Nuttynotty

Ok I have hit a wall, and now looking for help amongst the experts here.
Symptoms when cold or hot:-
Very little power between 1000 and 2000 RPM in any gear after 2k will red line with ease, even pulling away from the lights little power till 2k and then full power…..
Idle will never go below 950RPM, sits most of the time around 1000 RPM, pull the idle stabilizer plug and she splutters and levels out around 1500RPM, oil filler cap removal when running, she will try and cut out and then level out around 1000RPM.

No engine codes are reported !!!!. All temperature sensors replaces., O2 replaced, Idle and throttle position sensor checked out by Audi, both good. No air leaks from either the crank or from turbo. No turbo spindle end play, fuel filter replaced.
Plugs are golden brown when inspected, MPG sitting around 25~27 MPG.
Engine will splutter and back fire when reving engine (when stationary) or when decelerating.
Cold engine compression test reports 1,135psi. 2, 130psi. 3, 135psi, 4 130psi, 5, 125psi. total 10psi total drop. Engine has 181k on her she is a Quattro Turbo 20Valve.

Any idea on why the Idle is way high, and why I have no power between 1000 ~2000RPM. I believe that they are related, any pointers would be great, this was a intermittent problem which now has become constant.

Cheers

yodasfro

I'd revisit the TPS. It is really the only thing that would cause those symptoms high idle and stumble at low revs. Also check the vac. line that runs to the BPV and the valve itself. http://www.quattro123.com/Audi200Byp...eplacement.htm

audi_marv

Oil cap test points to you having a vacuum leak somewhere. The car should stall when you remove the cap, not sputter and then recover. Sounds like you're getting un-metered air from somewhere. Check hose from intercooler to throttle body (MM hose), underside of 3-way hose on valve cover, crankcase breather hose, and airboot w/hose to valve cover.

Also sounds like your ISV needs to be cleaned, or going bad....and/or
your air plate/plunger - throttle plate is sticking. Use throttle body cleaner, and not regular carb cleaner on these.

Nuttynotty

Hi Yodasfro,

I have replaced the crank breather hose and replaced the BPV with Audi new part along with the valve, I used the 034 breather hose and there replacement valve. the fire guard was retained.

I have rechecked the TPS and it “Appears to be correct” the resistance test shown in the Bentley manual all checks out correct, along with the Idle valve, But I know how resistance can change when hot, and I suppose this could be what is happening. But at $300 bucks, that is a lot of $$$ to see if it fixes the problem, Do you know of anywhere I can buy a sensor and return if it does not fix the problem ???/


Thank you for your help


Cheers

yodasfro

None of this applies to the 200 20v. Instead of just checking the TPS w/ a multimeter try adjusting it. You may need to pull the throttle body off to get the two screws on the TPS loose.

Nuttynotty

Hi Guy's
Too cold last night to pull the TPS of last night 15f ( yes I'm a wimp), I have however tried adjusting the TPS per the Bentley manual lasst weekend, If I adjust the TPS clockwise all the way, so the switch does not click when you move the throttle she will idle around 850RMP, but then she does not know when I come off the idle and will go into the limp mode, which messes with the timing.
So I am thing like Yodasfro and now leaning more over to the TPS sensor and will know more then I remove the sensor from the car and bench test it.


The ISV has been cleaned and checked out and is working great, Plus the internal diagnostic when ran shows the ISV to be working.

I have also pressurized the air intake system to 10PSI and no leaks are found, not even around the oil dipstick seals. So I think I’m good for leaks.

Nuttynotty

Update.

I removed teh TSP last night and ran a benck test, Pins 2 and 3 998 Ohms when Micro switch is clicked in and its smooth right up to 2800Ohms , which checks out per Bentley manual. the switch is also good.

No its not the TPS !!! So the only two things it can be is the Idel valve ???? cant see that affecting the boost. or a bad or broken wire from one sensor to the Computer, But that should thro a code ???? ( of which tere are none)



Anyone, any idears ???

yodasfro

Is the throttle body itself adjusted properly on it's stop? I'd try changing the ISV.

Nuttynotty

Hi Yodasfro,

I removed the ISV this morning and connected it to a variable power supply, 1v to 12v . the Valve works correctly, and is very smooth when ramping up the voltage from 4 Volts to 12v, plus it Ohms out per the Bentley manual.

So I again don’t believe that the ISV is at fault, plus the ISV I don’t think will create the power loss between 1 and 2K ( power loss I mean very little power as if the turbo is not spinning up or little fuel is getting to the engine, but once it hits 2K hang on to your seat).
I will re-set the TPS per the Bentley manual tonight ( after work). But I have been setting it so the Switch clicks on with .010” of play from end stop ( so when you just open the throttle the switch clicks. Switch works as the Diagnostics works perfectly).

I’m puzzled as this fault was intermittent and has now become a continuous issue, I used to drive the Audi 100 miles a day with no problems then the power loss between 1 and 2 K started to show, I noticed that the power loss would only show when the Idle went up to around 950 to 1000RPM, when the idle was at 850PRM there was never a problem.

The symptoms all point to a sensor going bad, But no Engine code its weird, have no idea where to start.

Nuttynotty

Update on the High Idle and no power between 1 ~2K

Splashed out on a NEW TPS ( $410 NAPA), cleaned connectors and installed the new sensor, Started her up, and Bingo perfect RPM and power between 1~2K. So this morning I drove her to work, But 25 miles into the journey she started to run a little rough and the Idle was back to 1000RPM and the no power issue is back. Still no engine code.

Could Fuel pressure cause this type of issue ? The Audi has 181K and she still has the original fuel pump and the original fuel pressure valve ???
Injectors have been tested and cleaned.