Constant Low Power ALH

ihredneck

Veteran Member
Joined
Dec 4, 2015
Location
Missouri
TDI
2000 Jetta, 2006 Jetta
This only became 100% evident when my brother complained of my car's lack of power compared to his 02 with 5-speed.
This is not what I would consider limp mode because I had a MAF go bad and that was worse then what I'm experiencing now.

255k miles with original injectors and injector pump.

The car will accelerate decently but never really gets up and goes. Seems to be lacking on the top end but I can get the RPM's easily up to 4000+. I noticed the difference between our cars what seemed like after the turbo lag in all gears. Mine didn't really have turbo lag but performed ok and his definitely had lag then pressed me somewhat into the seat.
To be honest though we don't know if his car ever had any mods performed on it. He got it with an engine swap and that's the only history we know.

List of items checked/done:
-cleaned intake
-checked snow screen
-new air filter
-new fuel filter
-checked fuel pickup assembly
-verified n75 operational and swapped with n18
-VCDS logged actual vs requested boost and curves follow closely (max psi about 14 psi boost and holds)
-checked timing with VCDS
-hammer mod performed (no change)
-swapped MAF no difference
-wired open anti-shudder valve
-new vacuum hoses
-verified 23" vacuum post n75
-new stock cam/lifters
-MPG about 42 mpg with mixed driving
-turbo actuator moves freely


Ideas:
-catalytic converter plugged
-weak injection pump
-bad injectors

Any ideas on tests I can perform?

Thanks
 

indysoto

Veteran Member
Joined
Mar 14, 2004
Location
Eugene, OR
Are you getting any black smoke? weak ip then?
intercooler cleaned(dunno if that would matter thou)?
Maybe a compression test??
Fill filter with diesel cetane additive run for a couple minutes shut down leave overnight?
 

bbexotics

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albuquerque
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2004 Passat,2006 Jetta, 2003 Jetta wagon, 2017 Cayman S
Bet egr valve and intake is full of carbon. Car can't breathe
 

ihredneck

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Dec 4, 2015
Location
Missouri
TDI
2000 Jetta, 2006 Jetta
No black smoke that I can see in the mirror. A puff of blue on start up is all.

I had the intercooler out about 25k miles ago checking for oil accumulation, didn't flush only drained.

No compression test performed

Any preference on additive? Does Moly have something? I did perform a lubri moly diesel purge within the last 40k miles. I believe I ran two cans worth through the IP.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
How were the intake ports in the head? (generally not as clogged as the intake runners get)

If vacuum is good and the actuator et al operate per spec then it's either an air or fuel restriction.

What's your timing like?

If one is really struggling with an engine's performance sometimes it's just a good idea to do a compression check.
 

ihredneck

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Dec 4, 2015
Location
Missouri
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2000 Jetta, 2006 Jetta
Head intake ports were very clean surprisingly, I have a record from previous owner showing the intake had been cleaned before.

I believe I have the timing set at just above the blue line on VCDS . I will need to verify though.

Planning to perform a compression test this week, maybe tonight.
 

ihredneck

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Dec 4, 2015
Location
Missouri
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2000 Jetta, 2006 Jetta
Confirmed timing is between 48-50, just below the blue line. I am trying to get IQ requested to match IQ actual.

Now got to locate a compression tester that will fit, thought I had access to one but no go.
 

indysoto

Veteran Member
Joined
Mar 14, 2004
Location
Eugene, OR
(via hermtdi)'Sounds like you have isolated your problem to a leak elsewhere in the vacumm system. Most likely a hose worn or one of the plastic unions / "T's" in the system. most likely the long vac hose that goes down to the turbo actuator.

One more thing (last thought). Look at the center line (mid car) on the fire wall.
There is a "Y" type fitting. Check this fitting to see if all three (3) hoses are connected.'

worth a shot, good luck!
 

ihredneck

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Dec 4, 2015
Location
Missouri
TDI
2000 Jetta, 2006 Jetta
indysoto,
I'm not sure how you were able to determine it is a vacuum leak issue?
I know boost holds at max psi and doesn't fall off so I don't appear to be having issues with vacuum to the actuator.

Can you please explain?
 

indysoto

Veteran Member
Joined
Mar 14, 2004
Location
Eugene, OR
indysoto,
I'm not sure how you were able to determine it is a vacuum leak issue?
I know boost holds at max psi and doesn't fall off so I don't appear to be having issues with vacuum to the actuator.

Can you please explain?
Sorry thought you had just checked the actuator and not from the top, I had copy and pasted from another forum post, so sounds like you already elimiated that.
 

ihredneck

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Dec 4, 2015
Location
Missouri
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2000 Jetta, 2006 Jetta
Okay thanks for clearing That up.

Found a compression tester so will get it tested here soon and should be able to report back.
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
I'm not sure how you were able to determine it is a vacuum leak issue?
I know boost holds at max psi and doesn't fall off so I don't appear to be having issues with vacuum to the actuator.
When you say 'boost holds at max psi and doesn't fall off' are you saying going down a flat highway you have 15 pounds of boost all the time?
I mostly have 3 to 5 pounds normally. I have a mechanical gauge tapped into the intake.
 

ihredneck

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Missouri
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2000 Jetta, 2006 Jetta
The boost holds at max psi when I'm accelerating up a hill or putting a load on the engine.

It holds constant also for cruising speed. Probably right about 3-5 psi via VCDS.
 

wonneber

Top Post Dawg
Joined
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Location
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TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
The boost holds at max psi when I'm accelerating up a hill or putting a load on the engine.

It holds constant also for cruising speed. Probably right about 3-5 psi via VCDS.
OK, that sounds better.
Mine gets up from 10 to 13 pounds (or so) on inclines.
 

ihredneck

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Location
Missouri
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2000 Jetta, 2006 Jetta
Just had the cat cut out and there was a slight improvement, but only seat of my pants dyno wise.

Still need to do a compression check.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
A bit late, but - FYI - I'd heard that one way to tell whether one has a significantly blocked CAT is to get temperatures from the inlet and outlet. Supposedly a blocked CAT would be significantly warmer (than a non-blocked CAT) at the inlet than at the outlet. Not sure if this is an old wives tale, though it does seem like there's some logic in it.
 

ihredneck

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Location
Missouri
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2000 Jetta, 2006 Jetta
A bit late, but - FYI - I'd heard that one way to tell whether one has a significantly blocked CAT is to get temperatures from the inlet and outlet. Supposedly a blocked CAT would be significantly warmer (than a non-blocked CAT) at the inlet than at the outlet. Not sure if this is an old wives tale, though it does seem like there's some logic in it.
There is truth to that.

I personally am glad it is out because I couldn't see daylight through it so it was plugged some.
 

ihredneck

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Missouri
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2000 Jetta, 2006 Jetta
I'm really leaning towards injectors are worn because on block 13 the injector values are really tight within 0.25 of each other and according to franko6 that is typically of old injectors that are weak.
 

UhOh

Top Post Dawg
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2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
I'm really leaning towards injectors are worn because on block 13 the injector values are really tight within 0.25 of each other and according to franko6 that is typically of old injectors that are weak.
Are you sure you are interpreting him correctly?

I'm pretty sure I've seen/heard of people having newly refreshed injectors show tight numbers.

Nearly all injectors could be found to profit from some work, but the issue here is whether doing so will resolve your issue of low power. There's a somewhat epic thread here where someone went along with having their injectors redone (and LOTS of other things) and it didn't solve their issue: yes, the injectors needed help, but, again, one needs to be more certain that a change (and $$) is going to resolve the issue at hand; I'd also note that in that situation/thread, even with "crappy" injectors, other than a vibration, which is what the real issue was, the engine seemed to run fairly well. While one cannot go wrong refreshing injectors/nozzles that don't mean they can go right either.
 

ihredneck

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2000 Jetta, 2006 Jetta
I don't plan on throwing parts at it for sure. I am going to borrow a good set of injectors and also verify if my brother's car has any performance mods we don't know of.

Here is franko6 comment

"The next important information to know about idle balance compensation; if the injectors are old, they will also be weak. That will make them run more equally."
 
Last edited:

UhOh

Top Post Dawg
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PNW
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2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)

ihredneck

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Missouri
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Yeah not as good as I hoped but it could have been the gauge, it leaked some and is a real old snap-on. I had a scare only getting 100 psi on one cylinder but I didn't have the hose coupled all the way to the adapter.

I'll post a log of all those items here in a day or so.

I did the last belt job and also did a stock cam and lifters replacement maybe 15k after the belt. It was still in time when I did the cam and no performance change after the cam. I could check again, but I'm fairly certain it is right on.
 

maxmoo

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Lakefield, Ontario, Canada
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2000 golf, 2001 golf, 2000 beetle, 2003 wagon, 2004 golf, 2004 jetta, all diesels
Yeah not as good as I hoped but it could have been the gauge, it leaked some and is a real old snap-on. I had a scare only getting 100 psi on one cylinder but I didn't have the hose coupled all the way to the adapter.

I'll post a log of all those items here in a day or so.

I did the last belt job and also did a stock cam and lifters replacement maybe 15k after the belt. It was still in time when I did the cam and no performance change after the cam. I could check again, but I'm fairly certain it is right on.
Might be worth checking that the cam to crank timing is bang on.
 

UhOh

Top Post Dawg
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2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
It has been said to use higher torque values (about 20%? that's what I do) on the cam gear bolt due to experiences with slippage of cam gears. No idea how prevalent this is or has been, but it's something to keep in mind (not like we don't have enough things to be paranoid about!). I would figure that other engines have experienced cam gear slippage, though I have no idea on the likelihood that one can slip just a little bit and then no more (w/o getting into the obvious trashing stage/point).
 

ihredneck

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Missouri
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2000 Jetta, 2006 Jetta
Data Logs:
Block 001: 903/min, 3.6 mg/str, 1.72-1.76V, 90.0 C
Block 003: 903/min, 275 mg/str, 270-290 mg/str, 79.7-81.7% (EGR looks a bit high)
Block 004: 903/min, 0.4 BTDC, 0.7 BTDC-1.1 BTDC, 2.8%
Block 010: 1275 mg/str, 979.2 mbar, 989.4 mbar, 0% (measured with engine off, key on)

For Blocks 008, 010 & 011 running 1500-redline in 3rd gear WOT look at the Google doc I created with tabs for each of these

https://docs.google.com/spreadsheets/d/1_lLX11JYQcCmo4atTRv_BlWFUZ-uUdYK71ftAGF3N3A/edit?usp=sharing
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
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PNW
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2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
BINGO! Just what I was expecting to see! Your ECU is calling for a lot more fuel than your hardware is delivering. It's like you've got a tune but are running stock nozzles: perhaps the same results if a tune and there's some other restriction.

Others can chime in, but I"m fairly certain I'm reading this correctly. For sure, the fueling request (45 mg/str) is well above what a stock tune's parameters are.
 

ihredneck

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Location
Missouri
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2000 Jetta, 2006 Jetta
BINGO! Just what I was expecting to see! Your ECU is calling for a lot more fuel than your hardware is delivering. It's like you've got a tune but are running stock nozzles: perhaps the same results if a tune and there's some other restriction.

Others can chime in, but I"m fairly certain I'm reading this correctly. For sure, the fueling request (45 mg/str) is well above what a stock tune's parameters are.
I'm no professional, but the 45 mg/str appears at the lower RPM's but at the 3000 RPM mark they are within spec of 40.0-42.0 mg/str.

Though a value that I believe is out of spec on block 008 is the IQ MAF Limit @ 3000 RPM. The log shows 32.8 mg/str and spec shows it should be 36.0-39.0 mg/str. Not sure how to interpret this though.
 
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