Questian about green vac line to ECU

[220bhp]

I bought a few bits today. New vac hose ,clips tees etc. I had the hose of the ecu and blocked it of so there was just the tee to the boost gauge , and up to the manifold. It holds vacuum . The hose to the moisture trap will not hold vacuum. This is using the suck, and Tung on the end method Sounds disgusting I know but I don't have a mityvac, and no one was watching. I have yet to test the hose into the ecu , abit worried about applying to much pressure there. So I will have to find the moisture trap and test it.
What happens if I bypass it.

[UrS4boy]

G71 Manifold Absolute Pressure (MAP) sensor info

... I have yet to test the hose into the ecu , a bit worried about applying too much pressure there. So I will have to find the moisture trap and test it. What happens if I bypass it.

As I suggested I am 99.996% sure that you will find your B3/B4 20VT moisture trap/fuel condensor in the left kick panel. If not, when you find it, please take photos of where you do find it (it will be near the ECU if not in the kick panel).

As for worrying about the MAP sensor. The 3B (200 20vt and early S2) came with a 2 Bar (200 kPa) MAP. The AAN (UrS4 and S6)and ABY (later S2) came with a 2.5 Bar (250 kPa) MAP. The RS2 (ADU) came with a 3 Bar (300 kPa) MAP. All of the factory MAPs were made by Bosch. As a result, as long as you apply 1 Bar less than the MAP sensor's capability, then there are no worries. With the 3B, this means about 14 psig.

G71 Manifold Absolute Pressure (MAP) sensor info:

http://forums.quattroworld.com/s4s6/msgs/20417.phtml

[UrS4boy]

. So I will have to find the moisture trap and test it.

If you look closely in this LHD B3/B4 S2/RS2 relay panel photo, you can see the white plastic of the moisture trap (fuel condensor) in the lower left(ish) corner, just behind the white tie-wrap, nestled in its grey foam holder.

[220bhp]

Thanks dave Mrc fitted a bosch 3bar map sensor in my ecu.

[newsh]

Whereabouts exactly is the Tee to the boost gauge?

[newsh]

When you say you "had the hose off the ECU and blocked it" do you mean actually at the barb on the ECU casing? If so then you've tested the moisture trap already.

My car has not had a moisture trap for a few years now, when the hard line split under the battery tray we just ran a new vac line from the IM to the ECU, my Tee is down there at the bottom right next to the ECU. I only found the moisture trap when I changed the heater box recently and I've been thinking of re-instating it.

The connection between the vac line and the ECU has a tendency to leak, the hose goes hard and forms to the shape of the barb and will leak even when the hose clamp is done up tight. I fixed this by cutting an inch off the end of the hose (its that cotton overbraided stuff) and re-making the joint. Make sure the clamp is actually squashing the rubber of the hose, if you're not sure then fit a smaller clamp, the original on mine would close before it was tight.

[newsh]

Post above edited ^^

[220bhp]

John the tee to the boost gauge is a couple of inches away from the ecu, and before the
moisture trap,if its behind the kick panel.
i assume the green line returns to a braided hose then on to the ecu,then on to the moisture trap.
Thats the way it looks. I take the line of that gos to the kick panel,Ican suck on it,and it does not holed pressure. I am going to take a look shortly.
Interesting that you do not have your moisture trap.

[twoqu]

Lou,
The line from the manifold should go to the moisture trap first as that is it purpose. Then the moisture free air goes through to the ecu and then on to the map sensor.
If you don't run one you will get all sorts of gunk in the map sensor.

[UrS4boy]

John the tee to the boost gauge is a couple of inches away from the ecu, and before the moisture trap,if its behind the kick panel. i assume the green line returns to a braided hose then on to the ecu,then on to the moisture trap.

Yes the green hard tube does go back to braided rubber just before the ECU. But as for the relative location of the moisture trap (fuel condensor), you really need to have another look at this diagram:

[newsh]

Questian about green vac line to ECU

That's what I'm saying Lou, the moisture trap is IN BETWEEN the IM and the ECU so you've already tested it from the engine end when you blocked the T to the ECU. If everything you've said is correct the I think your leak is either at the barb where the hose joins to the ECU or inside the ECU itself.

[UrS4boy]

G71 Manifold Absolute Pressure (MAP) sensor info

If everything you've said is correct the I think your leak is either at the barb where the hose joins to the ECU or inside the ECU itself.

As shown below:

G71 MAP sensor info:

http://forums.quattroworld.com/s4s6/msgs/20417.phtml

[220bhp]

Today I changed a few vac lines. Checked all the connections. Went through everything
as far as I know, that could cause the 00544 code.
Checked the plumbing to the n75, and found a couple of cracks on both ends of the hose from valve to wastegate. Trimmed the ends, and desided to change the n75 as well. What a shiit job that is.

Checked and cleaned maf plug, all looked ok.
Changed the maf for a spare that I had, and checked all the hoses.
The car runs low on the tempreture gauge. I think it s is because I have removed the aircon rad, and the shrouding.

The MFTS has no rubber boot so it is exposed to quite a lot of air rushing buy.

However my son thinks the car is running colder than it should. So he said changed the thermostat to make sure.

Of I go to GFS, to buy a new one. Gave them my reg. O thats an rare beast sir, But I have one in stock.

The last job today was to change it. Again not to easy. But I had a couple of bottles of g12 plus . So I took the old one out, and the new one was to big.
Cant get one till tomorrow. Cant test the car to see if I had acheived anything,as it was not worth refitting the old one.

Not very happy at the moment.

S6 is laid up at the moment. The only good news is that the s2 went straight through its M O T.

Anyway Thanks for all the help guys, Much appreciated

[UrS4boy]

Thermostat Diagnostic and Replacement Procedures

The car runs low on the temperature gauge. I think it s is because I have removed the aircon rad, and the shrouding. The MFTS has no rubber boot so it is exposed to quite a lot of air rushing by. However my son thinks the car is running colder than it should. So he said change the thermostat to make sure.

MFTS that is missing its rubber boot will produce a coolant temp gauge reading that appears too low. IF you have the Autoclimate control, you can use its Channel 51 to check the coolant temperature. The proper thermostat is an 87 C one.

Both of these are covered in this Thermostat post:

http://forums.quattroworld.com/s4s6/msgs/21881.phtml

[220bhp]

Thank you once again dave