If the check valve goes bad (part #5) it allows hot exhaust to travel backwards in the system and can easily melt down the valve. You'll need to check out that valve to see if it's leaking.
Start the engine and see if you can feel hot exhaust coming out the open end of the tube. If you can feel a flow of exhaust you need to get the check valve too.

It's part of the emissions system and injects air into the exhaust to help the catalytic converter better clean up the gasses in the exhaust. It helps the cat run hotter (proper temperature) so it functions better.

Part number #13 in this link

http://www.irollparts.com/parts/1994...iagram=9709190

 

Ok,
so, as it sits, not only is the cat not working as good as it should, but some exhaust gas is going into the engine bay. That gas is also not getting read by the O2 sensor, maybe further throwing off the computer's reading?

I will check the valve as you said...but judging by the pattern of how the part melted Im sure it is bad as you suggest. Its totally melted on the side going to the check valve, and the other end is slightly melted. The hose on that side was somewhat melted on and a pain to get off.

Im making a shopping list now

This baby only has 130k. If I can get all the neglected things out of the way it will make a good car. I just wish money wasnt soo tight right now!

 

If you're going to make a salvage yard run make sure to bring some penetrating oil, not WD40. If you don't have a preference, PB blaster works great.

 

I have cleaned the idle air control valve but id didnt fix my cold start issue. The car still has to be revved to 2k and held there for about a minute before it will idle on its own.
Any other ideas?
Oh, and is there a way to test the IACV to see if it functions?

 

My guess would be a bad coolant temp sensor located in the thermostat housing.

 

Is there a way to test it?
I meant to answer the question earlier, but while my temp only gets upto about 4 O'clock, it does start below the white mark when cold. Its almost completely vertical pointing down when cold. I think it was you who said that its possible the gauge needle was put on wrong or something like that. It does only take 3-5 mins to warm up to 4 O'clock.

does the temp sensor effect what the IACV does?
And could my exhaust leak effect the cold start?

I know Im asking a ton of questions....but I need to narrow down the parts that HAVE to be replaced for it to run decent as cash is very short. I want to get this car to a full stage 0 eventually, as it should last me a good long time given the milage and over-all shape.

 

I got 1 from the junk yard for $7. There is a way to test it with an ohm meter but I'm not sure how, you'll have to google it.

 

dang, $7, thats awsome.
As I had said, the junk yards around here suck. They dont keep older stuff and they think everything is made out of gold.
But I will call around and try anyway.

any idea what age and model range coolant temp sensor will work? will the turbo cars and those of later year 850 models use the same one?

I need to find a good emission shut off and check valve as well.

The vacume lines are an odd size as well (at least Napa and VIP didnt have anything the same size/type) and a couple of them could stand to be replaced.

 

850's and S/V70's. 1993 - 1998.

 

Thanx!

Do you think it would be possible to get a generic flex pipe from VIP, mount it to the nipple of the manifold (I broke the used flex pipe I was given, and then saw that with the flex pipe off the manifold has about a 1-1.5 inch round part) and then cut the downpipe just above the 02 sensor and mount the otherside to it? When I say mount, I mean a standard U bolt.
The leak is bad, wicked annoying and even if I could find a used manifold with good flex pipe I dont have the money to pay someone to install it. My efforts thus for to remove the manifold from the car have failled as I couldnt even get the heat shield off. I havent even tried the 4 bolts attaching the flex pipe to the down pipe. Considering the used manifold broke the head off a bolt in the same part, Im worried if I try to remove the bolts myself the same will happen and then Id be really screwed.

To bad there is no exhuast wrap or patch that could work on the flex pipe. Just something to get me 6-8 months untill I could afford to replace it.

 

I attempted to replace the flex pipe today.
It didnt take long to figure out that I couldnt get to it from the top or underneath to cut away the bad stuff....and it is still attached fairly solid.
Part of the problem from the top is the heat shield which has 2 bolts that stripped and I cant get off.

So I bought exhaust wrap and wrapped the crap out of it as best I could. This only cut the noise by a touch. To be honest, I almost wonder if the issue is a manifold gasket and not the flex pipe!

With the car on ramps I also found the tail pipe leaving the muffler is toast...holes right at the exit of the muffler and the last foot of the tail pipe is basically missing. That contributes to the exhuast noise some.

I have to figure out some way to get the heat shield and manifold off myself...its the only way to get the bad stuff out of there and replace with some good stuff (even if it is used)

A volvo is not one of those cars that can have a poor sounding exhaust. it just doesnt suit the classy look of the car. On my pickup or old civic I wouldnt have cared much. But I want the 850 to sound as good as she looks.

 

last night I took multiple tools to the heat shield over the manifold. I finally got it off. Now with the motor running, I can see the exhuast leak is NOT the flex pipe! Its the flange joint just past it. I havent figured out yet if it is the gasket or if its just behind the flange on the pipe. I have to clean up the area and check again. At any rate, this should be easier to patch.

But Ive found also that the tail pipe of the muffler is totally shot. Holes right at the exit of the muffler and the last foot of the pipe is gone all together.

For now, I will have to leave it as-is. Unless you guys know of a cheap, aftermarket, muffler that would be easy to bolt in place and not cost me $150 or more.



I also bought a used (cleaned and tested) AICV and a new coolant temp sensor. Hopefully one of the 2 will cure my cold start issue.

If I can fix the loud exhaust and cold start issue, next on the list is the upper strut mounts, man they are loud!

 

There have been posts on just cheap exhaust but so far there there isn't any know fitment anyone has come up with. I have seen some fairly clean replacements of the muffler but it's going to take a welder from what I remember. Part of the problem is it's a system that's metric instead of parts clamped together that are in inches. Since they intend for you to by a new stock part of the system there isn't any thought or design put into places where you can patch it. So the pipe isn't a standard diameter and in places it isn't even round as it's been flattened for clearance or makes curves.

Not sure if someone will come to you here on this one, you might need to do a search as this doesn't come close to the threads title.

http://www.matthewsvolvosite.com/for...hp?f=1&t=35675

http://www.matthewsvolvosite.com/for...hp?f=1&t=30844

https://volvoforums.com/forum/volvo-...exhaust-62768/

 

thanx
didnt realize its not standard diameter.

last year I had a 850 turbo and tried putting a Thrush $60 muffler on it. The muffler was constructed fairly well.....but sounded pretty bad. MUCH to raspy. I dont mind louder...if its deaper tone.

Ill scan youtube and see if I can find video of some low cost aftermarket mufflers that I like the sound of.

I did manage to get that thrush muffler mounted to the stock pipe. It was tricky tho.

I wish there was something left to the stock pipe leaving the muffler. The muffler itself is fine, but the exit pipe has a big hole that diverts gasses and you can hear it when you get on the throttle. If the hole were 1-2 inches further from the muffler I could make do with a patch.