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2000 SLK230
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14 Posts
Discussion Starter · #1 ·
I bought a 2000 slk230 with 100,000 on it and when it was delivered the cats had been stolen and exhaust was not connected. He also had the IAC disconnected.
I checked the codes and the only one is a pending PO450.
The car will crank on 1 or 2 cylinders then stop, sometimes it will backfire.
I also tried to put gas in it from a can and it just spills out like it's full?
Hopefully someone can help me get this running so I can finish my restoration.
I am a UAW trained technician but I never trained on this new beast called a Mercedes Benz.
 

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2003 SLK230
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219 Posts
The cats being missing will not show a code error because your model has only 1 O2 sensor . Your vehicle will run without them , yet I think if to be lawful in your country you can fit a single sports style cat . It would help if the exhaust was completely connected before you start on the electronics .
 

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2000 SLK230
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14 Posts
Discussion Starter · #4 ·
Thanks but it has 2 O2 sensors one just after the exhaust manifold and second just past the dual cats. I think I can just put 1 cat back on it, I have seen aftermarket exhaust with a single cat.
Another problem I forgot to mention is the alarm siren and plug are missing under the cowl. Will that affect it starting?
 

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2000 SLK230
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14 Posts
Discussion Starter · #7 ·
The cats being missing will not show a code error because your model has only 1 O2 sensor . Your vehicle will run without them , yet I think if to be lawful in your country you can fit a single sports style cat . It would help if the exhaust was completely connected before you start on the electronics .
Thanks and is there supposed to be some sort of cover plate covering the access to the torque converter bolts? Isn't one on here and the flywheel and teeth are rusty, afraid it might affect the crank sensor.
 

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2003 SLK230
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219 Posts
Thanks and is there supposed to be some sort of cover plate covering the access to the torque converter bolts? Isn't one on here and the flywheel and teeth are rusty, afraid it might affect the crank sensor.
Yes to the cover plate for the torque converter. When you take out the spark plugs ! It will be easier for you to turn the engine , now you can use a wire brush to remove the surface rust on the flywheel , turning the engine little bit at a time to get to it all . The rust will leave a stain , it will wear off eventually. Mine has a skid plate as well , I spose the person you purchased it from lightened your vehicle of that also?
 

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*Premium Member
1999 SLK230K
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1,200 Posts
Good advice @elphie on cleaning the flywheel, as you said @Silveradorick rust can very easily impede the crank signal just as much as the sensor itself could be at fault. But to test a sensor you need an oscilloscope, I think SDS can do it but that's just going to complicate things more. Do as elphie says clean the flywheel, pull all the spark plugs check the condition see if they're just heavily fouled (very like given the life the poor car has clearly had) but it could also be a coil pack as yours is a pre 2001 it should have two coils for four cylinders. So the fact it fires on 1-2 cylinders could be pointing to a bad coil pack as it would cause two cylinders not to fire, though the engine will normally still manage to run bad but it will run.

You seem like you know what your doing and have confidence in mechanical skill. one other thing to try if you have gone through the sensors and it's still not running, is verifying the timing simply just pull the valve cover (with all the plugs out) turn the crank to I think it's 20 degrees after tdc. Then on the cams there's two holes in the sprockets to lock the timing when dismantling the engine, find something that fits in these holes to lock the cams. If you can lock them between 20 to 29 degrees after tdc it's ok, if it's beyond 29-35 the chain is out of spec and has stretched too much and will need replacing. It is normal though to struggle to get the holes lined up on a worn chain, but also this is only if all the more simple measures fail it's just another way to make sure the mechanical side of the system is working as it should. I only suggest this as clearly the car has had a very hard life.

Main thing make sure the engine runs before doing anything else, headgaskets are also common on these engines with the age they are now the stock Victor reinz fiber headgasket has lived a thousand lives and doesn't have much left in it to give. Not a hard job for a competent mechanic thought, so with that said a compression test is always a good idea along with checking oil for water and water for oil.

However yours seems like it's more likely electrical than a physical mechanical issue, also make sure there's no vacuum leaks. I know you guys in the state's got all the emissions control stuff that a lot of us didn't get, this added a LOT of vacuum pipes to the equation and again with age rubber fatigues. Also if this system has been messed around with its very likely a port could have been left open.

As for the alarm I know people tend to disconnect the siren when they're having issues with it randomly going off, the cars still work normally after this. But I'm no expert and wiring is definitely not my forte so il leave that to someone else.

As for the fuel spilling out that's a new one, I'm assuming that the flap in the filler neck opens up to let you full it when you put the nozzle in? Maybe drain the tank and make sure it's got good fresh fuel in there. Ive never had to do this on a merc but you may be able to disconnect the feed line at the rail and use the stock fuel pump to pump out the tank into something.

I hope some of this helps 🙂
 

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*Registered
2000 SLK230
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14 Posts
Discussion Starter · #14 ·
Yes to the cover plate for the torque converter. When you take out the spark plugs ! It will be easier for you to turn the engine , now you can use a wire brush to remove the surface rust on the flywheel , turning the engine little bit at a time to get to it all . The rust will leave a stain , it will wear off eventually. Mine has a skid plate as well , I spose the person you purchased it from lightened your vehicle of that also?
Yes that moron, any idea where I can buy those or maybe just make some?
 

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*Registered
2000 SLK230
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14 Posts
Discussion Starter · #15 ·
Good advice @elphie on cleaning the flywheel, as you said @Silveradorick rust can very easily impede the crank signal just as much as the sensor itself could be at fault. But to test a sensor you need an oscilloscope, I think SDS can do it but that's just going to complicate things more. Do as elphie says clean the flywheel, pull all the spark plugs check the condition see if they're just heavily fouled (very like given the life the poor car has clearly had) but it could also be a coil pack as yours is a pre 2001 it should have two coils for four cylinders. So the fact it fires on 1-2 cylinders could be pointing to a bad coil pack as it would cause two cylinders not to fire, though the engine will normally still manage to run bad but it will run.

You seem like you know what your doing and have confidence in mechanical skill. one other thing to try if you have gone through the sensors and it's still not running, is verifying the timing simply just pull the valve cover (with all the plugs out) turn the crank to I think it's 20 degrees after tdc. Then on the cams there's two holes in the sprockets to lock the timing when dismantling the engine, find something that fits in these holes to lock the cams. If you can lock them between 20 to 29 degrees after tdc it's ok, if it's beyond 29-35 the chain is out of spec and has stretched too much and will need replacing. It is normal though to struggle to get the holes lined up on a worn chain, but also this is only if all the more simple measures fail it's just another way to make sure the mechanical side of the system is working as it should. I only suggest this as clearly the car has had a very hard life.

Main thing make sure the engine runs before doing anything else, headgaskets are also common on these engines with the age they are now the stock Victor reinz fiber headgasket has lived a thousand lives and doesn't have much left in it to give. Not a hard job for a competent mechanic thought, so with that said a compression test is always a good idea along with checking oil for water and water for oil.

However yours seems like it's more likely electrical than a physical mechanical issue, also make sure there's no vacuum leaks. I know you guys in the state's got all the emissions control stuff that a lot of us didn't get, this added a LOT of vacuum pipes to the equation and again with age rubber fatigues. Also if this system has been messed around with its very likely a port could have been left open.

As for the alarm I know people tend to disconnect the siren when they're having issues with it randomly going off, the cars still work normally after this. But I'm no expert and wiring is definitely not my forte so il leave that to someone else.

As for the fuel spilling out that's a new one, I'm assuming that the flap in the filler neck opens up to let you full it when you put the nozzle in? Maybe drain the tank and make sure it's got good fresh fuel in there. Ive never had to do this on a merc but you may be able to disconnect the feed line at the rail and use the stock fuel pump to pump out the tank into something.

I hope some of this helps 🙂
Thanks Alex,
The start error comes on everytime I try to start it, no idea what that means. No stored codes only the pending 450 code. I am going to pull the charcoal canister and purge valve and check them since it was VERY overfilled and fix the non working gas guage.
The engine compression is good (thank God) and so are the coils.
 

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*Premium Member
1999 SLK230K
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1,200 Posts
Thanks Alex,
The start error comes on everytime I try to start it, no idea what that means. No stored codes only the pending 450 code. I am going to pull the charcoal canister and purge valve and check them since it was VERY overfilled and fix the non working gas guage.
The engine compression is good (thank God) and so are the coils.
That's good news then the good compression also means the timing is probably in spec too, I suspect the sender is at fault for the gas gauge more than likely. But checking the charcoal canister is a good idea especially when it's been brimmed like that.

It does seem more like a crank signal issue, it's reasonably common for the sensors to go bad on these. Sometimes it can be the MAF in some cases but I'm very doubtful of that in this case. But to test the theory you can unplug it and start the car, it just won't engage the supercharger. That said some M111 Bosch me cars for what ever reason won't start with the MAF unplugged, but most do. Like I say I don't think it's that but throw it out there cause some people do get real rough running with the issue, oil gets recirculated in the intake when the breather valve becomes clogged then that oil coats the MAF element and prevents it from reading or left for long enough outright kills it that's when you get real rough running normally.

I know that's a bit of an over explanation of a problem that it probably isn't, but I like to try and get as much information out in one go as I can.
 

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*Registered
2000 SLK230
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14 Posts
Discussion Starter · #17 ·
That's good news then the good compression also means the timing is probably in spec too, I suspect the sender is at fault for the gas gauge more than likely. But checking the charcoal canister is a good idea especially when it's been brimmed like that.

It does seem more like a crank signal issue, it's reasonably common for the sensors to go bad on these. Sometimes it can be the MAF in some cases but I'm very doubtful of that in this case. But to test the theory you can unplug it and start the car, it just won't engage the supercharger. That said some M111 Bosch me cars for what ever reason won't start with the MAF unplugged, but most do. Like I say I don't think it's that but throw it out there cause some people do get real rough running with the issue, oil gets recirculated in the intake when the breather valve becomes clogged then that oil coats the MAF element and prevents it from reading or left for long enough outright kills it that's when you get real rough running normally.

I know that's a bit of an over explanation of a problem that it probably isn't, but I like to try and get as much information out in one go as I can.
The more information the better on a car I'm not use to.
 

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*Premium Member
1999 SLK230K
Joined
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1,200 Posts
The more information the better on a car I'm not use to.
Well if I don't over do it with links here's a few videos from my channel, I always make sure everyone know that even I get stuff wrong sometimes so everything I do should only be used as a guide.

You already seem to have a good idea where most sensors are so this may not be much good but there maybe something in it useful.


Then another thing to check is the swirl pot on the breather especially if it's as neglected as you say.


I also go into depth when not needed so people reading this in future if they're not as clued up it can help them navigate their issue.
 

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**Premium Member '02 R170 SLK V8 5.0 & '00 SLK320
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6,996 Posts
The start error comes on everytime I try to start it, no idea what that means.
Are you saying that your Dash Cluster displays a message saying "Start Error" ???????????

If so don't waste your money on chucking Sensors at it, that message means only one thing ................

Immobiliser is active, meaning there is a fault with one of 4 components or their respective wiring including the Powertrain CAN Bus ............

DAS / RF module is the usual culprit

Key

Key Reader Ring

Engine ECU

The only way to find out exactly which of those is to narrow it down with SDS, absolutely no other machine will do so ;)

HTH ;)
 

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2003 SLK230
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219 Posts
Yes that moron, any idea where I can buy those or maybe just make some?
It will be a good idea to visit breakers yards in your area . You need to find a complete vehicle of your model , the pre face lift . If what @Dave2302 has said is indeed the fault , that vehicle will be a godsend for the parts that you will need as well as the list you have now .
 
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