Sluggish at low gears

Vipaz

Member
Joined
Jun 4, 2018
Location
Lithuania
TDI
Golf MK4 1.9 81kw
Hey all, so I drive Golf IV 1.9 TDI 81kw and my problem: no power on low gears ( 1,2,3), everything seems fine on 4 and 5 , I mean I can feel the turbo on those gears, but on low gears it's like a diesel without a turbo :D , so what I have done and what my guess is:
1. Checked for codes with vcds, no codes at all, also no limp mode.
2. Changed MAF , cause old one was tottaly bad ( checked with vcds ), still sluggish on low gears, but goes good from 100 to 150km/h, old one can’t even pass 60km/h sometimes.
3. Adjusted TDI timing
4. Tried few N75 from good cars with same engine , no difference ( it was even much worse with one N75 from a really good 81kw Golf which was running good with it).Anyway changed it with new ( used ) one which seems to run maybe little little better.Turbo actuator leg seems to move freely.
5. My TURBO was repaired like 8-10k km ago, anyway then it wasn’t my car.So Just in case I tried to use Wynn’s turbo cleaner ( which helped few of my friends ) , seems that it helped little bit, but I feel that turbo should be good or maybe I’m wrong.
6. Cleaned my fuel system with Wynn’s diesel purge ( I connected it straight to fuel lines, when I cleaned it looked totally clean , I even used small filter and it was clean after like 40minutes of cleaning )
7. Changed vacuum hoses but I’m not sure if they are good , I mean I searched in few local stores in my city, but can’t find any vacuum lines :DDD , one seller told me that fuel hoses are totally fine for vacuum, so I changed all vacuum lines with fuel hoses, not sure if they are good to keep them or should I search only vacuum hoses ?
8. Changed all filters.
9. Done some logs with vcds , I was doing it alone so I just pressed log button and started driving from 1 to 3 gear , flooring the acceleration pedal.If I done something incorrect please tell me , I will re do it.Here are graphs, I’ve done 3, 11 and 15.
https://log.malonetuning.com/chart/233129#H8KLCADDuX0VWwIDbcKNw4sOw4IgEEXDv2XDlkMCanx8C2HCgTLCoSQVwpphasKqX2%2FCoUnDo8OCw6XCvcOnPsKswoVHecOeUyYVwrnDjFMFw5QOwps5Fk4fWiVCwqRMw6zChWAjw7lFLErCilrClF9Sa2zCnSEFUsOBwovCryTDjTzCosOwTMO%2Fw4hlJz4Ew7XDnmfCgFMcwqTDn8Ksw4kfYDUawrzCosOReMOAM8OeHMKCw6kpP0vCqcOTwpjDusKqOTnDtwXDo8Oxwqdhw5AAAAA%3D
Really don’t know what to do more, maybe:
1. My car engine is already tired :D ? I mean it’s clear that it have done many kilometers, I don’t even watch my odometer cause it’s totally fake for a 1998 car :D.
2. Maybe it’s turbo ? If logs are good which I done, maybe someone can comment them ?
3. Maybe it could be a leaking turbo actuator, maybe it won't hold vacuum ? Don't know ho to check cause I don't have vacuum pump.
4. Can bad MAP ( not MAF ) cause power loss ? Can I unplug it to test how car runs without it ? or it won’t make any difference for
power ?
5. Also I have medium size bubble in clear fuel line.When engine is running I can’t see any bubbles, but when it’s not, I can see one bubble, sometimes it’s really small sometimes it’s bigger, can it cause power loss ? Fuel lines seems good for me, tried to reconnect them few times still same bubble.
 
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Rob Mayercik

Veteran Member
Joined
Dec 19, 2001
Location
NJ, U.S.A.
TDI
2002 Jetta GLS, Baltic Green/Beige
You said turbo has been "repaired" and the actuator rod moves freely, maybe it's misadjusted and just not putting on much boost down at lower speeds? Do you recall what the repair was?

Can you get a hand-vac pump (mityvac) and check at what vac levels the actuator rod starts and stops moving at? You should be able to buy or rent one at a parts store?
 

Vipaz

Member
Joined
Jun 4, 2018
Location
Lithuania
TDI
Golf MK4 1.9 81kw
You said turbo has been "repaired" and the actuator rod moves freely, maybe it's misadjusted and just not putting on much boost down at lower speeds? Do you recall what the repair was?

Can you get a hand-vac pump (mityvac) and check at what vac levels the actuator rod starts and stops moving at? You should be able to buy or rent one at a parts store?
I probably didn't said it clear enough that when the turbo was "repaired" I didn't owned the car, but when the car became mine, I found papers about turbo repair and assuming to odometer it was repaired like not more 5000 km ago ( but it was in the past ) now I done like 5000 km more with this low power issue.Anyway let's get back to the point, when I got the car it wasn't running good also, but I though it was because of bad MAF ( found fault code with vcds , and also it wasn't passing 400mg/str when viewing in meas. blocks, so I changed.Still I bought an used one, but it won't throw any code and keeps with required value for MAP, also tried few MAP's from other good running cars, no difference..So yeah then I started doing all things which I already listed above...

About the vacuum hold on actuator, I probably won't buy vacuum pump cause can't find any cheap one in my local stores and it's only for one time use..I will try to search to rent one :)
 
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BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Hmm, thought that was a pretty standard tool, vacuum pump & gauge. But more to the point- Borrow one and see how the actuator is adjusted, should be 3.5 to 5.0 "Hg. Could be the cause of the issue.
The reason we always go thru the 20 questions bit is we see a lot of sub par turbo repairs. The fact the it goes full power in higher gears is a good sign.
 

Vipaz

Member
Joined
Jun 4, 2018
Location
Lithuania
TDI
Golf MK4 1.9 81kw
Okay some updates:
1. I didn't found where to rent vacuum pump, probably it's quite rarely used tool in my country :D , still will be searching for it.
1. I have again checked and reconnected some vacuum lines, and now I have problem! My N75 valve started buzzing for like 5 seconds after I shutdown engine.I heard it first time.Anyway I had my old one N75 which I was using for like 2years without any buzz sound, so I just swapped it and what I heard? My old one also starts buzzing after engine shutdown.I checked all vacuum lines again few times, everything is fine so I don't know what can cause that buzz sound, definitely it's not a bad N75, thinking that it leaks vacuum somewhere.
2. Another thing that I done, changed vacuum check valve ( that black/white thing ), I tried blow air to both ways and it was going both ways, so I suppose it's bad ? Anyway I changed it and it was totally bad because with the new one I see little improvement on power! Also the buzz sound it now very very short, I mean before check valve change it was like not less than 5 seconds and it was quite loud, but now I can only hear it very short time like second or two and it's very silent.
3. Also what I noticed, I'm not a expert in understanding how vacuum works, but what I noticed: when I shut off engine, vacuum lines which goes from N75 but only those 2 the big ones, one to turbo actuator and another one which goes and splits to other lines ( including those lines too ) are really hard, can't press them, so it seems that there is air inside ? All other lines are easy to press, anyway what I also noticed that waiting about 10minutes, all other lines also goes hard.Anyone can explain this ?

All in all I probably gonna recheck vacuum lines again cause I totally sure that it's problem in vacuum system, changed that vacuum check valve and I noticed an improvement in power right away I started driving.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Those fuel lines could work as vacuum tubes, generraly fuel lines are a bit too stiff, so if you got them on without kinking them they should be O.K. Vaccum tubes are nothing special, small ones are 3.5mm(3 works) medium stiff silicone. There is some 4 or 5mm in there as well.

Have you tried excersizing the turbo actuator? It should move back and forth roughly an inch (25mm). Once that's freed up, watch it while you start the car, it should move.
The vacuum pump and gauge is nothing fancy. Perhaps it goes under a different name.
 

Vipaz

Member
Joined
Jun 4, 2018
Location
Lithuania
TDI
Golf MK4 1.9 81kw
Those fuel lines could work as vacuum tubes, generraly fuel lines are a bit too stiff, so if you got them on without kinking them they should be O.K. Vaccum tubes are nothing special, small ones are 3.5mm(3 works) medium stiff silicone. There is some 4 or 5mm in there as well.

Have you tried excersizing the turbo actuator? It should move back and forth roughly an inch (25mm). Once that's freed up, watch it while you start the car, it should move.
The vacuum pump and gauge is nothing fancy. Perhaps it goes under a different name.
Haven't tried excersizing the turbo actuator.But when I start engine it moves, same as this video ( it's not mine ) I watched how it moves so I can say that it moves same as in this video, it's good or bad ? https://www.youtube.com/watch?v=vb3ykdxbdJE

Also can bad vacuum reservoir , I mean that black ball , cause power loss problem ? I don't know if it's bad or no , I don't even know if they can go bad.Anyway my brake system is working good.Thinking of changing all vacuum line splitters ( I mean those https://www.caprinesupply.com/media/catalog/product/cache/1/image/220x/9df78eab33525d08d6e5fb8d27136e95/0/3/031-vacuum-line-splitter.jpg ) maybe they can leak vacuum :D
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
That's good, the only other check requires the pump and gauge bit. If symptoms came on suddenly, I'd interweb guess the actuator is adjusted O.K.

Vacuum pumps can go bad, yours is doing some work. Testing involves reading the vacuum produced and checking for leaks.
Having full go in 4th and 5th is also a good sign, turbo does most of it's business in 4th and 5th at higher RPMs.
 

Rob Mayercik

Veteran Member
Joined
Dec 19, 2001
Location
NJ, U.S.A.
TDI
2002 Jetta GLS, Baltic Green/Beige
The N75 shouldn't be buzzing like that when you shut the engine off. Mine started doing that and when I tested it with a vac pump I found it was leaking the vac system back to atmosphere pressure.

I didn't take my "singing" N75 apart (just replaced it), but my suspicion is that when my turbo actuator failed some time previously, some debris from that got into the thing and eventually ended up in a spot where it would cause the valve to not close off properly (though I don't recall any drivability problems). You might be able to clear it out by running compressed air through it in different directions, but I've never tried to clean one.

Since it seems in your case it's not the N75, here's an easy way to try and find it: Take a piece of hose, one end by your ear and one end goes by different things; buzz gets louder by something, that's your source. This is a simple version of the "mechanic's stethoscope".

Surprised your local auto parts stores don't have a hand vac pump to loan/rent. Maybe they call them something else in your part of the world? Just as a sanity check, here's a link to one online: https://www.amazon.com/MV8000-Autom...e=UTF8&qid=1528919957&sr=8-3&keywords=mityvac
 
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Vipaz

Member
Joined
Jun 4, 2018
Location
Lithuania
TDI
Golf MK4 1.9 81kw
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