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Discussion Starter · #1 ·
First hello to everyone,I own 1997 SAAB 9000cse 2.0i turbo intercooler and it has BRC sequent LPG that is installed in official BRC shop in Belgrade,and I have done some sort of engine rebuilt,I replaced everything in engine from timing chains to piston rings,but I didn't do I don't know how it's said,widening of cylinders,so everything is STD,here is my problem,car goes well turbo charges well and every thing runs smoothly,but sometimes and more and more often,engine turns off in middle of driving,and its always when I remove my foot from the gas pedal quickly,for example when I need to press the break,or change gear could anyone tell me what it's the problem there? and another thing when I dismantled the engine I didn't found some thing called knock sensor,so does anyone knows if this type of saab has something like that,and if it does where is the location of it,and another problem I have is temperature gauge,it always shows half of centimeter from zero,normal when the engine is cold its on the zero but when engine gets warmer it goes half of centimeter up and stop,and I replaced temperature sensor on the left of the cylinder head with brand new original for my type of saab,does it have more than one temperature sensor,and could the temperature gauge be the problem??
 

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What does the engine idle at usually?

The idle air control valve may be faulty.

There is no knock sensor on this engine.

There are two coolant temperature sensors. The second is in the thermostat housing.

On my car, 195F has the temp gauge at about 30%.

Connect an OBDII scan tool to determine if the detected temperature is valid before replacing any more sensors.

What thermostat are you running?
 

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Discussion Starter · #3 ·
you mean engine idle RPM, is normal,and running smooth on LPG,but on gasoline it's a nightmare,because LPG system is such that engine has to warmup before switch to gasoline,but in that time it's a nightmare,first start always fail,second start sometime fails,then it runs smooth until switch to gasoline,but that is with out pressing the gas paddle,when it runs smooth on gasoline idle,and when I press the paddle,engine immediately turns off,but I suspect(and I'm sure) that problem are the injectors,because when it turns to LPG it runs smooth(LPG has separate injectors),but what can make engine turn off in the middle of driving?? and I noticed that it turns off when I change gear on high RPM(and not so high around 3000 RPM),and when I drive in higher gear on low RPM,example driving in 3rd gear I slow down,RPM goes down to 1500RPM then I press clutch to change the gear,take my foot from gas paddle,then engine turns off :confused: and have idle air control valve cleaned(before engine dismantle) that is what most people recommend to do,but can it break down completely?? as for the thermostat it was a quick fix I bought thermostat from vw golf,but I didn't know that it has temperature sensor in thermostat housing,if that is the problem,then it will be fixed in a week,because I have already ordered thermostat for my type of saab ;) and are you sure about knock sensor? because i did some googleing and I think it's the integral part of APC system...
 

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I'm not sure of the specifics of the LPG system.

Does this LPG system intercept and read the ECU's injector output?

If it breaks the feedback loop, the ECU's trim values will run away and cause poor performance.

On your model year, there is no discrete knock sensor, however the knock sensing function is performed through ionic sensing by the DI.
 

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Discussion Starter · #5 ·
I think it does but I don't know really,it's been done by the BRC shop,and when the engine runs on LPG it has ECU of the LPG that controls injectors of the LPG,but when the engine works on gasoline it has everything normal like it doesn't have LPG system,and engine works fantastic on LPG,and it didn't shut down in the middle of the driving before this engine rebuild,I was thinking if I didn't connect some kind of sensor that is causing this problem??
 

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can anyone else help me with this problem??
Probably not, unless you can provide a lot more information about your auxiliary fuel system.
As a WAG, I bet with the throttle closed and high vacuum, both fuel systems are shut off.
 

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Discussion Starter · #9 ·
@Twinsen the car starts on gasoline,and when it warms up enough,it switches automatically to LPG

but people LPG is not the problem,the car worked fine until I disassembled the engine,I was thinking if the problem is in some kind of sensor or hose,that has malfunction or not been connected,but I've been very careful and tagged every connection before i took it off,but still I got this problem...

@Jim Mesthene I didn't quite understand what you're trying to say

"As a WAG, I bet with the throttle closed and high vacuum, both fuel systems are shut off. "

where is this high vacuum,and how is throttle closed??
 

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High vacuum in the intake manifold occurs when you take your foot off the gas pedal; that's closing the throttle.
Simple fuel systems often use the presence of high vacuum to operate a switch to shut off fuel supply.
Keep in mind, I know nothing about LPG systems in general, and less about yours in particular.....As I said, a Wild A** Guess.
 
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