Ongoing saga of Bank 1 - Lean

[Forbez]

17536 - Fuel Trim: Bank 1 (mult) system too lean
P1128-35-10--------intermitant


This damn code is driving me bonkers, even more so now i've got Revo, i seem to go into Limp mode more now.

I've read all i can read, and found these as the possible symptoms:

17536/P1128/004392 - Fuel Trim; Bank 1 (Mult): System too Lean
Possible Causes
Mass Air Flow Sensor faulty
Oxygen Sensor Control faulty
Fuel Injector(s) faulty

Possible Solutions
Check Mass Air Flow Sensor
Check Oxygen Sensor Control
Check Fuel Injector(s)

Recent swap of the ECU from Oettinger to Revo, car seems to boost to about 16psi, then shortly after I get limp mode.
I've reset the TB, and cleared fault codes, and on start up the car is rough has hell, very lumpy, and needs Rev's to keep it running, after a short while its still a little lumpy until the ECU adapts, which then gives me the Error.

Now I've logged the MAF, and it appears to be ok, getting around 150g's at around 5k rpm (stopped due to slow car in front), so that seems ok.
I 'have also replaced the N75F with a new one.
Also swapped all the Vac hosing, so no leaks or cracks.

I still have to check the FMIC hosing and joints to ensure that there are no leaks with that.

The other two options seem to be either the injectors, or the Pre Cat o2 /Lambda sensor.
I've logged both 032 and 033 blocks for the lambda, but i'm unsure of what i should be looking for. Can post logs if needed, but got a low sample rate due to logging 2 things at once, as i was in a hurry.

I haven't done anything to the injectors, so any suggestions would be appreciated, as im not sure what would be best to do with them.

Also cleaned the AIT sensor, as I was trying everything!

DV is on tightly, and i have a Forge TIP, which all appears to be fitted correctly, and tightly.

Any idea's or suggestions on what could be the problem?

 

[sonic_vi]

I know it sounds obvious and you probably have already tried it, have you swapped the coil pack from cylinder 1 to cylinder 2 and see if the symtoms follow it?

If you're not getting proper ignition you could get this error.

I had this come up as an intermittent and a new coil pack solved it.

Could be worth trying

They are naff all from GSF car parts (sub 20 quid) and its always worth having a spare as they are prone to failiure

 

[Forbez]

No mate, hadn't tried that, but thinking about it, good point, i'll swap them on the way to work this morning.

Cheers

 

[Forbez]

Swapped them, and car seemed ok, running about 14psi but flying, after a quick stint on a dual carriageway, seemed to get claudia limplemode, but no engine light.

Will see how it is later, as im in work now.

 

[sonic_vi]

just run a scan and see if theres anything on there.

If its followed it or has dissapeared from cylinder 1 could be worth changing the plugs

how many miles have they done?

could be a combination of a dodgy coil and a plug on its way out?

Just change one thing at a time and report back
Russ

 

[PhilW]

Check the voltage on the lambda sensor?

My guess would be the sensor has thrown a **** fit.

 

[Forbez]

With Vag Phil?

Group C:	'033	
	Lambda	Voltage
TIME		
STAMP	%	 V
1.15	25	0.055
2.14	25	0.06
3.18	25	0.1
4.39	0	0.64
5.45	18	0.045
6.46	25	0.08
7.45	25	0.11
8.45	25	0.085
9.46	25	0.12
10.44	25	0.095
11.51	0	0.72
12.63	0	0.005
13.63	0	0.005
14.63	0	0.025

 

[sonic_vi]

has it thrown any more DTC's?

has it moved cylinders or anything?

 

[Forbez]

DTC's? < What are these?

No engine light at present, but i will see, as i've gotta drive home, so i'll let you know .

 

[sonic_vi]

Sorry

It means fault codes in vagcom

Diagnostic Troubleshooting Codes

 

[Forbez]

LOL Cool,

Nope nothing at the moment, but also gimp mode all the way home, 15 miles.

Will see if i can vagcom it, in the next few days to check for faults.

Cheers mate, i appreciate the help.

 

[sonic_vi]

also when did you change the plugs last?

VAG COM can be funny sometimes

I was getting system too lean errors even when i knew it was overfuelling like crazy.

I found that it can alert you to the problem area although the ECU may not necessarily log codes that are 100% true lol.

 

[Forbez]

Just checked, didn't realise it had been that long, i'd say about 12k ago!

Any recommendations?

 

[sonic_vi]

hmm should be ok

mine had done 40k+ before they started to go.

should be done every 25k ish i believe.

I'd vagcom it with the coil pack moved before trying anything else

clear the codes and then go for a blat and see if you can make it go to limp mode.

when you get back check the faults and see where you are at.

Also how many miles has the car done?

coil packs have been known to go at as little as 40k miles.

Mine had done 85k on the original set before one went and the rest are still going strong so depends on how lucky you are i guess.

Generally speaking people don't rate them much past 70k

 

[Forbez]

Car's on about 70k, and i haven't replaced a coil pack yet, (touch wood)

I'll try to get it on Vag this morning.

 

[tompotts]

This thread is insanely helpful, guys, Im having the same problem at the moment, so this is greatly appreciated.

I had her in the garage on saturday to have a leaking pipe replaced, but on the way home yesterday the engine light came back on. ran a quick check with my 'trusty' hand held diag toll and got bank one too lean. gonna give her a good run all this week and then try and clear the code, hopefully its just cack built up from when she was running wrong.

Cheers

 

[tompotts]

one more thing... How easy are the coil packs to change? I havnt got a clue about them.

 

[sonic_vi]

coil packs are a doddle

basically there are 4 that slot into the top of the engine

just unplug them from the wiring clips, yank them out and replace with new one and plug back in.

If you want i can get some pics if you are stuck.

They are underneath the plastic engine cover, you'll have to unbolt the n249 valve to get to cylinders 3 & 4 but its just the frame and it should then lift out the way without disconnecting any pipes etc.

Russ

 

[Forbez]

As said mate easy to swap.

Sonic, reset the errors this morning, had bank 1 lean again, ran the car to work and back to limp mode, so will see now what error's i have and whether its moved onto bank 2 or not.

Fingers crossed its just a dodgy coilpack, and it can be resolved, the lumpy cold starts are abit worrying.

 

[PhilW]

Eh? Swapping coilpacks wont swap the bank 1 or 2.

Bank one is lambda sensor before the cat. Got any downpipe studs loose?