'96 850R Very low mpg, very low power.

[erikv11]

You can get a VERY good idea of where the cams are, without taking off the distributor and the CPS, by just looking at the triangles formed by the cam sprocket bolts. When the sprockets are on the mark, the crank should be on the mark, the intake cam should have the triangle base up, and the exhaust cam should have the triangle base down.

Look at the first pic from rspi - you can see the triangles. The slot on the back of a cam is exactly parallel to the appropriate edge of the triangle on the front. Will not be affected by someone moving the sprockets either, the relationship is to the bolt holes in the front of the cam, not to the sprocket.

The discussion of cover marks is interesting but as far as figuring out what is going on with the car's timing, square one is to check if those three marks (sprockets, slots, crank) are in time. Can't really discuss anything until square one is established.

[bmessina]

Just confirming - Are these the marks I should be lining up on the crank?

[erikv11]

You want to line up the upper square on the block, with marks on the pulley teeth. Either one notch down in the valley between the teeth, or two notches up on the peaks. I do not see either of those crank pulley marks in your pic. I am not familiar with the lower stamp mark in the bottom red square there.

[erikv11]

There are a lot of pics of timing marks on the forum, here is one that shows the crank mark pretty well:
https://www.matthewsvolvosite.com/forums ... =1&t=52960

EDIT: and check out post 28 in this thread, there may be others in there too:
https://www.matthewsvolvosite.com/forums ... 3&start=28

[bmessina]

Oh, is it not visible unless the pulley is removed?

The "squared" (I tried to draw a circle) notch is on the pulley, there's one on the backside of the pulley and one directly opposite on the front.

[bmessina]

Found a picture that makes more sense to me, in terms of the notch/mark on the crank sprocket... I'll try again tomorrow if I have time.

[erikv11]

No you can see the marks on the car, that #28 is just a real nice shot of where they come from. But the marks are very small, can be a PITA.

Yes, that pic you posted, you can barely see it but there is one notch down in the valley. Here are a couple more like that:



Here is a pic of the other style, where there are two notches up on the teeth instead of one in the valley:

[bmessina]

Haven't gotten back to the timing, but something weird happened. I had a flat tire and the battery about died today. Wife came out to jump me, and when I got the 850 started it's... not 100% but 2-3x better than it was. Revs more freely, and actually feels good throughout the rev range. I have changed NOTHING else. Just jump started it.

So... yeah.

[bmessina]

Ok - Right when I started it last night it seemed to be significantly more excited than it was on the drive home. First sign of this was that immediately after starting it jumped to 2k RPM and held that for about 20-30 seconds. After that it tapered off to a normal idle. It hasn't been doing this for the last few months, it starts and goes right to normal idle speed.

It felt like the improvement held into this morning, though it still will not rev above 4.5k rpms in gear.

[erikv11]

I didn't read through the whole thread again, don't know what all the symptoms were but when an engine "gets better" without doing anything, it usually indicates a small vacuum leak or an intermittent sensor problem (e.g. MAF or TPS). Which means it will come back, so keep an eye out for it.

Not sure if you are serious about swapping in an ECU, but for the record any turbo ECU will be just fine.

A 96 or 97 ECU would be best to avoid CEL from potential emissions differences (EGR or SAS) between the swapped vehicles, but otherwise the only difference in the R ECU is that is has an extra 18 hp in the top of the RPM range. Without a stopwatch it us very difficult to notice the 18 hp difference between an R ECU and a regular T5 ECU.