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Discussion Starter #1
When I bought the car i had no boost, Went investigating and finally found out the problem was a broken wastegate actuator. I got a good one off another turbo and installed it. Car was fast. Week later I lost boost again. Hooked up boost gauge and found Im only getting 2psi max when pushing the car hard and it doesnt hold either. I have looked at all the vacuum lines, i dont hear any leaking either, vacuum is normal (around 18-20in) Car runs fine just isnt boosting. I checked to make sure everything was connected. Checked the resistance in the boost control valve, I read the maf is a possible cause, but I dont know the specs on resistance or where the maf is located. This is driving me crazy! I dont see how it can be the dv because that should only have to do with turbo lag between shifts. Replacing the wastegate actuator was a BIG job (figured out thats why Vw just replaces the whole turbo) Need Help with this fast as possible. TIA
 

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If the stock DV grenaded, that would cause enough of a leak to limit boost to a very low #. I've seen two failure modes. One is the diaphragm tearing, and the second is the ultrasonic weld that hold the top on loosing it (pop), the later being very easy to diagnose:)

In regards to the MAF. You can take a quick look at it by measuring the resistance between all 4 (or 5 depends on the model) pins. There should be either kOhm or MOhm resistance. If there are any open circuit readings the element is blown. If you get K readings from the MAF, you may as well clean it while it's out. Don't physically touch the sensor. I use both electronic cleaner (spray) and a soak in isopropyl alcohol (5 minutes or so). Get's all the EGR deposits off.
 

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vwpassat980 said:
I dont see how it can be the dv because that should only have to do with turbo lag between shifts.
No, the DV needs to shut or you will never have much boost. Your symptoms are *exactly* what happens when the DV starts leaking. Borrow a friend's DV or drop $35 at the audi dealer for the TT version and see what happens.

You may want to find a vag-com in your area and look at MAF data and fuel trim data before you rule out the vacuum leak: large positive numbers for *additive* trim = vac leak at idle --> bad seal at DV under boost conditions.
 

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Discussion Starter #4
Couple more things, after reading this post:

http://www.clubb5.com/forums/viewtopic.php?t=73178&highlight=mass+air+flow&sid=762bf990d29d2627e563a3a6f2942a95

My air intake from the box all the way through to the thottle body has oil in it. Is this normal, or like someone in the post said will it mess up my maf or anything else? Also I have a haynes manual but the air box is a little different then mine so Im not sure where my maf even is. The pic shows the transister, maf, and intake air temperature sensor. There is a hose at the top of the box (towards inside of car) Whereas my box has a hose on the front of the box (turbo inlet) There is no maf in that hose but there are more things on/in the box itself. Is this the way the 98's were then they changed it? Where is my maf? There a 5pin and a 4 pin connector on the top of the box. Im thinking its one of the two, but why would they put it above the filter? That doesnt make sense to me as the air hasnt gonna thru the filter yet. I am going to pull off the dv again and have a look at that too
 

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Discussion Starter #6
Ok, I pulled the dv and it looked fine and it was closed all the way so it shouldnt be leaking or anything. I unplugged my maf and the engine stalled. So its def doing something at least. I guess I should remove it tomorrow and see if I can clean it up if that helps. Cant find any leaking vacuum lines or disconnected/loose hoses. Wastegate actuator is good, boost control valve checked out ok for resistance, fuel injectors checked out good for resistance. Valvetrain noise has gotten quite loud in the last month. Not only are the lifters noisy but it sounds like I can hear the cams rotating. The fuel injectors tick little on the louder side but ive been told its normal. Also at idle there is a low kinda whinning noise I cant pinpoint, maybe something with the v-belts. Hard to explain noise. I dont really get this, everything seems to be fine yet Im hardly boosting. Even if I have excessive cam and lifter wear which would affect performance I should still be boosting. What is wrong with this damn thing?! :mad:
 

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Discussion Starter #7
I have not checked the turbo shaft play and turbine since the first time I had no boost, but come on when I replaced the wastegate actuator and got this baby running she flew when I lost boost again there was no sudden noise or anything, just went for a drive and hey no boost
 

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In general, wait about 24hrs before a ^bump^... people will get back to you, just be patient.

The MAF is inside the airbox, above (after) the filter element, inside a 3"-ish diameter tube that eventually becomes the intake hose. It is normal to have some oil in the intake hoses (the crankcase breather system dumps into the intake -- think of your intake system as a garbage disposal for everything that the EPA wants to reduce your emissions of). However, there should not be any oil inside the airbox, itself, since the breather lines plug into the intake system after the airbox.

The spring inside the DV can fail to provide enough stiffness long before you are able to see any gap or other distress... borrow someone else's DV -- it's the easiest way to diagnose the problem.

You say everything seems fine yet you are hardly boosting... is it possible the boost gage is not working correctly? What kind of gas mileage are you getting? How about acceleration? With no boost the engine has little power -- certainly not enough to say everything seems fine.

BTW, when you say wastegate actuator, do you mean the "N75" valve that attaches to the intake hose, or do you mean the actual rod & mechanism on the turbo housing, itself?
 

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Discussion Starter #10
Allright, Im going to pick up an audi tt dv today and throw that in. When I spoke of the wastegate actuator that is what I am speaking of the actually mechanical mechanism. Everything seems fine meaning i cant find any leaks or such. The car runs fine, gets good gas mileage but lacks acceleration. The engine does not run rough or anything other than my noisey valvetrain (gonna look into another day) So its still possible then that the whole boost issue (robbing about 13psi) is from the dv? I thought I read that you generally couldnt lose that much boost from the dv alone
 

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If the DV is leaking, the turbo just pushes lots of air in a circle... However, gas mileage tends to suffer. Try the TT DV, and find someone in your area with a vag-com. Are you near Dallas? - pm me and I can help you out.

BTW -- don't take this the wrong way, but it's strange that you can get access to (and replace) the wastegate actuator rod, but you've had trouble taking apart the airbox/finding the MAF. Getting access to our turbo is at least an "eight f--k" job (how many times you'll swear before getting the job done).

This is interesting stuff... keep us posted on your repairs.
 

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Discussion Starter #15
Picked up a audi tt dv and installed it. Once again checked all hoses and vacuum lines. Took for road test. NO DIFFERENCE! I just dont get it. The only other thing I can think of at the moment is that since my valvetrain has gotten REALLY noisy maybe theres sludge in the engine or the lifters and/or the cam lobes are REALLY worn. Either way theres clearly a oiling issue because the valvetrain is loud. The lifters are very noisey and it sounds like I can hear the camshafts rotating. Could it be theres enough of a valve train issue that my valves arent open enough to allow for boost? Like I said tho the car runs fine just doesnt accelerate like it did. If it does have to do with the valvetrain then that should just limit boost not cut it off all together because I had boost then one day it was gone. Has anyone desludged their engine and has it helped with valvetrain noise?Someone posting that they starting getting ticking lifters and ran engine cleaner thru and cleaned the sludge screen in the oil pan, but they never said if it quieted it down. WHERE HAS MY BOOST GONE? :???:
 

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Discussion Starter #16
I REALLY DO NOT want to take this to a dealer or shop to have inspected, I cant afford it and I hate paying someone to do something Im trying to learn myself but I may have to give up and do that if I cant find this problem
 

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@vwpassat980 -- where are you located? you need to find someone in your area with a vag-com. Post where you are, and maybe someone nearby can help.

Some more ideas:

1. you replaced the wastegate actuator - can you confirm it's working? Maybe the wastegate is stuck open. (Popping the hood and revving in neutral won't help diagnose this, since the wastegate is only closed when the ECU senses a need for more torque.)

2. vag-com to check maf data, fuel trim (fuel:air ratio, too), measured vs. actual boost, and look for fault codes, too.

look at the problem from two different directions: either you *can* make boost, but it's leaking before it can do any good, or you *can't* make boost, but the ECU thinks you can. "Get thee to a vag-com" :)
 

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Discussion Starter #18
I've been wanting to get a vag com but just dont have the money at the moment. Im located in Central NY about a 1/2 hour south of Syracuse.


The wastegate actuator is fine, Could it may that somehow my car doesnt sense that it needs additional torque? Can there be a problem with vacuum hoses even if they look fine?

"2. vag-com to check maf data, fuel trim (fuel:air ratio, too), measured vs. actual boost, and look for fault codes, too. "-Pete1

If there is an issue with the fuel trim and such will this takeaway my boost or just hurt performance? Also can the maf be malfunctioning without the car running rough (mine runs fine)
 

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vwpassat980 said:
I've been wanting to get a vag com but just dont have the money at the moment. Im located in Central NY about a 1/2 hour south of Syracuse.
Post a new message "Looking for VAG-COM in New York State" -- someone should respond. Also, there are some web lists such as http://www20.brinkster.com/beowulf9/tdi/vagcom/vagcom.asp that may help.

The wastegate actuator is fine, Could it may that somehow my car doesnt sense that it needs additional torque?
Not likely -- more likely it either 1) doesn't want to give torque (limp mode, severe retardation of timing due to knock) or 2) thinks it's producing it, when its not.

Can there be a problem with vacuum hoses even if they look fine?
Yes.

"2. vag-com to check maf data, fuel trim (fuel:air ratio, too), measured vs. actual boost, and look for fault codes, too. "-Pete1

If there is an issue with the fuel trim and such will this takeaway my boost or just hurt performance?
a little of both... but i'm really looking to diagnose clogged fuel injectors/fuel pump/fuel filter and such. If the engine is always running lean (not enough fuel for the amt. of air) it will reduce boost and modify the throttle position as best it can to reduce the amt. of air and have a more sane air:fuel ratio. Depending on the trim values, you can also diagnose vac leak vs. boost leak.

Also can the maf be malfunctioning without the car running rough (mine runs fine)
possibly... it depends on what's wrong with the maf.
 

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Discussion Starter #20
I should have mentioned that I replaced the fuel filter and ran fuel system cleaner. I had posted already about looking for a vag com, no replies other than the webpage i asked for. I found a guy close to me but when i contacted him he informed me he was no longer in ny. So Im gonna have to try a few more people that are a little farther way. Unless someone replies to my post.
 
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