VVT solenoid, misfire, lean condition, smell gas

[scot850]

No vacuum???

[scot850]

Try running a tank of gas with Seafoam through is and see what happens. If you do a cylinder compression test, that is the simplest to diagnose piston ring or valve. Check compression with cylinder dry. Add a couple of teaspoons of engine oil into the sparkplug hole and test again. If no change in compression, then valve issue. If compression goes up, then piston ring issue.

Like abscate suggests something like Marvel mystery oil added to the cylinder and left over night might be good enough to loosen a stuck ring, or even run Seafoam in your engine oil for about 100 miles and then do an oil and filter change and you can test the compression to see if it improves.

Neil.

[Chuck W]

I'm assuming the PCV system is off for a service in that pic?

[FireFox31]

My main question now is:
What engine part could function poorly from idle to 5% throttle but function well from 6% to 100% throttle?

I've got a bad coil in Geronimo and that misfire feels much more violent than my misfire. Feels like I've only got partial failure, perhaps something sticking (like you've all said), compared to the total spark failure on Geronimo.

There may be a vacuum leak but the vacuum system remains a mystery to me so I don't know how to check. The brake booster vacuum check valve recently failed so I'll replace it. I'll research how to diagnose this system.

To apply the Marvel Mystery Oil, do I remove the plug a pour a little in its hole? I'm due for an oil change in 3k miles (trying 9k total per Blackstone) so I could try Seafoam in the oil, then change. Compression looked only a little low on cylinder 1 so I'll run the test again and add oil as you suggest.

I'm tempted to take off the head to check the valves, seals, etc like abscate did. The car has oil consumption, coolant loss, and an overall lack of performance, so I'd love to identify and resolve the sources of those problems.

Yes, the PCV was off for that engine picture. I was surprised to see so much oil caked under cylinder 1, the alternator bracket, and the A/C compressor. The PCV was barely clogged so it only contributed a little. Behind the belts is clean. When I removed the VVT solenoid, I saw evidence of oil leaking from it, caked on the cam pulley.

[FireFox31]

I took the car to a local Volvo specialist for a smoke test. He reported smoke gushing out from the intake manifold around cylinders 1-3. Somehow, the manifold must have worked its way off the block, hurting vacuum and/or air mixture. Any ideas how that could have happened?

This loose manifold issue happened once before. I removed the manifold for the PCV job, reinstalled it temporarily, than removed it again to have it cleaned. During the few weeks between those removals, oil had stained the manifold gasket and leaked down the front of the block. I'm tightening the bolts to the torque specified by the Haynes so something else is wrong.

A machine shop cleaned the manifold by soaking, sand blasting, and painting it. Paint may not have caused the failure if it was working loose in the interval before I got it painted.

I have a new gasket on hand. I'll remove the manifold, clean any vaporized oil off the block, and check the manifold for a flat mating surface. What else could I check while I have it all apart?

[454cid]

Is there a sequence for tightening the bolts that you may have missed? How about dirty threads in the head or bolts throwing off your torquing procedure?

Maybe check both surfaces for burrs. Any chance the replacement gaskets are thinner than original?

How are you checking for flatness? Maybe it's warped?

[Chuck W]

I wonder if a hose or something got pinched in between the manifold and head?

[FireFox31]

The Haynes doesn't specify an intake manifold bolt tightening sequence, just a spec of 20 Nm / 15 lbft. I can try to check VIDA but I'm not really sure how to find the procedures in there. Maybe tightening a few bolts with a U-joint delivered less torque.

I will check flatness of the manifold by running a metal straight edge over it. I'll look for burrs and more. Perhaps oil staining from the intake leak will reveal where there's a breach.

[scot850]

Did you check the inlet manifold is flat across the flanges?

Neil.

[FireFox31]

I finally got to check the intake manifold bolts and they were all torqued to spec. There is wet black fluid down the front of the block beneath cylinder 1 while all other areas around the manifold look clean. This matches what I saw when I did the PCV job, finding black staining below cylinder 1 and, oddly, behind the alternator bracket. Old pictures from 8/21 attached.

It is suspicious that cylinder 1 is reporting the misfire and there's oil leaking all around cylinder 1. What could be causing this leak?

I never did track down what caused that staining so perhaps it's still leaking. Maybe I did something wrong with the PCV install causing a leak. I still hear the chirping of air escaping which I assume is from the fuel injector o-rings not being lubricated upon reinstall.

Also, I'm loosing coolant even though I'm not driving the car. The level dropped about 1/4" in the tank in 1-2 months since I last checked it and last drove it. Of course, I assume this car can be fixed and refuse to believe all of these leaks are a major problem.