Dead cylinder for the first mile

[philski o'flood]

do the spark plugs work correctly in another car

 

[ZVOLV]

Have you tried setting it on fire!?

 

[morsing]

It sure seems like there's still a completely dead cylinder. Ignoring the testing that you've done already, I'd suspect a bad part in the high voltage path - plug wires, coil wire, cap, rotor. Have you tried misting it with a water spray bottle in the dark to see if you can see any arcing?

Just went out to check this in the dark but realised I'd removed to much to start it up. Will try to remember for tomorrow evening.

In your video, the cable from the distributor sensor is clipped to the high-voltage cable from the coil. There's a chance that this is causing electrical noise in the disti sensor. As a test, remove the cable clip and separate those cables by a couple inches.

I moved it out of the way but it didn't change anything. It has been that way from the factory though.

do the spark plugs work correctly in another car

Not tried but I have another set of plug and wires and have swapped them over many times. Just tried swapping #1 again but it made no difference.

I've been out all afternoon looking at it. It was very difficult to start and stank of fuel, so I removed the plug from #1 and it was soaked. Stuck my borescope in the cylinder and it was wet everywhere.

When it finally started the exhaust was clouds of white smoke which I think smelt of fuel. I ran it warm and stuck my exhaust gas analyser up the tail-pipe thinking maybe it was just over-fueling but the CO level was pretty good.

I then did a smoke leak-detector test but nothing of interest showed up. Injector seals and inlet manifold weren't leaky. I also tried un-plugging one of the manifold vacuum nipples between #1 & #2 runners thinking if it was running rich it would run better but it ran worse, so it is definitely not rich.

I have retrieved my fuel pressure test kit and will test control- and system pressure tomorrow. I might try powering the cold-start injector when the engine is running and see what happens. I also need to run the engine without the fan belt to see where that smoke is coming from.

Here is the requested injector spray test video:

Looks fine to me.

Have you tried setting it on fire!?

Not very helpful. It has been an incredibly stressful two months and I am constantly coming up with excuses to not go into the office. I have probably put 100 000 miles of wear on that cylinder driving 500 miles with it not firing.

Regards,
Henrik Morsing

 

[dl242gt]

That's a good spray pattern. Makes the correct sound, too. Is the spark color nice and white on the plug when you tested spark? I'm wondering if it's fouling the plug so you lose the cylinder. Even a slightly weak spark in that cylinder could cause the plug to foul and not fire. That is barring any mechanical issue it's got hidden from you.

 

[apollokid]

I think that since we have a complicated problem it must not be tested the spray of a single injector only but also that all the sprays of all the injectors are even.
Furthermore I discourage to spray the fuel into air, the risk of fire is very high. It is sufficiente to insert each injector into a transparent plastic bottle to avoid fire hazards and to compare all the sprays together.

 

[JW240]

While I have no good ideas to try, as a lot had been suggested already, I have been thinking about this.

Before it started to behave so badly. How did the plugs look like if you would have stopped during the fist mile with the misfire?

Could you perform an compression test right away after the first mile?

Would it still misfire for the first mile with a few drops of in the cylinder, to see if bad rings are the culprit? Not sure how fast oil is washed away.

Have you tested coolant for HC with contrast liquid?

Checked for sticking valves or something crazy like that? Bad valve spring, when things have been moving for some time and have warmed up they might be free to move..

Just some ideas.

 

[tbrcktch]

Henrik,
I thought that the white "smoke" might very well be unignited gas. That's why I wanted you to smell it. I think you, also, initially had a leaking head gasket/cracked head issue, which is now, hopefully, behind you. I also think that you picked up an injector issue, post head gasket, possibly even to a degree at the same time you were having the head gasket issue. Could be why the missing cylinder moved on you. I'd recommend doing another video of injector testing, but test all 4 injectors. It's best to have all four spray patterns to really compare. It makes a weaker pattern stand out more obviously, and also to compare opening pressure differences. Also you really don't want all that fuel from that injector, that isn't being tested to just be washing out that #3? cylinder. If you could lay, on top of that clear plastic "shiny" lid, a non reflective black sheet of plastic, rubber, a towel, anything that will allow a good visual of the spray pattern (makes it a lot easier for us to see). Try to keep the injectors spaced apart so patterns don't overlap. The biggest thing about testing a CI injector, is the opening pressure, and pattern at opening pressure, and at just a hair above that opening point. This is where you really want to concentrate on checking your spray pattern. A good injector will be sealed, no fuel leak/dribble, no fuel atomization, until you reach opening pressure. And then it should be a good atomized spray pattern. Any dribbles,seeping,streams of fuel are no good. You have to really creep up on it. It can be difficult to get, just at that point, but get it there and keep checking that. Try applying just a little rotational twist, at an angle, to the tool, while pulling up the metering plate, not enough to change the adjustment, but to just help it keep tensioned in the allen head, so it doesn't pull out of the allen head, Also, if you can get a parts wash can with a long spray straw to spray down into the opening of the allen head, to make sure the allen head doesn't have crud built up in there, keeping you from getting your tool all the way down in there. It's not so important about what your pattern looks like at partial through full throttle, that's not where your injector spray pattern is going to be, when cranking to start it up, also your engine runs fine, other than the misfire, above idle. What's most likely happening is that, if it is an injector issue, the spray pattern may not be atomizing at initial opening, and shooting out unburnable streams of fuel, or just dribbles out fuel, which is fouling out the spark plug before the engine even gets started. At which point that spark plug is not going to fire until it becomes dry. The same thing that happens when you flood a carbureted engine by pumping the gas pedal too many times on start up. Also I'd recommend swapping #1, an#2 injectors with hoses attached again, on start up, just as an additional diag test.

 

[apollokid]

Like in pulsed ignition systems I think that it's important to measure the fuel flow and check that it is the same across all the injectors

 

[morsing]

Erm... Does anyone know where drafts go (to die)?

I was writing something yesterday and saved it several times. How do I retrieve it? The floppy disk icon sometimes has a green dot but when I click it it only has "Save" and "Delete".

Regards,
Henrik Morsing

 

[morsing]

Good news in that the Saab passed the re-test so I no longer have to rely on the Volvo to get to work. It has taken a load of my shoulders and means I can work at a more thorough and relaxed pace and remove things from the car without the time-pressure of getting it drivable again.

I also bought these (not the cat, she was free):



I will rig them up to a board and shove the injectors in there so I can check low/high pressure spray, evenness and flow-rate. I will remove the inlet manifold so they can sit in a better position.

That's a good spray pattern. Makes the correct sound, too. Is the spark color nice and white on the plug when you tested spark? I'm wondering if it's fouling the plug so you lose the cylinder. Even a slightly weak spark in that cylinder could cause the plug to foul and not fire. That is barring any mechanical issue it's got hidden from you.

I'm not very good at reading spark plugs but they look OK and identical to me.

But, on that comment, if I hold the revs steady at 2000rpm for 5-10 seconds, the issue clears up and #1 kicks into life. Let off the throttle and it will idle OK for about two seconds, then #1 dies again. It's a bit odd and does point to over-fuelling or a bad spray, however, I tried removing to hose going to the dashboard eco-gauge form the inlet manifold nipple which sits between the #1 & #2 runner thinking if it was running rich it would make it run better, but it only made it worse.

Also, when I am out driving, if I hold the throttle steady at a light to medium load, maybe around 25%, #1 kicks in again after about ten seconds. Any deviation from that, more or less load, and it dies again.

I tested the fuel distributor control pressure last weekend and it was spot-on, 1.3 to start with (5C ambient temperature) and once I connected the power up to the WUR, it went to 3.6 after about 4 minutes. Three years ago, I had it all apart and painstakingly set everything correctly on the fuel distributor.

I think that since we have a complicated problem it must not be tested the spray of a single injector only but also that all the sprays of all the injectors are even.
Furthermore I discourage to spray the fuel into air, the risk of fire is very high. It is sufficiente to insert each injector into a transparent plastic bottle to avoid fire hazards and to compare all the sprays together.

I totally agree on both points which is why I was hesitating doing the spray test, it's cumbersome and end up being a mess unless you setup a proper rig to do it, which I will do soon.

While I have no good ideas to try, as a lot had been suggested already, I have been thinking about this.

Before it started to behave so badly. How did the plugs look like if you would have stopped during the fist mile with the misfire?

I didn't try, but as above, I'm not very good at reading spark plugs.

Could you perform an compression test right away after the first mile?

Would it still misfire for the first mile with a few drops of in the cylinder, to see if bad rings are the culprit? Not sure how fast oil is washed away.

I think the issue, if it is even the same issue (?!), is way past just being the first mile.

But, I have done a full set of compression and leak-down testing and the dead cylinder is by far the healthiest.

Have you tested coolant for HC with contrast liquid?

Is that the tester you put on top of the coolant reservoir or something else? If yes, then, I have, several times, never with any result pointing to a problem.

Checked for sticking valves or something crazy like that? Bad valve spring, when things have been moving for some time and have warmed up they might be free to move..

Yup, valve springs were replaced three years ago and shims measured and checked and when I had the head off last month I checked the valves and they all moved firmly and freely.

Just some ideas.

Thanks, always appreciated

Henrik,
I thought that the white "smoke" might very well be unignited gas. That's why I wanted you to smell it. I think you, also, initially had a leaking head gasket/cracked head issue, which is now, hopefully, behind you.

Replacing the head-gasket made no difference. It also did not have any obvious signs of being faulty. It has minor signs that could possibly be a leak, but it was not really clear.

I also think that you picked up an injector issue, post head gasket, possibly even to a degree at the same time you were having the head gasket issue.

No, that was one of my very first posts, back in July, cold-start injector leaking which I replaced and subsequently tested.

Could be why the missing cylinder moved on you. I'd recommend doing another video of injector testing, but test all 4 injectors. It's best to have all four spray patterns to really compare. It makes a weaker pattern stand out more obviously, and also to compare opening pressure differences.

Also you really don't want all that fuel from that injector, that isn't being tested to just be washing out that #3? cylinder.

I agree and agree, building a rig. For some reason an injector test stand with a pressure gauge costs many hundreds pounds, very annoying. I was wondering if I could build one myself.
Last weekend I had a brilliant idea on howto test opening pressure but I now can't remember what it was.

P.S. I think my fuel pressure test kit has the right size banjo bolt to intercept one of the injector outlets on the distributor. Once the inlet manifold is out, it would be easy to hook up to and I can test opening pressure.

Try applying just a little rotational twist, at an angle, to the tool, while pulling up the metering plate, not enough to change the adjustment, but to just help it keep tensioned in the allen head, so it doesn't pull out of the allen head, Also, if you can get a parts wash can with a long spray straw to spray down into the opening of the allen head, to make sure the allen head doesn't have crud built up in there, keeping you from getting your tool all the way down in there.

I'm not sure what you are referring to here, do you mean the CO-adjuster?

It's not so important about what your pattern looks like at partial through full throttle, that's not where your injector spray pattern is going to be, when cranking to start it up, also your engine runs fine, other than the misfire, above idle.

It also dies again above 50% throttle.

What's most likely happening is that, if it is an injector issue, the spray pattern may not be atomizing at initial opening, and shooting out unburnable streams of fuel, or just dribbles out fuel, which is fouling out the spark plug before the engine even gets started. At which point that spark plug is not going to fire until it becomes dry. The same thing that happens when you flood a carbureted engine by pumping the gas pedal too many times on start up. Also I'd recommend swapping #1, an#2 injectors with hoses attached again, on start up, just as an additional diag test.

I've swapped them many times. Injectors also aren't the original, 34 year old injectors. They are 15 years old, I know, not brand-new, but at least not many decades old.

I also swapped the distributor cap and rotor back to my old ones last weekend, and it made no difference.

I which I could borrow a distributor to test, it's the only thing, and a single point of failure, I haven't tried to swap in the ignition system.

Onward and upward (hopefully).

P.S. Would it be worth changing the fuel filter? Just to eliminate? It is six years old and has done 30 000 miles. Does seem a bit a shot in the dark.

Regards,
Henrik Morsing

 

[dl242gt]

I would do the fuel filter just because it's a kjet maintenance item that is very important in this system. I've changed the filter on neglected kjet systems and that disturbed enough crud that it then proceeded to clog the injectors. I had to change all four on that one.

The kjet injector cleaner was a very handy tool to have. That lets you test opening pressure, and spray pattern. I always wanted to buy one but never got around to it. I always ended up doing the messy diy method using a air hose and carb cleaner to clean kjet injectors. Which I won't do anymore.

 

[tbrcktch]

Yes, the mixture adjusting screw.