Estonia200

Car:
Audi 200 2.1 10v turbo quattro 134kw KG 1987 treser.

Car will start and run at idle for about 1 minutes and then starts rpm floating until car dies. If i try to start again then it wont start until i wait 5 min. or so.
When i get car started and hold foot on gas for about 5 min. or when engine is warm then car wont die but idle is floating and has bad acceleration.

Things i changed:
Idle switch
idle valve
1 pin sensor near coolant outlet from valve head
2 pin sensor on coolant outlet from valve head
warmup valve
idle relay
ecu
fuel pump relay
ignition distributor
engine speed impulse sender
injectors

Vacuum is -5 and boost is 0.7bar.
fault codes also doest show codes.

Fuel pump pressures measured from cold start valve injector line.
Start 4.1bar
idle 5.5 bar
full throttle 4.5 bar

Here comes my questions now:
Probably fuel pump is bad but this isn't causing idle problem because?
Can CIS head make this problem?
What is the problem?
Can ignition timing sender be faulty?

Estonia200

Hi again, seems like audiworld doesn't have much audi fans as Estonia have.

I have managed to get engine running now fine but have new problems.
First of all timing belt was installed 1 tooth wrong and second cis head fuel mixture was too low, thats why it died when cold.

Right now i setted co emissions good when idle but in accelerate it has too low fuel and starts to sputter.
When engine is cold then i can hear detonation and wants to die when i hit gas.
I have told it must be warmup valve but i changet it with no success.

Prospeeder

Sounds like it has an air leak after the airflow plate. Spray brake cleaner around all the injectors and see if it changes how its running, them and their holders are very suspect for vacuum leaks, I know you said you replaced injectors, but did you replace the rubber orings on the holders they push into?. CIS is very very sensitive to unmetered air leaks. Have you verified ignition timing also?

Estonia200

Ok i think i found the problem. The fourth cylinder piston is broken.
Camshaft valves are aslo in bad shape. I considered to rebuild the engine but my friend offered me an another audi inline 5 engine that is build from different parts and uses efi with megasquirt instead of cis. block and head are i5 2.1 10v 96kw with 2.1t pistons and have 2.1t kg inlet and outlet manifold. 20v 3b injectors with custom fuel rail and 3b spark plugs, intercooler, oil cooler, wastegate spring.

Here are some pics of my broken engine: Eesti Audi Klubi foorum - Audi 200 treser 2.1TQ -1987- Taavi.M

Diablo_666CZ

OMG my friend,what did you do with this Audi?Its for complete rebuild.But head is not bad,but cilinders must be rebuilded with new pistons,and I dont know if Mahle is making new pistons for KG engine?I was made rebuild of MC engine and I was bought pistons from 1B.Same diameters but biger compresson.

Estonia200

Well i have already a new piston and i can get new rings and halls also if i want but for now this engine is going to wait some other times because i have already a new engine (used one) with megasquirt what is waiting for me to install it

In my opinion why piston has broken down is that piston ring may have stuck or detonation due to wrong air fuel ratio.