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Discussion Starter #1
I timed the engine put in the new tensioner and started the car. It ran perfect for about 4 or 5 minutes and then made a loud sucking noise though the intake and shut off now the car wont start again. its a 97 s420



any ideas

happy new years everyone

Thanks
 

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Wow that sucks, The first thing i would do is a compression test, because none of use were there to hear the car run, or what noise it made when stopped i think thats the easiest test to perform. Did the timing jump? A compression test will show at least if there are no bent valves, if you have good compression at least you will know that the valve train isnt damaged. Thats the first thing i would do. How did you "set the timing"? What was the problem with the car prior to this?
 

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Discussion Starter #3
timing is good. The problem before this was the head needed to be replaced the valves were bent and causing a loud knocking noise. I replaced the head and timed it with a new tensioner. I lined up the notch sticking out of the water pump with the 4|5 on the crank pulley and then lined up the holes in the cam gears with the holes in the head and then put the tensioner in. It ran pefect for 5 minutes then made a sucking noise and shut off. I was also below a quarter of a tank of gas at the time and i put in 7 gallons and it still wont start. It sounds like it wants to but no go.
 

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An easy way to see if it's fuel related would be to give it a shot of starting fluid and see if it runs. If it does, then you know ignition & timing are correct and you can start looking at injectors, fuel pump, filter, etc.

Are there any fault codes?
 

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Im not sure if the starting fluid is a wise idea. Theres got to be a better way of testing it. I agree that it would determine a fuel problem fast but its not a dodge daytona,or metro. One backfire through the throttle body could damage it. Bobs your right, but a bit more precision i feel is required for these cars. Not trying to step on anyones toes! Good luck
 

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I would assume that the intake cams were in the full retarted position?
I would double-check this. I replaced my chain/tensioner this summer and although I do not have access to alldata, I am told that their description of how to set the cams in the retarded position is vague. This pic is of the cam in the retarded position.
 

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Discussion Starter #9
i dont understand how u can time the cams that way i just lined up the holes there and on the exhaust cam with the holes shown in that pic
 

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The cam timing is relative to the sprocket, as the sprocket adjusts the cam to be advanced at speeds above 3000 RPM. So, while setting the cam using the locking pin is correct, the sprockets must be rotated all the way clockwise, looking at the front of the engine, before you set the timing chain.

Just for clarity, I had already removed the locking pins in the pic I posted. I can see where that can be confusing. Is that what you mean?:confused:
 

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Discussion Starter #11
mine is just like that except my locking pin holes lined up. The only code i got this time is IAT MALFUNCTION. I have a new iat sensor that i will be putting in today. The car ran peftect this time. No missfires on 4 cylinders or anything. So hopefully it will start for me again today.
 

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Discussion Starter #12
still no start. Checked timing again just to be sure and everything is perfect. Car after a crank or 2 it backfires through the intake a little bit. Maybe i have no spark?
 

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Have you tried a compression test ? Back firing through the throttle body can be a timing issue or a valve issue. If the car is backfiring it must be getting spark, if it wasnt it wouldnt backfire. A simple compression test will tell you alot without alot of work. It boils down to this, if you have fuel, compression, and proper time the car will run. If you rule out all the key items then you can look elsewere. Like engine management,so on and so on. Good luck!
 

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Discussion Starter #14
Good compression on all cylinders checked again today. Also Fuel pressure is still good with key on engine off and when cranking i get about 20lb more fuel pressure. Timing is dead on ive checked it 3 times. Im going to check the resistance on the cps today and if theres any ideas you would like for me to check ill check them too today.
 

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You didn't damage the cam position sensor on the front of the engine block when doing repairs did you? That would cause the car to think that the timing was off even when it was not.
 

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Discussion Starter #16
its possible that became damaged but i havent had that sensor or cover off since i did the timing and it ran after it was all on maybe it got damaged ran and then the car noticed it wasnt right and not just wont start???
 

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Discussion Starter #17
just an update i wiggled around the wire on the round piece that goes into the coming cover for the intake cam on the passenger side The side i was mainly working with and the car started and ran for 10 seconds and seized up so i think its time to let go of this benz even though now ill lose all the money i invested into it
 

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The motor siezed up? Or stopped running again? If it siezed up what do you plan on doing to the car now? Are you going to put another motor in the car? Dont give up on the car! I think everyone will agree that giving up on the car is not the thing to do. Keep us informed about the progress on the car and good luck. Pm sent.
 

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Discussion Starter #19
the engine magically unseized itself somehow i left it for a few weeks and tried it the other day and cranked fine maybe the starter locked from cranking it over so many times now it cranks fine i checked the oil it was full. Car ran for 10 minutes stalled and now wont start again. it still cranks though
 
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