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Old 04-15-2020, 02:56 PM   #1
MisterBLC
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Default '96 960 - Engine Flooded after sitting for a few weeks

Folks,

After a few weeks of sitting thanks to Covid, I went out to start my '96 960. The battery was weak but it turned over and then fired for a second or two and then died. I then tried to start it again and it now cranks like it has lost all compression. I am assuming this means it is flooded, but I have no idea why this would be. Anyone experienced a similar issue? I am trying to understand what could have caused the engine to flood so quickly, especially in all cylinders. Bad ECU? Busted pressure regulator?

I am going to go pull the spark plugs and check them next to confirm flooding. If it was flooded, I am going to clean the plugs, let the gas evaporate, and then squirt a little oil into each cylinder and crank it to ensure I get compression back, then try to diagnosis why I am flooding. Any help or ideas would be great!

Thanks,
Brian
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Old 04-15-2020, 04:45 PM   #2
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Check cam belt/timing?
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Old 04-15-2020, 05:06 PM   #3
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Cam belt timing is my worst fear, definitely on the list. I assume crank it to TDC and then ensure that the cam gears are lined up?
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Old 04-15-2020, 05:28 PM   #4
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It's an issue with the lifters. Typical if the engine is shut down soon or immediately especially when cold. Needs good voltage and several long cranks with pauses inbetween. Sometimes I've had success with short cranks.

Slowly the lifters start working again and compression returns cylinder by cylinder. Keep your foot on the pedal because it will need gas when it finally gets going. A bit of gas helps too when it sounds like it'll run. You need to keep it running it at least a minute or so, or up to temp.
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Old 04-15-2020, 05:28 PM   #5
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Oops, double post.
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Old 04-15-2020, 06:18 PM   #6
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Originally Posted by Lankku View Post
It's an issue with the lifters. Typical if the engine is shut down soon or immediately especially when cold. Needs good voltage and several long cranks with pauses inbetween. Sometimes I've had success with short cranks.

Slowly the lifters start working again and compression returns cylinder by cylinder. Keep your foot on the pedal because it will need gas when it finally gets going. A bit of gas helps too when it sounds like it'll run. You need to keep it running it at least a minute or so, or up to temp.
Wouldn't the valves refuse to open if the lifter's were not filled with oil? I can't figure out how non filled lifters would cause low compression.

I will say that I fired up a B6304 that had sat for over a year and the lifters did tick for like 15 minutes. It cleared up when the engine was fully warm with fresh oil.

My guess is that OP has a snapped timing belt and probably bent some valves. Now it won't build compression and spins over easy.
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Old 04-15-2020, 06:42 PM   #7
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It could be the lifters or sticky valves. Keep on cranking... Or pull the one bolt to remove the timing cover for a peace of mind.
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Old 04-15-2020, 07:01 PM   #8
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Wouldn't the valves refuse to open if the lifter's were not filled with oil? I can't figure out how non filled lifters would cause low compression.
In this kind of situation lifters get stuck and valves stay open a bit all the time. It's a common thing with 5- and 6-cyl whiteblocks with hydraulic lifters. I know of and have had to start such engines a lot(tens) during the years. The less maintenance and wear the more likely.

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It could be the lifters or sticky valves. Keep on cranking... Or pull the one bolt to remove the timing cover for a peace of mind.
Valves won't stick like that. But yeah, it's a quick check to open timing cover.

Last edited by Lankku; 04-15-2020 at 07:09 PM..
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Old 04-16-2020, 12:00 AM   #9
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Ok pulled the timing cover...no snapped belt and everything looked OK, thank goodness. Pulled a spark plug and didn't look fouled, so I cranked for a good while with the injectors disconnected to get oil pressure flowing. I put the injectors back on and it fired up, with lots of ticking to start and some oil smoke (250k miles on this motor and she burns a little oil). But she smoothed out, stopped smoking, and ran fine after a minute of running. I also couldn't explain how the lifters would cause low compression, but definitely seemed like that was the culprit (plus the wear on the motor).
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Old 04-16-2020, 01:47 AM   #10
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If the intake valve isn't opening there is no air to compress.

I had a training excercise recently on misfire diagnosis and we had no compression on one cylinder on a car with only 10 miles on it. Hmmm, the intake rocker arm adjuster was backed all the way out= no intake valve lift= no compression.

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Old 04-16-2020, 03:50 AM   #11
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Hydraulic lifters open the valves even when they have totally bled down. That is not what was going on.
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Old 04-16-2020, 01:57 PM   #12
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If the lifters are deflated the valve will open, but not all the way.

Valves CAN stick open and cause zero compression on a cylinder. I work on a certain generation engine where sometimes it sits for months/years and the valves stick open from carbon deposits. We put a battery charger on it and crank it until it fires up and we try not to burn up the starter. After we get it running we do a valve cleaning (fuel induction service. Aka seafoam) sprayed in the throttle and an oil change.
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Old 04-16-2020, 03:08 PM   #13
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Seems more likely it was the rings, if you google "whiteblock lawnmower syndrome" you'll find a lot of posts talking about it. TLDR is that it seems like these cars can wash down the cylinder walls with fuel if they're started after sitting for a while and it stops the rings from sealing.
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Old 04-16-2020, 04:17 PM   #14
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A customer of mine has a 240 that was doing the fuel wash, low compression syndrome big time. It would barely start. The back 2 cylinders were 100 psi and 105 psi. The front 2 were 120 psi each.
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Old 04-16-2020, 06:22 PM   #15
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I had a 4 cylinder 2013 Corolla recently lose compression on the middle two cylinders. Down to 60 psi. No start. Tons of cranking got it to start again. I didn't get a chance to figure out why. It's been driving fine for weeks now.


16V head conversions here have had issues with lack of compression on first start. Sticky valves or no oil in the lifters are a possibility.

Without doing a leakdown test, it's a guess.
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Old 04-16-2020, 08:12 PM   #16
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Quote:
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Valves CAN stick open and cause zero compression on a cylinder.
This issue with whiteblocks can occur even with the car sitting overnight. Some(rare) cases have been with warm/almost warm engines. You might not have to do anything else than start the car, move it a couple car lengths or run 20-30 seconds, shut off and next time cranking there is no compression. Doesn't matter if you crank it immediately or next month.

If valves would stick, then I should have had some in the whiteblock heads I have on the shelf. And those can sit there for years without cleaning until it's their time. Never had any stuck valves, all move freely.

There are also cases in which people have towed(manual) the car because cranking has not given enough rpm. The better chances of starting when there is good battery and good rpm.
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Old 04-17-2020, 01:31 PM   #17
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Quote:
Originally Posted by Lankku View Post
This issue with whiteblocks can occur even with the car sitting overnight. Some(rare) cases have been with warm/almost warm engines. You might not have to do anything else than start the car, move it a couple car lengths or run 20-30 seconds, shut off and next time cranking there is no compression. Doesn't matter if you crank it immediately or next month.

If valves would stick, then I should have had some in the whiteblock heads I have on the shelf. And those can sit there for years without cleaning until it's their time. Never had any stuck valves, all move freely.

There are also cases in which people have towed(manual) the car because cranking has not given enough rpm. The better chances of starting when there is good battery and good rpm.
The range of the plunger travel is limited in a hydraulic lifter. When they leak down You might loose 3mm of valve lift. The valves don't stay closed.
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Old 04-17-2020, 05:33 PM   #18
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The range of the plunger travel is limited in a hydraulic lifter. When they leak down You might loose 3mm of valve lift. The valves don't stay closed.
I haven't said that valves would be closed. If they would be, there would also be a lot of resistance when rotating the engine.
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Old 04-17-2020, 08:39 PM   #19
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And to add one more thing. Years ago I've had this happen to two customer 960 whiteblocks where fuel does not play a role. Cold start(above freezing), drive inside, shut off immediately, new headgasket, first crank with unplugged injectors for oil pressure and no compression. Basic routine, cranking with short pauses until it fires up.
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Old 04-22-2020, 11:39 AM   #20
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All this guessing is driving me crazy. The no start/no compression symptom comes up often, but nobody has a reasonable answer. Understandable that any car that sits for a year and a half would need some special care when starting up. But for an everyday driver engine to lose compression, only 1 thing would cause it. That would be valve(s) stuck open. Likelihood of ring failure (injector leaking?) is pretty far out there, and even so there would not be a major compression loss after several hours or a couple of days. So we are really looking at stuck valves.

To those who blame lifters, please review your engine basics. The operating range of lifters is small and they will not prevent a valve from closing. It is more likely that a faulty lifter would keep a valve from opening fully, but in that case the engine would still start.

That brings us back to stuck valves, not lifters, not timing belts, and 99.9% not faulty piston rings. Stuck valves can be easily confirmed by removing the valve cover.

Narrowing down further, valves can stick for 2 reasons. 1, they are bent due to timing problems in an interference type engine And 2, the valve stem is glued or "welded" to the valve guide. We will dismiss the bent valve condition, which would be obvious, and which would NEVER allow the engine to start without a major overhaul. Going further, we can reasonably say that it will be the exhaust valve(s) that will stick due to high temperatures, the need for cooling through the guides, and the need for lubrication on the stems.

So finally what causes valve stems to get stuck in the valve guides? Some possibilities:
-Poor design of the cylinder head - not enough oil to the valve guides (design department)
-No operating clearance between stem and guide, incorrect installation @ factory, etc.
-Mismatch between the valve material and the guide material. (design department)
-Exhaust valves cannot dissipate enough heat through the guide (design department)
+++In conjunction with+++
-Incorrect oil. Some synthetics (i.e. Amsoil) can clog the guides because they do not burn at engine temperatures.
-Dirty oil

In my personal opinion, the real fix is to select a better combination of valve and guide materials. If alternative parts are not available, ream the exhaust valve guides slightly to increase clearance and use standard or semi-synthetic oil. That's the way I see it.

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Old 04-25-2020, 01:41 PM   #21
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My explanation is that with cold oil the lifters get stuck to max lift position and it takes time(cranking) for them to get set. All that matters is that engine is cold, excluding few cases. Whether its overnight or years the result is the same if engine dies or is shut off soon after starting up. After that there is no compression in all cylinders, not just in one or two. And that happens every time. And there is always compression when cranking and starting up before this.

This issue has never occurred on whiteblocks with solid lifters and I have never seen a stuck valve in any engine though my experiences are limited to Volvos. Neither of the two headgasket jobs mentioned had valves open when the head was off.

It's not also a case of flooding the engine. When the compression returns the car will fire up and run even if the injectors have been connected the whole time.
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Old 04-26-2020, 07:15 PM   #22
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Getting into the basics of valve lifter operation is necessary to put this theory to rest. Older service manuals used to specify a leak-down rate for a working lifter using a special leak-down tool. A certain amount of weight pressing down on the lifter should take x number of seconds to collapse, and so on. Hydraulic lifters do not "stick open". Even if ALL the lifters in an engine were collapsed, the engine would still start and run. Lifters are just cylinders that hold oil, with a small hole that lets the lifter leak down just enough to take up valve lash.

With the engine stopped, any open valve will apply the force of the valve spring against the lifter plunger, forcing the remaining oil out of the lifter's cylinder and thus collapsing the lifter. The lifter cannot pump up again until engine oil pressure builds up at the next start.

But, since the operating range of the lifter (the difference between a collapsed lifter and a fully pumped up lifter) is small, a collapsed lifter will tick until engine oil pressure builds up, but it will still open a closed valve. Thus we have to focus on those valves that are open when the engine stops. Those are the valves that can remain open if they are stuck, and are not affected by the operation of the lifter or pushrods. Back to the question about why the valves are sticking. That's a pretty serious design screw up and I imagine Volvo would be embarrassed to have it widely known. Just a guess.

The theory that raw gas flushes oil from the cylinders, causing a no compression situation, is really unlikely. Of course after minutes of straight cranking the cylinders are no doubt a little damp, but washed completely of all oil? I doubt it. But the question still remains, why didn't the engine start within the first couple of cranks? The no compression condition exists right away because of stuck valves, not lifters, not timing belt and not raw gas dumped into each cylinder. The raw gas in the cylinder problem is really limited to carbureted lawn-mowers and 2-stroke single cylinder engines.

-L
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Old 04-27-2020, 03:20 PM   #23
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But the question still remains, why didn't the engine start within the first couple of cranks?

-L
Just like it did happen with OP, engine always fires up at first. After that no compression happens if the engine dies for a reason x or is shut off soon. If the engine is going to die and you are ready for it(you know it has happened to that engine before), you can keep it running with gas and after that it'll settle and run normally.

When taking the head or cams off the lifters seem to keep the oil inside the hydraulic unit and no compression occurs after assembly. But only if the engine has died after cold start or it has been shut off soon(start and drive from outside to the lift). It's a pretty marginal problem considering how many engines there are but still an annoying one.
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