SiGainey
Guest
OK. unplugged the MAF and the car barely runs and struggles to idle.... Any ideas why this might be? I thought you could run without the MAF connected 
-
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SiGainey
Guest
If it runs worse with the MAF unplugged, then you should look for problems elsewhere first.
-Uwe-
-Uwe-
SiGainey
Guest
Thanks for that - any hints as to what to check out next? Was thinking Lambda sensor but do we have a MAP sensor on these engines? Can't think of what else to try!
If you're having misfires, always check the ignition components first.
I don't know whether you've got a MAP sensor. What's your engine code? Or ECU part number?
-Uwe-
I don't know whether you've got a MAP sensor. What's your engine code? Or ECU part number?
-Uwe-
SiGainey
Guest
Sorry, I've got a APU Audi A6 engine 1.8T. The missfire is very intermittent but the car hesitates on partial throttle and just doesn't have the va va voom I was expecting from a turbo'd car
SiGainey
Guest
Cool. Below are the readings from a VAGCOM log when the missfire was present - can you spot anything? Is it best just to replace it and see?
Code:
Group B: '115
Engine Speed Engine Load Spec. Boost Actual Boost
TIME 740-6800 RPM 15-175%
STAMP /min % mbar mbar
0.27 760 15 1000 1020
1.17 760 15 1000 1020
2.27 1280 24.1 1000 1030
3.38 1360 24.1 1000 1040
4.26 1080 13.5 1000 1040
5.36 800 12.8 1000 1030
6.56 760 14.3 1000 1030
7.46 760 14.3 1000 1020
8.57 1160 18 1000 1030
9.77 1240 32.3 1000 1080
10.77 1160 28.6 1000 1070
11.76 1160 22.6 1000 1050
12.76 1280 19.5 1000 1050
13.87 1440 29.3 1000 1050
14.86 1240 21.1 1000 1070
15.97 1120 24.8 1000 1050
17.07 1160 22.6 1000 1050
18.06 1280 31.6 1000 1040
19.07 1480 21.1 1000 1050
20.15 1480 18 1000 1040
21.15 1520 18 1000 1040
22.25 1200 12.8 1000 1040
23.25 800 13.5 1000 1030
24.35 800 14.3 1000 1030
25.36 1320 29.3 1000 1040
26.45 1280 43.6 1000 1070
27.46 1840 41.4 1000 1150
28.46 2640 31.6 1000 1330
29.65 1640 25.6 1000 1100
30.56 1880 25.6 1000 1090
31.66 2040 16.5 1000 1070
32.85 2000 14.3 1000 1050
33.75 1920 13.5 1000 1060
34.85 1840 12.8 1000 1050
36.04 1600 12.8 1000 1050
37.14 1520 12.8 1000 1040
38.24 1360 12.8 1000 1040
39.34 1240 12.8 1000 1040
40.25 1240 17.3 1000 1030
41.34 1360 48.1 1000 1040
42.34 1720 41.4 1000 1200
43.44 1960 35.3 1000 1150
44.54 2080 15.8 1000 1090
45.55 2080 13.5 1000 1060
46.65 2080 14.3 1000 1050
47.64 1920 13.5 1000 1050
48.74 1800 12.8 1000 1050
49.84 1800 16.5 1000 1040
50.95 1800 18 1000 1040
51.94 1920 22.6 1000 1040
52.94 2040 25.6 1000 1060
54.04 2400 52.6 1530 1230
55.14 2680 13.5 1000 1200
56.13 2480 13.5 1000 1110
57.23 2160 14.3 1000 1080
58.33 2000 13.5 1000 1060
59.44 1880 12.8 1000 1050
60.43 1800 12.8 1000 1050
61.53 1680 12.8 1000 1050
62.62 1480 12.8 1000 1040
63.53 1040 12.8 1000 1040
64.63 1000 39.8 1000 1020
65.74 1320 50.4 1000 1100
67.4 1760 19.5 1000 1170
68.5 1720 12.8 1000 1070
69.5 1560 12.8 1000 1050
70.6 1000 12.8 1000 1040
71.6 800 14.3 1000 1030
72.7 960 32.3 1000 1030
73.8 1440 19.5 1000 1090
74.8 1040 50.4 1210 1060
76.01 1640 54.1 1570 1210
77.11 2360 63.2 1440 1500
78.2 3200 66.9 1430 1470
79.3 4000 63.9 1480 1460
80.3 4680 61.7 1440 1450
81.4 5360 77.4 1000 1380
82.49 4360 12.8 1000 1200
83.7 2640 13.5 1000 1120
84.79 1320 13.5 1000 1070
85.9 1000 15.8 1000 1050
86.89 800 18.8 1000 1040
88.09 800 18 1000 1030
89.19 800 18 1000 1030
90.19 800 18 1000 1030
91.29 840 18 1000 1030
92.28 840 18 1000 1030
93.38 1680 15.8 1000 1030
94.49 1720 21.8 1000 1040
95.49 1720 19.5 1000 1050
96.69 1760 24.1 1000 1050
97.69 1760 25.6 1000 1070
98.78 1760 29.3 1000 1090
99.79 1720 32.3 1000 1110
100.89 1680 35.3 1000 1130
101.98 1640 36.1 1000 1140
103.09 1640 54.9 1550 1250
104.28 1640 61.7 1540 1410
105.19 1680 64.7 1540 1480
106.28 1720 66.9 1530 1530
107.37 1760 26.3 1000 1340
108.47 1720 15 1000 1080
109.57 1680 12 1000 1060
110.67 1600 12 1000 1050
111.68 1600 48.9 1530 1070
112.77 1680 56.4 1550 1290
113.78 1720 21.1 1000 1300
114.87 1520 14.3 1000 1080
115.97 1920 9.8 1000 1050
117.08 2440 12 1000 1050
118.08 2480 12.8 1000 1050
119.18 2560 51.9 1480 1170
120.28 2880 66.2 1430 1470
121.38 3160 66.9 1430 1460
122.38 3040 12 1000 1200
123.48 2240 54.1 1000 1300
124.37 2240 21.1 1000 1220
125.47 2160 15 1000 1090
126.67 2080 14.3 1000 1060
127.77 2040 12.8 1000 1050
128.86 1280 12 1000 1040
129.96 1040 12 1000 1030
131.06 800 13.5 1000 1030
132.06 760 14.3 1000 1030
133.16 800 14.3 1000 1030
134.26 760 14.3 1000 1020
135.16 760 15.8 1000 1020
136.26 1120 18 1000 1020
137.26 1160 48.9 1300 1030
138.27 1560 53.4 1550 1170
139.27 2080 61.7 1460 1430
140.46 2920 66.2 1430 1480
141.46 3600 64.7 1460 1470
142.56 4320 63.2 1470 1470
143.66 4960 60.2 1410 1420
144.66 5480 56.4 1370 1370
145.76 5840 53.4 1370 1350
146.87 6280 49.6 1350 1330
147.96 4320 58.6 1430 1410
148.96 4520 61.7 1440 1460
150.06 4240 15 1000 1200
151.15 3360 12.8 1000 1140
152.15 2200 14.3 1000 1100
153.26 3480 30.8 1000 1070
154.25 3920 63.9 1490 1480
155.35 4600 63.2 1460 1500
156.35 5240 59.4 1390 1410
157.45 5680 54.9 1370 1360
158.55 6080 51.9 1360 1330
159.75 5760 40.6 1330 1370
160.85 4480 60.9 1440 1440
161.95 4720 60.9 1430 1450
163.05 4960 59.4 1400 1410
164.15 5200 57.9 1390 1380
165.93 5520 55.6 1370 1370
167.03 5680 54.9 1380 1360
168.03 5840 54.1 1380 1360
169.03 5960 52.6 1380 1370
170.02 6120 51.9 1350 1340
171.02 6280 19.5 1330 1600
172.22 4400 12 1000 1280
173.42 3720 11.3 1000 1150
174.61 2640 12 1000 1120
175.62 3680 12 1000 1120
176.72 3360 12 1000 1120
177.91 3240 12 1000 1120
178.9 3160 12.8 1000 1110
179.9 3040 12.8 1000 1110
181.1 2920 12.8 1000 1100
182 2800 12.8 1000 1100
183.11 2720 13.5 1000 1090
184.21 2720 32.3 1000 1060I don't see anything obvious there, but I'm not the world's foremost authority on 1.8T motors. Actual seems to track requested decently.
-Uwe-
-Uwe-
h100vw
Guest
The boost seems low but you haven't done any WOT that I noticed.
Try running from about 2000 revs in 3rd up to the red line with your foot hard down. If you can do it up a hill that would be better as the car wil accelerate slower, you need to get a good five seconds for acceleration on boost for a decent log.
James at CC looks at 115 020 and 031.
If you have a long enough road using 4th will slow down the acceleration. Just bear in mind the speed you'll get to.
With those blocks you can see if the timing is being retarded at all. Along with boost and airflow.
Gavin
Try running from about 2000 revs in 3rd up to the red line with your foot hard down. If you can do it up a hill that would be better as the car wil accelerate slower, you need to get a good five seconds for acceleration on boost for a decent log.
James at CC looks at 115 020 and 031.
If you have a long enough road using 4th will slow down the acceleration. Just bear in mind the speed you'll get to.
With those blocks you can see if the timing is being retarded at all. Along with boost and airflow.
Gavin
h100vw
Guest
Are you coming off the throttle at all, the boost doesn't seem to be holding very well. You don't get much above 60% throttle unless I am mistaken.
I wonder if the TB needs adapting?
Please note I am no expert on these yet but I aim to be.
You need to do deliberate logging runs I think. Just capturing data whilst going to the shops doesn't really tell much. No offence if you were doing them on purpose Si.
If you do those 3 I put up, you get more data from each run. VAG-COMs sample rate is a bit slow (no offence Uwe) to get real time data, which is why you need to run for a good 5 seconds at WOT.
I'll keep my eye on this thread.
Gavin
I wonder if the TB needs adapting?
Please note I am no expert on these yet but I aim to be.
You need to do deliberate logging runs I think. Just capturing data whilst going to the shops doesn't really tell much.
No offence if you were doing them on purpose Si.If you do those 3 I put up, you get more data from each run. VAG-COMs sample rate is a bit slow (no offence Uwe) to get real time data, which is why you need to run for a good 5 seconds at WOT.
I'll keep my eye on this thread.
Gavin
SiGainey
Guest
h100vw said:
I wish
Corresponding group which logs throttle angle shows 100% very occasionally on the same run but it's 99% and upwards for the vast majority of that 160 seconds into the run.h100vw said:
Did that first day I bought the car
h100vw said:You need to do deliberate logging runs I think. Just capturing data whilst going to the shops doesn't really tell much.
No offence taken
It was a general run to grab as much data as I could whilst the miss-fire was happening 
. More than happy to and will use the groups you have suggested There's a general lack of power and I'm loathed to change the MAF just cos as it's 70 quid and the first born's due this time next week so money is tight h100vw said:
The rate this car's accelerating, that'll be first gear then
h100vw said:
Cheers. All advice appreciated
h100vw
Guest
SiGainey
Guest
h100vw
Guest
You're welcome Si.
Another note on this subject. I had the same probelm on a friends APU engine A4 Avant. It seemed to go well enough but when I logged it prior to doing the remap for him. I did comment how it seemed to take ages to pick up.
He replied that some days it was better than others? This was possibly confirmed during a later logging session, where the measured airflow was dropping to 0 intermittently during high rev/full boost conditions. At the time the only other 1.8Ts I had driven were an 2001 LC this year and my own S plate tiptronic Passat estate, which I sold 3 years ago.
The LC was much faster, being a lighter car with more power as std and then with the remap better still.
The Passat always seemed dead thirsty, 26 MPG no matter how you drove it. 110 MPH all through France on the way skiing and back, 26 MPG. 70 MPH touring round Scotland, 26 MPG. The only way to get it over 30 was to accelerate and coast over and over. As it was an auto the engine speed comes right down with the closed throttle, saving fuel. Made the kids feel sick as well.
Anyway, I can't help wondering now having fixed my mates A4 and seeing all the other MAFs getting replaced if the one on my Passat was dead too? I suffered that crappy mileage for 2 years before getting rid. If only I had known.......
Side note on my mates A4. I bought another MAF from GSF and fitted it in the carpark outside. The car ran like a bag of ***te, missing, not accelerating (this was at a standstill in the car park still). I thought I'd knocked something off or split a pipe?? Anyway, after much messing about I disconnected the 'new' MAF and miracle, it ran lovely again.
Back into GSF for a rant and another MAF. This new one did the trick. It looks like someone pulled a fast one and sent back a bad MAF, claiming it didn't fix the snag and they didn't need it.
The first one I fitted had Bosch AND VW/AUDI part numbers like an OE one. The genuine Bosch one ONLY had a Bosch number. My advice is insist on having one from an unopened box, they are sealed initially, and check the part only has a Bosch number on it.
Gavin
Another note on this subject. I had the same probelm on a friends APU engine A4 Avant. It seemed to go well enough but when I logged it prior to doing the remap for him. I did comment how it seemed to take ages to pick up.
He replied that some days it was better than others? This was possibly confirmed during a later logging session, where the measured airflow was dropping to 0 intermittently during high rev/full boost conditions. At the time the only other 1.8Ts I had driven were an 2001 LC this year and my own S plate tiptronic Passat estate, which I sold 3 years ago.
The LC was much faster, being a lighter car with more power as std and then with the remap better still.
The Passat always seemed dead thirsty, 26 MPG no matter how you drove it. 110 MPH all through France on the way skiing and back, 26 MPG. 70 MPH touring round Scotland, 26 MPG. The only way to get it over 30 was to accelerate and coast over and over. As it was an auto the engine speed comes right down with the closed throttle, saving fuel. Made the kids feel sick as well.
Anyway, I can't help wondering now having fixed my mates A4 and seeing all the other MAFs getting replaced if the one on my Passat was dead too? I suffered that crappy mileage for 2 years before getting rid. If only I had known.......
Side note on my mates A4. I bought another MAF from GSF and fitted it in the carpark outside. The car ran like a bag of ***te, missing, not accelerating (this was at a standstill in the car park still). I thought I'd knocked something off or split a pipe?? Anyway, after much messing about I disconnected the 'new' MAF and miracle, it ran lovely again.
Back into GSF for a rant and another MAF. This new one did the trick. It looks like someone pulled a fast one and sent back a bad MAF, claiming it didn't fix the snag and they didn't need it.
The first one I fitted had Bosch AND VW/AUDI part numbers like an OE one. The genuine Bosch one ONLY had a Bosch number. My advice is insist on having one from an unopened box, they are sealed initially, and check the part only has a Bosch number on it.
Gavin
Last edited by a moderator:
also remember that is very important that if you have you car chipped you should reduce your Plug Gap!!... for every 50hp recude 0.004
so you should be around .032 in your gap.
greetings
so you should be around .032 in your gap.
greetings
h100vw
Guest
surfo, not saying you're wrong but could you qualify that statement with a link or something? I have heard about big boost 'blowing out' sparks before, is that the reason?
Gavin
Gavin
h100vw said:
here are some... as you can see all modified cars should gap in a closer number.. and as you haven´t change your gap as I said before you should be around .032 so if you are chipped you should go for .028 and be safe for further modifications...
http://forums.vwvortex.com/zerothread?id=1813271
http://forums.vwvortex.com/zerothread?id=2181674
http://forums.vwvortex.com/zerothread?id=1972245
http://forums.vwvortex.com/zerothread?id=1628743
