20mpg on TDI

[Big_daddy]

My mPG has suffered alot, i taught it was petrol prices but i dont think so. According to MPG computer it varies from 18mpg to 29mpg, some times im lukcy 33mpg.
I have alhambra 1.9 PD TDI with stage P-Torque remap.
Past month ago i cleaned the egr valve, then lowered the setting for it on vag.

Other symptons i have also countered were

*it smokes on cold engine some times
*3rd gear feels dead but 2nd gear ok(i think), i could hear the turbo chatter loud from the WG when i come off heavy boost (right foot).
*Normaly 95% of time the cars 1st click instant, and once here and there it just struggles to fire up.

Dont know realy what to do

 

[ChrisGTL]

Any fault codes showing up?

If not, do what I've just done and reset ECU fully by removing negative battery terminal for 30mins.

Remember to have your radio code if needed though after reconnecting as EVERYTHING will be lost.

 

[Big_daddy]

No faults what so ever, i done reset, still no luck,
is the mpg computer suppose to drop when idling im at 9mpg WTF!

Guna do a quick power run of the air mass and boost, any suggestion on what other block to measure?

 

[muddyboots]

My MPG has suffered a lot, I thought it was petrol prices but I don't think so.

Why do you think the cost of fuel makes any difference to your MPG ???


What sort of driving do you do - stop-start urban driving, motorway cruising, etc etc ?

 

[muddyboots]

And are you sure your trip computer readings match up to the amount you're *really* using ?

 

[ChrisGTL]

No faults what so ever, i done reset, still no luck,
is the mpg computer suppose to drop when idling im at 9mpg WTF!

Guna do a quick power run of the air mass and boost, any suggestion on what other block to measure?

Fuel and coolant temperatures, but not sure which blocks these are.

As you say MAF and Boost are a good place to start.

Do a 3rd gear run from 2000RPM to redline without lifting off inbetween.......on a private road of course (once engine oil is hot)

 

[muddyboots]

is the mpg computer suppose to drop when idling

Yes, because you're using more fuel but your mileage isn't changing while you're stood still...

 

[Big_daddy]

3rd gear

Group A:	'003				Group B:	'010			
	RPM	Mass Air / Rev.	Mass Air / Rev.	Duty Cycle		Mass Air / Rev.	Absolute Pres.	Absolute Pres.	Load
TIME					TIME				
STAMP	 /min	 mg/R	 mg/R	 %	STAMP	 mg/R	 mbar	 mbar	%
0.01	924	295	264.6	58.6	0.36	289.1	989	1000	4.7
0.76	924	295	274.4	63	1.18	597.8	989	1000	72.5
1.58	1008	850	622.3	4.8	1.98	676.2	989	1142	100
2.38	1092	850	725.2	4.8	2.78	759.5	989	1326	100
3.18	1239	850	872.2	4.8	3.58	984.9	989	1652	100
3.98	1428	850	1127	4.8	4.38	1249.5	989	2132	100
4.78	1701	850	1249.5	4.8	5.2	1249.5	989	2530	100
5.61	1995	850	1249.5	4.8	6.03	1249.5	989	2560	100
6.43	2289	850	1249.5	4.8	6.84	1249.5	989	2560	100
7.24	2604	850	1249.5	4.8	7.66	1249.5	989	2560	100
8.08	2898	850	1249.5	4.8	8.49	1249.5	989	2560	100
8.91	3171	850	1249.5	4.8	9.32	1249.5	989	2560	100
9.72	3402	850	1249.5	4.8	10.12	1249.5	989	2560	100
10.52	3612	850	1249.5	4.8	10.92	1249.5	989	2560	86.7
11.35	3780	850	1249.5	4.8	11.74	1220.1	989	2560	57.6

4th gear

Group A:	'003				Group B:	'010			
	RPM	Mass Air / Rev.	Mass Air / Rev.	Duty Cycle		Mass Air / Rev.	Absolute Pres.	Absolute Pres.	Load
TIME					TIME				
STAMP	 /min	 mg/R	 mg/R	 %	STAMP	 mg/R	 mbar	 mbar	%
0.4	1386	850	651.7	4.8	0.01	578.2	989	1224	0
1.2	1428	850	955.5	4.8	0.8	813.4	989	1306	100
2.03	1533	850	1205.4	4.8	1.63	1171.1	989	1887	100
2.86	1680	850	1249.5	4.8	2.45	1249.5	989	2234	100
3.68	1827	850	1249.5	4.8	3.28	1249.5	989	2438	100
4.48	1953	850	1249.5	4.8	4.08	1249.5	989	2530	100
5.28	2100	850	1249.5	4.8	4.88	1249.5	989	2550	100
6.08	2247	850	1249.5	4.8	5.68	1249.5	989	2560	100
6.88	2373	850	1249.5	4.8	6.48	1249.5	989	2560	100
7.68	2499	850	1249.5	4.8	7.28	1249.5	989	2560	100
8.48	2625	850	1249.5	4.8	8.08	1249.5	989	2560	100
9.28	2751	850	1249.5	4.8	8.88	1249.5	989	2560	100
10.09	2856	850	1249.5	4.8	9.68	1249.5	989	2560	100
10.93	2982	850	1249.5	4.8	10.51	1249.5	989	2560	100
11.76	3087	850	1249.5	4.8	11.34	1249.5	989	2560	100
12.56	3192	850	1249.5	4.8	12.16	1249.5	989	2560	96.5
13.36	3276	850	1249.5	4.8	12.96	1249.5	989	2560	100
14.16	3360	850	1249.5	4.8	13.76	1249.5	989	2560	84.3
14.96	3402	850	1249.5	4.8	14.56	1249.5	989	2550	67.8

Just a drive back on the way home, (Spirited driving and traffic)

Group A:	'003				Group B:	'010			
	RPM	Mass Air / Rev.	Mass Air / Rev.	Duty Cycle		Mass Air / Rev.	Absolute Pres.	Absolute Pres.	Load
TIME					TIME				
STAMP	 /min	 mg/R	 mg/R	 %	STAMP	 mg/R	 mbar	 mbar	%
0.01	903	250	249.9	84.5	0.4	274.4	989	989	0
0.81	903	250	264.6	84.5	1.23	264.6	989	989	0
1.65	966	820	382.2	19.9	2.06	553.7	989	1010	16.9
2.46	1281	515	470.4	43.8	2.89	494.9	989	1142	19.6
3.31	1071	595	592.9	43.4	3.73	715.4	989	1244	26.7
4.14	1785	830	886.9	4.8	4.54	793.8	989	1836	35.3
4.94	2583	570	784	65.3	5.34	710.5	989	1540	0
5.74	1743	250	661.5	84.5	6.14	686	989	1255	34.5
6.57	1659	850	994.7	4.8	6.99	1249.5	989	1989	78
7.41	2226	850	1141.7	4.8	7.82	1092.7	989	2071	32.2
8.22	2121	240	710.5	4.8	8.62	632.1	989	1346	21.2
9.02	1575	850	945.7	4.8	9.42	1063.3	989	1734	45.1
9.82	1743	850	1205.4	4.8	10.22	1249.5	989	2346	90.2
10.65	1995	850	1225	4.8	11.07	1249.5	989	2275	77.3
11.48	2247	850	1146.6	4.8	11.9	666.4	989	1632	0
12.32	1491	375	602.7	83.3	12.72	661.5	989	1265	28.6
13.12	1575	760	886.9	4.8	13.52	1029	989	1693	48.2
13.92	1638	850	1127	4.8	14.33	896.7	989	1795	26.7
14.75	1659	585	847.7	55	15.16	666.4	989	1489	14.5
15.57	1659	280	514.5	80.5	15.98	539	989	1193	0
16.4	1596	250	475.3	84.5	16.8	465.5	989	1061	0
17.2	1554	250	426.3	84.5	17.6	396.9	989	1030	0
18	1512	250	392	84.5	18.4	362.6	989	1000	0
18.8	1428	250	382.2	84.5	19.2	362.6	989	1000	0
19.6	1218	250	377.3	84.5	20	235.2	989	1010	0
20.4	903	250	245	84.5	20.83	254.8	989	1000	0
21.24	903	250	264.6	84.5	21.66	269.5	989	1000	0
22.08	903	250	245	84.5	22.48	259.7	989	1000	0
22.88	903	250	274.4	84.5	23.28	254.8	989	989	0
23.68	903	250	264.6	84.5	24.08	264.6	989	989	0
24.48	903	250	279.3	84.5	24.88	259.7	989	989	0
25.28	903	250	259.7	84.5	25.68	264.6	989	989	0
26.11	903	250	274.4	84.5	26.52	259.7	989	989	0
26.94	903	250	279.3	84.5	27.36	259.7	989	989	0
27.77	903	250	249.9	84.5	28.17	249.9	989	989	0
28.57	903	250	259.7	84.5	28.97	274.4	989	989	0
29.37	882	250	240.1	84.5	29.77	259.7	989	989	0
30.17	882	250	259.7	84.5	30.59	274.4	989	989	0
30.97	1134	550	529.2	19.9	31.37	441	989	1010	0
31.77	924	255	264.6	63.8	32.17	254.8	989	1010	0
32.57	903	250	269.5	73.3	32.97	274.4	989	1000	0
33.37	924	860	578.2	4.8	33.79	583.1	989	1020	25.9
34.2	1260	905	769.3	19.9	34.62	700.7	989	1346	25.9
35.02	1554	850	867.3	4.8	35.43	984.9	989	1714	38
35.83	2394	650	882	81.3	36.23	715.4	989	1693	0
36.63	2079	240	686	4.8	37.03	681.1	989	1306	18.4
37.44	1575	780	808.5	4.8	37.83	921.2	989	1530	30.6
38.23	1806	820	1014.3	4.8	38.63	1195.6	989	2009	71.4
39.03	2289	850	1205.4	4.8	39.43	1249.5	989	2356	77.6
39.83	2877	850	1205.4	4.8	40.23	1092.7	989	2132	12.2
40.63	2541	250	700.7	4.8	41.03	671.3	989	1397	12.2
41.43	1890	550	632.1	61	41.83	828.1	989	1469	41.2
42.23	1995	850	1156.4	4.8	42.67	1151.5	989	2122	100
43.08	2247	850	1195.6	4.8	43.5	1249.5	989	2285	90.6
43.91	2478	850	1249.5	4.8	44.31	1220.1	989	2264	91.4
44.71	2709	850	1249.5	4.8	45.11	779.1	989	2315	0
45.51	2184	240	651.7	4.8	45.91	573.3	989	1295	0
46.31	1869	245	441	83.7	46.73	416.5	989	1132	0
47.11	1869	250	372.4	71.7	47.53	382.2	989	1132	17.3
47.93	1806	390	396.9	62.2	48.34	387.1	989	1142	17.6
48.76	1827	580	656.6	49	49.18	553.7	989	1418	23.5
49.59	1827	525	509.6	53.4	49.99	524.3	989	1489	24.7
50.39	1827	650	661.5	47.8	50.79	931	989	1601	46.3
51.19	1869	850	1229.9	4.8	51.62	1131.9	989	2275	94.5
52.04	1974	850	1136.8	4.8	52.44	1156.4	989	2132	83.1
52.86	2079	850	1033.9	4.8	53.27	837.9	989	1795	20.4
53.69	2100	240	632.1	4.8	54.09	612.5	989	1275	0
54.47	2037	240	602.7	4.8	54.87	602.7	989	1204	14.1
55.27	1974	240	450.8	84.5	55.69	592.9	989	1142	0
56.09	1953	240	411.6	83.7	56.49	382.2	989	1142	0
56.89	1806	245	377.3	84.5	57.29	421.4	989	1071	0
57.69	1323	250	436.1	84.5	58.09	352.8	989	1040	0
58.49	924	250	279.3	75.3	58.89	284.2	989	1020	0
59.29	903	250	269.5	84.5	59.69	259.7	989	1010	0
60.09	1428	340	470.4	28.3	60.49	298.9	989	1030	12.5
60.89	1407	495	543.9	60.6	61.29	455.7	989	1132	21.2
61.69	1449	470	676.2	47.8	62.09	308.7	989	1204	14.1
62.49	1491	270	298.9	66.9	62.89	455.7	989	1102	11.4
63.29	1491	255	421.4	84.5	63.69	392	989	1051	11
64.09	1512	250	392	84.5	64.49	387.1	989	1020	8.6
64.89	1470	250	367.5	84.5	65.29	612.5	989	989	18
65.69	1491	475	323.4	54.6	66.09	578.2	989	1132	21.2
66.49	1491	665	700.7	26.7	66.89	759.5	989	1357	25.9
67.29	1575	615	436.1	57	67.69	803.6	989	1479	25.1
68.09	1617	560	543.9	84.5	68.49	695.8	989	1479	22.4
68.89	1659	540	504.7	77.3	69.29	279.3	989	1469	22.7
69.69	1680	540	739.9	68.1	70.09	504.7	989	1489	22.7
70.49	1680	535	607.6	44.6	70.89	661.5	989	1469	22.7
71.29	1722	530	88.2	77.3	71.69	607.6	989	1489	22.4
72.09	1764	520	573.3	83.7	72.49	553.7	989	1448	21.6
72.89	1785	535	833	19.9	73.29	833	989	1469	25.1
73.69	1848	530	749.7	84.5	74.09	651.7	989	1550	24.3
74.49	1869	525	465.5	79.3	74.88	102.9	989	1540	24.3
75.27	1890	520	34.3	52.6	75.68	127.4	989	1591	23.9
76.09	1911	515	475.3	53	76.48	784	989	1520	23.1
76.89	1953	505	411.6	62.2	77.29	583.1	989	1530	22.7
77.69	1995	460	421.4	58.2	78.09	470.4	989	1489	20.4
78.49	1848	245	357.7	84.5	78.9	588	989	1214	0
79.32	1197	290	303.8	84.5	79.73	666.4	989	1163	25.5
80.15	1386	730	808.5	4.8	80.57	779.1	989	1448	16.5
80.96	1386	250	730.1	84.5	81.36	583.1	989	1193	0
81.76	1323	250	480.2	84.5	82.18	436.1	989	1061	0
82.58	1281	250	411.6	84.5	82.98	392	989	1020	3.5
83.38	1281	530	592.9	37.1	83.78	274.4	989	1071	3.5
84.18	1218	250	421.4	84.5	84.58	406.7	989	1020	0
84.98	1134	250	401.8	84.5	85.38	235.2	989	1020	0
85.78	903	250	264.6	82.1	86.18	274.4	989	1000	0
86.58	903	250	269.5	84.5	86.98	269.5	989	1000	0
87.38	903	250	264.6	84.1	87.78	249.9	989	1000	0
88.18	903	250	254.8	84.5	88.58	245	989	989	0
88.98	903	250	254.8	84.5	89.38	240.1	989	989	0
89.78	903	250	254.8	84.5	90.18	245	989	989	0
90.58	903	250	264.6	84.5	90.98	264.6	989	989	0
91.38	903	250	245	84.5	91.78	259.7	989	989	0
92.18	903	250	259.7	84.5	92.61	284.2	989	989	0
93.03	903	250	240.1	84.5	93.44	259.7	989	989	0
93.86	903	250	254.8	84.5	94.26	245	989	989	8.2
94.66	1155	510	548.8	45.4	95.06	514.5	989	1061	15.7
95.46	1008	565	612.5	45.4	95.86	548.8	989	1142	15.7
96.26	1218	590	529.2	42.2	96.66	784	989	1265	31
97.06	1869	550	896.7	33.1	97.46	382.2	989	1622	0
97.86	1365	250	651.7	84.5	98.26	269.5	989	1183	12.9
98.66	1197	850	695.8	4.8	99.06	764.4	989	1316	36.1
99.46	1428	850	882	4.8	99.86	984.9	989	1663	40
100.26	1764	850	1131.9	4.8	100.66	1053.5	989	2040	38.4
101.06	2079	685	911.4	64.5	101.46	744.8	989	1683	0
101.86	1575	250	588	84.5	102.26	592.9	989	1214	21.2
102.66	1365	850	798.7	4.8	103.06	891.8	989	1489	32.9
103.46	1470	850	950.6	4.8	103.86	984.9	989	1765	28.2
104.26	1575	695	1019.2	4.8	104.66	1004.5	989	1846	28.6
105.06	1659	665	975.1	4.8	105.46	931	989	1744	30.6
105.86	1785	850	989.8	4.8	106.26	989.8	989	1846	32.9
106.66	1911	705	911.4	58.2	107.06	715.4	989	1744	23.5
107.46	1701	250	622.3	84.5	107.86	646.8	989	1244	12.2
108.29	1407	850	749.7	4.8	108.71	896.7	989	1428	73.7
109.12	1449	850	1082.9	4.8	109.54	1210.3	989	2081	93.3
109.94	1575	850	1215.2	4.8	110.34	1249.5	989	2244	67.5
110.74	1680	850	1171.1	4.8	111.14	1097.6	989	2101	50.6
111.54	1785	850	1048.6	4.8	111.94	886.9	989	1836	13.3
112.34	1764	245	641.9	84.5	112.74	524.3	989	1255	11.8
113.14	1764	855	779.1	4.8	113.54	955.5	989	1571	16.5

 

[Big_daddy]

Why do you think the cost of fuel makes any difference to your MPG ???


What sort of driving do you do - stop-start urban driving, motorway cruising, etc etc ?

Well i use the car mainly around town, going shopping, dropping/ picking kids. Ive used it on the motorway and the mpg only increased to around just under 40mpg

And are you sure your trip computer readings match up to the amount you're *really* using ?

I dont realy use the mgp, i jsut fill a certain amount and calcuate it my self.
for example, if i put £10 of diesel @1.09 a litre i get 50 at the most and that with boosting at all (just a tiny bit ). I mainly use shell (normal stuff and V-stuff), ive tried other stations still no different.

 

[Muttley]

Best way to guess at fuel usage is to fill the tank until the pump cuts off, that is, always fill it to the same level. Note down your mileage at the same time, then next time you fill up you will know how much fuel you used between fills and what mileage you did.

A remap will always make the consumption worse.

PD's all have VNT turbos, no wastegate. In any case, the turbo shouldn't chatter, it's a sign of abuse, but if your VNT turbo is chattering something is really wrong.

 

[JayFR150]

Best way to guess at fuel usage is to fill the tank until the pump cuts off, that is, always fill it to the same level. Note down your mileage at the same time, then next time you fill up you will know how much fuel you used between fills and what mileage you did.

A remap will always make the consumption worse.

PD's all have VNT turbos, no wastegate. In any case, the turbo shouldn't chatter, it's a sign of abuse, but if your VNT turbo is chattering something is really wrong.

Your wrong about the remap making the consumption worse, its made my car much easier to maintain healthy mpg, its only when u hammer it the remap uses more fuel but casual driving my avg mpg has greatly improved.
Also my fr 150 has a wastegate nois, i believe from the actuator? mayb your just talking from experience with your car?

 

[JamesL]

My mum has a VW Sharan, and her mpg is pretty much always around 40 mpg or less.

 

[ChrisUK]

A remap will always make the consumption worse.
.

Your wrong there mate !

A remap should actually increase your MPG when driving "normally".

 

[Big_daddy]

Are boost / maf readings fine? PLus what other block do you suggest to measure? How do i check if all the injectors are work as required?

 

[Muttley]

All PD engines use a variable-geometry turbocharger. Instead of a wastegate this has a set of moveable stator vanes in the turbine section which close to reduce the turbine inlet area at low revs (which generate low volumes of exhaust gas) and thus keep the gas flow up to speed through the turbine, keeping the compressor spinning to produce useful boost down to much lower revs. The vanes gradually open under ECU control as the revs (and exhaust volume) rise, controlling the turbine rpm. At full revs the vanes are fully open: the turbo is sized that way so as to waste as little of the exhaust energy as possible. Turbo control is handled solely by the vanes: there is no wastegate, and no need for one.

The vacuum actuator on the VNT turbos is there to move the vanes, but looks exactly like the device that opens the wastegate on the TDI 90 turbo.

http://www.technologie-entwicklung.de/Gasturbines/VNT15-Turbo/vnt15-turbo.html

As far as a remap improving fuel consumption, I'm guility of the assumption that a remap is performed in order to boost performance. Once remapped, if you don't use that performance then you have wasted your money. Hence remapped cars are usually driven harder and return mpg figures consistent with the increased performance being used.

Of course it is possible to remap a car for economy rather than performance. I don't know if it has ever been asked for, though.

 

[Big_daddy]

The alhambra comes as 115bhp standard, the remap is mainly help aid of qucik pick up, espically with full house.

Other thing i forgot to mention was, around 1200rpm, eg 2nd gear, if you keep the gas pedal steady, you hear the turbo boosting up'/ then cutting of, then boosting up. like some on'ing and off'ing a vacum.

When is the turbo suppose to cut off? Mines turns of at 3500, rpm, it, was told by P-torque it suppose cut off then, because the car feels abit laggy, by ttime it spools at 3000rpm it dies at 3500? whats point of that?

 

[ChrisGTL]

if you keep the gas pedal steady, you hear the turbo boosting up'/ then cutting of, then boosting up. like some on'ing and off'ing a vacum.

This is exactly what I have now on my Leon. Does yours only do that on part throttle? Never does it on full throttle?

I've bought a new BOSCH MAF, which I will be fitting this weekend, will clean my current MAF with Isopropanol and keep it as a spare.

I'm going to swap my N75/N18 over too this weekend, but I don't want to fix it without knowing what the actual failed component is so I may just try one thing at a time.....

Fixing it without knowing how i've fixed it will really piss me off.

 

[Big_daddy]

This is exactly what I have now on my Leon. Does yours only do that on part throttle? Never does it on full throttle?

I've bought a new BOSCH MAF, which I will be fitting this weekend, will clean my current MAF with Isopropanol and keep it as a spare.

I'm going to swap my N75/N18 over too this weekend, but I don't want to fix it without knowing what the actual failed component is so I may just try one thing at a time.....

Fixing it without knowing how i've fixed it will really piss me off.

It only occurs when part trottle between 10- 50%. Ive cleaned MAF so that didnt help. Do let me know how it goes

 

[ChrisGTL]

It only occurs when part trottle between 10- 50%. Ive cleaned MAF so that didnt help. Do let me know how it goes

Tried clamping the EGR vacume pipe?

EGR only works on part throttle, and as our problems only seem to be when using part throttle i'm looking at the obvious 1st.

I got the BOSCH MAF brand new for £30, so thought may aswel, then I can put a lovely clean MAF on when I come to going stage2 or hybrid next year.

 

[Big_daddy]

Tried clamping the EGR vacume pipe?

EGR only works on part throttle, and as our problems only seem to be when using part throttle i'm looking at the obvious 1st.

I got the BOSCH MAF brand new for £30, so thought may aswel, then I can put a lovely clean MAF on when I come to going stage2 or hybrid next year.

shall i just remove it and block of the vacum line to egr instead?