P80 PCV System Repair on a Volvo 5-cylinder (-1998)

[gdict]

Well, I'm not sure if my answer will be found in this thread, but here goes.

I had a laundry list of things to do on my 94 850T5, so I decided I would do the PCV replacement as part of the big fixorama. I bought the kit from FCP and was pretty happy with the parts quality. It was a bit confusing since they give you clamps you don;t need and the long hose doesn't need the vacuum line routed with it on my car. Minor stuff.

This is what I did to the car.

Used AC compressor and new receiver drier installed. AC system charged. (It works! Woo hoo!)
New timing belt. New serpentine belt. New spark plug wires. (plugs cap and rotor done recently)
All new PCV and related vacuum lines. New injector o-rings. Replaced both knock sensors with later style combined harness.

After all this work was done (about 20 hours over three weeks), I turned the key and it sprang to life as expected. It runs great. My turbo boost is back thanks to the new (used) knock sensors and I have been getting at least 2 mpg better mileage on average. Here's the caveat.

I took it in for my California enhanced smog check and it failed. This car has never failed a smog check. The results showed greatly elevated hydrocarbons, which points to the engine running rich. So, O2 sensor, MAF, fuel pressure regulator, all culprits.

During the repairs, I broke the vacuum nipple off the PTC valve. I fashioned a brass nipple and threaded it into the PCT. I don't think this would affect anything, but I thought I would mention it. Is the vacuum flow critical on this nipple?

I also have a CEL with code P0400 EGR Flow. I haven't had this code since I did the whole EGR cleaning thing about 80K miles ago. This CEL is persistent and comes back in short order after being cleared.

I also had an O2 sensor code come up shortly after the repairs, but I cleared it and it has not come back.

So, now what i'm looking for is advice as to what I should check next. I don't want to just throw parts at the problem, so I'm hoping someone could give me some guidance as to what they think I should do next.

Thanks in advance.

Greg

[Juan62]

I'll try and let others chime in;
1. Vacuum flow critical on PTC nipple; Yes, very.
2. EGR Flow; clean and change out gasket. Clean MAF with CRC MAF cleaner.
3. Clear all codes, run the car Highway about 20 miles, shut off, and run diagnoses to see if any codes return.

[gdict]

When you say critical at the PTC, do you think the size of the nipple orifice would affect things? Or does it simply need good vacuum flow. If anything there is more flow with my fix.

I was hoping to avoid the $100 to buy the whole pipe assembly with a new PTC. It seems this is a dealer only part.

I suspect it is not the EGR valve itself, as it was not an issue before the repairs were made.

Thoughts?

[Juan62]

As long as you have the correct PTC Nipple and it was cleaned before you re-installed, it would be okay. I assume you mean more flow=because you put a brass fitting (better than the plastic)? Only if your lines/hoses are bigger would you acheive that concept like the NHRA cars. Dose it leak at the PTC Nipple (air or oil)?
The PTC nipple is a dealer product, but you can purchase an after market Turbo Air Intake Tube or Hose.. www.snabb.us
I did order a new PTC nipple from the stealership, Part # 8643644, but it was the wrong PTC Nipple for my car. One end where the small Flam Trap connects to was closed or sealed off. On my original PTC Nipple, the part numbers stamped on it is # 1275996 (Volvo). FCP groton and others will only sell you the entire Turbo Air Intake w/PTC Nipple, Part # 8186200 for my car.

EGR: you stated that you had a P0400 code. That was the reason I addressed that solution. If you just need a used PTC Nipple one, E-bay has one, part # 1275996, and they sell the complete Turbo Air intake Tube. Just make sure you check for exact part/parts for fitment. Please let us know when and how you repaired it...it benefits everyone here.
Thanks.

[jblackburn]

You've got a vacuum leak, pure and simple. That explains the O2 sensor code, running rich, and possibly the EGR flow code. At this point, the nipple for the PTC sounds like a pretty good suspect.

94's are kind of oddballs in that they don't have the vacuum port on the left side of the intake manifold and instead have it on the vacuum tree itself. Nonetheless, you can steal a PTC/entire air intake hose from any 1994-1998 turbo model you might happen to run across at a junkyard.

[850T1995]

Okay its been more than a year since you posted this walk through; by the way awesome guide. I just did this same operation to my 850T. however I did not have the luck that you had. I had one snag, I can not for the life of me remember what line was hooked next to the PTC on the intake tube. I have the PTC hooked up but there is nothing hanging and I am brain locked on this puzzle. I was wondering if you could tell me what is that nipple for I have no idea.

[jblackburn]

I want to say it goes to the front of the intake manifold. I'll get back with you this weekend; I'm basically tearing all this stuff out to replace that URO PCV hose in there.

[E Showell]

My dipstick is blowing smoke like Mt. St. Helen's ready to blow -- no wonder my oil consumption has been high with no signs of a leak. I may take a crack at the repair this weekdn, but my timing is such that I will have to do it immediately after I drive the car for 15 min. Can I do this on a "warm" engine? I may leave it for my mechanic. His labor rate is $95/hr. I'll supply the parts to replace the whole system -- FCP kit. What would be a reasonable charge? He's told me he's never done this repair before.

[jblackburn]

DO NOT buy the kit with just URO parts. I had to replace all of the hoses in mine after only 15 months. That's awful.

It took me over 5 hours the first time because I had no idea what I was doing. I think I was done with this part of the fiasco in 2 hrs this time around.

You can leave the hood open for maybe an hour after you get home and go at it (I've done this with spark plugs and they were sufficiently cool enough by then), but it's not something I would want to even touch on a just-driven HOT engine.

[E Showell]

Any idea what the Volvo Part Nos. are for real parts? I'll get them from my local dealer.