WTF is going on with my car...

muddyboots

Still hanging around
Oct 16, 2002
5,739
1
Just before I started up when I left work, I plugged the laptop in and looked at the reported fuel temp.
Outside air temp: 10degC
Fuel temp: 14.4degC
Coolant temp: 17degC

I suspect for the fuel temp, maybe 14.4 is the bottom end of the scale and it will always report that until the real temp rises above it...
Be interesting to see. In a sad way :)

Anyway, it's not a million miles out anyway so I can't see it being the cause of any problems.
 

EdButler

Full Member
Apr 24, 2005
713
1
Sheffield
Just before I started up when I left work, I plugged the laptop in and looked at the reported fuel temp.
Outside air temp: 10degC
Fuel temp: 14.4degC
Coolant temp: 17degC

I suspect for the fuel temp, maybe 14.4 is the bottom end of the scale and it will always report that until the real temp rises above it...
Be interesting to see. In a sad way :)

Anyway, it's not a million miles out anyway so I can't see it being the cause of any problems.

Snap Matey - Mine was 8 Degrees ambient and ive got very similar results - 16.2 Degrees Fuel, 19.8 Degrees Coolant.

Heres the first minute or 2 of me going down to my local Shell Garage armed with Sport 4 and Power Plus :D

Start looking elsewhere matey!

Code:
		Fuel Temp	Fuel cooling state	Intake Air Temp	Coolant Temp		Engine speed	MAF (specified)	MAF (actual)	EGR duty cycle				
	TIME	~Amb.Temp.*C	On:100%-Off:0%	~Amb.Temp.*C	~Amb.Temp.*C	TIME	790-870	230-310	210-350	40-75%	TIME			
Marker	STAMP	°C	 %	°C	°C	STAMP	 /min	 mg/str	 mg/str	 %	STAMP			
	0	17.1	0	9.9	19.8	0.32	0	850	1249.5	4.8				
	0.64	16.2	0	9.9	19.8	0.96	0	850	1249.5	4.8				
	1.28	16.2	0	9.9	19.8	1.6	0	850	1249.5	4.8				
	1.92	16.2	0	9.9	19.8	2.24	0	850	1249.5	4.8				
	2.56	17.1	0	9.9	19.8	2.88	0	850	1249.5	4.8				
	3.2	16.2	0	9.9	19.8	3.52	0	850	1249.5	4.8				
	3.84	16.2	0	9.9	19.8	4.16	0	850	1249.5	4.8				
	4.48	16.2	0	9.9	19.8	4.8	231	850	294	4.8				
	5.12	16.2	0	9.9	19.8	5.44	1092	495	455.7	48.6				
	5.76	16.2	0	9.9	19.8	6.08	966	530	470.4	43				
	6.4	16.2	0	9.9	19.8	6.74	924	560	450.8	27.9				
	7.06	17.1	0	9.9	19.8	7.4	882	605	455.7	19.9				
	7.72	16.2	0	9.9	19.8	8.04	903	590	460.6	19.9				
	8.36	17.1	0	9.9	19.8	8.68	924	560	475.3	19.9				
	9	17.1	0	9.9	19.8	9.34	903	565	460.6	19.9				
	9.68	17.1	0	9.9	19.8	10	924	550	475.3	19.9				
	10.32	17.1	0	9	19.8	10.64	903	525	455.7	19.9				
	10.96	17.1	0	9	20.7	11.48	924	490	455.7	19.9				
	11.8	17.1	0	9	20.7	12.12	903	455	460.6	21.1				
	12.44	17.1	0	9	20.7	12.76	903	435	455.7	24.3				
	13.08	17.1	0	9	20.7	13.4	903	405	460.6	31.5				
	13.72	17.1	0	9	20.7	14.04	903	375	455.7	41				
	14.36	17.1	0	9	20.7	14.68	903	350	441	54.6				
	15	17.1	0	9	20.7	15.32	903	340	367.5	59.4				
	15.64	18	0	9	20.7	15.96	903	340	323.4	60.6				
	16.28	18	0	9	20.7	16.6	903	340	338.1	60.6				
	16.92	18	0	9	20.7	17.24	903	345	333.2	60.2				
	17.56	18	0	9	20.7	17.88	903	340	328.3	60.6				
	18.2	18	0	9	20.7	18.52	903	335	323.4	60.2				
	18.84	18	0	9	20.7	19.16	903	335	323.4	60.6				
	19.48	18	0	9	20.7	19.8	903	330	323.4	61				
	20.12	18	0	9	20.7	20.44	903	330	328.3	61.4				
	20.76	18	0	9	20.7	21.08	903	330	323.4	61.4				
	21.4	18.9	0	9	20.7	21.72	903	340	323.4	60.2				
	22.04	18.9	0	9	20.7	22.36	903	335	338.1	60.6				
	22.68	18.9	0	9	20.7	23	903	335	308.7	60.2				
	23.32	18.9	0	9	20.7	23.64	903	330	333.2	60.6				
	23.96	18.9	0	9	20.7	24.28	903	330	313.6	60.6				
	24.6	18.9	0	9	20.7	24.92	903	330	328.3	61.4				
	25.24	18.9	0	9	20.7	25.56	903	325	308.7	61.4				
	25.9	18.9	0	9	20.7	26.22	903	325	308.7	60.6				
	26.56	18.9	0	9	20.7	26.88	903	330	318.5	60.6				
	27.2	18.9	0	9	20.7	27.54	882	350	313.6	58.2				
	27.86	18.9	0	9	20.7	28.2	903	340	333.2	59				
	28.52	18.9	0	9	20.7	28.84	903	340	338.1	59.8				
	29.16	18.9	0	9	20.7	29.48	903	335	328.3	60.2				
	29.8	18.9	0	9	20.7	30.12	903	335	313.6	60.2				
	30.44	18.9	0	9	20.7	30.76	903	335	328.3	60.2				
	31.08	18.9	0	9	20.7	31.4	903	335	313.6	60.2				
	31.72	18.9	0	9	20.7	32.04	903	330	328.3	60.2				
	32.36	19.8	0	9	20.7	32.68	903	330	313.6	61				
	33	19.8	0	9	20.7	33.32	903	330	338.1	60.6				
	33.64	19.8	0	9	20.7	33.96	903	325	313.6	61.4				
	34.28	19.8	0	9	20.7	34.6	903	325	303.8	61				
	34.92	19.8	0	9	20.7	35.24	903	325	308.7	61				
	35.56	19.8	0	9	20.7	35.88	903	325	318.5	60.2				
	36.2	19.8	0	9	20.7	36.52	903	325	308.7	60.2				
	36.84	19.8	0	9	20.7	37.16	903	325	333.2	61				
	37.48	19.8	0	9	20.7	37.8	903	325	333.2	61.8				
	38.12	19.8	0	9	20.7	38.44	903	325	313.6	61.4				
	38.76	19.8	0	9	20.7	39.08	903	325	323.4	61.4				
	39.4	19.8	0	9	20.7	39.72	903	325	318.5	61.4				
	40.04	19.8	0	9	20.7	40.36	903	330	333.2	61.4				
	40.68	19.8	0	9	20.7	41	903	325	323.4	61.4				
	41.32	19.8	0	9	20.7	41.64	903	320	313.6	61.4				
	41.94	19.8	0	9	20.7	42.26	903	320	313.6	61.8				
	42.58	19.8	0	9	20.7	42.9	882	340	313.6	60.6				
	43.22	19.8	0	9	20.7	43.54	819	490	343	52.6				
	43.86	19.8	0	9	20.7	44.2	945	355	411.6	57.4				
	44.52	19.8	0	9	21.6	44.86	945	330	338.1	59.8				
	45.2	19.8	0	9	21.6	45.52	924	325	323.4	60.6				
	45.84	19.8	0	9	21.6	46.18	924	325	303.8	59.8				
	46.5	19.8	0	9	21.6	46.82	966	635	338.1	35.1				
	47.14	19.8	0	9	21.6	47.48	1155	405	465.5	50.6				
	47.8	19.8	0	9	21.6	48.12	1071	375	465.5	4.8				
	48.44	19.8	0	9	21.6	48.94	1029	360	367.5	57.4				
	49.26	19.8	0	9	21.6	49.58	882	450	460.6	48.2				
	49.9	19.8	0	9	21.6	50.22	924	340	387.1	56.2				
	50.54	19.8	0	9	21.6	50.86	924	320	318.5	61.4				
	51.18	19.8	0	9	21.6	51.5	903	335	303.8	58.6				
	51.82	19.8	0	9	21.6	52.14	903	335	308.7	59				
	52.46	19.8	0	9	21.6	52.78	861	390	362.6	52.6				
	53.1	20.7	0	9	21.6	53.42	1113	410	485.1	49				
	53.74	20.7	0	9	21.6	54.06	1092	355	441	52.6				
	54.38	20.7	0	9	21.6	54.7	987	370	396.9	51				
	55.02	20.7	0	9	22.5	55.34	903	335	352.8	59.4				
	55.66	20.7	0	9	22.5	55.98	924	320	333.2	61.4				
	56.3	20.7	0	9	22.5	56.62	882	355	303.8	60.6				
	56.94	20.7	0	9	22.5	57.26	987	285	406.7	55.4				
	57.58	20.7	0	9	22.5	57.9	945	320	333.2	61				
	58.22	20.7	0	9	22.5	58.52	903	335	318.5	59				
	58.84	20.7	0	9	22.5	59.16	882	600	445.9	45				
	59.48	20.7	0	9	22.5	59.8	945	485	470.4	37.9				
	60.12	20.7	0	9	22.5	60.44	882	460	465.5	41.8				
	60.76	20.7	0	9	22.5	61.08	861	400	445.9	51.4				
	61.4	20.7	0	9	22.5	61.72	945	315	343	60.2				
	62.04	20.7	0	9	22.5	62.36	924	320	323.4	61.4				
	62.7	20.7	0	9	22.5	63.02	903	320	323.4	61.8				
	63.36	20.7	0	9	22.5	63.7	903	325	333.2	58.2				
	64.02	20.7	0	9	23.4	64.36	924	320	303.8	61.4				
	64.68	20.7	0	9	23.4	65	924	320	284.2	59.8				
	65.34	20.7	0	9	23.4	65.66	924	320	323.4	60.6				
	66	20.7	0	9	23.4	66.34	903	320	303.8	61.4				
	66.94	20.7	0	9	23.4	67.26	903	320	323.4	61.4				
	67.58	20.7	0	9	23.4	67.9	903	320	318.5	62.2				
	68.22	20.7	0	9	23.4	68.52	861	330	313.6	61.4				
	68.84	20.7	0	9	23.4	69.16	987	535	426.3	24.7				
	69.67	20.7	0	9	23.4	69.98	924	530	470.4	31.5				
	70.3	20.7	0	9	23.4	70.62	1008	405	455.7	29.5				
	70.94	20.7	0	9	23.4	71.26	1176	380	455.7	53.4				
	71.58	20.7	0	9	24.3	71.88	1302	335	382.2	65.3				
	72.2	20.7	0	9	24.3	72.52	1365	290	318.5	70.1				
	72.84	20.7	0	9	24.3	73.16	1323	280	323.4	63				
	73.48	20.7	0	9	24.3	73.8	1218	280	328.3	68.1				
	74.12	20.7	0	9	24.3	74.44	1029	280	240.1	68.1				
	74.76	20.7	0	9	24.3	75.08	882	320	274.4	60.2				
	75.4	20.7	0	9	24.3	75.72	840	345	362.6	58.2				
	76.04	20.7	0	9	24.3	76.36	882	350	352.8	57.8				
	76.68	21.6	0	9	24.3	77	924	340	343	59.4				
	77.32	21.6	0	9	24.3	77.64	924	315	328.3	61				
	77.96	21.6	0	9	24.3	78.28	945	315	303.8	61.8				
	78.6	21.6	0	9	24.3	78.92	1092	370	338.1	57.4				
	79.24	21.6	0	9	25.2	79.56	1302	295	308.7	67.3				
	79.88	21.6	0	9	25.2	80.2	1449	285	284.2	68.9				
	80.52	21.6	0	9	25.2	80.84	1533	280	298.9	66.1				
	81.16	21.6	0	9	25.2	81.48	1596	270	294	67.7				
	81.8	21.6	0	9	25.2	82.14	1638	265	289.1	69.3				
	82.48	21.6	0	9	25.2	82.8	1638	265	249.9	72.1				
	83.14	21.6	0	9	25.2	83.46	1659	265	254.8	72.9				
	83.78	21.6	0	9	25.2	84.1	1596	270	245	69.7				
	84.42	21.6	0	9	25.2	84.74	1491	275	264.6	68.9				
	85.06	21.6	0	9	25.2	85.38	1449	275	284.2	69.3				
	85.7	21.6	0	9	25.2	86.02	1386	275	279.3	69.7				
	86.34	21.6	0	9	25.2	86.65	1260	275	269.5	69.7				
	86.96	21.6	0	9	25.2	87.55	924	315	284.2	61.8				
	87.88	21.6	0	9	26.1	88.19	903	315	313.6	59.8				
	88.52	21.6	0	9	26.1	88.84	903	315	313.6	60.6				
	89.15	21.6	0	9	26.1	89.47	903	315	308.7	60.6				
	89.8	21.6	0	9	26.1	90.12	903	315	313.6	61				
	90.43	21.6	0	9	26.1	90.75	882	315	313.6	61.4				
	91.08	21.6	0	9	26.1	91.4	819	445	377.3	49.4				
	91.72	21.6	0	9	26.1	92.03	924	370	431.2	52.6				
	92.35	21.6	0	9	26.1	92.68	1218	470	480.2	4.8				
	93	21.6	0	9	26.1	93.32	1428	445	539	4.8				
	93.64	21.6	0	9	26.1	93.96	1764	480	568.4	4.8				
	94.28	22.5	0	9	26.1	94.6	2100	460	499.8	56.6				
	94.92	22.5	0	9	26.1	95.24	1323	275	392	78.9				
	95.56	22.5	0	9	26.1	95.88	1344	550	568.4	4.8				
	96.2	22.5	0	9	27	96.52	1533	795	607.6	4.8				
	96.84	22.5	0	9	27	97.16	1764	600	637	41.8				
	97.48	22.5	0	9	27	97.8	1953	490	583.1	58.6				
	98.12	22.5	0	9	27	98.44	1701	260	441	84.5				
	98.76	22.5	0	9	27	99.08	1302	385	548.8	70.5				
	99.4	22.5	0	9	27	99.72	1323	385	372.4	66.9				
	100.04	22.5	0	9	27	100.36	1344	360	352.8	66.5				
	100.68	22.5	0	9	27	101	1365	335	313.6	66.9				
	101.32	22.5	0	9	27	101.64	1386	375	333.2	61.8				
	101.96	22.5	0	9	27	102.3	1386	295	343	68.1				
	102.64	22.5	0	9	27	102.96	1407	285	318.5	68.9				
	103.3	22.5	0	9	27	103.64	1386	275	328.3	64.9				
	103.96	22.5	0	9	27.9	104.28	1365	275	328.3	66.5				
	104.6	22.5	0	9	27.9	104.92	1344	275	318.5	71.3				
	105.24	22.5	0	9	27.9	105.56	1302	275	294	74.1				
	105.88	22.5	0	9	27.9	106.2	1260	275	264.6	73.3				
	106.52	22.5	0	9	27.9	106.84	1218	275	254.8	72.1				
	107.15	22.5	0	9	27.9	107.46	1155	275	240.1	69.7				
	107.78	22.5	0	9	27.9	108.1	1092	275	230.3	66.9				
	108.42	23.4	0	9	27.9	108.74	1029	275	254.8	64.5				
	109.05	23.4	0	9	27.9	109.38	903	315	318.5	59.4				
	109.69	23.4	0	9	27.9	110.02	903	315	303.8	59				
	110.33	23.4	0	9	28.8	110.66	903	315	318.5	59.4				
	110.98	23.4	0	9	28.8	111.29	903	315	308.7	60.2				
	111.62	23.4	0	9	28.8	111.93	903	315	313.6	60.2				
	112.26	23.4	0	9	28.8	112.58	1092	295	298.9	62.6				
	112.9	23.4	0	9	28.8	113.22	1134	395	475.3	4.8				
	113.54	23.4	0	9	28.8	113.86	1260	395	357.7	59.8				
	114.18	23.4	0	9	28.8	114.5	1407	395	406.7	66.9				
	114.82	23.4	0	9	28.8	115.14	1575	375	333.2	63				
	115.46	23.4	0	9	28.8	115.78	1785	480	539	4.8				
	116.1	23.4	0	9	29.7	116.42	1827	255	426.3	69.3				
	116.74	23.4	0	9	29.7	117.06	1113	470	524.3	4.8				
	117.38	23.4	0	9	29.7	117.7	1218	390	494.9	56.6				
	118.01	23.4	0	9	29.7	118.34	1281	365	352.8	64.1				
	118.66	23.4	0	9	29.7	118.98	1281	280	318.5	68.1				
	119.3	23.4	0	9	29.7	119.62	1302	285	308.7	72.9				
	119.94	23.4	0	9	29.7	120.26	1302	290	475.3	4.8				
	120.58	23.4	0	9	29.7	120.92	1281	285	289.1	71.3				
	121.24	23.4	0	9	29.7	121.57	1260	275	289.1	64.9				
	121.9	23.4	0	9	29.7	122.22	1197	275	284.2	67.3				
	122.53	23.4	0	9	29.7	122.86	1134	275	269.5	67.3				
	123.17	23.4	0	9	30.6	123.5	1113	280	254.8	69.3				
	123.81	23.4	0	9	30.6	124.32	1134	400	455.7	4.8				
	124.63	24.3	0	9	30.6	124.95	1176	290	323.4	66.9				
	125.27	23.4	0	9	30.6	125.59	1197	280	318.5	67.3				
	126.17	24.3	0	9	30.6	126.49	1239	465	499.8	4.8				
	127.09	24.3	0	9	30.6	127.4	1302	305	313.6	70.5				
	127.71	24.3	0	9	30.6	128.03	1323	290	303.8	72.1				
	128.35	24.3	0	9	30.6	128.67	1344	295	289.1	72.1				
	129	24.3	0	9	30.6	129.31	1323	295	279.3	65.3				
	129.63	24.3	0	9	30.6	129.95	1260	270	377.3	57.4				
	130.27	24.3	0	9	30.6	130.59	1302	530	494.9	4.8				
	130.91	24.3	0	9	30.6	131.23	1407	555	558.6	26.3				
	131.56	24.3	0	9.9	30.6	131.88	1512	480	573.3	52.6				
	132.19	24.3	0	9.9	31.5	132.52	1512	270	392	74.9				
	132.83	24.3	0	9.9	31.5	133.15	1386	270	308.7	78.9				
	133.47	24.3	0	9.9	31.5	133.79	924	310	274.4	76.5				
	134.11	24.3	0	9.9	31.5	134.43	903	310	249.9	64.9				
	134.75	24.3	0	9	31.5	135.07	903	310	298.9	60.6				
	135.39	24.3	0	9	31.5	135.71	903	310	294	59.4				
	136.03	24.3	0	9	31.5	136.35	903	310	313.6	59.4				
	136.67	24.3	0	9	31.5	136.99	840
 

muddyboots

Still hanging around
Oct 16, 2002
5,739
1
Ed - thanks for that, looks like temp sensors are OK then.

OK, I took another log this morning (tried yesterday but it lost comms at the most crucial point, think it's my lead :redface: ).
This time I have logged blocks 008 and 011.

Parameters logged:
Engine speed (rpm)
IQ limit (driver request, mg/R)
IQ limit (rpm, mg/R)
IQ limit (MAF, mg/R)
Specified intake pressure (mbar)
Actual intake pressure (mbar)
MAP sensor duty cycle

This is how I understand Injection Quantities (IQ) to work:
There are 3 sources of information for how much fuel should be injected.
First there is the drivers request - IE how far down your foot is. Ranges from 0-70 mg/R.
Next is the maximum amount the ECU says can be injected at a given RPM.
Finally, is the maximum amount of fuelling the ECU says can be injected for the amount of air being sucked in (from the MAF reading).
The lowest of the three values is selected.

Intake pressures are straightforward: Specified is what pressure the ECU says it wants, actual is how much is generated by the turbo. Figures are in millibars, to work out boost you need to subtract atmospheric pressure (usually around 1000millibar give or take).

Here is today's log: http://www.seat-ibiza-mk4.co.uk/files/LOG-01-008-011-xxx.csv

Some areas of interest:
- Time stamp range 518.43-527.23 was a steady cruise on the cruise control, road reasonably level but with some slight undulation. Was around 70mph in 6th IIRC.
- Time stamp range 810.84-830.03 was a full power run, I think in 6th.
- Time stamp range 985.88-1003.48 was a full power run, I think in 4th.
- Time stamp range 1964.45-2047.64 was a variety of full power bursts, as and when traffic permitted on a dual carriageway. Unfortunately a few gaps here and there due to traffic, but you can see the full power bursts as this is anywhere the IQ Driver request sits at 70mg/R.

A couple of interesting observations:
On full power runs, the limiting factor for the fuel injection quantity is the fuelling map (IQ from RPM). The IQ for the MAF readings is always slightly higher, suggesting there is always enough air coming in. However, it was smoking again today, which does fit in with the possibility of a boost leak - the ECU would see enough air coming in and inject enough fuel accordingly, but not all of that air is reaching the engine, causing slight overfuelling and smoke.

During just one of the full power runs, the specified intake pressure was approx 2.5bar, whilst the actual sat just over 2.6bar. Any theories on why this would happen ?

Over to you, my fellow geeks :D
 

EdButler

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Apr 24, 2005
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During just one of the full power runs, the specified intake pressure was approx 2.5bar, whilst the actual sat just over 2.6bar. Any theories on why this would happen?

It just does on all of them mate, maybe something to do with the actuator not being infinitely variable.

Boost.gif


I really dont see any problems mate, the boost levels seem ok. Its better to go from 1200-4700 with 100% Acc in 4th though as it shows how and when your turbo is spooling.

Have you tried removing the pipe to your EGR and seeing if its coked up in there and potentially your inlet manifold? Also make sure the Butterfly is fully opening and actuating properly.

One other thing is that i know many on TdiClub complain about a "Snowscreen" on their air intakes of Golf/Bora Chassis cars. Its like a fine mesh that catches bugs on the intake snorkel - many remove it (isnt this what the Air Filter is for!!). Try having a look there and something may be lodged in there.
 

cheshire cat

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Dec 28, 2002
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does that initial gap between the RED and GREEN signify an over optimistic venting ofthe vac or may be sticky vanes ? you could try a restictor in the tubo vac line but it would need to be in the 1/4-mm region, jus a thought- I'll get me coat!
 

EdButler

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Apr 24, 2005
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does that initial gap between the RED and GREEN signify an over optimistic venting ofthe vac or may be sticky vanes ? you could try a restictor in the tubo vac line but it would need to be in the 1/4-mm region, jus a thought- I'll get me coat!

Thats my car mate - its all fine an healthy! I was just showing Muddy that mine's actual is sometimes more than requested

Id get ya coat ;)
 

muddyboots

Still hanging around
Oct 16, 2002
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Ed, thanks for your help on this, it does all look OK so far.

My question is this: if I did have a bit of a boost leak somewhere - would it necessarily show up in the logging ?
Presumably the ECU will specify the required boost pressure, and use the feedback from the MAP sensor to wind the VNT up far enough to achieve it and overcome the pressure loss due to a leak ?
 

EdButler

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Apr 24, 2005
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Yes a boost leak should throw an error but not necessarily a CEL.

The fault with be something like "Charge Pressure Control - POSITIVE Deviation". If its Negative though its a bit more terminal as it usually means a dodgy VNT mechanism or similar.

Also those logs say your producing a steady 1.6 BAR which is healthy - have you got any logs before it feeling lethargic as some maps have slightly higher boost.
 

MAdMAtt84

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Aug 9, 2004
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Heya muddy,

I feel sorry for you this problem is abit of a pain isnt it, dirty filter, maf issues, boost leaks, ecu reset? egr is a pain when clogged up. How many miles are you on now? having said that do you rememeber the problems i was having with mine when going thru the warm up stage of hesitating etc 1 month in at the dealers :(

Those logs, a few to many numbers for me but those graphs looked a lil out of sync in places, hows it going now seeing as te last post was 16th of this month.

Matt
 

basstard

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I'd try a go with that intake cleaner stuff and reset the ecu too,,,

this obviously isn't the prob since the intake doesn't clog from one day to another but it might help,,, [unless you want to leave things as they are to point out the real probl],,,
 

stoneyfordNI

GGG GGG GGGIGITYYY
Jan 9, 2005
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lee if the boost leak is after the map sensor it wont be "seen " as such , i had fluctuating boost issues last month and changed the top boost hoses , seals clips etc and boost is up and steady now
 

muddyboots

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Oct 16, 2002
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lee if the boost leak is after the map sensor it wont be "seen " as such , i had fluctuating boost issues last month and changed the top boost hoses , seals clips etc and boost is up and steady now
That was my thinking too. The turbo will crank up until the MAP sensor is reporting the required pressure is reached. The only thing that might be noticed is a slightly higher reading from the MAF,

I changed another one of the clips and seals at the weekend, and while this didn't make a difference, I noticed a part of this rigid plastic pipe section (which runs around the back of the engine and down the side on the Passat) was suspiciously coated in a layer of crud, which suggests there could be a leak in the pipe around there allowing oily air to come out.
I sprayed a load of cleaner on and wiped the muck away, but ran out of time to look any further, and it started raining too. I think the hissing might be slightly louder now - so perhaps I've uncovered the source of the leak. Or perhaps I'm just imagining it, which is equally possible.

Gradually eliminating possible leak sources though !
 

craig-pd130

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May 7, 2003
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Muddy, I'd be suspicious of that pipe too, it feels very flimsy & cheap to me and several thousand heat cycles plus oil & vibration ain't gonna help ...

I was once advised by a VW tech that they do see Passats that need either the flexible "elbow" from I/C to plastic pipe, or the plastic pipe replacing due to softening / cracking.
 

muddyboots

Still hanging around
Oct 16, 2002
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I was once advised by a VW tech that they do see Passats that need either the flexible "elbow" from I/C to plastic pipe, or the plastic pipe replacing due to softening / cracking.
That's interesting.

I think the leak must be from the plastic pipe; I can hear it quite clearly from inside the car so reckon it must be pretty close to the bulkhead.
 

craig-pd130

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I think he meant cracking around the joints where the flex hose plugs in ... but the plastic pipe does not feel sturdy and it would only need a weak casting mark or a small crack to give a leak.
 

muddyboots

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Oct 16, 2002
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Yup, gut feeling was that it may be leaking where the engine cover support bracket is "cast" on the side of the plastic pipe.
 

craig-pd130

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hmmmmmmm, can't really use any silicone sealant even if you do find a split as best case it would get blown out by the pressure over time, and worst case it might go into the inlet.

However, aluminium tape is great for sealing hairline cracks like that. The exhaust header on my motorbike has a hairline fissure and a "patch" of tape, secured by 2 or 3 turns of tape around the pipe, has held gas-tight for several hundred miles.

And this is on a crack which is two inches from the exhaust port at several hundred Celsius, under positive pressure.

If the surface it's sticking to is clean and grease free (use something like tape head cleaner to clean the surface), the tape will stick forever.
 

muddyboots

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Oct 16, 2002
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I've been thinking about using some kind of tape or sealant to at least pin down where the leak is.
 

stoneyfordNI

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Jan 9, 2005
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Stoney, how much did that cost for the hoses & clips, out of interest?

the clips and seals are a few pence each , the dearest part was the right angled pipe at the EGR ( £ 20 or so) mine never looked "sealed" so this was one i wanted changed , just watch tho , the clips and seals are all different diameters etc , so is a bit of a kerfudle to get the right one where they should
 
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