960 coil on plugs

[liamcafs]

Anyone know how to test the cops. Is it something that can be done diy?

Cheers

Liam Mc

[classicswede]

Just swap them around and see if the misfire moves

[rogerthechorister]

If she is running on 5 just disconnect one at a time until you find the one that causes no change when removed. Pattern ones are not that expensive, but it's obviously better to change one than 6. They are quick and easy to change (but do not overtighten the screws or they become hard to remove again) so if she won't go at all, if you know anyone else with the same generation 960, just meet up and swap them over for half an hour.

[liamcafs]

The car idles ok initially at approx 1250 but then aftr 5-10 seconds the rpm start to drop to 800-900 at this point the idle gets lumpy and eventually the car stalls. If during this time I give any throttle the car just stalls pretty much right away. If I time the throttle right though, I can get the car to rev and drive but you have to keep the revs above about 1.8k - 2k otherwise it'll die. Also quite a lot of white smoke initially.

Full disclosure; this engine and box is destined for my 240 as an engine swap and will be run on a standalone Emerald ECU with all new sensors and engine bay loom. I'm wanting to switch the COP to a 6cyl wasted spark setup for simplicity but I'd feel more comfortable if it was running better before I yanked the engine.

Sorry if this offends the purists. Its not like I am taking a beloved 960 off the road this was on its way to the big Volvo garage in the sky when I bought it so at least the engine and trans will live on.

If anyone has any advice I'd appreciate it.
Many Thanks

Liam Mc

[heckflosse]

White smoke is ominous. Might be worth a cylinder leakage test to check for a coolant leak. Perhaps run it up, then leave overnight and pull the plugs from cold-any coolant on them? Is it an earlier donor car? If so you could read the flash codes easily, failing that it might be worth plugging it in just to see what is stored in there. Coils do go down.
You could also spray a bit of WD40 or carb cleaner around the inlet bellows. As I remember these sometimes gave air leaks.
Good idea to get it 100% before swapping, and good luck in the 240.
Jim.

[Laird Scooby]

Originally Posted by liamcafs

The car idles ok initially at approx 1250 but then aftr 5-10 seconds the rpm start to drop to 800-900 at this point the idle gets lumpy and eventually the car stalls. If during this time I give any throttle the car just stalls pretty much right away. If I time the throttle right though, I can get the car to rev and drive but you have to keep the revs above about 1.8k - 2k otherwise it'll die. Also quite a lot of white smoke initially.

White smoke or steam? Steam will clear fairly quickly but smoke will hang about for ages. If it's white smoke it's burning oil, if it's steam it's burning coolant.
It could be a mixture of both, pointing at the head gasket, cracked head or worse still, a cracked block.

It also suggests it's running lean as if you give it any throttle it just dies.

I'd also suggest a compression test, hot with wide open throttle (WOT) and make sure you disable the fuel pump first so you don't get fuel injected into the bores without it being burned as this can cause very strange compression readings!

Will be a nice conversion for your 240, i love the idea of retro-modding, particularly fitting a more modern engine to gain improved power, economy, unleaded compatibility etc.

[liamcafs]

Its a M-reg manual 960 with the B6254FS engine

Its definitely oil smoke you can taste it. Though it stops producing it shortly after startup (i think) Its hard to pay attention when you trying to keep the engine from stalling.

Thanks for the advice fellas. I intend doing a compression check as well as a leak down check before I extract the engine.

I'll update with my findings

[liamcafs]

Finally managed to do the compression check last night, showed 210 on all cylinders except number 3 which varied anywhere from 120 to 180 the times i tried. Drop of oil cylinder 3 and the test result jumped up to almost 300.

This was all done cold by the way as the car isn't running properly (electrical problems) What do people recommend next?? Leak down check to confirm rings/crack or open the engine......?????

Any advice would be most welcome.

[Laird Scooby]

Based purely on those results, i would suggest a broken compression ring on that cylinder. It may be worse, the piston may have broken around the land (the space between piston rings) causing loss of compression.

If you don't already have one, i'd spend a fiver or so on a USB boroscope, whip the plug out and poke the boroscope in and see if you can see anything.

https://www.ebay.co.uk/itm/Waterproo...ZR7Adon0UeZ6Gw

You may be able to see the problem from that or at least get a better idea of what the cause is.

If my suspicion about the piston being broken is correct, it could have been caused by detonation which in turn could well have been caused by that cylinder running lean, suggesting a faulty or dirty fuel injector. As such, it may well pay to have the injectors ultrasonically cleaned and flow-tested :

http://www.emeraldm3d.com/emerald-se...ditioning.html

That price is per injector by the way. When you refit them, use new seals/"O" rings and smear them with silicone grease to help them slide easily into their gas-tight position.

That's my take on it, see what others say, there could be another cause i haven't thought of.

[liamcafs]

I have a borescope so will check that tonight and post results. Good call on getting the injectors cleaned I'll look into doing it.