand new one but the car still won't start.

Any ideas? I have had no issues with starting before.

Cheers
Dale

[nutco]

you may have knocked the crank sensor lead at the back of the engine they are known to get worn thru and brittle with age, mine broke and did the same thing as yours

[Vintoni]

Sounds plausible. Is it easily replaceable? Is it the thin lead that plugs into the engine below the heater pipes at the back there and then has a connection up at the top of the bulkhead on the driver's side?

[Vintoni]

Yeah, this: https://www.ebay.co.uk/itm/273886776535

[nutco]

Yep thats the one

[Vintoni]

I've just removed it and it looks pretty gnarly. Hopefully that's the issue. Replacement on the way.

Thanks a bunch, much appreciated. Still on my voyage of discovery with this car, I'm used to old Fords....

[stegreg]

sometimes you do tend to find a load of rubbish has attached to the tip of the crank sensor, most will wipe off and you can lightly run a file over and around just to clean it up, but don't go too mad and over file the tip or it alters the air gap.
watch the hoses on the valve you have just replaced, if they feel "soft" be worth changing before they split, which they are prone to do, I changed the hoses on mine same time as the valve.
the other water hose to look at is the one on the bottom of the oil cooler, better seem from underneath, below the oil filter...if that looks "bulgy" yet another suggestion to swap out before you loose all the coolant.

[Laird Scooby]

Originally Posted by stegreg

you can lightly run a file over and around just to clean it up, but don't go too mad and over file the tip or it alters the air gap.

Not a good idea! Wipe it with a lint-free cloth (mocrofiber cloths are good) with some brake cleaner, carb cleaner or similar solvent cleaner.

Don't EVER file the tip, it's slightly magnetic and will pull tiny particles out of the file (you may not even see them) not to mention the fact that it can lead to premature danage inside the sensor itself.

[arctan]

On my 940, when turning over the engine, the rev counter in the dashboard 'kicks' a little, if the sensor is OK, before the engine fires.
And I'd say do the heater hoses whilst you are in there, then forget about that area for a bit! Some heater valves are better than others, the all plastic ones possibly the least good, as they'll crack again in time. As well as the search option in this forum, you can use google to look through previous postings.
Drop this exact line in to google search:

site:volvoforums.org.uk 940 heater valve

or

site:volvoforums.org.uk heater valve

Also, plenty of info at:
https://www.volvoclub.org.uk/faq/Eng...stition_Sensor

[arctan]

https://www.volvoforums.org.uk/showthread.php?t=298684