Still chasing hesitation!

[Lee1892]

So I have been chasing hesitation for what seems like forever!

The car is stage 1 AMK LCR, 103K miles and was showing absolutlely no codes on vcds.

The only code showing is P1296 - Error in Mapped Cooling System - The thermostat has just given up, I know it needs replaced I have 2 green top CTS as well and have tried both in the car.. The car has been hesitating since just after I got it...

So far I have changed/cleaned the following.

* N75 Silicon hose from charge pipe changed
* CV Hose from Charge pipe changed
* Forge 007p with green spring
* Forge TIP
* JR 80mm Cone filter
* Vac hoses changed from DV to Inlet etc
* PCV system removed and a new crank case breather fitted

Now I have found if I unplug the N75 the car is a lot smoother as it is running less boost, I have also unplugged the MAF at the same time, and on its own.

When I unplug the MAF the hesitation is still there but not as profound as before. It's kind of like a pulsing/surging, can happen in any gear and when its on then off then on again, it holds back and I can hear the DV release and turbo chatter as it dumps quite loud then the thing builds up and takes off...

When I drive it with the MAF and N75 unplugged it still holds back a bit but is definitely easier to drive. I also not that when these are unplugged my MPG is considerably better!

car also has a bit of a lumpy idle, hunts between 720 and 780...

At my wits end with it now!

Anywhere else to look??

 

[mty12345]

I think you need to plug everything back in and do some logs with Vagcom/VCDS and post them up.

Unplugging either the MAF or the N75 will just mean that the ecu switches to running less power and uses an "emergency backup" map to take it's best guess at the airflow etc. I don't think that will get you any closer to an answer and will probably just complicate things.
The mpg is calculated using the MAF and the injection duration. With it unplugged you are getting a false reading.

 

[mty12345]

If the engine isn't getting hot enough then that will affect the fuelling very slightly, would be worth getting the thermostat done too IMO. One more thing to rule out as it needs doing anyway.

 

[Lee1892]

Cheers mate, what should I be logging on VCDS, any idea of what groups to be checking and under what circumstances, i.e half throttle, full throttle etc?

Car was doing this for the last couple of months, thermostat had always been great til just a few days ago, proper knackered by the looks of it. Only gets hot when in traffic/idle. Will be buying the Thermostat this week...

 

[mty12345]

Yeah the thermostats fail all the time for some reason,but at least they always seem to fail open rather than closed. They are a real pain in the ass to get to though on the AUQ, not sure about the BAM may be easier to get at with the different manifold.

As for logging, as far as i can remember off the top of my head, i think i would do 002,114 and 115. Usual practice is to do a run on a flat straight road,in 3rd gear from lowish revs all the way to the redline.... Reason being that 1st and 2nd gears go past too fast to be of much use and obviously redline in 4th would be 100mph+

As far as i can remember:
002 should show air flow and injection period
114 should show the duty cycle of your N75 and what it's doing
115 should show boost pressure requested vs the actual pressure.

Maybe do a log of 002, 020 and 032 for good measure.

020 being knock control
032 being learnt fueling
Vagcom itself tells you what each group is when you hover the cursor over each box, they are the things you are looking for though.

 

[Lee1892]

Yeah the thermostats fail all the time for some reason, at least they always fail open rather than closed. They are a real pain in the ass to get to though.

As for logging, as far as i can remember of the top of my head, i think i would do 002,114 and 115. Usual practice is to do a run in 3rd gear from lowish revs all the way to the redline.... Reson being that 1st and 2nd gears go past too fast to be of much use and obviously redline in 4th would be 100mph+

As far as i can remember:
002 should show air flow and injection period
114 should show the duty cycle of your N75 and what it's doing
115 should show boost pressure requested vs the actual pressure.

Outstanding mate, will try get that done tomorrow if I can! Will plug everything back in, hopefully it will show up whats wrong!!

 

[mty12345]

Outstanding mate, will try get that done tomorrow if I can! Will plug everything back in, hopefully it will show up whats wrong!!

Fingers crossed for you buddy, it should at least help rule some things out including the N75 and the MAF.

 

[LongDave]

Have you logged the EGT probe readings? i had a problem for months that i spend hundreds on replacing parts only to find the EGT sensor was providing dodgy readings occasionally (> 1000 degrees) so the ECU was dumping fuel into the cylinders when there was no need, causing symptoms similar to what you describe

 

[Lee1892]

Cheers lads.

I got a couple of Logs last night on what people have been saying.

Here's the first lot...

Group A:	'002				Group B:	'114				Group C:	'115			
	RPM	Load	Inj. On Time	Mass Flow		Load	Load	Load	Load		RPM	Load	Absolute Pres.	Absolute Pres.
TIME					TIME					TIME				
STAMP	 /min	%	 ms	 g/s	STAMP	%	%	%	%	STAMP	 /min	%	 mbar	 mbar
0.35	1760	15.8	1.7	5.44	0.66	138.3	137.3	15.8	0	0.95	1760	16.5	970	970
1.27	1760	15.8	1.7	5.36	1.57	137.6	135.8	17.3	0	1.87	1760	18.8	970	970
2.16	1760	42.1	5.44	18.53	2.47	138.3	137.3	64.7	0	2.76	1840	65.4	970	1000
3.08	1880	50.4	3.4	11.06	3.37	143.6	141.8	18	0	3.68	1920	18	970	1010
3.98	1880	15.8	1.36	5.11	4.28	145.1	143.3	21.8	0	4.57	1920	25.6	970	980
4.89	1880	33.8	3.4	12.72	5.18	145.1	143.3	32.3	0	5.49	1960	34.6	970	980
5.79	1960	33.8	3.06	12.83	6.09	147.4	146.3	33.8	0	6.39	2000	32.3	970	990
6.7	2000	30.1	2.72	11.69	7	152.6	150.7	27.8	0	7.3	2040	28.6	970	990
7.6	2040	25.6	2.38	9.67	7.89	154.9	153.7	22.6	0	8.19	2000	17.3	970	990
8.51	2000	16.5	1.7	6.83	8.81	150.4	149.3	16.5	0	9.11	2000	16.5	970	980
9.41	2040	20.3	2.04	8.14	9.71	151.1	149.3	20.3	0	10.02	2000	21.8	970	970
10.32	2000	24.1	2.38	9.17	10.62	150.4	149.3	26.3	0	10.91	2000	27.8	970	970
11.22	2000	27.1	2.72	10.69	11.51	151.1	149.3	27.8	0	11.83	2000	27.8	970	980
12.12	2040	32.3	3.06	13.17	12.43	156.4	155.2	39.8	0	12.73	2080	50.4	970	980
13.03	2120	63.2	6.46	28.44	13.33	169.9	168.7	66.2	0	13.63	2240	70.7	1270	1070
13.94	2320	88.7	9.18	44.56	14.24	175.2	173.1	100.8	95.3	14.54	2520	112.8	1840	1440
14.84	2680	128.6	13.6	77.64	15.14	179.7	177.6	151.1	84.7	15.45	3000	186.5	2170	2360
15.75	3200	191.7	22.1	142.14	16.05	187.2	185.1	191.7	65.9	16.35	3600	191.7	2300	2460
16.65	3760	191.7	19.38	139.86	16.95	191.7	192.5	191.7	63.5	17.26	4160	191.7	2320	2420
17.56	4360	191.7	19.72	165.5	17.86	191.7	195.5	191.7	61.6	18.16	4720	191.7	2360	2460
18.46	4960	191.7	19.38	183.22	18.76	191.7	197	191	59.6	19.07	5280	186.5	2260	2390
19.37	5440	186.5	17.68	193.69	19.67	191.7	197	189.5	58	19.97	5760	178.2	2300	2270
20.27	5920	178.9	18.7	200.06	20.58	191.7	192.5	160.9	61.6	20.89	6160	177.4	2230	2120
21.18	6280	160.2	15.98	201.75	21.49	191.7	189.6	175.2	71.4	21.78	6520	145.1	2210	2280
22.09	6640	165.4	15.98	201.67	22.4	191.7	189.6	174.4	63.5	22.7	6520	15.8	970	2180
22.99	6000	13.5	1.36	0.31	23.29	191.7	197	14.3	0	23.59	5280	51.1	2100	970
23.9	5240	102.3	11.22	152.03	24.2	191.7	197	165.4	91.8	24.5	5400	191.7	2340	2540
24.8	5560	191.7	22.78	206.25	25.1	191.7	197	191.7	88.6	25.4	5680	191.7	2320	2380
25.71	5760	187.2	20.06	200.06	26.01	191.7	195.5	175.2	87.8	26.32	5920	176.7	2280	2340
26.61	6000	178.9	19.38	201.67	26.91	191.7	191	175.9	85.9	27.21	5960	86.5	970	2540
27.53	5560	12	1.36	0	27.82	191.7	197	14.3	0	28.12	4640	14.3	970	1120
28.42	4840	13.5	1.7	11.72	28.71	191.7	197	12	0	29.02	4760	12	970	1020
29.33	4720	12.8	0	11.28	29.63	191.7	197	12	0	29.93	4680	12	970	1010
30.23	4640	12	0	10.92	30.53	191.7	195.5	12	0	30.82	4560	12	970	1010
31.14	4480	12	0	11.31	31.44	191.7	195.5	12.8	0	31.73	4360	12.8	970	1000
32.04	4320	12.8	0	10.42	32.34	191.7	195.5	12.8	0	32.64	4240	12.8	970	1000
32.94	4200	12.8	0	10.42	33.25	191.7	194	12.8	0	33.55	4120	12.8	970	1000
33.84	4080	12.8	0	10.25	34.15	191.7	194	12.8	0	34.45	4040	12.8	970	1000
34.75	4000	12.8	0	9.86	35.06	191.7	194	12	0	35.36	3960	12.8	970	1000
35.66	3920	12.8	0	10.03	35.96	191.7	192.5	12.8	0	36.27	3880	12.8	970	1000
36.57	3840	12.8	0	9.53	36.87	191.7	191	12.8	0	37.17	3800	12.8	970	1000
37.47	3760	12.8	0	9.61	37.76	191.7	189.6	12.8	0	38.08	3720	12.8	970	1000
38.38	3720	12.8	0	9.5	38.68	191	189.6	12.8	0	38.98	3680	12.8	970	1000
39.28	3640	12.8	0	8.83	39.58	190.2	188.1	12.8	0	39.89	3600	12.8	970	1000
40.19	3560	12.8	0	8.92	40.49	188.7	186.6	12.8	0	40.79	3520	12.8	970	1000
41.09	3520	15.8	2.04	11.25	41.39	188	186.6	16.5	0	41.7	3480	15.8	970	990
42	3480	15.8	1.7	11.06	42.3	187.2	185.1	15.8	0	42.6	3440	14.3	970	990
42.9	3400	13.5	0	9.31	43.2	186.5	185.1	13.5	0	43.51	3360	13.5	970	1000
43.8	3360	13.5	0	9.03	44.11	185.7	183.6	13.5	0	44.41	3320	13.5	970	1000
44.7	3280	13.5	0	9.03	45.01	185.7	183.6	13.5	0	45.31	3240	13.5	970	1000
45.62	3240	14.3	2.04	9.47	45.92	185	183.6	16.5	0	46.22	3200	15.8	970	990
46.52	3200	15.8	1.7	9.78	46.82	184.2	182.1	15.8	0	47.13	3160	15.8	970	990
47.43	3120	15.8	1.7	9.69	47.73	183.5	182.1	15.8	0	48.03	3120	15.8	970	980
48.33	3080	15.8	1.36	9.47	48.64	182.7	180.6	15.8	0	48.94	3080	15.8	970	980
49.24	3080	16.5	1.7	9.97	49.54	182.7	180.6	15.8	0	49.84	3040	15.8	970	980
50.14	3040	15.8	1.7	9.39	50.45	182	180.6	15.8	0	50.75	3000	15.8	970	980
51.05	3000	15.8	1.7	9.31	51.35	182	180.6	15.8	0	51.65	2960	15.8	970	980
51.95	2960	15.8	1.7	9.25	52.26	181.2	179.1	19.5	0	52.56	2960	55.6	970	960
52.86	2960	75.9	8.16	53.22	53.16	182	180.6	93.2	51.8	53.46	3040	127.8	1660	1580
53.76	3120	160.2	16.66	119.72	54.07	184.2	182.1	191.7	67.5	54.37	3200	191.7	2240	2520
54.67	3320	191.7	20.06	120.81	54.97	186.5	185.1	191	61.6	55.27	3440	186.5	2270	2290
55.58	3480	186.5	18.7	121.67	55.88	188.7	186.6	189.5	62	56.18	3600	190.2	2290	2300
56.48	3640	191.7	19.38	141.19	56.78	191	189.6	191.7	55.7	57.08	3720	191.7	2270	2540
57.38	3720	180.5	18.7	143.28	57.69	191.7	191	163.9	0	57.99	3840	145.9	1670	2270
58.29	3840	119.5	10.2	62.25	58.59	191.7	191	63.9	0	58.89	3840	12.8	970	1240
59.2	3840	14.3	1.36	5.61	59.5	191.7	191	13.5	0	59.8	3800	12.8	970	1030
60.1	3760	12	0	8.28	60.4	191.7	189.6	12	0	60.7	3720	12	970	1010
61.01	3720	12	0	8.78	61.31	191	189.6	12	0	61.61	3680	12	970	1000
61.91	3640	12	0	8.94	62.21	190.2	188.1	12.8	0	62.5	3600	12	970	1000
62.82	3600	12	0	8.75	63.12	189.5	188.1	12	0	63.42	3560	12.8	970	1000
63.72	3560	12.8	1.7	9.94	64.02	188	186.6	15.8	0	64.33	3480	15.8	970	990
64.63	3480	15	1.7	10.42	64.93	188	186.6	15.8	0	65.23	3440	16.5	970	990
65.53	3440	16.5	1.7	11.17	65.83	187.2	185.1	16.5	0	66.13	3440	15.8	970	990
66.44	3400	15.8	0	10.97	66.74	186.5	185.1	12.8	0	67.03	3360	13.5	970	990
67.34	3320	13.5	0	9.08	67.64	185.7	183.6	13.5	0	67.94	3320	13.5	970	1000
68.24	3280	13.5	0	8.69	68.55	185	183.6	13.5	0	68.85	3240	13.5	970	1000
69.15	3240	13.5	0	8.61	69.45	185	183.6	13.5	0	69.74	3200	13.5	970	1000
70.06	3160	13.5	0	8.5	70.36	184.2	182.1	13.5	0	70.65	3160	13.5	970	1000
70.96	3120	13.5	0	8.08	71.26	183.5	182.1	13.5	0	71.56	3120	13.5	970	1000
71.87	3080	13.5	0	8.44	72.17	182.7	180.6	13.5	0	72.46	3040	13.5	970	1000
72.77	3040	13.5	0	7.92	73.06	182	180.6	13.5	0	73.37	3000	13.5	970	1000
73.68	2960	13.5	0	8	73.97	181.2	179.1	13.5	0	74.29	2920	13.5	970	1000
74.58	2920	13.5	0	7.97	74.89	180.5	179.1	13.5	0	75.19	2880	13.5	970	1000
75.48	2840	13.5	0	7.92	75.79	180.5	179.1	15.8	0	76.09	2840	19.5	970	990
76.39	2840	22.6	2.38	12.67	76.7	179.7	177.6	24.8	0	77	2800	24.8	970	990
77.3	2800	25.6	2.38	13.78	77.6	179.7	177.6	27.8	0	77.9	2800	29.3	970	990

 

[Lee1892]

And now with 118 too which I was informed would check the EGT..

Group C:	'118			
	RPM	Temp	Load	Absolute Pres.
TIME				
STAMP

        /min °C        %      Mbar
	
0.3	1240	24	0	970
1.21	1800	24	0	1000
2.12	2560	23	3.5	1110
3.03	3400	21	0	1320
3.93	3320	21	0	1110
4.84	2400	21	0	1000
5.74	2520	22	0	1020
6.65	2680	22	0	1040
7.55	2800	22	0	1030
8.46	2880	22	0	1010
9.35	2760	23	0	1000
10.27	2680	23	0	990
11.17	2640	24	0	980
12.08	2720	24	0	990
12.99	2840	23	0	1040
13.89	3000	22	0	1050
14.8	2960	21	0	1030
15.7	2960	23	0	990
16.61	3000	23	0	1010
17.51	3240	21	0	1150
18.42	3600	21	0	1330
19.32	4080	21	5.1	1610
20.23	4480	21	0	2490
21.13	4320	18	0	1150
22.04	3080	20	0	1010
22.94	3200	21	0	1290
23.85	3160	21	0	1070
24.75	3120	21	0	1010
25.66	3000	22	0	990
26.56	2920	23	0	990
27.47	2880	23	0	990
28.37	2760	23	0	980
29.28	2680	23	0	980
30.18	2640	24	0	980
31.09	2560	24	0	980
31.99	2480	24	0	980
32.9	2440	24	0	970
33.8	2400	24	0	990
34.71	2400	24	0	1000
35.61	2520	23	0	1090
36.52	2640	21	0	1170
37.41	2800	21	0	1250
38.33	2960	21	45.9	1290
39.23	3280	21	21.6	1800
40.14	3680	21	84.3	2210
41.04	4440	21	80.4	2540
41.95	4640	21	0	1700
42.85	4320	20	0	1070
43.76	3960	21	0	1020
44.66	3760	23	0	1000
45.57	3640	24	0	1000
46.47	3520	24	0	1000
47.38	3440	24	0	990
48.29	3400	24	0	990
49.19	3400	24	0	1000
50.1	3320	24	0	1000
51	3240	24	0	990
51.91	3320	24	42.7	1220
52.81	3760	24	71.8	2540
53.72	4720	24	64.7	2490
54.62	4400	21	82.7	1670
55.53	5000	24	81.2	2540
56.43	5200	27	0	2540
57.34	5120	23	0	1120
58.24	4880	24	0	1010
59.15	4400	24	0	1000
60.05	3880	25	0	1000
60.96	2600	26	0	1000
61.86	1480	26	0	990
62.76	1120	26	0	980

I ain't got a clue what I am looking at, but hopefully someone will!

Any help appreciated

 

[mty12345]

I'm not an expert, but I can't see anything obvious wrong with it buddy. Your maf looks fine, peak reading of 207g/s is roughly 260bhp so i would say that's probably spot on for a stage1 AMK. It looks like it's building and dumping boost as requested. The mixture looks about what i would expect to see, it's richening up under boost etc.

Somebody who's a proper expert on logs my be able to spot something i've missed though.

 

[Lee1892]

Cheers matey...

Hopefully something will show up, I am gonna set it to log and take it for a normal drive tonight try get it to hesitate badly see if anything is obvious.. Wasn't too bad when logging last night! Typical.

...or if anyone has a list of groups they want me to log, that's not a problem either!

 

[LouisAUQ]

Thoughts its worth noting. I've had this exact issue for about a year, replaced coil packs, MAF and a torn hose with no avail. Saturday i cleaned the throttle body and fitted new gasket. Its been working perfectly since then, actually a joy to drive!

 

[martin99uks]

i think this is the same problem i have with my fr tdi. will look into the inlet manifold tomorow n see if it sorts it.