Low power - MAP/EGR testing

[gavin0268]

Cloggs

Sorry to be so rude in not replying to your post - I've not been able to do anything with the car given the weather up here the last couple of weeks - the bonnet was frozen shut apart from anything else! All defrosted now so hoping to have another look this weekend.

Anyway, I don't think a vacuum pipe went through the bulkhead (unless it's the one going to the brake servo?). They're reasonably straightforward to follow round the engine and cheap to replace anyway.

Hope Martin's mail was of help as well though.

Cheers

Gav

[fisheggs]

Do you get excessive smoke black or white when you are on the road with the throttle down expecting the turbo to kick in?

[gavin0268]

Hi fisheggs

No excessive smoke at all that I've noticed (but not had anyone following me to really check). Certainly not belching smoke the way my van did when it's MAF died, that was embarassing beyond belief

Gav

[Novica]

Hi,

I read all, as per ELSA manual, during driving test in 3rd gear, full-100% throtlle, at 3000 rpm for engine AVF, the data should be in group 10:
1 column mass air drawn in 850 ... 1050 mg/S
2 column atmospheric press no specification
3 column intake manifold pressure 2100 ... 2600 mbar
4 column accelerator pedal position 100%

If you have in column 1 data below 850 mg/s its mean that rpm is too small or too big, or low preesure of turbine or (which I think that is your case) defective MAF and you will get constant data of 539 mg/s in column 1 because the computer cannot achive data from MAF and he is taking substitute. That is written in ELSA.
According this and your fault stored you should look for MAF and his connections, computer does not read data from him.

Hope this help

Cheers

hi
Sorry for long time to reply, can only work on the car on dry weekends!

OK, to summarise, I'vev replaced the MAF, coolant temperature sensor and most recently the EGR, with little effect on the performance. Have also tried putting the old MAF back in with no difference.

Have replaced all the vacuum hoses I can think of, checked the 3" hoses and they appear OK. The VNT mechanism is moving up and down as the car is turned on and off.

I've logged these measuring blocks - basically the MAF and EGR values seem to be static - MAF at 539, EGR at 4.8%. Second last reading (bold) is 3000 rpm in 3rd gear.

Any suggestions what to try next? MAP looks OK from the readings. N75 valve perhaps?

Thanks for all the help so far

Cheers

Gavin


Group A: '003

Time Engine speed MAF (specified) MAF (actual) EGR duty cycle
790-870 230-310 210-350 40-75%
/min mg/str mg/str %
0.76 1239 360 539 4.8
1.96 1113 545 539 4.8
3.16 903 810 539 4.8
4.36 882 585 539 4.8
5.56 1302 610 539 4.8
6.75 1722 755 539 4.8
7.95 2121 800 539 4.8
9.16 2520 785 539 4.8
10.36 2184 245 539 4.8
11.56 1869 850 539 4.8
12.76 2037 850 539 4.8
13.96 2184 850 539 4.8
15.15 2331 850 539 4.8
16.34 2478 850 539 4.8
17.54 2667 850 539 4.8
18.74 2835 850 539 4.8
19.94 2982 850 539 4.8
21.15 3150 830 539 4.8
22.34 3255 415 539 4.8
23.54 3213 395 539 4.8
24.74 3129 380 539 4.8
25.94 3024 365 539 4.8
27.14 2961 390 539 4.8
28.34 3024 705 539 4.8
29.54 3213 775 539 4.8

Group B: '010

Time MAF Atmos. pressure sensor Intake air press. Throttle
900-1250 2100-2600 100%
mg/str mbar %
0.01 539 969 1006.2 0
1.16 539 969 1088.1 27.8
2.36 539 969 1216.8 34.5
3.56 539 969 1240.2 0
4.76 539 969 1123.2 32.5
5.96 539 969 1380.6 42
7.15 539 969 1907.1 56.1
8.36 539 969 2351.7 60.4
9.56 539 969 2164.5 59.2
10.76 539 969 1240.2 34.1
11.96 539 969 1883.7 75.7
13.16 539 969 2234.7 78.8
14.36 539 969 2316.6 76.1
15.54 539 969 2398.5 79.2
16.74 539 969 2410.2 82.4
17.94 539 969 2340 83.1
19.15 539 969 2234.7 83.1
20.34 539 969 2269.8 82
21.54 539 969 2211.3 63.5
22.74 539 969 1298.7 29.4
23.94 539 969 1275.3 29
25.15 539 969 1263.6 27.8
26.34 539 969 1275.3 28.2
27.54 539 969 1357.2 39.2
28.74 539 969 1708.2 55.7

Group C: '011



Time Engine speed Spec. intake press. Actual intake press. D.cycleMAP 2850-3150 2200-2400 2100-2600 35-80 %
/min mbar %
0.37 819 1050.6 1006.2 19.9
1.56 1134 1244.4 1134.9 19.9
2.76 1134 1366.8 1251.9 19.9
3.96 819 1060.8 1146.6 19.9
5.16 1176 1264.8 1193.4 19.9
6.36 1596 1662.6 1532.7 33.5
7.55 1995 2111.4 2070.9 41.8
8.75 2394 2091 2340 61
9.96 2667 1081.2 1907.1 47
11.16 1827 2203.2 1415.7 26.3
12.36 1974 2264.4 2035.8 33.1
13.56 2142 2295 2281.5 44.6
14.75 2268 2315.4 2340 47
15.94 2436 2335.8 2421.9 53.4
17.14 2604 2346 2410.2 57.4
18.34 2793 2346 2281.5 55
19.54 2940 2346 2246.4 55.4
20.74 3087 2346 2293.2 57.4
21.94 3255 1407.6 1836.9 72.5
23.15 3213 1224 1275.3 52.2
24.34 3150 1224 1287 51.8
25.54 3066 1213.8 1263.6 51
26.74 2982 1213.8 1263.6 50.6
27.95 2982 1417.8 1509.3 61.4
29.14 3129 1836 1930.5 67.3

[gavin0268]

Thanks Novica - I've been struggling to understand the significance of the static values.

Any idea how to check the connectivity of the connections or what value might be expected? I have a multimeter but have never used it!

The MAF was the first thing I replaced so unless I've been unlucky with VW part I don't think it's the MAF itself

Thanks again everyone

Gavin

[Camb-Tech]

You have a broken maf connector or broken wiring hence the error that you have been told to ignore.

You MAF values are way too low and the ecu is using the limp home ones.

[gavin0268]

Hi Camb-tech

Yep - you're spot on.

Unfortunately I gave up and took it to the local VW garage (this week coincidentally!) and that's what they diagnosed! £100 and all good now.

But not to worry - I've learnt a huge amount over the last few months while the car's been off the road, now know how the turbo system works, and having never done more than an oil change, am happy(ish!) to do a lot more on the car than I did before I started. Electrics were beyond me though.

So a huge thank you to all the guys on here for having the patience and taking the time to suggest ways forward - great forum.

Cheers

Gav

[fordsmith]

Here you have not mention compression testing. If it is munched with its own turbo which you want to imply, the cat may be blocked up also try de-cating if it may make difference. Also check all the seals which include the intake manifold, turbo and oil return. If you have loss in vacuum pressure than your running of the car will mess up. So clean your EGR valve regularly so that it will give you more power.