NefMoto > Technical > Diagnostics > 1.8T engine is running too rich - Long Term Fuel Trim -19% please help :(
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Author Topic: 1.8T engine is running too rich - Long Term Fuel Trim -19% please help :(  (Read 86517 times)
Carsinc
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Vaccum leak? The check valve under the intake in the crack case breather if it still there, the hockey puck in the TIP.
If those are not it, check the front o2? Is that car a wideband? I've seen narrowband passats drive the fuel trim but I
have not seen a wide that bad, unless leaded fuel was used and I've seen 116oct destroy o2s..
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userpike
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Quote from: Malinovsky on June 26, 2013, 02:51:21 PM
how to get any results during this test if there is underpressur in the system?
OEM pcv system is out including pcv valve.
I changed pcv system to closed oil catch tank system
you can see it here on my car:


do you mean DV valve?
if yes, it is changed to new made by forge.
and what IF ecu by this -18% is removing fuel that SHOULDN'T be there?
my car is using more fuel during drive than it should, so maybe I realy have to rich mixture during normal daily drive?
during logs STFT is perfect, so you can even see on log that during making it my LTFT is getting better because of perfect STFT
but during normal city drive STFT values goes to big minus values. In my opinion this is the cause of my big LTFT,
but I still can't find why my STFT goes down during calm daily city drive.
Is injector time value correct on my log?
Maybe there is any other sensor connected with fueling or air in car that is broken and gives wrong values to ecu so injectors have wrong timing during city drive?
In my opinion injectors are fine but are working wrong because of ecu. Is this theory possible?
 
you think that my stock ecu can be damaged  Huh
nope - like I said - I swapped my fpr with one from car with no trim problems - and I still got same trim problem after ecu reset on my car
so it's definitly not a fpr fault
nope, bought 2 OEM factory new bosh maf dedicated by numbers for my carwhat do you mean ? and how can I check it ?I will
yeap, I also think that this is not a leak problem,
but like I wrote before I double checked it anyway
hmm on hot engine? I will try it
Is there any sense in this soapy water leak test here?
I mean there is underpressure in the system so I won't see aby bubbles anyway...
Am I wrong here? How should I perform this test with underpressure in the system?
thanks I know this one, and a few more, including OEM bosh service manual.
I understand the theory - I mean I know how it works,
what I don't know is how exacly LTFT value is creating by the ECU,
are there any car sensors (more than maf and o2) connected with the proces so I can check it?

Sorry for any confusion. Do the boost leak test with the spray bottle full of soapy water. So run the engine, warm it up. turn it off. Then pressurize the system to a psi higher than what the car is set to make on boost. Spray lots of soapy water and watch for bubbles.
For vacuum leak, run the engine, when warmed up, use propane or some other flammable gas and direct it at the hose joints. if the idle rpm raises then you have a vacuum leak in that area.

The pressure regulating valve I am talking about is NOT the DV. VW calls it a "pressure regulating valve". (the hockey puck thing that connects the PCV to the TIP, in your case the catch can to the TIP).

What do you mean by perfect fuel trims above? If they are within +/-5% you are good to go.

There is only one other thing that I can think of that may cause your trim issue...and that is an exhaust leak between the cylinder head and B1S1 02 sensor.
The 02 sensor would see this as a lean condition, therefore the ECU would be adding more fuel to compensate. Your idle trim would be in the positive values somewhere and partial/multiplicative value would be in the negative like you are experiencing because the "perfume bottle" effect would be nonexistent in part throttle and WOT.
So the ECU "sees" this condition and sets idle trim accordingly then at partial throttle and above(block 32, 2nd value) when the fuel trims are set after some driving around awhile, the ECU now takes fuel away from "target fueling" because the condition at idle is no longer existent because you aren't at idle.
« Last Edit: June 26, 2013, 11:44:30 PM by userpike » Logged
Malinovsky
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Quote from: ddillenger on June 26, 2013, 02:52:41 PM
I'd be willing to bet you have the wrong MAF.
well I don't think so  Roll Eyes, but of course I can check it once more  Grin

Quote from: vdubnation on June 26, 2013, 02:57:05 PM
have you tried running the maf unplugged ?
no, should I try?
how long can I drive with unplugged MAF to not damage the car ? I mean approximately minutes or kilometers.

Quote from: Carsinc on June 26, 2013, 06:48:04 PM
The check valve under the intake in the crack case breather if it still there,
the valve is out

Quote from: Carsinc on June 26, 2013, 06:48:04 PM
the hockey puck in the TIP.
hmmm never thought about this one  Undecided
its construction looked so simple to me that I thought it can't be broken ;]

Quote from: Carsinc on June 26, 2013, 06:48:04 PM
check the front o2?
is there any test to check it?
I bought OEM factory new twice, but I don't know how to check it

Quote from: Carsinc on June 26, 2013, 06:48:04 PM
Is that car a wideband? I've seen narrowband passats drive the fuel trim but I
have not seen a wide that bad, unless leaded fuel was used and I've seen 116oct destroy o2s..
unfortunately it is narrowband
I'm using only european 98 oct fuel

Quote from: userpike on June 26, 2013, 07:30:02 PM
Sorry for any confusion. Do the boost leak test with the spray bottle full of soapy water. So run the engine, warm it up. turn it off. Then pressurize the system to a psi higher than what the car is set to make on boost. Spray lots of soapy water and watch for bubbles.
ok I will do it

Quote from: userpike on June 26, 2013, 07:30:02 PM
For vacuum leak, run the engine, when warmed up, use propane or some other flammable gas and direct it at the hose joints. if the idle rpm raises then you have a vacuum leak in that area.
hmmm flammable gas on hot engine? isn't this kinda risky? Wink

Quote from: userpike on June 26, 2013, 07:30:02 PM
The pressure regulating valve I am talking about is NOT the DV. VW calls it a "pressure regulating valve". (the hockey puck thing that connects the PCV to the TIP, in your case the catch can to the TIP).
like I answered to previous quote - if this will be the cause I wil go crazy Wink
I totally ignored this valve Wink

Quote from: userpike on June 26, 2013, 07:30:02 PM
What do you mean by perfect fuel trims above? If they are within +/-5% you are good to go.
I was talking about my Short TFT during logs (fully open throttle),
I noticed that after reseting ecu to get 0% trims,
when I start driving hard with high rpm then my stft are near zero and ltft also stays fine.
But when I change drive style to calm, about 2000-3000 rpm my stft goes down to big negative values and this is the moment when my LTFT starts to also go down to big negative values.
So looks like the cause of my negative ltft lies in something connecting with low rpm driving.

Quote from: userpike on June 26, 2013, 07:30:02 PM
There is only one other thing that I can think of that may cause your trim issue...and that is an exhaust leak between the cylinder head and B1S1 02 sensor.
yes, I also thought about it,
I changed only cat back exhaust is it any test to check leaks in the exhaust section that you mentioned?


I also thought about some experiments with open/closed loop. But I don't know if this is a good idea.

and last but not least, did anyone check my car's OEM ecu file that I attached to my last post ? is it fine ?
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userpike
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Quote
hmmm flammable gas on hot engine? isn't this kinda risky?

not really...unless you have backfires? lol it might light your propane torch for you!

What all have you deleted emissions wise and the such?

maybe a check valve somewhere is stuck open in the vacuum system?

as far as checking for leaks in the exhaust between the head and S1 02 sensor...check the gaskets  between head and turbo mani, turbo outlet to DP, make sure your 02 sensors are tight, and last but not least....look at the pic. look for cracks in the pipe...no the pipe is not red hot in the pic lol
 edited the pic for better view..
Image Hosted by ImageShack.us" border="0
« Last Edit: June 28, 2013, 11:08:45 PM by userpike » Logged
Carsinc
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I still like the hockey puck for this, but do you have a intake spacer? I've seen them melt and leak.
Since exhaust leak was brought up it could be between the manifold and turbo I've seen that leak
alot but you can hear it. Make sure the front o2 is working proper, I'm not going to explain that but
there is alot of videos on reading the front o2.
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Malinovsky
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userpike who made toe pic ? Wink the quality is horrible  Grin I see almost nothing there Wink
Can I simply remove this hockey puck valve for tests or should I swap it for new one ?

Quote from: Carsinc on June 27, 2013, 07:55:55 PM
Make sure the front o2 is working proper, I'm not going to explain that but
there is alot of videos on reading the front o2.
Can you give me a link to this kind of video or instructions ?
I was looking for o2 diagnostics for some time but found nothing helpful
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userpike
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Quote from: Malinovsky on June 28, 2013, 03:29:42 AM
userpike who made toe pic ? Wink the quality is horrible  Grin I see almost nothing there Wink
Can I simply remove this hockey puck valve for tests or should I swap it for new one ?
Can you give me a link to this kind of video or instructions ?
I was looking for o2 diagnostics for some time but found nothing helpful

it is a pic from my old DP! lol I know the resolution sucks but who cares? The point is, the light coming through what looks like holes but really is a crack in the pipe. just "connect the dots" in your mind to visualize the crack that is actually there.
I guess I could try to take a better pic as I have the DP sitting in the shed as a future conversation piece but I don't think I really need to.

I don't have time as I am leaving for work right now but when I get home if no one has given instruction on how to test the "hockey puck" then I will at that time. Good luck!
« Last Edit: June 28, 2013, 07:50:59 AM by userpike » Logged
userpike
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To test the pressure regulating valve (hockey puck) put your thumb over one of the openings and put suction on the other( I just use my mouth). If suction doesn't hold, replace the part.

Also, while performing the first operation you should hear or maybe feel the vibration of something moving inside as suction increases. If you release the suction immediately you should hear or feel what's moving inside spring back to it's original position.

It must pass both of these tests for it to be functioning properly.

I noticed you said the check valve(PCV) between the intake mani and PCV system has been deleted. So is the port just closed up or do the hoses still reside but without that check valve? What about the opening on top of the oil cooler. Is closed up also? If so, what did you use to do that with?
« Last Edit: June 28, 2013, 08:10:21 PM by userpike » Logged
Carsinc
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front 02 http://www.ttforum.co.uk/forum/viewtopic.php?t=184323
hockey puck http://forums.vwvortex.com/showthread.php?5051507-Hockey-Puck-Pressure-Regulator-Valve
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Carsinc
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Quote from: userpike on June 28, 2013, 07:54:05 PM


I noticed you said the check valve between the intake mani and PCV system has been deleted. So is the port just closed up or do the hoses still reside but without that check valve?

I was thinking the same thing when looking for the links for him.
but in his pic it looks like it goes to the catch can and then to valve cover?
PS what the hell is that other hose?
« Last Edit: June 28, 2013, 08:01:27 PM by Carsinc » Logged
userpike
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Quote from: Carsinc on June 28, 2013, 07:58:20 PM
I was thinking the same thing when looking for the links for him.
but in his pic it looks like it goes to the catch can and then to valve cover?


yea I dunno either until he chimes in. The pic doesn't really show under the intake that well.
I must say about the only thing good in the thread about the "hockey puck" you gave a link to is the schematic of the valve. The rest of the content is pretty much useless..don't confuse the man! lol
If it doesn't do what I explained, the part is faulty and needs to be replaced, bottom line.
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Carsinc
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Yea I posted for the schematic, I kind of suck at the internet, but I know 1.8t
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userpike
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Quote from: Carsinc on June 28, 2013, 08:22:35 PM
PS what the hell is that other hose?

Which hose? The one with the orange stripe? If so, that comes from his DV I believe. I think he has a cold side DV relocation kit and hasn't plugged the opening where he was running the DV or BOV before in the pic.
« Last Edit: June 28, 2013, 08:40:35 PM by userpike » Logged
Carsinc
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Ahhh yes I should have noticed.
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userpike
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Hey Malinovsky, when was the last time you reset the adaption values?

Were you running a BOV or DV before the pic was taken?

I think I know what the problem is depending on your answers to these 2 questions.
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