Lean Running 1.8T problems. Vagcom Logs attached *** PROBLEM SOLVED ***

[Cupra Ross]

Will try and get one done today Bill. I appreciate your assistance. I'm fitting the new Lambda probe so hopefully it won't be an issue after that. The N249 is bypassed in the normal way but I did try the car with it connected up in standard fashion and it made no difference to the issues.

 

[james walker]

which way is your n249 connected up ross?

 

[thewiizard]

Keep us posted Ross. I've got similar issues and so far this thread is awesome for troubleshooting running problems.

Definitely recommended for a sticky once we hear back on the front Lambda probe!

 

[Cupra Ross]

which way is your n249 connected up ross?

James,

If its the same as mine its a single connection from the intake manifold to a T-piece and then a connection to the Fuel Pressure Regulator and one to the vacuum nipple on the Diverter valve.

The remaining small vac nipple on the intake manifold is blanked with a short length of silicone hose and a screw. This way of doing it can give a Secondary Air Injection Incorrect Flow fault code but should not give an Engine Management Light.

The other way of doing it without the possibility of any fault codes is as above but leave the maze of N249 pipework connected and put a bolt into the original dump valve vacuum connection. You're relying on all the little vacuum hoses for the N249 being airtight if you do it this way. I don't trust them that much.

Keep us posted Ross. I've got similar issues and so far this thread is awesome for troubleshooting running problems.

Definitely recommended for a sticky once we hear back on the front Lambda probe!

Thanks mate, I'll keep it updated. My number one forum bugbear is "using the search button", finding thread after thread that describe a similar problem to your own and then getting to the end to realise that the original poster has either never fixed the problem or plain hasn't bothered their ar*e posting their results There are plenty of those types of thread on here. I'm alright Jack, up yours.

The new Lambda probe is fitted but I've only had a short drive and although the car feels better and is boosting much more eagerly, its still holding back between 3-4000rpm. I've disconnected the battery for the last hour to make the ECU forget all its fuel trims etc and I'm just going to do a few logs now.

Fingers crossed!

 

[james walker]

can you post some pics of your n249... sounds mucho different to mine mate, mine is vac pipe from original fpr nipple under manny, t piece with line to fpr then to dv nipple.. oem dv pipe blocked off and vac reservoir removed and that pipe blocked off.

 

[Cupra Ross]

can you post some pics of your n249... sounds mucho different to mine mate, mine is vac pipe from original fpr nipple under manny, t piece with line to fpr then to dv nipple.. oem dv pipe blocked off and vac reservoir removed and that pipe blocked off.

Thats exactly the same mate, just a different way of saying it. Vac reservoir is optional. It only functions via the N249 valve anyway. If that connection is removed from the intake manifold, there will be no vacuum to "reserve".

 

[james walker]

hmmmh, have you removed the cluster of n249 soft pipes under the metal tray nexto inlet manny?

 

[Cupra Ross]

hmmmh, have you removed the cluster of n249 soft pipes under the metal tray nexto inlet manny?

They're not removed but they are disconnected from the forward vac nipple on the intake manifold.

 

[james walker]

so you get the code then ross or have you added a resistor, as they are effectivly rendering the n249 valve itself redundant that way,,,,does the ecu pick this up then?

sorry to jack your thread a bit

 

[Cupra Ross]

No. They are still electrically connected, I've just unplugged the vacuum hose from the manifold.

 

[Cupra Ross]

Ok, the saga continues...........

Still having nightmare problems with the car. Sometimes it'll fly, other times it just doesn't want to go at all. 3krpm in 5th gear earlier and the car wouldn't rev any higher even on full throttle. I heard a bit of a pop earlier so I think my Forge TIP is incorrectly seated.

Out of time with this at the moment, the car is going to get some paintwork done tomorrow and I won't have it back until Thursday lunchtime. I'll fit the new fuel pump and refit the Forge TIP on Friday morning and if its no better, I'll take the car down to Awesome GTi for a reflash of the APR Stage 2 software.

If its still playing silly buggers, I'm going to put a gallon of V-Power in the drivers seat, quickly followed by a lit match

 

[Cupra Ross]

Guys,

Thanks for all of the assistance. As promised, I said I'd update the thread when I found a solution. It turned out to be the fuel pump. I fitted an aftermarket PWM pump which is a direct swap and has the fuel level sender incorporated. This pump is compatible with the 225bhp BAM engine so it should flow a decent amount of fuel.

My car was pulling back on boost and was very stuttery between 3000rpm and 4500rpm, it just didn't want to go at all and it was showing as running lean on VAG-COM. It was dropping requested boost and the wastegate duty cycle was very low. It was getting worse to the stage that the car was shuddering on full throttle and wouldn't go over 3500rpm in 4th gear. The boost fluctuations and forced closing of the throttle butterfly also caused my charge pipe to pancake pipe hose to pop out of its clamp.

I changed the pump today and the old one looked very dirty inside the fuel supply port. The return port was clean as a whistle so I assume that almost 8 years of fuel delivery was as much as the original pump could manage.

No bad thing but I've replaced the following items on the car in the last 2 weeks trying to get to the bottom of this:

MAF sensor
Coolant temperature sensor
Thermostat
Injector o-rings and manifold inserts
Turbo Intake Pipe (fitted a forge one)
Boost hoses (4-ply red silicone)
Fuel filter
Front (pre-cat) Lambda Sensor

Hopefully that lot will keep her ticking over nicely for a while. I've ordered a new charge pipe to pancake pipe boost hose, clamps and o-ring and I'll be fitting that tomorrow.

The car is now absolutely flying, I'm finally able to enjoy the benefits of APR Stage 2. Will post some logs tomorrow to show the difference.

 

[rsmith]

Fair play to you Cupra_Ross, its a great buzz when you get something like this sorted and get her back running on full steam.I'll be checking the for sale section for all the bits and bobs you have spare now


Well done for posting up the solution, to many people get there problem sorted and never update the thread.

 

[Damoegan]

Glad you got to the bottom of it, Ross

 

[Cupra Ross]

RSmith and Damien, thanks fellas. It feels like a totally different car now. I think I'll treat her to a bottle of redex and a tank of Tesco 99 this afternoon. I might even take the long way home.

 

[DPJ]

Good one Ross! I've been scratching my head over this, but been a bit busy to get very involved (sorry). Have you logged it since sorting?

 

[Cupra Ross]

Thanks Dave, you've been more than helpful to me on many issues. The logs weren't exactly decisive but they did point toward a lambda failure or a fuel starvation issue. There are so many things on the 1.8T that can give similar readings though. Coolant temp sensor failure, MAF failure, manifold/exhaust leaks and the list goes on....

I haven't logged it yet but I'll do it tomorrow when I've changed the charge pipe to pancake pipe hose and couplings. I'm sure thats losing me a few PSI even though the car was making requested boost. If its tight as a drum it should pick up a bit quicker. I'll try a quick log later just to check the fueling so I'll probably post that up tonight and do some more comprehensive ones tomorrow. My logging hill can give some brown trousers moments as redline in 3rd on the Bora is in excess of 3 digits and our local roads aren't exactly straight as an arrow

 

[SalSheikh]

well done for sticking with getting it sorted, no matter the cost!

 

[Cupra Ross]

well done for sticking with getting it sorted, no matter the cost!

Thanks mate. It couldn't have left it as it was even if it was only a small problem. I'd get a second job to fund it rather than drive a car I knew wasn't right.


Here we go Gents, logs that now say what they should be saying:

Boost and Airflow

Friday	30	April	2010	20:02:27									
06A 906 032 HJ 		1.8L R4/5VT      01 0002											
													
	Group A:	'002				Group B:	'115				Group C:	 Not Running	
		Idle speed	Engine load	Inj. period	Air mass in		Engine Speed	Engine Load	Spec. Boost	Actual Boost			
	TIME	700-820 rpm	15-25%	2.0 - 4.0 ms	2.0-4.5 g/s	TIME	700-6800 RPM	15-150%	990-1800 mbar	<=1800 mbar	TIME		
MARKER	STAMP	 /min	%	 ms	 g/s	STAMP	 /min	%	 mbar	 mbar	STAMP		
	0.49	2440	12.8	1.7	6.03	0.01	2440	12.8	990	1000			
	1.51	2400	12.8	1.7	6.36	1	2440	12.8	990	1010			
	2.51	2360	12.8	1.7	5.92	2	2400	12.8	990	1010			
	3.51	2440	31.6	3.74	15.75	3.02	2400	23.3	990	1000			
	4.71	2560	36.8	4.08	18.64	4.04	2480	33.1	990	1020			
	5.74	2600	32.3	3.74	16.58	5.22	2560	25.6	990	1020			
	6.75	2680	34.6	4.08	18.33	6.23	2640	33.1	990	1020			
	7.75	2800	48.9	5.78	28.83	7.23	2720	37.6	990	1030			
	8.76	3080	79.7	8.84	50.89	8.24	2920	52.6	990	1120			
	9.75	3560	109	12.58	81.33	9.25	3280	93.2	1370	1320			
	10.77	4480	171.4	21.08	150.42	10.25	4000	154.9	2080	1930			
	11.91	5480	157.9	19.72	163.81	11.34	4960	174.4	2010	2060			
	12.98	6280	146.6	18.02	172.94	12.47	5920	151.1	1840	1820			
	13.98	6680	59.4	3.74	47.75	13.48	6560	138.3	1830	1740			
	15	4600	129.3	17.68	138.19	14.47	5680	11.3	990	1130			
	16.01	5040	166.2	20.74	156.11	15.49	4800	163.9	1990	2020			
	16.99	5360	156.4	20.4	161.53	16.49	5200	155.6	1930	1910			
	18.06	5720	151.1	20.06	164.92	17.49	5560	153.4	1860	1850			
	19.21	6040	146.6	20.4	168.36	18.67	5880	150.4	1820	1810			
	20.22	6320	142.1	19.72	171.31	19.71	6200	145.1	1800	1770			
	21.23	6560	133.1	18.7	167.86	20.73	6440	139.1	1760	1770			
	22.22	5000	12	0	10.42	21.74	5720	11.3	990	1170			
	23.25	4680	12	0	10.61	22.73	4840	12	990	1050			
	24.23	4400	12	0	10.67	23.73	4520	12	990	1040			
	25.34	4160	12.8	0	10.36	24.74	4280	12	990	1040

Very pleased with this one, holding onto its boost right up to the redline and good MAF values. On most maps this car would be making about 215bhp with those MAF and boost numbers. I have it on excellent authority from a friend at Awesome GTi that the APR Stage 2 software makes nearly all of its extra power from Timing advance. The car feels every bit as fast as my Leon did and it was running 230bhp. I can't wait to get it on the rollers but my estimate is 225-230bhp.


Fueling:

Friday	30	April	2010	20:13:56											
06A 906 032 HJ 		1.8L R4/5VT      01 0002													
															
	Group A:	'031				Group B:	'115				Group C:	'002			
		Lambda Factor	Lambda Factor	Bin. Bits	Bin. Bits		Engine Speed	Engine Load	Spec. Boost	Actual Boost		Idle speed	Engine load	Inj. period	Air mass in
	TIME					TIME	700-6800 RPM	15-150%	990-1800 mbar	<=1800 mbar	TIME	700-820 rpm	15-25%	2.0 - 4.0 ms	2.0-4.5 g/s
MARKER	STAMP					STAMP	 /min	%	 mbar	 mbar	STAMP	 /min	%	 ms	 g/s
	0.5	1.008	1	        	        	1.02	1280	32.3	980	990	0.01	760	19.5	2.38	2.75
	2.01	1.023	1	        	        	2.52	1280	33.1	980	990	1.51	1200	38.3	4.08	8.39
	3.52	0.977	1	        	        	4.03	1200	45.9	980	1000	3.02	1120	36.8	4.42	8.61
	5.18	0.992	1	        	        	5.73	2280	63.9	980	1120	4.62	1440	48.9	5.78	15.19
	6.75	1.016	1	        	        	7.24	1520	63.2	990	1040	6.24	1920	14.3	1.7	4.11
	8.25	1.039	1	        	        	8.76	2040	92.5	1350	1230	7.74	1640	72.9	7.82	24.61
	9.76	0.93	0.914	        	        	10.26	3040	154.9	2060	1960	9.25	2320	104.5	11.9	48.53
	11.33	0.828	0.836	        	        	11.96	4560	179.7	2100	2190	10.76	3480	162.4	20.06	105.83
	13	0.821	0.828	        	        	13.49	5840	151.1	1840	1840	12.48	5080	163.2	20.4	154.83
	14.49	0.75	0.774	        	        	15.01	6200	11.3	980	1420	14	6160	145.9	18.36	171.31
	16	0.805	0.914	        	        	16.5	4640	163.2	2030	2040	15.5	5200	12.8	0	11.25
	17.5	0.828	0.828	        	        	18.05	5160	157.1	1960	1950	17.01	4840	164.7	20.4	147.64
	19.22	0.75	0.789	        	        	19.73	5240	11.3	980	1370	18.71	5360	154.1	21.08	158.19
	20.72	1.991	1.047	        	        	21.24	4240	12	980	1030	20.23	4360	12	0	9.28
	22.23	1.991	1.047	        	        	22.73	4040	12	980	1020	21.75	4160	12	0	9.33

Again, I'm really happy with those figures. You couldn't ask for better. 0.75 lambda factor at 6000rpm and wide open throttle. This is 11 parts air to 1 part fuel, exactly what you're after for safely delivered power. A tiny bit lean at low revs, again this is exactly what you're looking for.

Thanks to all for any assistance given. I hope this thread might be of some use to forum members experiencing similar problems in the future.

 

[DPJ]

Yes, that looks much more like it, Ross.

I'm guessing I know where your logging road is......