Hi to everyone!!!



Bare with me, this is my first post. I have reached the point of frustration while trying to troubleshoot my V70. Here are the facts:

• I just replaced all five ignition coils with brand new Bosch coils.
• I just replaced all five spark plugs with NGK Iridium plugs.
• I just replaced my cracked intercooler with a new one, (Sweet turbo's back).
• I drove to work on my hour commute, the car was running better than it ever has during my ownership.
• On the way back from work, I was passing a car going uphill (Yes, I was on the throttle a little bit...I just got my damn turbo back.) All of the sudden I get a Check Engine light and the car starts shaking from misfiring. I swear I smelled a faint, but nasty burning smell briefly.
• $#@&!!
• Get home, run the code and get a P0303 code, "Cylinder 3 misfiring".
• Pop all coils off one at a time and inspect for cracks to confirm which cylinder is the problem visually and by listening to idle changes, confirm it is cylinder 3 and confirm that cylinder 3 coil is not the problem by switching it with another coil and obtaining the same result.
• Switch out cylinder 3 spark plug...no improvement. Test spark of plug by watching it arc outside the block.
• Test cylinder 3 coil's wiring and obtain the same voltage and frequency of other coil's wiring, therebye eliminating the wiring as the problem.
• It's not spark so I move into fuel supply. Remove injector #3 and see nothing wrong, but spray with carb cleaner and switch with another injector anyway. No change, cylinder 3 is still the problem and fuel supply has been eliminated as far as I know?

So here I am, my baby is sick and I think it's come down to compression. This is not my area of expertise, I've only tested compression once before, and then my compression tester was stolen with my tools. I'm getting another one tomorrow and will test.

My questions are these:

Have I missed something in my analysis?

I believe I will find low compression in cylinder 3, does this mean I burnt a valve, or piston rings? There is no clanking or ringing or rattling, and the exhaust is normal except for a rich running smell.

Any expert help is greatly appreciated,

Thanx

 

Sounds like you're on the right track; ck the compression on all the cylinders and report back.

If #3 is low on compression, squirt just a few drops of light oil in there and ck again; if it goes up significantly, it's the rings; if not, then valve(s).

Also get yourself a decent compression gauge; the cheap ones tend to be in-accurate.

BTW: didn't catch how many miles are on the clock?

 

Thanks for your input Gdog, I just got some time off from work to focus on this thing. I will be testing the compression tomorrow. I'm assuming that you mean to squirt the oil into the spark plug hole, correct? I will use your advice when purchasing the compression tester, thanx. The car has about 137,000 miles on it and I have only owned it for about the last 30,000, so the car's history before that is a mystery to me.

I'll be sure to post the results from the compression test as soon as I have them.

Thanx again for your time.

 

Performed the dry/wet compression tests last night. Cylinders 1,2,5 were 160 psi. Cylinder 3 was 0 psi, and Cylinder 4 was 140 psi. The wet test of Cylinder 3 resulted in no change. Additionally, I pulled my dipstick out to find a mess of bubbly, chocolate milk oil, with sludge in it. The expansion tank and oil both smell of gas, as well.

I have made my own determination that at least the head gasket is done. Do you think a valve is burnt as well? Anyway, ordered head gasket kit and a new set of head bolts today. I recently downloaded and fixed myself a copy of VADIS, so I will perform the work when the parts get here.

Does anyone know where I can find some examples of homemade Volvo tools necessary to complete this job?

 

Excellent head gasket writeup is here:

https://volvoforums.com/forum/volvo-850-16/tutorial-1996-volvo-850-head-gasket-timing-belt-water-pump-etc-lots-pics-44879/

 

Wow; that's a real bummer man...

If it were me, i would wait until you get it apart before you order any parts; you just don't know what you're going to find at this point....

 

Got the engine apart a couple of days ago. Cylinders look good, no discoloration or scars on the walls. You can still see the original honing marks on the walls. There was a 1/2" hole in one of the exhaust valves on cylinder 3. Took the head down to a machine shop in Reno. The guy I talked to said he's going to do a head job including a vaccum test, cleaning, replacement of any needed parts. He noticed a spot where my head gasket had blown on cylinder 3 (there was a dark color where there should have been nothing). Because of this, he said that I should resurface the head, I told him that was fine, called around and pricing seemed really reasonable considering that other shops recommended these guys. I would too, (A plus machining in Reno), they actually showed me how to do some steps to save myself some cash as they are overloaded with work.

My head should be ready mid to late next week, but I have a problem. When I was taking off the camshaft cover I built my own cam locking tool similar to the one that I found on the link that bw77 recommended above. The problem is that I have variable valve timing, which differs from the tutorial provided. My intake cam's slot was exactly horizontal when I put the homemade locking tool on, but my exhaust cam was tilted slightly clockwise in relation to the intake cam. To fit it on the locking tool, I had to rotate the exhaust cam counter-clockwise slightly to make it work.

The problem here is that when I took the VVT unit off (attached to the exhaust pulley), I was amazed to find that the pulley is not keyed to the camshaft in any way. There are only four small holes. I marked the pulley at the top, but how do I align it with the camshaft when I put this thing back together?

 

Surprised no one has responded to this... I would help but am not familiar with VVT on these; never had one apart...

 

There are quite a few threads about VVT on this forum, the key to finding them is to use the tag search
on the search page. If you search for the word VVT if comes up with nothing, because the word is too short.


Also, this thread on another forum discusses the VVT:

http://volvospeed.com/vs_forum/index...t-on-99v70-t5/