Xu9jaz Idle Problem

[Guest ajsik]

I have XU9JAZ engine, and I am having troubles when engine is idling warm.

 

gutmann camshaft

gutmann ecu map

conus air filter

adjustable timing belt wheel on the camshaft but in stock position

 

everything else in engine is stock

 

When cold it starts nice and after a few sec it runs on nice 1000rpm without missfiring into the exhaust, but after a few minutes when it goes warm it starts to run poor, revs doesn't go down but it starts to run very rough and often revs fall under the 800 and it misfires into the exhaust and in few second it dies with firing into the intake and smoke appears around the airflow meter and engine doens't go over the top dead centre or bottom dead centre simple like goes in one rmp

 

then it is very hard to start, i have to start with full throttle pedal and it takes several attempts to start it but without helping it wih throttle it dies again...

 

on the full throttle, or in mid range (2000-4000)) it runs smooth and nice with plenty of power.

 

I have change:

- faulty lambda with new one

- i have change the electro magnetic vent which leads to the active coal canister

- test the SAD which is closed on wrm engine, and opened on cold

- measured AFM which gives right voltage on ECU pins in specific revs ranges

- measured the signal for both pair of injectors in ECU - seemed to be good

- measured the engine temp sensor, in full range till 90°C - works well

- try to setuped the idling revs with the throttle body screw, but with no effect turning it clockwise or not it has no effect only it goes worse or same.

- try to setuped AFM screw on AFM body, only effect is misfiring into the exhaust so i change AFM with other one with untouched screw

 

I am not sure about other sensors wich can affected idle , I spent 2month in this "French revenge", like I called it these days and I am lost with no ideas please help

Edited June 25, 2006 by ajsik

[Guest ajsik]

I have just found an article about refurbishing the AFM which leads to stable idling I will try it , but anyone who has some idea pls write it here

 

thanks

[cybernck 400 1 Cars]

i'm a month late ... but have you checked your TPS (throttle position sensor) on the throttle body?

[PumaRacing 1]

Sounds as though the mixture is too rich when it's hot. You need to get it on a CO meter to find out what is happening. What you haven't checked is the fuel pressure so I suggest you do that or swap to a known good pressure regulator.

 

Also if the ecu map is wrong or the ecu faulty then you'll never make it right with idle screw adjustments. Maybe just try a known good standard ecu and see what happens.

[2-Pugs 57]

Sounds as though the mixture is too rich when it's hot. You need to get it on a CO meter to find out what is happening. What you haven't checked is the fuel pressure so I suggest you do that or swap to a known good pressure regulator.

 

Also if the ecu map is wrong or the ecu faulty then you'll never make it right with idle screw adjustments. Maybe just try a known good standard ecu and see what happens.

 

I'd agree with that - I had similiar problems on a Jetronic 1.9 a few years back. It turned out to be overfuelling. The cause was a defective engine temperature sensor. I cannot say for sure on the Motronic, but the Jetronic uses all these sensors to determine the fuel pulse length and hence the mixture; a faulty sensor can hence throw it out a long way. Try checking the resistances of the various sensors on the engine.