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89 Firebird V6 doesn´t start anymore


Caddy59

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Hello everybody,

concerning a more modern car....anyway hoping for help. I´m German and I´m owning an 89 Firebird,3.1 L V6 , injected engine.

Recently the car broke down after a 30 miles trip, it started afterwards once whilst poor throttle response, broke down again immediately and didn´t start anymore at all (starter motor was working and engine cranked ok). Car was picked up by breakdown service, it´s now at home. Supposedly I think it might be a fuel pressure problem, there´s rather a bit of fuel once I have checked the testing valve at the fuel rail, but probably poor pressure.

Now I´ve provided a pressure testing gauge and try to find the fuel pump relais, but didn´t find it as yet. I use a Haynes Repair Manual, unfortunately something disappointing Information. I rather found  the testing connector underneath the dashboard,  fault code reading has been done, no code stored. According to Haynes Manual, the fuel pump should been activating by applying voltage to a pin within this testing plug ( with what the code reading has been done), but on the particular Position whats Haynes stated, there´s no pin at all. Furthermore, I don´t find the fuel pump relais to bridge the pump, but no link where it is located. Unfortunately, more likely disappointing and not that helpful. I have to activate the fuel pump anyhow to test the pressure, can anyone tell me how?

 

Probably someone is familiar with this engine and knows these symptoms. Additionally to say: When bridging a spark plug cable  to ground, it´s sparking like crazy, so I think it´s not a sparking problem.

 

Thanks a lot for your advices !

 

Udo

 

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How many miles/kilometers are on the car?  If it is in the 135,000 miles/ 200,000 kilometers, good chance it is a fuel pump.  Fairly typical.

 

The best way to check fuel pressure is to just turn the key to the on position, radio and everything off and if you listen carefully you should hear the electric fuel pump run for about 6 seconds and then turn off.  If you do not hear this, bad pump.  If you hear this then you need to check the fuel pressure.

 

Under the hood there is a Schrader valve connection to the fuel rail like a tire stem.  You will need to put a gauge on that to read the pressure in the fuel rail. I am guessing that it is a port fuel injected engine.  If it is a port fuel the fuel pressure must be at least about 45 psi/ 300 KPA.  Ideally it should be about 60 PSI / 400 KPA.  If you do not have these readings, then it is time to put a new fuel pump in the tank.

Edited by Larry Schramm (see edit history)
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Put a fuel pressure gauge on the fuel rail test port.  Attempt to start the car.  The electric fuel pump (located inside the fuel tank) is supposed to turn on for two seconds when you first turn the key to START to build pressure in the EFI system. If the pressure does not reach about 45 psi, either the pump is bad (not uncommon) or the relay is bad.  If the car actually stopped running while driving, I would strongly suspect the pump is bad.  The relay is only used during the start sequence. Once the engine is running, fuel pump current flows through an oil pressure switch and bypasses the relay anyway.

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Same thing happened to my '91 Camaro. Turned out the fuel pump went bad. It's in the fuel tank.

 

A real bugger to replace. You're supposed to drop the fuel tank, which involves removing all sorts of extra parts. Or you can take a shortcut and cut a 8" hole in the metal under the back seat and get access to the fuel tank from the top. Not supposed to do that but most mechanics will. 

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I wonder if the easiest alternative would be just to bypass the intank pump with an external pump that goes inline with the fuel line unless the pump in the tank would restrict any fuel draw.

It will probably only be needed to do once whichever way is chosen. I wonder how hard it will be to find a new fuel pimp in Germany?

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There is a diagnostic port near the steering column where you can plug in a computer. It will get codes from the car's computer telling you where the problem is. All garages and dealers have these diagnostic computers. If your local garage cannot diagnose your car, you can order the correct plug and wire to plug it into your laptop computer, and buy a program to load into your laptop. I believe your car uses the OBD1 system.

 

This will eliminate a lot of guess work, and help pin point the bad parts.

 

It is possible to get the codes without the scanner and without any tools except a short piece of wire.

https://www.thirdgen.org/service-engine-light-error-codes/

Edited by Rusty_OToole (see edit history)
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If the fuel pump does not run, no trouble codes will be set! BTDT.

 

My '94 Caprice did the die, restart but poor throttle response thing when its fuel pump died.

 

On some GM products, there is a 1/4" quick connect type connector hanging off the wiring harness near the underhood fuse box. This is the "hot" wire to the fuel pump, and putting 12 volts on it will power the pump, bypassing the relay (computer controlled).  Maybe 89 Firebirds do not have this.

 

A fuel pressure gauge is needed, as Larry says, connect it to the Schrader valve on the fuel rail. 

 

Three things needed to run, Spark, Fuel and Air. You have spark, probably have air (unless a mouse built a nest while you were driving down the road!), so I also think the fuel pump gave up the ghost.

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Guys, thanks for your advices. 

@Larry Schramm: The cars mileage is just 44000, but anyway 29 years old......

 

@Rusty_OToole: I blinked out the fault codes, but it only showed 12 what is just the standard code given out if there´s no fault at all. But I have to admit that i disconnected the battery in between before I tried to read the codes, shit happens. But: The fault lamp definitly didn´t burn when the car broke down.  Maybe the system will not store codes after reconnecting the battery when just cranking the engine, supposedly it has to run fired.

 

My most urgently question: How can I make the fuel pump work with bridging the relais or get access to do this with the fault reading code plug? I suppose that the fuel pump will not provide enough pressure to measure it with the gauge whilst just running the pump for some seconds in the starting mode. The gauge has to be bled out the air, then the pressure will raise down and I won´t get an evaluated pressure result. I´m rather sure that the pump should be bridged to run all the time to get real pressure readings. But how to do? Where´s the relay? How to make the pump work all the time?

Could i probably bridge the oil pressure switch to make the pump run? Where is the oil pressure switch? I didn´t find it as yet.

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If you put a fuel pressure gauge on the rail first and then turn the key to the on position, while it is running for the 6 seconds it will make enough pressure to tell you if it is good or bad.  It must build pressure immediately so the car will start quickly.  If it does not start quickly, the starter will just keep running for a while and then you have more  problems.

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1 hour ago, Larry Schramm said:

If you put a fuel pressure gauge on the rail first and then turn the key to the on position, while it is running for the 6 seconds it will make enough pressure to tell you if it is good or bad.  It must build pressure immediately so the car will start quickly.  If it does not start quickly, the starter will just keep running for a while and then you have more  problems.

 

As noted back in post #3.  Unfortunately it sounds like the OP lacks troubleshooting skills and/or tools. And as I pointed out above, on GMs, the ECU only runs the pump for two seconds, not six.  The pressure builds in those two seconds.

Edited by joe_padavano (see edit history)
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And, you can can turn the key ON- OFF- ON- OFF several times to see if the pressure builds.

 

As I said, no fuel pump running is a NO CODE condition!.All the normal monitored functions are working (spark, signal to injectors, etc.) so no code will be set. BTDT!!!

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Now I´ve checked the fuel pressure as you adviced, Joe was right when he said that 2 sec. pump running are long enough to build up the pressure. It was immediately appr. 40 psi ( 2,8 bar).

So I suppose that neither the pump itself nor the filter is the problem. Then I removed the fuel rail completely with the injectors ( with a rag underneath ), left the fuel lines connected and let my wife start. There was no fuel coming out of the injectors, nothing at all. The injectors seems to be not activated at all.

BTW, I also removed the distributor cap to have a look to the finger  and to eliminate a mechanical problem ( broken or worn timing chain or sth.). That was not the case, but the distributor and the coils at the bottom of the housing  are in a terrible condition. The six induction fingers of the distributor are heavily rusted, and the isolation of the coil ist powdered. Even when the distributor would still work, it has to be replaced due to this condition. Does anyone know if the coils underneath has something to do with the operation of the injectors? Or what component might be broken if the injektors doesn´t work when starting and fuel pressure is ok? 

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55 minutes ago, Larry Schramm said:

40 PSI is not enough.  Should be in the 60 psi range.  Need to change the pump.

Sorry but that is not correct. The spec for the 1989 3.1 is 40-47 PSI. More to the point, if there is ANY fuel pressure and nothing is coming out of the injectors, the pressure is NOT the reason why the car won't run (or at least not the primary problem). Figure out why the injectors are not firing first.

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I think so, Joe. Even when the pressure would be at the lower range, the engine has to start and to run wobbling at least.  Since I have removed the throttle with the vaccum lines for the map sensor ( to pull out the injectors) , could it be that there´s no injection because the map sensor thinks the engine is not running? And hence needs no fuel? No vacuum, no injection? 

Or could it be - worst case - the ECU is broken? 

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  • 1 month later...

The car isn´t running yet always ( less time to look for ;-() I´ve now a new distributor what I want to install tomorrow afternoon. I´ve found out in the meantime that the engine rpm sensor is not a real crankshaft sensor as on modern cars, the rpm information for the ECU comes from the distributor what is an induction typ with a small coil inside. The condition of the distr. was really terrible so I provided a new one, but I´m not sure if this will fix the problem of no injection.

Unfortunately, on the wiring charts the are rather all electric parts figured out, but the function inside is not explained, just "black boxes". So I have to go on with try and error and have to provide part after part from USA what is really a big expense, however Rockauto is a great shop and the shipping is really quickly.

If the distributor doesn´t help to make the engine run  again, does anyone know if there´s only the ECU what might be broken finally? Or could it be any other sensor such like throttle - Map - Water temp - air inlet temp  ? I think that a slightly wrong voltage signal might cause the engine to wobble or poor starting, but not to give no signal at all to the injectors? As a reminder, fuel pressure is ok and there´s pressure on the fuel rail, but the injectors doesn´t work at all once starting, not one droplet at the nozzles. Hopefully is there anybody who is experienced in these engine and have an idea.......

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On ‎4‎/‎29‎/‎2018 at 3:39 AM, Caddy59 said:

.Recently the car broke down after a 30 miles trip, it started afterwards once whilst poor throttle response, broke down again immediately and didn´t start anymore at all (starter motor was working and engine cranked ok).

 

OBD1 has a habit of deleting codes that are not hard engine threatening codes when the ignition is shut off and my favorite first roadside trick for this specific failure is to make sure the butterfly in the throttle body isn't stuck closed, the air filter is clean enough to pass air then unplug the air sensor and if the engine starts and runs replace the sensor before you ruin the catalytic converter.

 

More than a dozen things, some common and some you have to be kidding kind of odd can cause these same symptoms, a couple of the more common causes have already been covered. Unplugging the MAP forces default readings and if the engine starts you've found the problem, if not it eliminates one of the you've got to be kidding odd problems.

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@Joe Padavano: Sorry, what is VATS? (Remember I´m German :unsure:)

    If you should mean an immobiliser, yes, but it just bypasses the starter wiring. If it would have been failed, the car wouldn´t crank any more. But since it cranks, so I assume that it´s not the reason.

 

@Digger914: I think in any way the injectors have to work when cranking, I have the fuel rail removed (but connected to the fuel line) and can look when starting if the are injecting or not. Till now, they don´t, I will check it out the next days with the new distributor (hoping there was the rpm signal missing on the old one). I will try to look for the injector signal at the plugs. But if there is one, all injectors has to be broken what wouldn´t be realistic.

 

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3 hours ago, Caddy59 said:

@Joe Padavano: Sorry, what is VATS? (Remember I´m German :unsure:)

    If you should mean an immobiliser, yes, but it just bypasses the starter wiring. If it would have been failed, the car wouldn´t crank any more. But since it cranks, so I assume that it´s not the reason.

 

 

Vehicle Anti Theft System.  This is the factory-installed system that uses a resistor pellet in the key.  It disables the pulses to the injectors if the system does not detect the correct key resistance value. It also disables pulses to the injectors if the system is not working properly.  Once again, have you verified that you are actually seeing pulses at the injectors?  It's hard to provide helpful info if you won't answer questions about the car.  The mind reading still isn't working.

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Thanks.....I promise to give you the right info as soon as I´ve provided it. The cars key looks as there would be a resistor pellet inside the key, yes. Tonight, I will fit the new distributor and if it  still doesn´t run, I`ll check the pulses of the injectors.

In case there are none, what part seems to be failed then? Is it the ECU, or the key itself?

 

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3 hours ago, Caddy59 said:

Thanks.....I promise to give you the right info as soon as I´ve provided it. The cars key looks as there would be a resistor pellet inside the key, yes. Tonight, I will fit the new distributor and if it  still doesn´t run, I`ll check the pulses of the injectors.

In case there are none, what part seems to be failed then? Is it the ECU, or the key itself?

 

 

It could be the ECU, the key, the lock cylinder, or the VATS system itself.

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I have worked on thousands of cars in my life and still do.

However if my 03 Dakota wont start I will have to take it to someone that understands it. Same with my Powerstroke.

Some cars that are now considered to be antique cant be fixed without the right knowledge or trouble shooting tools, just like brand new cars.

I have an ASE certified nephew that calls me on occasion to ask me about carburetors or points.

Trying to save  buck on these things is futile.

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1 hour ago, JACK M said:

I have worked on thousands of cars in my life and still do.

However if my 03 Dakota wont start I will have to take it to someone that understands it. Same with my Powerstroke.

Some cars that are now considered to be antique cant be fixed without the right knowledge or trouble shooting tools, just like brand new cars.

I have an ASE certified nephew that calls me on occasion to ask me about carburetors or points.

Trying to save  buck on these things is futile.

 

Just because you choose not to learn about or procure tools for newer cars doesn't mean that only a dealer can fix them.  Repairing ANY car requires the right knowledge and troubleshooting tools.  You'd be amazed at how many first-time owners of older cars have no idea how to install or adjust points, or what a dwell meter and timing light are.

 

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@Jack M:

All my approach to find out why my cars doesn´t run is logical.  I am myself  mechanic since 40 years and I´ve worked in motor racing for a long time. I have found out that the reason is not the sparking, there´s no fault code, fuel pressure is tested and ok, just the injectors doesn´t work, there´s no crank rpm sensor, this function is covered by the distributor.

Due to the fact that I´m German and the cars are not very popular over here, it´s very helpful if someone how Joe Padavano can advice some checking procedures due to his experience. I´ve checked out the wiring chart, but unfortunately some items are black boxes and it´s not possible to figure out the complete function of all components. So it´s a bit of instinct to find the problem.....but definitly it´s not the way to take the car to a whatever garage where the guys are not specific specialists of this car. Without better wiring charts, no one can find out the problem better or quicker. I´ve now spent appr. 4 hours of searching in summary, however the car is broken down 8 weeks before. I have 4 other cars to work on, one 59 cadillac engine to rebuild :rolleyes:

Anyway, thanks to everyone who takes the time to advice sth.

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I guess I should have said "Futile to me"

My history is in marine propulsion. Mostly out board motors, mysteries to most that own them. Same as these computer controlled cars are mysteries to me.

Coming away from the auto trade to boats in the mid seventies, the auto technology passed me by.

Those that came along with that technology always make it look easy just like I make boats look easy. But I wont beat my head up against a wall on something that I don't understand.

I learned a long time ago not to try and beat a guy at his own trade.

I have followed tis thread with interest, but you have me confused.

Caddy, I hope you get it figured out before you pull all of your hair out. :D

Joe, I agree that most car owners don't know how they work. I wish they did, it would make my life easier. I am trying to be retired...

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On ‎6‎/‎6‎/‎2018 at 5:29 AM, Caddy59 said:

@Joe Padavano: Sorry, what is VATS? (Remember I´m German :unsure:)

    If you should mean an immobiliser, yes, but it just bypasses the starter wiring. If it would have been failed, the car wouldn´t crank any more. But since it cranks, so I assume that it´s not the reason.

 

@Digger914: I think in any way the injectors have to work when cranking, I have the fuel rail removed (but connected to the fuel line) and can look when starting if the are injecting or not. Till now, they don´t, I will check it out the next days with the new distributor (hoping there was the rpm signal missing on the old one). I will try to look for the injector signal at the plugs. But if there is one, all injectors has to be broken what wouldn´t be realistic.

 

 

The multiport defaults to all spritz on start because the engine doesn't know which cylinder is next to fire until it gets position signal. Choke on starting is a computer thought process that considers sensors from throttle position, engine temp and air to feed the injectors. If the engine controller doesn't see crank signal it stops spritzing fuel. Pulling the MAP forces cold default start readings and with spark moving from plug to plug as you've described  you should get a good spritz of fuel. Be careful with this, tube your injectors to a safe collection location, spritzing fuel with sparking plugs, can cause explosive flash.   

 

As you have fuel pressure, if you spritz no fuel you are looking for wire connection or engine controller.

 

 

 

 

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2 hours ago, JACK M said:

I guess I should have said "Futile to me"

My history is in marine propulsion. Mostly out board motors, mysteries to most that own them. Same as these computer controlled cars are mysteries to me.

 

With world wide parts sourcing, programing software for computer controlled cars is the only real mystery that manufactures have to protect parts sales and service. I have recently discovered that marine propulsion has its own illuminati as I purchased an old boat to get the 1971 black Mercury 650 and it is nothing like the little red headed Scott Atwater that I kept running for years and years and years.

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Guys,

thanks for your comments, today I have to report success: After fitting the new distributor ( what includes as well a small control unit) the injectors were firing !!!!

Unfortunately, in the meantime battery voltage was very low and the injectors of the right bank (1,2 and 3) were working , on the left bank only 6, 2 + 4 not yet. To your info: I can´t start the engine in this condition, because to get access to the injectors, I have to remove the upper part of the inlet manifold and have to remove the throttle, some vacuum lines, EGR tube a.s.o. and the engine can´t run this way. I just can check if the inj. are firing.  I guess it was a result of the low voltage what was hardly enough to crank the engine. As far as i know, with less voltage than 9 volts the ECU doesn´t work and maybe that the voltage was as low when starting. Now I have the battery on the charger and tomorrow  will try again, the engine is completed and finish to start. To my opinion, it was the crank signal from the distributor out of the small control unit what wasn´t present and that was the reason why the inj. didn´t fire. I can´t believe that there´s another issue what came up with the 2 injectors 2+4, I hope the engine runs tomorrow ok. I will tell you tomorrow whats going on.

@Jack: No Problem, but you see that I didn´t hit my head ?‍♀️

@ Digger: Funny, I didn´t know the word "spritzing". First I thought you will kidding me because in German injecting is "Spritzen" . Was really funny when I found out that it´s a correct English term, i never heard it ??? The engine needs a 1st cylinder position, but then all injectors of bank 1 are firing together and all of bank 2. You see it as well on the wiring chart. On the cyl. what needs the fuel one cycle later, the fuel will be "stored". Thats no problem. Sequential injection wasn´t usual at this time.

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@Caddy59,  With mechanical distributors the 9 volts isn't exactly set in stone, and at 10 years old some controllers didn't work at 10 volts while others worked well enough to get you home from 20 miles away with a fried alternator  and a battery so low that turning on the headlights, or even pushing in the cigarette lighter drew enough power to kill the engine.

Spritzing is the English spelling of spritzen, und ich nech seir gut spell auch Deuitch

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Guys,

Unfortunately the car is f***ing kidding me....it doesn´t run as I hoped yesterday. The engine was completed and with the new charged battery it didn´t start again. With spraying brake cleaner into the throttle whilst starting, it starts immediately as long as I sprayed, afterwards it breaks down again. I removed again the manifold and put out the injectors, tried again to start and sometimes a bit of injection, but very diffusely…..I have put ground to one side of the injector plugs and they sprayed all the time. Next test will be to measure the pulsing of the injector wire from the ECU as Joe recommended. If there is none, I would suppose that the ECU is the reason…..

 

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3 hours ago, Caddy59 said:

. If there is none, I would suppose that the ECU is the reason…..

 

 

OR it could be the VATS, as I have posted about three times now.  You seem determined to spend money on an ECU, however.

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If you don't have a bad wire connection and pulling the MAP plug doesn't get you started you might just need the ECU and luckily the car is old enough that the ECU doesn't need to be programed to the car so you don't need special tools and software to install a remanufactured or good used part.  

 

This might help and it could be a wild goose chase. A few years back, more than 10 less than 20, I got a rust free 85 Firebird V6 out of Nevada, everything that baked in the sun needed to be replaced. The car was low mileage, the air blew cold and it ran like a champ until it did about the same thing to me as your car is doing to you. I was in a parking lot, no code from turning the key to count light flashes and pulling the MAP didn't get it started, but it seemed like it wanted to start. Eventually I got mad and put the gas peddle to the floor and cranked the engine like it had a carburetor. The car started, it ran like crap, blew black smoke out the exhaust and I had to play with the foot feed all the way home. I checked for vacuum leaks, replaced the MAP, then the throttle position sensor, then checked every wire and cleaned every connection After I replaced the engine computer I had the car towed in to Pontiac. $1.50 in parts and a couple hundred dollars in labor later, I got the car back and it was running like a champ. A vacuum T was melted almost closed on one end, you couldn't see it with the hose on, it wasn't laying on the engine block or exhaust manifold and the mechanic that handed me the bad part couldn't say for certain what caused it.

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  • 2 weeks later...

Guys,

now the problem is fixed finally and I would like you to know it. It was one injector of cyl. 4, it has had a shortcut inside. I found it out with starting the engine with fuel pressure and looking to the spray pattern. Then I found that the complete left bank doesn´t spray, the right bank did. Then i started to measure the resistance of the injectors and I found the fourth with nearly no resistance, just 1 ohm.

The others were figured out with about 12,8 ohm. This shows an shortcut within the fourth inj. Looking to the wiring chart, I found that all injectors of one bank are fused with one fuse together. Due to the short and it´s low resistance, i could calculate that theres a voltage of about  12 amps. what makes the fuse of this bank knock out, so no injector of this bank is spraying at all.. 

 

Today, after changing alle injectors to new ones ( thanks to rockauto) and a new fuse the car was running as never would has been broken down. 

Thanks to all who gave their  advices to me !

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