MAP/IAT sensors  (Pressure uses pins 1, 3 & 4, temperature 1 & 2).

Pin 1 Brown to ECU pin 108 (earth)

pin 2 Green to ECU pin 85

pin 3 Red/Green ECU pin 98 (+5V)

pin 4 Brown/White ECU pin 109

 

TB like this:

 

 

 

Ideally you'd measure resistance of each wire end to end (preferably with a bit of wiggling of the wiring anywhere it looks vulnerable), and resistance to earth for each wire. If you're really keen, resistance from each wire to all other wires in each connector of MAP and TB, with all connectors unplugged (looking for wire to wire shorts, rather unlikely, but possible).

 

Also, look for any wetness/liquid contamination around the area of the relevant pins at the ECU connector end.  Another member recently had the bizarre occurrence of the coolant temperature sensor springing a leak inside itself which sent pressurised coolant up inside the insulation of the CTS wires  to wreak short-circuiting havoc at the ECU connector end! And the CTS was still giving acceptable readings.

Edited 10 October, 20187 yr by Wino

Both TB and MAP/temp wiring is low resistence and connected. Nothing to earth. There is a high resistance link between map plug wires 1 and 3. Reads 2.5 when the scale is on 200K ohms. I think this is an anomaly.

Readings are wiggle resistant.

9 minutes ago, LB123 said:

There is a high resistance link between map plug wires 1 and 3. Reads 2.5

That might be down to other sensors sharing the same 5V and earth connections, via in-loom joins. I'll try to see which other sensors share those rails, with a view to disconnecting them and re-measuring. Back in a bit.

EGR valve and CAM sensor both use the same +5V supply and earth, so if you disconnect both of them and re-measure, I'd think the 2.5k Ohms will go to infinity. Try the EGR first, that may do it on its own.

Sorry to be slow in reply. Been doing the core plugs in the head of a friends focus. Plug valley full of rusty water and a missfire. Both core plugs proved to be fine on removal so its the known windsceen washer head leak. Just drips/squirts into the plug valley! Stupid design. But I digress.

 

As you say with both cam and egr disconnected resistance between pin 1 & 3 went to infinity.

I have a new genuine MAP sensor to fit tomorrow. No confidence it will fix it.

While the last event was going on, sitting with the engine hunting, throttle pedal movements had no effect on revs. As if it was electrically disconnected. Will have a look at the pedal and its wiring tomorrow also. Will also check EGR just in case. I know its only a year old but...........

 

Should also change the heading of this thread. Pretty sure I did cure the intake leak a month ago. These two new episodes prevent driving which is new. But still the same codes. Confusing.

Edited 11 October, 20187 yr by LB123

3 minutes ago, LB123 said:

I have a new genuine MAP sensor to fit tomorrow

Ah, good, that saves me hunting round in my shed to try to find one to lend you for experiment (which I was intending to suggest next).

 

Looking forward to learning from this when you finally resolve it, which I'm sure you will.

 

 

Curious. Big loom check with nothing found. New TB and EGR gaskets fitted and both readapted. Starts fine today. Cleared codes and further VCDS scan no codes. Thought I would look at measuring blocks 62 to see the potentiometers working which they do and glitch free. For the TB values for G187 and G188 should add up to 100 and be inverse of each other ie. when G187 is 15% G188 should be 85% and so on and they are.

However for the throttle pedal G79 and G185 both run from 0 to 100 (limits are 3 to 97 in VCDS) and G79 reading should be twice G185 as they go up. Mine are equal and run in exact parallel as I press the pedal. All i can find on the internet so far confirms G79 readings should be double G185.

Wonder if I have a throttle G185 pedal sensor problem?

If useful I can check my car later for comparison but my gut feeling says that'll be normal, cos I can't imagine how it could behave that way otherwise 

Just swapped to an old pedal which gives exactly the same readings. So that is normal for a 16v fab but different to some other VAG cars. Car is driving fine this morning with no codes!!! Lurking doom. I'm off for a drive.

Edited 13 October, 20187 yr by LB123

How did you solve it, I Experience the same problem, the same thing, It is really egr faulty ? It is new(6 month), When I unplug the egr car runs fine, but with epc and check engine light :(

PLease lb123 tell me how did you manage it up ?

On ‎07‎/‎10‎/‎2018 at 15:37, LB123 said:

Crankcase breather is fine. If I block the throttlebody end of it, oil filler cap in place and apply vacuum to the camcover vent the engine holds vacuum! So no leak there.

I can only conclude the MAP or throttlebody are faulty in some way. Might try the local scrappies for replacements.

Sods law. The car of course is running fine with no faults showing.  Thanks for all the help even if it has only managed to rule out stuff.

 

I didn't realise this at the time you posted it, but you didn't test what you thought you were testing here. The camcover hose isn't a 'vent', it's a clean air intake, with a one-way valve at the point it attaches to the camcover, inward only. Item 35 here: https://skoda.7zap.com/en/cz/fabia/fab/2005-453/1/103-103040/

So you only vac tested that length of hose between free end and that valve.

 

Also, re-reading earlier posts with MAP data logging, yours seemed to sit at 360mbar at fully warmed up idle, versus 300 on my BBY. Now they aren't quite the same engine but that's quite a chunk of pressure difference, it would be interesting to see another log now; if problems seem to have gone away.

 

@Edwin98 what year is your car and which engine code? Did you already carefully check the brake servo vacuum hose for cracks and leaks?

@freedom I experience the same tought as LB123, engine code APE, fuse1 it keeps burnt up related to N80 valve. Hard start engine in the morning. No vaccum leaks

Freedom is my membership category; Wino is my username

 

Seat or VW car? Which model? Which year?

 

I don't recognise the word 'tought'

 

Do you have any fault code numbers?

 

You say no vacuum leaks but have you inspected the specific hose I mentioned, it's a very common problem, check particularly at the non-return valve, looking for problems with the hard plastic hose that look like this:

 

 

 

 

 

Polo clasic 3 2001 ape 1.4 16v, no vaccum leaks, they are replaced already, in your photo mine does not have leaks, it is about short to ground in my case  N80

I don't have wiring info for any Polo before 9N/2002 unfortunately. 

Another member @nige8021 may have something useful, and he knows his way around Polos so if you're lucky he may be able to help.  

That's a big collection of fault codes, have they all arrived together or have they been increasing as time goes by?

They arrived together, can you forward your friend to this topic ?

They are relatednto fuse1 10A, all sensors and n80 are shord to ground, fuse every time blow up if I replace it

Edwin98, I am copying my answer to your message here for information. It helps to have all suggestions on the board so more people can see them and help.

Just had a look at the thread you have posted and you have a lot of faults and you say they came at the same time and you have a fuse that blows. I don't think you have same problem as me. Yours sounds like you have a short, live to ground, in one of the circuits supplied through that fuse. A trick I have used in the past is to replace the fuse with a stop lamp bulb wired across it. It will light up while the short is present. Then you can follow the wires supplied by that fuse, examining, wiggling, disconnecting, tracing. If the light goes out you know you have just interrupted the short so this narrows down your search. Also saves on the cost of fuses.

timing belt tensioners they are plastic coated and the plastic coating can come off which puts the timing slightly out causing, this is my problem i think, I left only with barometric problem. Same as yours.

I replaced the timing belts on my BBZ engine a year ago. They are toothed belts. I didn't see any plastic coating, not even on the tensioner pulley! Even if there was wear on the pulleys the timing would only move by a fraction of a degree. Not enough to change the engine running. I don't think that idea is even remotely likely the cause of your problems.

With regard to the fuse blowing, have you tracked down the cause of that and sorted it out?

I don't come on the board often these days as the car still runs fine so it's better to keep everything on the thread rather than personal messages.

Probaly the first fuse was bad, it sorted out, but in the morning car start hard, changing map resolved your problem?

Eventualy yes, but I had to logically work through a whole list of possible causes of the engine ECU registering excess intake air before I arrived at the solution. You should do the same list.

Only things left are map sensor and tax times

 

same problem in the morning, no start sometimes. Map sensor replaced, nothing changed.

Should I GO for belt tensioner ?

@Wino@LB123 A little help ?