Ticking and Smoking After Leaky Injector Install

[logscool]

Is it possible you might have a leaky/damaged injector O-ring, or corrosion or damage of the cylinder bore that the injector(s) go into is preventing a good seal? As the engine warms up the the metal expands altering the diameter of the hole slightly and the o-rings become somewhat softer/pliable to conform better to an imperfect or damaged bore or damaged o-ring that no longer fits perfect, between the two (heat and pliability) the leak seals up and a lean condition (and the tick) disappears.

Could a small leak at an o-ring, maybe not necessarily enough to make the cylinder dramatically lean, disturb the injector spray pattern enough to cause 'unbalanced combustion' ...think along the lines of gasoline direct injection running in 'lean mode' where the fuel mix within the cylinder isn't evenly distributed across the air withing the cylinder. With an 'uncontrolled distribution' as such I could imagine knocking/ticking/pinging to be a plausible effect. Most air leaks we are accustomed to dealing with are upstream - not right up within millimeters of the intake valves.

So you are saying there is a small vacuum leak at the injector which causes an improper or uneven fuel mixture? I don't see how this would cause the ticking noise. If it was causing an engine knock the ECU would retard the timing until it went away or throw a check engine light if it can't, right? Also the injector seals are all brand new and I lubricated them with silicone before installing.

I'm thinking it's definitely something mechanical in the engine and as it warms up and tolerances adjust the noise goes away.

[RickHaleParker]

Also the injector seals are all brand new and I lubricated them with silicone before installing.

It would take 30 seconds to test his theory.

Spray starting fluid around the injectors when the engine is cold and running. If the engine surges, his theory is confirmed.
Nothing ventured nothing gain. You don't have the answer now, if his theory does not pan out, you lost nothing.
If his theory does pan out, you will have a answer and will know why you could not find it.

[logscool]

Thanks for that test suggestion. I will go ahead and do that in a couple weeks as I am out of town for now.

[mrbrian200]

If the tick was never ever present before messing with the injectors, then suddenly the noise appears immediately after some or all of these were switched out it's got to be something directly related to them. Nothing else gets disturbed just pulling the fuel rail. Unless you drove it a really long time with a bad/leaky injector in which case you could have a sticky valve from carbon buildup or a damaged exhaust valve guide after running lean. But if it never made the noise before the day you switched injectors my opinion is that's unlikely.

[tardcart]

it sounds like he is not using the car, so I think its just a coincidence. a sticky valve would do that too, good idea. But would that go away when warm and then return?

[logscool]

Yes I am not using it at the moment but I have put about 400 miles on it since this happened and will be using it when I'm back. I don't think it's a coincidence as the noise appeared immediately after the faulty injector was installed and removed.

I really think it's related to the fuel that was dumped into the cylinder when started with the faulty injector. The noise has continued even as I have switched out the injectors since then, at first back to the old ones and then back to newly cleaned ones after getting a replacement.

I will definitely check the leaky injector seal theory when I return, but I think it would cause very different symptoms.

[tardcart]

I guess the sticky valve is best theory so far. what to do about that? snake oil? I had a bunch of old gas and figured a 86 chevy truck can burn anything. really stank and then two valves stuck and bent the push rods. It was like burning varnish. so excess gas could cause sticky/carbon build up in this case too.

[logscool]

I don't think that starting it a couple times flooded with fuel would have caused carbon build up. Gasoline is actually a pretty good solvent for removing carbon. That's part of why port injected engines usually have cleaner intake valves. Also carbon build up has to be built up so it does not happen quickly. It could be that the gasoline may have dislodged some carbon and caused issues getting stuck somewhere.

[tardcart]

agree, so we are left with normal. all mine tick to lesser or more extent. these are not quiet engines.

[mrbrian200]

it sounds like he is not using the car, so I think its just a coincidence. a sticky valve would do that too, good idea. But would that go away when warm and then return?

Yes, as the valve guide warms up it expands and releases it's grip on the valve stem. Snake oil maybe, or just run a high quality synthetic oil in it and the issue may resolve on it's own over time. I would hear a 'light tick' sometimes when cold on my '06 i5 2.5L when I first bought it. After the switch to full synth and feeding it top tier premium gas I stopped noticing the noise somewhere in the 6-9 month time frame, or about 2 years ago.

Edit.. At first I was using Amsoil signature. They they had a price increase (from~ $10/qt up to around $13), and as the Volvo uses over six quarts as opposed to 4.5 that my previous car needed I decided Amsoil pricing was getting a little out of hand and researched other Synthetic oils. DIY oil change including a filter was approaching $100 (ridiculous!) The more I think about it, it was shortly after I settled in to using Quaker State Ultimate Durability that the tick went away, stayed away and I've never noticed ever since.