1998 V70 T5 Manual Emissions Issues

[Seaway]

So, I bought a 1998 V70 T5 Manual that is in really nice condition from a member here. It has some slight modifications including SAS delete, a stock 1999 downpipe mated to and IPD Cat back exhaust. It sounds wonderful, pulls like a freight train and handles on the H&R lowering springs like it is on rails. I love it.

It failed Virginia emissions inspection miserably. High CO and HC. It was throwing codes for both O2 sensors so I am in the process of changing them (need to retap the bung for the rear sensor, not a big deal, I can see the threads and what needs to be fixed). I am hoping once they are in, the emissions problems will be solved and I can have the car retested. If it doesn't pass at that point the next step would be to have a new cat installed, I guess. If I spend the state mandated $780 in repairs at a certified shop, I can get an emissions waiver good for 2 years. This is almost sounding like the best plan. Take the car to the shop, have an IPD exhaust put on and sell the downpipe and exhaust I have.

Anyone have any Virginia emissions experience? Anyone have any emissions suggestions at all? I can't even register the car here until it passes the emissions inspection.

[misha]

If you have codes for BOTH o2 sensors,it usually means that you have a vacuum leak somewhere.

They can't both be bad in the same time.

What codes do you have?

[Seaway]

If you have codes for BOTH o2 sensors,it usually means that you have a vacuum leak somewhere.

They can't both be bad in the same time.

What codes do you have?

Sorry, I should have included the codes. P0131 and P0141. The rear sensor was cross threaded and not fully seated when I went to remove it, so I am unable to reinstall it as the threads are shot so I will clean up the threads in the bung and put a new sensor. I may also change the front so I can have a confirmed baseline. I checked all of the vacuum lines at the intake hose, TCV and turbo and everything back to the vacuum tree looks good. I will double check those unless there is an obvious line I am missing?

I am also going to swap in the new MAF on my other 1998 V70 and make sure that is not contributing to the problem. I will be checking the plugs, cap, wires, etc but all of these components only have about 7000 miles on them. There was an unexpected and unexplained stall when I first picked up the car and after that the idle was jumpy for about 30 minutes in traffic. Basically it simply quit running at a sop light. It fired right back up, however. After that I was on the highway for about 4 hours and had no issues at all. The idle was solid at toll booths and rest stops and the car was extremely responsive through the gears. Back in stop and go traffic when I got it home it was great with no issues.

[misha]

That jumpy idle could be from bad Maf.

When it's bad,idle is going up & down from 500-1200rpm and after a while it settle,but exhaust smoke is black and smells on a raw fuel.

When front o2 sensor is bad,there is a black smoke from the exhaust and ubnormal fuel consumption along with a smell of unburnt fuel.

If your rear o2 sensor is seated correctly in it's hole,i guess that you would not have the code for it.

Another thing that could affect emissions is bad fpr(fuel pressure regulator).It can leak internally or at vacuum side.

[villagepc]

vacuum lines, vacuum elbows, and more vacuum lines. Go over them with a fine tooth comb. Like misha stated, the odds of having both o2 sensors dead at the same time are pretty astronomical.

The two codes you posted looked like they were both for the downstream O2 sensor ?

There is one vac line located at the end of the intake manifold toward the front (timing belt) of the engine. Its hidden up in there near the ECT area - and tends to pop off at will. It has some hard plastic tubing that runs under the intake manifold to a rubber elbow...

One last thing to check - your ECT. If its stuck thinking the engine is cold, it will dump more fuel to compensate - and like misha says about that one - use OE Volvo.

[Seaway]

That jumpy idle could be from bad Maf.

When it's bad,idle is going up & down from 500-1200rpm and after a while it settle,but exhaust smoke is black and smells on a raw fuel.

When front o2 sensor is bad,there is a black smoke from the exhaust and ubnormal fuel consumption along with a smell of unburnt fuel.

If your rear o2 sensor is seated correctly in it's hole,i guess that you would not have the code for it.

Another thing that could affect emissions is bad fpr(fuel pressure regulator).It can leak internally or at vacuum side.

I thought of the MAF as well. I am going to swap the known good one (with about 4000 miles) over and see what kind of results I get. There is no black smoke from the exhaust, however and I have not really driven the car enough to know if fuel consumption is bad. I can tell you it is not great as it was only about 21 mpg on the 250 mile ride down 95 I took when I got the car. But there is no other obvious problem shown in the exhaust via smoke, etc.

I spent yesterday trying to get the bung on the cat cleaned up enough to get the O2 sensor to thread into it, but was not able to get it in. I am going to try a back tap before giving up, cutting the cat out and having a new one welded in. Or I may simply give up and install an entire new exhaust from the turbo back. This would satisfy the state mandated $780 figure for emissions work and I could actually drive the car and see what is going on.

I also looked through all the vacuum lines including the line to the intake manifold behind the power steering pump. It was on and clamped, but that doesn't mean the elbow isn't damaged, I suppose. I also checked the hoses to the IAC and they appear to be fine. I do seem to have a boost leak as well, so something is clearly not right. I removed the intake hose to the turbo and all the lines from the TCV and the PTC were connected well and in what seemed to be good shape. I have some silicon tubing so I am going to swap out the lines from the TCV to the turbo.

Perhaps the next step is spraying carb cleaner on the hoses to see if I can (hopefully) get the engine to stumble and easily ID the bad vacuum line. I suppose if I can't find one that looks bad, the next step would be to begin replacing the lines with new good ones. I need to get the bung O2 sensor back in before I do that as I am only allowed to work inside the garage I rent and filling it up with raw exhaust isn't my idea of a good time.

[Seaway]

vacuum lines, vacuum elbows, and more vacuum lines. Go over them with a fine tooth comb. Like misha stated, the odds of having both o2 sensors dead at the same time are pretty astronomical.

The two codes you posted looked like they were both for the downstream O2 sensor ?

There is one vac line located at the end of the intake manifold toward the front (timing belt) of the engine. Its hidden up in there near the ECT area - and tends to pop off at will. It has some hard plastic tubing that runs under the intake manifold to a rubber elbow...

One last thing to check - your ECT. If its stuck thinking the engine is cold, it will dump more fuel to compensate - and like misha says about that one - use OE Volvo.

How do I test the ECT? Whatever the problem is, it seems to me that the ECU is overfueling and as a result I am getting the high HC numbers in the emissions.

[misha]

You would have a code for bad ect.

[Seaway]

You would have a code for bad ect.

Gotcha. I don't have that one, only the codes relating to the O2 sensors. One for the front sensor and one for the rear. I did discover that the rear sensor was not the correct one, so maybe changing them out will not all be in vain.

[Seaway]

I also should have mentioned that I pulled the plugs yesterday and they were all fine. No fouling or anything. The plugs and wires and distributor have about 7000 miles on them and look brand new.