tandem pump help

[TDI wesley]

having a constant p0299, ton of white smoke, no power at all. After checking for boost leaks and vaccum leaks I believe the vaccum level is low, I do not have a tester but by feel from the check valve It hardly feels like any vaccum. I also tried pressure going from the check vale to the tandem pump and brake booster but all I hear is the air going under the valve cover and after taking off oil fill cap am 100% sure that any pressure i put into the vaccum comes out into valve cover. Have I found my problem and does the mean a bad tandem pump or seal? any help is greatly appreciated

also have fuel mixing with oil that I thought was caused by injector orings but after that did not solve the problem I am thinking that this is caused by the tandem pump bushing. So would tandem pump cause diesel to mix with the oil and then after 10-20k miles of this problem would the vaccum part of the tandem pump fail??

 

[Windex]

There is a seal in the tandem pump, which can fail and cause fuel tonmix into the oil, yes.

 

[truman]

I would be inclined to put in a new pump and rebuild the old one as a spare.

 

[afarfalla]

I have a good used OEM pump if your interested

 

[Mozambiquer]

I would test the vacuum to be sure, but could be your issue with both of those issues.

 

[MEgearhead]

The vacuum section of the tandem pump discharges into the valve cover area so pressure leaking through the vacuum pump into that area is not surprising to me.

As far as fuel in the oil, the tandem pump would be the next thing I would try. Since the fuel section is the most rearward, it seems fuel would have to leak past the vacuum section first. I had my old one apart a few times trying to fix a leaking fuel section cover, but can't remember just exactly how it was constructed (that was 100k miles and 7 years ago). All attempts we're futile, and after the leaking fuel destroyed all the hoses, the temp sensor, and the coolant flange, I just bought a new one.

When I replaced mine, it was around $200 for a new Pierburg. I agree with Mozambiquer. Get a vacuum gauge and check the vacuum. If it's not producing vacuum you're going to replace it anyway, and you can see if that solves the fuel in oil issue. At least you won't just be throwing expensive parts at it.

Truman,
Do you know of a source for rebuild kits, and have you had any luck rebuilding the Pierburg tandem pumps? That would be some useful info.

 

[PickleRick]

I bought a cheap sub 150 dollar China knock off tandem pump @190k

I have both a new oem and rebuilt one waiting to be installed when it fails. That was 4 years or so ago and I'm at 270k