# P1136 17544 - Fuel Trim: Bank 1 (Add): System too Lean??



## 289066 (Sep 20, 2006)

Hi,
My chipped 2002 1.8T 180bhp TT has recently been feeling a bit sluggish - It's like the acceleration is gone back to pretty much what it used to be without me feeling any of the power that was once there when it was initially remapped. When i accellerate fully now it feels like the car is being restricted in some way.. like it CAN go faster, but something isn't letting it!
During some light traffic the other day the CEL came on, I used a vag-com cable to read the fault:
17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 35-00 -
This is the second time this fault has appeared.
I suspected it was the MAF - i used vag-com to take a reading from the MAF while redlining the car in 1st and 2nd gear - in both gears it read 169g/s which I think is about right for a chipped 1.8T right?? I also drove the car with the MAF disconnected and didn't really notice any change in performance.
Can anyone tell me what else it could be?? I did two 0-100 tests last night for the sake of curiosity and they were 7.75 and 7.45 respesctively (the second time i just launched off a bit faster). This 0-100 time seems to confirm the car is running almost like a non-remapped stock 180bhp.
I'm gonna tear my hair out!! Please someone help me before I end up balding myself!









_Modified by DaFlip at 8:48 AM 9-20-2006_


_Modified by DaFlip at 8:50 AM 9-20-2006_


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## [email protected] (Jun 5, 2002)

*Re: P1136 17544 - Fuel Trim: Bank 1 (Add): System too Lean?? (DaFlip)*

Try logging group 115 for a full throttle run from idle to redline in a single gear and post the results.


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## 289066 (Sep 20, 2006)

*Re: P1136 17544 - Fuel Trim: Bank 1 ([email protected])*

Hi - thanks for the reply!
I couldn't go from idle stright to the redline because of traffic but the most relevant bit is attached below. The general trend here is seems to be at low loads the cmd pressure & intercooler pressure are almost the same.. once the engine load increases they start differing quite alot - does this mean I've some sort of leak somewhere?


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## [email protected] (Jun 5, 2002)

*Re: P1136 17544 - Fuel Trim: Bank 1 (DaFlip)*

Could be - that looks like an awfully big difference between requested and delivered boost.


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## 289066 (Sep 20, 2006)

Awh damn .. that sounds serious! Where should I look? The N75/DV?


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## [email protected] (Jun 5, 2002)

*Re: (DaFlip)*

Check the whole intake tract from the turbo to the throttle body including the intercooler connections.


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## 289066 (Sep 20, 2006)

*Re: ([email protected])*

Hmm.. this sounds a bit beyond me! I'm only new to all this but I am trying to learn about all this stuff while i'm at it








If i bring it in to a garage and get them to do it they'll know what i'm talking about right?
I've also been told that I still may have a faulty MAF or it could also be dirty injectors and some injector cleaning fluid could sort it out?? 
Is the normal procedure here something along the lines of check the tracts from the intake if they all look ok start replacing parts until you get the right one? I don't really wanna order a new MAF unless I know it's broken, but at the same time if there's a chance it'd fix my problem then I'd be a happy man!
I appreciate your help on this.
Thanks


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## 289066 (Sep 20, 2006)

*Re: (DaFlip)*

My problem still exists. 
I now also get these faults thrown every so often:
16804 - Catalyst System: Bank 1: Efficiency Below Threshold 
P0420 - 35-10 - - - Intermittent
and this is more common:
P1136 - 35-00 - -17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) 
P1297 - 35-10 - - - Intermittent

I have replaced the MAF, I have also replaced the divertor valve with an aftermarket one (hyperboost dx). I've checked the piping around the DV valve and don't see any cracks or leaks anywhere. I've gotten the pressure drop between turbo and throttle before and after i swapped the DV valve.
The car is getting slower and slower overtime.. it now doesn't even feel like a 180bhp anymore. Also, from the passenger side i hear a whoosh of air that i didn't hear before.. it's strange.
A friend of mine who knows a thing or two about this sort of thing tried to help me out by doing a process of elimination - he got me to take the hose which goes to the top of the DV valve and plug it into another metal pipe which stems from the same place the DV valve pipe goes to - this would supposedly give me full boost again but the result of me doing that was nothing changed - the car performed the same except for an even weirder "blow off" type sound. Could it be the oxygen/lambda sensor? 
I've brought the car to a vw/audi tuner and he's blaming the map but i really, really don't think this could be so - the car ran flawlessly at one stage. I am convinced this has to be a "hardware" related thing.
Can anyone help me out any further? I am totally stuck








Thanks in advance


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## 289066 (Sep 20, 2006)

*Re: (DaFlip)*

Also i may aswell add that i have a FMIC kit to be installed - the mechanic in the vw/tuner company said that it may be better not to install this until i fix the existing problems. I do suspect that this guy is blaming the map because it's easy to blame (he also claimed he couldn't read it because of different software and that the problem is a fueling problem)
I am thinking if i get the kit installed then while the bumper is off he can also try swapping the lambda probe, since he'll be installing the FMIC kit then that will also rule out IC connectors - would this be a good plan??
Thanks!


_Modified by DaFlip at 11:56 AM 10-24-2006_


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## Uwe (Jan 16, 2000)

*Re: (DaFlip)*

I'd suspect a leak in your intake somewhere.
Even the original code: *Fuel Trim: Bank 1 (Add): System too Lean* can be the result of an intake leak.
-Uwe-


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## 289066 (Sep 20, 2006)

*Re: (Uwe)*

My MAF is reading the correct readings according to vag-com- does this matter? 
Could a leak in the intake also be the cause of the pressure drop fault?


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## Uwe (Jan 16, 2000)

*Re: (DaFlip)*


_Quote »_Could a leak in the intake also be the cause of the pressure drop fault?

Yes.
-Uwe-


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## 289066 (Sep 20, 2006)

*Re: (Uwe)*

Thanks - I appreciate your help.
I've ordered a new front lambda probe.. I'll let ye know what happens when it's swapped out.


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## [email protected] (Jun 5, 2002)

*Re: (DaFlip)*


_Quote, originally posted by *DaFlip* »_Thanks - I appreciate your help.
I've ordered a new front lambda probe.. I'll let ye know what happens when it's swapped out.


That's among the least likely causes for the problems you reported, but it's your money. What about the tests that were suggested to you?


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## 289066 (Sep 20, 2006)

*Re: ([email protected])*

I've checked every hose i can find - they all seem fine.
That still doesn't explain why the car performed just fine when the map was first installed - the software doesn't change (except for the fuel trim learning) - some piece of hardware must have failed or i have a leak somewhere right?? Please correct me if i'm wrong here ...
I expressed these thoughts to the guy in the tuning company and all he said was that the ecu does some learning after a new map's installed - isn't that all reset when you clear the fault codes ? This whole thing is driving me crazy! 
The guy in the tuning company appears to have no faith (or much experience) in remaps and his idea of increasing performance is all strictly performance upgrades like larger turbos etc. Then on the other hand the guy who's done the remap keeps telling me it's not the map and it's possibly the MAF or the DV or the lambda probe etc.. between these two guys I cannot find anyone who's capable of finding out what's wrong with the car! 
The tuning company is local and the remapping company is up the country from where I am. The guy in the tuning company is blaming everything (including the pressure drop fault code) on the remap. I have searched the 'net far and wide for information on the faults i'm having and anyone I find never has a solution. The remap guy is telling me the front lambda probe is reading incorrectly and the ecu is blowing off air in an attempt to meet the required air/fuel ratio's.
Up to 3k RPM really is fine then you hit a flat spot and everything beyond there feels anything but smooth. It's because it's fine accellerating in lower rpm's that the guy in the tuning company believes it's a fueling problem with the map.
I am going to check the intake for leaks tomorrow. 
Is there anything else I can do? I am all out of ideas







Any suggestions at all would be greatly appreciated. 




_Modified by DaFlip at 6:03 PM 10-27-2006_


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## 289066 (Sep 20, 2006)

*Re: (DaFlip)*

The only other thing I'm going to do which i suspect is take a look at the throttle body - this wasn't cleaned at the last service. If it's not a leak could this be the culprit?


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## CruiseVW (Feb 23, 2003)

*Re: (DaFlip)*

I had that same CEL on my 12v. I replaced my entire exhaust, dp back and O2 sensors and the code disappeared. Dunno if that will help you or not. Pretty sure it was just the O2 sensors though, they had 177k on them and were toast.


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## 289066 (Sep 20, 2006)

*Re: (CruiseVW)*

I've only 55k miles/88k km on my clock








I checked all hose connections i could see this morning can couldn't find anything. 
I did a vagcom log of a few small runs just now ...
http://www.dot-ie.com/LOG-01-002-031-032.CSV 
http://www.dot-ie.com/LOG-01-115-002-032.CSV 
The fault codes were reset on monday by the tuning company - no CEL's have come back yet, it usually takes a few days before the system too lean CEL comes on.


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## barmato (Jul 6, 2004)

*Re: P1136 17544 - Fuel Trim: Bank 1 (DaFlip)*


_Quote, originally posted by *DaFlip* »_Hi - thanks for the reply!
I couldn't go from idle stright to the redline because of traffic but the most relevant bit is attached below. The general trend here is seems to be at low loads the cmd pressure & intercooler pressure are almost the same.. once the engine load increases they start differing quite alot - does this mean I've some sort of leak somewhere?









Sorry for asking this question in your thread but what does it mean when the engine load is greater than 100%? That doesn't make sense to me but I see it all the time including on my own car. Is that 100% of some calibrated measure for the power made by a stock (1.8T in your case) car? 
BTW I feel your pain with the car not running right. I'm having problems with my R32 feeling sluggish (and pulling loads of timing) and I haven't had the time to really look into it yet. Good luck!


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## [email protected] (Jun 5, 2002)

*Re: P1136 17544 - Fuel Trim: Bank 1 (barmato)*


_Quote, originally posted by *barmato* »_Sorry for asking this question in your thread but what does it mean when the engine load is greater than 100%? That doesn't make sense to me but I see it all the time including on my own car. Is that 100% of some calibrated measure for the power made by a stock (1.8T in your case) car? 

The convention seems to be 100% would be complete cylinder filling with atmospheric pressure. Since forced induction engines cram in more than atmospheric, the % is over 100 when they are boosting.


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## VW00M (May 7, 2002)

*Re: P1136 17544 - Fuel Trim: Bank 1 (Add): System too Lean?? (DaFlip)*

i had this same fault code in my V6 4motion. The code popped up after i found out i was leaking coolant, and then had the leak fixed. Then had the fault code reset and hasn't popped up again. Don't know if that was the main problem.


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## [email protected] (Jun 5, 2002)

*Re: P1136 17544 - Fuel Trim: Bank 1 (VW00M)*

I can't see the correlation between leaking coolant and a fuel trim error, but good for you.


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## 289066 (Sep 20, 2006)

*Re: P1136 17544 - Fuel Trim: Bank 1 ([email protected])*

Just to put this one to bed. 
My new FMIC came with a new inlet manifold. While replacing the manifold they discovered a hose underneath it which was split. They have replaced the hose and now the car's pulling like a train! No CEL's or anything.
Unless they took off the manifold they'd have never been able to spot it! Tricky one!

Thanks for all your help


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## makdaddy (Apr 3, 2003)

*Re: P1136 17544 - Fuel Trim: Bank 1 (DaFlip)*

Would you mind letting us know which hose was split?
I started throwing that code after an FMIC install and will try tightening all the hoses again this weekend to see if it helps.


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## yoshimitsu (May 20, 2007)

*Re: P1136 17544 - Fuel Trim: Bank 1 (DaFlip)*

Please, add a photo to show the problem. I'm having the same problem as you.


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## Theresias (Feb 11, 2004)

*Re: P1136 17544 - Fuel Trim: Bank 1 (DaFlip)*


_Quote, originally posted by *DaFlip* »_Unless they took off the manifold they'd have never been able to spot it! Tricky one!

A proper test would have revealed it anyway. Proper means for example to set the whole intake pipe system under pressure (i.e. using a compressor and a pressure gauge).


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## yoshimitsu (May 20, 2007)

*Re: P1136 17544 - Fuel Trim: Bank 1 (yoshimitsu)*

Photo please


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## yoshimitsu (May 20, 2007)

*Re: P1136 17544 - Fuel Trim: Bank 1 (yoshimitsu)*

Damn, I just realized that I'm almost 2 years late...


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## Markhall (Apr 11, 2008)

*Re: P1136 17544 - Fuel Trim: Bank 1 (yoshimitsu)*

Hey guys, Please check this for ****S and GIGGLES!...The hose going from your brake Vacuume to the intake manifold...You know that big, plastic hose that connects the too to get brake presure, and it comes from the back of the manifold....Mine is cracked. I taped it up last night, and it held for a bibt, not that loud. And this morning is a different story.. 20 mions the CEL light came on, and i got out, the tape is failing..I knew it would, JUSt a temp fix till the hose comes in. But check that out..The cracks are hard to find..You may have to take off hoses..Every thing is plastic now days, and their alot of seams, checks those as well. TYhey are hind to find, but this is caused by a vac leak. 
The fact that others had luck chainging things and it was fixed maybe the fact that hose hose was connected better, or who knows...But start replaceing the hoses first, not the other stuff.
Sorry for the typing.


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## Markhall (Apr 11, 2008)

*Re: P1136 17544 - Fuel Trim: Bank 1 (Markhall)*

JUST to FYI you....That's what my problem was, and has been on 3 other car's, vacuume leaks! Their is not much to leak, but what is their can, and will. Even more so since the engines are mostly plastic junk now. 
Your brake booster line is very prone to leak! and crack..I have a car with under 100k and it had 5 cracks on it! 
If you have frayed threds over rubber hose, replace them..Their is not many, they are short, but you cant see the leaks under the thred..Rubber does die out after a while..Just replace them..
STOP CHANGING THE MAF, WIRES, PLUGS, O2 SENSOR'S!! And if you really must change them, send me the money! i could use it! 
And anyone else who can't figure this out, PM me, or stop by my shop, and i'll show you whats up!
1.8T people, dont kid, you have tons of vac lines! If you have a FMIC, that leaks as well if not installed right, or correctly. SOme FMIC come with extra Vac line connections, PLug them if your not going to use them, and make sure you plug them well..
TRUST ME IN SAYING A SMALL LEAK IS HARD TO FIND, BUT VAC HOSES, AND THAT STUFF IS ALOT CHEEPER THEN THE OTHER THINGS YOU HAVE BEEN REPLACING. pRESURIZE THE system if you cant find it...NOt hard, grab a air line, and a air gun, go to town. Clean your engine first!! 
This code only pops up due to vac leaks! thats it! Stright from the horses ass! lol


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## Markhall (Apr 11, 2008)

*Re: P1136 17544 - Fuel Trim: Bank 1 (Markhall)*

Please list up wht leaks you had, or have to help others?
1. Brake booster....Bad tube...
2. still looking for the rest.


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## vdubracer94 (Dec 16, 2006)

*Re: P1136 17544 - Fuel Trim: Bank 1 (Markhall)*

thats all i found with mine also! still searching


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## rabi (Feb 5, 2007)

*common issue and simple fix worth trying*

1 Fault Found:
17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 35-00 - -


I realize this is an old thread, but seems to me that no one has mentioned what is a common cause for this fault code.

The EVAP system does a check for every once in a while, and there's a valve (N80) which lets the fuel vapours from the charcoal canister to be routed into the intake. When this N80 reed valve opens, the system expects a fuel rich condition.

There's a tiny filter sock inside the valve which gets dirty overtime, and prevents the fuel vapours from reaching the intake--hence the "system too lean" error code, when the system expects additional fuel vapours to be routed through the EVAP system.

On my MkIV VR6 the N80 valve is located on the passenger front inner fender wall, between the windshield washer and the coolant reservoir. I tend to clean this valve using compressed air, or backwash the filter sock, once every 48k and this has worked well for me over the past 260k 

Rabi


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