Please help :(

[Zman6000]

hi guys getting abit desperate now so here goes, 1999 Audi A3 Quattro sport 180bhp. Slightly high lambda readings on emissions and overboosting issues? Pretty much standard has a backbox on, panel filter, 710n recirc valve, stage one remap. I've tried to bring this little gem back to life, it's had a full service, also had cambelt water pump thermostat coolant temp sensor, n75 replaced, several vac pipes at a loss? Fault code maximum boost pressure exceeded only? Also had a new lambda sensor and it has a double capacity side mount intercooler. Cheers all.

 

[superkarl]

Who mapped it?

 

[Zman6000]

Who mapped it?[/QUOTE
Top gear tuning?

 

[Zman6000]

Who mapped it?

It was mapped when it was completely standard and was ok. But didn't drive it much then overboosted once decatted but I've put the cat back on to eliminate it but to no avail mapping company said the maps fine but they would say that.....

 

[Zman6000]

Who mapped it?

ALso had it on a scanner the lambda sensor shows no activity but the heater is switching? New sensor 3 months ago

 

[ayfreetee]

Wiring?

 

[Retroman]

Usually high lambda readings in the emissions is an exhaust leak somewhere - nothing to do with the so called "lambda sensor". Is this just a single pre-cat lambda sensor? Sensor inactivity might suggest the combustion mix it is receiving is good but that a problem exists further downstream after the sensor. As well as causing exhaust leaks, air gets sucked into a leak disrupting normal exhaust flow as well as giving a high lambda reading at the tailpipe.

If you are convinced the lambda sensor is faulty, sometimes budget aftermarket ones can cause a problem from new.

 

[Zman6000]

Usually high lambda readings in the emissions is an exhaust leak somewhere - nothing to do with the so called "lambda sensor". Is this just a single pre-cat lambda sensor? Sensor inactivity might suggest the combustion mix it is receiving is good but that a problem exists further downstream after the sensor. As well as causing exhaust leaks, air gets sucked into a leak disrupting normal exhaust flow as well as giving a high lambda reading at the tailpipe.

If you are convinced the lambda sensor is faulty, sometimes budget aftermarket ones can cause a problem from new.

Pretty sure there's no leaks silicone all over it lol lambda I'm going to check again on scanner? Booked it at a mates garage now they have a smoke tester and access to better mapping equipment going to put the standard map back on and see how it drives? Yes it only has one lambda sensor on my car before the cat? Failed emissions on lambda on original lambda this is the 2nd one in 12months from euro car parts? Bosch equivalent apparently? Thank you for the reply

 

[Zman6000]

Wiring?

The appear ok buddy? Thanks for the reply

 

[ayfreetee]

Apparently ecp lamda's aren't up to much.

 

[Zman6000]

Al post what happens tomorrow fingers crossed it's just a hidden vacuum leak :s

 

[Zman6000]

My bad Its next Monday it's going in for a smoke test al post findings then

 

[Zman6000]

Hey guys, had a smoke test and pressure test all come back ok just doing some more tests now....

 

[Zman6000]

All sorted now, the tuner said when it was warm the n75 valve was playing up no more boost issues. Only issue I have now is slight hesitation on part throttle only after 3000rpm? Any ideas?

 

[superkarl]

All sorted now, the tuner said when it was warm the n75 valve was playing up no more boost issues. Only issue I have now is slight hesitation on part throttle only after 3000rpm? Any ideas?

Check your plugs, plug gap, coil packs, coil pack wiring harness and coil earth

 

[Zman6000]

Check your plugs, plug gap, coil packs, coil pack wiring harness and coil earth

Wires all appear ok, I'll whip the plugs out later, I've heard if it's remapped you should change the spark plug gap? Not sure why as I've had many tuned cars and not changed the gaps??? Not sure how I will test the coils other than swapping them around? All earths appear clean no green fur around them

 

[superkarl]

Wires all appear ok, I'll whip the plugs out later, I've heard if it's remapped you should change the spark plug gap? Not sure why as I've had many tuned cars and not changed the gaps??? Not sure how I will test the coils other than swapping them around? All earths appear clean no green fur around them

How old is the car, and have you had the wiring loom apart? Otherwise how do you know the wiring is ok?
Spark plug gap should be 0.7mm.
Grade 6 plugs for stock or mildly tuned cars. Grade 7 for higher tuned cars.
Use vcds to monitor the misfire counter on each cylinder. Swap coils accordingly.

 

[Zman6000]

How old is the car, and have you had the wiring loom apart? Otherwise how do you know the wiring is ok?
Spark plug gap should be 0.7mm.
Grade 6 plugs for stock or mildly tuned cars. Grade 7 for higher tuned cars.
Use vcds to monitor the misfire counter on each cylinder. Swap coils accordingly.

1999, been into an electrician matey. I'll check the plugs after my next mot and limited use of a vcds pain in the *** to get my mate down lol have got cars on laptop and use of a snap solus ultra

 

[Zman6000]

17964 latest fault code negative deviation? Any ideas anyone? Lost boost for the first time since being live mapped at another garage guess it wasn't the software as I've noticed the guys have wound my actuator out or in whichever to lower boost? So a little annoyed it's not really fixed if the actuator has been messed with and now I've lost boost again?

 

[superkarl]

17964/P1556 - Charge Pressure Control: Negative Deviation
Possible Symptoms

• Reduced power output
• Limp mode

Possible Causes

• Boost Pressure too Low
• Hoses/Pipes incorrect connected, disconnected or leaking
• Charger Pressure Control defective
  • VNT (variable nozzle turbo): nozzles stuck
• Solenoid Valve for Boost Pressure Control (N75) defective

Possible Solutions

• Check Hoses/Pipes to/between Components
• Check Solenoid Valve for Boost Pressure Control (N75)
• Check / Clean / Replace Charge Pressure Control
  • Check / Clean mechanism for variable nozzles

 

[Zman6000]

17964/P1556 - Charge Pressure Control: Negative Deviation
Possible Symptoms

• Reduced power output
• Limp mode

Possible Causes

• Boost Pressure too Low
• Hoses/Pipes incorrect connected, disconnected or leaking
• Charger Pressure Control defective
  • VNT (variable nozzle turbo): nozzles stuck
• Solenoid Valve for Boost Pressure Control (N75) defective

Possible Solutions

• Check Hoses/Pipes to/between Components
• Check Solenoid Valve for Boost Pressure Control (N75)
• Check / Clean / Replace Charge Pressure Control
  • Check / Clean mechanism for variable nozzles

That's just a copy of Ross tech info which non of the above seem at fault. Everything has been replaced and been mapped by two garages

 

[<tuffty/>]

negative deviation is when it can't make the requested boost...

Log block 115 boost request vs actual...

<tuffty/>