low power continues on my B4V

Yeah so i'm working through GoFaster's thing. But since I can't do anything for a few days while it is being driving around (and i don't have parts at the moment) lets do some good old school GeWilli hashing a problem out online. Yeah? Sound like good old days fun? I thought so to (no not really, i worked so much this weekend alone and with no resolution on the problem on the car that i got sick).

Brief History: Downpipe fell off going to a race before Thanksgiving. Tank was nearly empty - planned to fill it up but, well downpipe fell off. It wasn't being driven (much). So I go to pull the flange off (well a friend with smaller hands did the deed) and the top two studs snapped off. Great. Now i had turbo with broken studs. So it was just driven a bit but mostly parked. Parked at the airport while i was at Nationals. It was cold but the B50 was working okay in the tank.

Get to New Years day. I'd procured a replacement Downpipe, and some glow plugs for the Golf that didn't want to start in the cold. Replaced the battery in the Golf when the plugs helped it start evenly but still too cold to really start well (time and trip meter would reset). With that car working I went to take the Passat apart. Turbo off. Got the studs out. It was sitting on ramps in front of the house (not on grass, on driveway) outside waiting for it to warm up before putting it back together.

Well. Golf catches fire. It is 19°F and I have to put the passat together because we have to be somewhere later in the day.

Everything went back together great except there was no power. No boost. Gutless off the torque peak. Drivable but not right.

So with my girls out of town this weekend I went to work on it. Started with Thursday night's trip to get some vacuum hose length.
The MAP hose was short. I added a section and made sure there were no kinks.

Didn't help.

Took fuel filter out thursday night after the hose didn't help (it had B50 in there as I had mentioned) warmed it up. And on saturday I flushed it with regular diesel a few times. Filled the tank up with regular diesel (it was warm 55F).
Didn't help.
BUT there are a good number of bubbles coming through the hose at idle.

Yes it did have the 00575 code. Saturday driving around (since clearing the 00575 code) i don't have a code.

Hooked a T into the Red hose. Boost, but nothing above 8 sustained spikes to 10 but settles to 8 no matter what.

watching block 011 at this time i noticed that below 2000 rpm i was seeing higher than requested boost, by 200 or so. And I'm getting boost w/o load on the car (parked rev'n the throttle)

Hooked a T into the blue hose. So it was seeing pressure. When i slowly brought it up to about 2500 rpm in 3rd gear and put the throttle to the floor the pressure would go to zero. and i'd be down well below requested on block 011.

Hooked the T into the MAP hose and boost was consistent with Vag-com.

After Saturday's saga it appeared the N75, wastegate and ECU were seeing and doing what they were supposed to. Just no boost or fuel (requested fuel was low to match boost).

What to check next? Well Sunday I started with the AirBox. It was good.

Next step. Take the downpipe off to see if the 'new' used cat was plugged.

That helped actually, but still no boost (better turbo response). So with a hammer drill and my brother's help we gutted the cat, i mean performed an exhaust adjustment.

And just because Lug_Nut suggested it i pulled the intake hoses off (air box was in great shape) and checked. No rags stuck against the intercooler or in any other pipe.

And that's how it stands right now...

Thinks i haven't done:
Pull the fuel pick up out (tank has 18 gallons indicated - took the fuel out of the golf and put it in there).
Remove the Check valve (good idea?)
Pull intake manifold back off.

I used one of TDIPart's gaskets on the intake when doing the head and just re-used it when it was20 degrees and i had to get the car working. But it was slightly bent despite my care. No i don't remember a crease but i also didn't really check for one. So it is bugging me.

The EGR pipe seems tight but something could be keeping one of those gaskets from making a perfect seal above 8psi.

I get 10 psi spikes that tail off to 8-9psi. Even when the car is requesting 1800 (get max 1500 on actual in the ECU).

N75 appears to be working (from readings off the blue and red hoses directly with a gauge) and the ECU is seeing proper MAP readings that coorelate with a gauge 't'd into the boost line.

There are a lot of bubbles (steady stream of little ones) coming out of the fuel filter at idle.

The car is not smoking.

Just gutless, drivable around the torque peak as long as you don't have to go up hill fast or accelerate much.

Until the fuel gets used up (or i siphon 6 or more gallons out of the tank) and until we hit the weekend so I can work on the car sometime other than in the dark. Does anyone have any suggestions?

It is our only car as i mentioned (with the Golf being a stinking car-b-que in the driveway).

Fuel would be the simplest solution that B50 should have been pretty gelled up at 20°F and i don't think the 55°F we hit on Saturday is warm enough to re-suspend it. I've re-used gaskets before, but then again it could be bent and have a small leak only at pressure above 8psi.

Thoughts?

Comments?

Peanut Gallery?

you already have the best B4V mind on the task. . (Mr.Bartlett)

check the 3rd injector (needle lift) connector. maybe it got jostled loose.

also, as all the hoses ans stuff came apart recently, dbl check all routing of the vacuum hoses.

good ole' Lug_Nut will figure it out!

Back to basics

It seems you are already aware of various things which are not as they
should be ( re-used intake gasket, tiny bubbles in fuel, use of 50% biodiesel in cold weather with possibility of congealing problems, etc. ).

Why don't you address the known problems first and then look for
the obscure stuff ?

It reminds me of the scene on Christmas morning, in which father and
son have completely disassembled the electric train in an attempt to
find out what's wrong with it, only to have the mom point out that the train's
transformer is not plugged into the electric receptacle. It all comes down
to the need to make sure the basics are in proper order, and then proceeding from there.

Get the basics right, then proceed from that point. Even the best ( especially the best ) techs know this is the way to go when things don't seem to make
sense.

In the mean time, it's often possible to rent a car at a price which is more
reasonable than you might guess, provided you shop around and haggle
with the rental agent. Perhaps a few days away from the problem car is
what you need to provide a fresh perspective.

Great! Now the pressure is on....
I gave it my best supposition already, and came up with bupkus based on the results posted here.
I might have to see/hear/feel/smell/touch/...maybe taste even, to have a chance at providing anything more plausible than I have already.

G, How's this weekend for you? Saturday will be too late?

What about the hose inside the ECU?

Bubbles in the fuel line is not necessarily an issue. BIG bubbles are!

If you want to chase the bubbles, I would start with the thermostatic T.

Check the wastegate actuator with compressed air. It should move with about 8-10psi.

Tony

I'm guessing it will come down to a pressure/vacuum line, N75, or wastegate issue.

I've still got to mail you a care package. Hopefully, this week.

I checked the lines. (vacuum ones).

I haven't tried hitting the Wastegate with compressed air to see if it opens yet. BUT

if the wastegate wasn't opening it'd be overboosting into a limp mode from what i understand.

The weekend would be fine - i'm not getting a chance to work on it until then anyway.

Mini-GTG here? I have to check see what the schedule is, there might be a few family social things I can't get out of.

As far as the bubbles. They are a steady stream of not so small bubbles. I got the bubbles even when pulling fuel with mity-vac out of the hose from the tank (I blamed it on loose connection but maybe not).

I can probably remove the check valves (replace them with 3/8" fuel hose from reading other threads) before the weekend to eliminate that. But I'm not going to be able to pull the intake until the weekend at the earliest. Gotta get new parts anyway...

GeWilli said:

I get 10 psi spikes that tail off to 8-9psi. Even when the car is requesting 1800 (get max 1500 on actual in the ECU).

Click to expand...

Since the wastegate takes about 10 psi to open, what are the chances that the N75 has failed internally (basically, seized open) and is simply letting boost pressure through even when it's not supposed to?

This happened to me a while ago, not as severe as this but basically the same symptoms - unable to get to max boost even though everything else seemed to check out. New N75 cleared it right up.

Disconnect the wastegate hose and take it out for a spin and see if you get more boost. Just be careful not to overdo it since there won't be anything telling the wastegate to open (until you hit limp mode).

i think the odds of the N75 dying while it was sitting there is pretty low.

And it is working properly based on the gauges I hooked into it. Blue line would go to zero PSI when the car was requesting 1800 psi and not seeing it. And then would show pressure at lower boost ranges.

From all I can tell the N75 is working properly.

GeWilli said:

Blue line would.......show pressure at lower boost ranges.

Click to expand...

That's what doesn't make sense to me. Pressure in the blue line is trying to open the waste gate to dump turbo pressure. My expectation is that there would be no pressure in the blue line until the ECU said "enough boost, already!"

no pressure in the blue line = closed waste gate = make more boost please

pressure in blue line = open up we've got to make less boost

N75 hoses routed correctly? Black hose intake to top of N75, blue hose side of N75 to actuator, red hose bottom of N75 to pressure nipple on turbo.

N75 meet internal resistance spec of 25-45 ohms? Click when actuated?

Did you clean the intake out while you had it off? Nothing clogging up the neck of the intake? No soot or peanut shells (from the peanut gallery)?

Injectors gunked up by the peanut oil, um, B50 after sitting for the extended period? Examine with an electron microscope.

Boost leak from intercooler or piping connectors?

Exhaust manifold gaskets installed correctly?

It needs to be treated for depression after the loss of its younger sibling?

N75 routed correctly? Yes.

Have not checked but it clicks and was working when i took it apart.

Also injectors were working when i took it apart.

Intake is pretty damn clean, not enough build up to make it worth bothering with (maybe a mm, and yeah, for me that's not worth getting dirty compared to some i've seen).

All piping connections seem to be okay and well attached (double checked them). Intercooler? Haven't checked that, but working before.

Depression? That could be it. Or anger. Or it just wants to make sure i take it completely apart again and again and again so i really get to know it.

Laying in bed sick today I got thinking about the fuel check valve, some 3/8" hose and a handful of clamps and I can eliminate that pretty easily, at least until the fuel tank gets low enough that i can pull the sender/pickup without making a total mess.

GeWilli said:

i think the odds of the N75 dying while it was sitting there is pretty low

Click to expand...

Wouldn't surprise me. The same oily film that coats the inside of the intake plumbing also makes it's way through the N75; if it's not exercised regularly it's not inconceivable that it could get gummed up and stuck. And the engineers so wisely located the N75 bypass hose right near where the CCV puck dumps into the intake so oil migration into the N75 is pretty much guaranteed over time.

However, that being said...

GeWilli said:

And it is working properly based on the gauges I hooked into it. Blue line would go to zero PSI when the car was requesting 1800 psi and not seeing it. And then would show pressure at lower boost ranges.

Click to expand...

...it sure does seem to be behaving like it should.

What's weird is that you say you're getting spikes that trail back off - if you're not losing boost through a split hose, that seems to imply that the wastegate is opening prematurely. Wouldn't a fuel restriction just ramp up boost and essentially plateau at whatever level can be sustained by that amount of fuel, rather than spike and fall back?

It's gotta be somewhere in the wastegate control system...or a blown-out intake hose that you certainly would have caught by now. Go for a run with the wastegate uncorked and see if you get your boost back. If you do, it's the N75. If you don't, you're back to boost leaks, fueling, timing, clogged exhaust, dying turbo....

Great idea! Pull the blue hose off so that no pressure gets to the wastegate. Boost would be unlimited until the ECU throws a hissy-fit and puts things into limp mode. Cycle the ignition key to re-set the ECU if that happens.
Leave the boost gauge operational and reading the intake tract, back off the accelerator if you get a display north of 18~20 psi, or use the key to re-set the ECU limp mode if you need to.

I'd go do it right now but i'm still not feeling well enough to get out and work on it - this Flu has me nailed to the couch.

if the intake or egr gaskets are leaking i won't see any difference and the car will drive the same.

and if it is fuel - i may see a boost difference at lower requests but not at the high end.

pretty simple. good idea. saturday is play with it day, i'll start the blue hose and go from there. i should have a new intake gasket and fuel filter on hand. I found, oddly enough (in the 30 minutes i was feeling okay today - no the passat wasn't here then), a nice length of 3/8 fuel hose and 4 properly sized solid metal hose clamps.

hopefully I should be ready to solve it this weekend if i get my strength back

I just read through the posts and it was mentioned by TonyJetta I believe-the hose in the ecu-you haven't mentioned if you have put a new hose in there or not.

the hose is connected well, not kinked or plugged. the ECU is reporting what I'm seeing with a boost gauge t'd in before the hose so i feel pretty nearly 100% confident that it is doing what it should be. originally i thought because it was short and pulled tight it might not be working but i put a splice in and added a good 6" and made sure there wasn't a crimp or kink with good flow all the way to the ECU.

GeWilli said:

the hose is connected well, not kinked or plugged. the ECU is reporting what I'm seeing with a boost gauge t'd in before the hose so i feel pretty nearly 100% confident that it is doing what it should be. originally i thought because it was short and pulled tight it might not be working but i put a splice in and added a good 6" and made sure there wasn't a crimp or kink with good flow all the way to the ECU.

Click to expand...

inside the ecu itself.theres a tiny hole inside.very common for it to get a pin hole.another easy fix.

My own .02 (based on not much of anything) is that you're not getting fuel. I have a mis-selected A3/B4 fuel filter sitting in my garage. I could send it to you if you'd like.

Peter, thanks for the offer and the thoughts

i just ordered a fuel filter and intake gasket from IDParts yesterday.

Fuel would make the most sense given the B50 the cold and the fact that i've put on countless intakes, reusing gaskets, w/o problems before.

we'll find out tomorrow soon enough, the bubbles (a constant stream) lead me to think it is a fuel issue.

If you get gelled fuel in the filter media I don't think you can rinse it out. Hope this works.

got the filter today - and the other bits - tomorrow we see what kind of magic I can work.

First off.
It is working.
Secondly - it wasn't anything I thought it might be.

It got pretty warm and the sun had been beating down on the car for a couple hours, air temp was 40, might as well head out and get dirty.

I started with pulling the fuel pick up. All clear. Realized that I couldn't easily remove the check valve so i just hooked it back up. The 3/8" hose wouldn't have worked to replace it because the other end of the hose on the other side of the check valve was way under the tank and I wasn't going to go through jacking it up and working underneath it at this point. I figured if there was any resistance using the Mity-Vac up by the filter before the filter then i'd go back and deal with it. My to my delight I found it took nearly no resistance to pull fuel up with the Mity-Vac (fuel filter disconnected).

So then I put the new fuel filter in, it was pulling a bit more resistance than w/o filter but seeming less than w/the old one. I had hopes maybe that would fix it.

But before heading out for a test drive. I figured I should check the wastegate. Used a mini-bike pump and plugged into the blue line and pumped it up, hey the wastegate moves. Vent and it goes back to closed.

It is working. The wastegate that is.

Hooked up the temporary boost gauge and went for a ride.

no change, still gutless. crap. crap. crap. (actually the word i used started with a F and rhymes with duck).

So before heading home I pulled into a parking lot and I pulled the wastegate hose and figured on seeing if i can get boost.

nope.

no change.

Crap (really actually F word again).

Then I had a just wackadoodle idea.

The idea based on something from the morning of the golf going up in flames, while waiting for everyone to get back with some krazy glue so i could fix a bit of broken plastic, i had stuck a waterbottle brazon bolt in that leaky oil hole on the EGR with a bit of gasket maker. It was making a mess all over the engine.

I popped it out and holy **** - i got power back.

Awe crap seriously? All that screwing around for THAT? A damn idiot move on my part?

The EGR isn't plugged in. I guess well now i know this car REALLY well. how it works and all that. and i have no doubts about any of the systems now!

So there ya go - i learned the hard way ya can't plug that damn hole up.

Now the car is working.

I have power.

I know it inside and out.

And thanks for all the suggestions.

Sorry to say no one guessed the problem. And IIRC it isn't on the GoFaster trouble shooting list. newbies - don't plug that hole.

I'm sad that I wasn't right, but happy it's working. Perhaps with the hole plugged you were constantly bleeding off boost, or something like that.

At least you had a pretty nice day to work on it. Enjoy the (somewhat) power.

after two weeks of bleeding boost off right now it feels supercharged.

and i don't have the golf to go back to to make it feel slow (RC3 + 205s)

but

I got a package from someone in KY named Bruce today.

gotta let my wife drive it like this for a few days before adding some more power to it.

then injectors (i have a set kicking around) - well two sets some 764?? nozzles and a set of bodies with "205s" on them...

but i'm happy with current power at the moment!

GeWilli said:

I got a package from someone in KY named Bruce today.then injectors (i have a set kicking around) - well two sets some 764?? nozzles and a set of bodies with "205s" on them...

but i'm happy with current power at the moment!

Click to expand...

Put the .205s in with the package. You'll be pretty happy.

haven't tried the package yet but...

the car is working great. more power than it ever has had and it isn't smoking at all. that old cat must have been clogged too or something or a combination of everything.

just have to deal with the bouncy rear suspension now