Sometimes won't start
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Super Member
Joined: Dec 2008
Posts: 526
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From: MD
2007 C230 and 1985 Monte SS
Sometimes won't start
2007 C230 SS
Just finished replacing the balance shaft myself. I had the battery unhooked throughout the repair (which was over 2 months because I broke my leg the day after pulling the engine out.) Now the car won't start every time. Sometimes it fires right up, other times it cranks until it times out. It seems pretty random.
I checked the fuel pressure and it was 52 psi on prime, and didn't bleed down at all during the 30 minutes we waited. There are no codes and all readiness monitors are ready. I have driven the car over 200 miles with no change in the starting behavior.
I took it to a shop today and (after a couple hours of diagnostics) they said that the immobilizer authorization sometimes shows that it recognizes the key and sometimes is blank. It seems to correlate with the times where it will start or not start, respectively. They called an MB engineer who said it might need a new key.
Has anyone had experience with this?
Just finished replacing the balance shaft myself. I had the battery unhooked throughout the repair (which was over 2 months because I broke my leg the day after pulling the engine out.) Now the car won't start every time. Sometimes it fires right up, other times it cranks until it times out. It seems pretty random.
I checked the fuel pressure and it was 52 psi on prime, and didn't bleed down at all during the 30 minutes we waited. There are no codes and all readiness monitors are ready. I have driven the car over 200 miles with no change in the starting behavior.
I took it to a shop today and (after a couple hours of diagnostics) they said that the immobilizer authorization sometimes shows that it recognizes the key and sometimes is blank. It seems to correlate with the times where it will start or not start, respectively. They called an MB engineer who said it might need a new key.
Has anyone had experience with this?
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From: Orange County
2005 C Wagon (No snickering please!)
Have you tried the other key? If the key were at fault, chances of both of them being intermittent seems remote.
It does not make sense that the key is bad if the EIS authorizes the starter, unless something in the key is stopping before the engine has started.
To start the car the key communicates with the EIS through the infrared window. The batteries can be removed from the key because it does not need them to start the car. The power for the key electronics comes from a transformer primary in the EIS and a secondary in the key. Sometimes the transformer secondary in the key comes loose from dropping the key, or from the ingress of moisture. Sometimes a through cleaning of the red Ir window in the key and EIS can restore the intermittent functions.
It does not make sense that the key is bad if the EIS authorizes the starter, unless something in the key is stopping before the engine has started.
To start the car the key communicates with the EIS through the infrared window. The batteries can be removed from the key because it does not need them to start the car. The power for the key electronics comes from a transformer primary in the EIS and a secondary in the key. Sometimes the transformer secondary in the key comes loose from dropping the key, or from the ingress of moisture. Sometimes a through cleaning of the red Ir window in the key and EIS can restore the intermittent functions.
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From: Mississauga, Canada
2003 CL203 C320, 2002 W208 CLK320 cabriolet, 2012 A207 E350 cabriolet, 2011 X204 GLK350 4matic
Did they use STAR to diagnose the issue? If not, I wouldn't go straight to assuming that it's an EIS error. As Moviela said, try both keys. If they both cause intermittent starting, and STAR says that the key isn't recognized half the time, it's probably your EIS. If they didn't diagnose it with STAR, then I'm assuming it's something mechanical.
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Joined: Dec 2008
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From: MD
2007 C230 and 1985 Monte SS
Unfortunately, I only have one key. I bought the car used and it only came with one.
The scanner they used was described as a "$10,000 Bosch scan tool" so I don't know if it was STAR or not. The shop specializes in German vehicles.
I don't think it's a mechanical issue. They said the fuel system is disabled when it won't start. It has pressure, so I'm guessing that means that it doesn't fire off the injectors.
Thanks for the help guys. I'll try cleaning the IR windows and see where that gets me.
The scanner they used was described as a "$10,000 Bosch scan tool" so I don't know if it was STAR or not. The shop specializes in German vehicles.
I don't think it's a mechanical issue. They said the fuel system is disabled when it won't start. It has pressure, so I'm guessing that means that it doesn't fire off the injectors.
Thanks for the help guys. I'll try cleaning the IR windows and see where that gets me.
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Joined: Mar 2013
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From: Mississauga, Canada
2003 CL203 C320, 2002 W208 CLK320 cabriolet, 2012 A207 E350 cabriolet, 2011 X204 GLK350 4matic
Also make sure that the circuit board in the key isn't falling out. I'd say take it apart and glue what needs to be glued.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
For guts of key reference. Make sure nothing has come unsoldered or has poor connection with the board.
https://mbworld.org/forums/clk-class...t-key-wet.html
https://mbworld.org/forums/clk-class...t-key-wet.html
Thread Starter
Super Member
Joined: Dec 2008
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From: MD
2007 C230 and 1985 Monte SS
Thanks again. I'll check that out tonight.
I see in the other thread that it mentions that the EIS evaluates the coolant temperature and the fuel pressure. Is the coolant temp sensor used by the EIS the one in the thermostat housing? Where is the fuel pressure sensor? The coolant sensor was unplugged during the repair, but I have triple checked that the connector is secure. I don't think I had to unplug the a fuel pressure sensor, but I may be wrong.
It just seems odd that this would occur 'by chance' immediately after the balance shaft repair.
I see in the other thread that it mentions that the EIS evaluates the coolant temperature and the fuel pressure. Is the coolant temp sensor used by the EIS the one in the thermostat housing? Where is the fuel pressure sensor? The coolant sensor was unplugged during the repair, but I have triple checked that the connector is secure. I don't think I had to unplug the a fuel pressure sensor, but I may be wrong.
It just seems odd that this would occur 'by chance' immediately after the balance shaft repair.
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From: VA
THE C350
I would look in to buying/barrowing a star system. You could hook it up when the car won't start and see if the EIS is happy or not or if any other sensors are giving strange readings. They have gotten so cheap that you can have the multiplexer for under $250 (no clue how good but mine is probably the same thing) and the software can be found online and the one I found is better than the one that came with my unit.
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Member
Joined: Mar 2013
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From: Mississauga, Canada
2003 CL203 C320, 2002 W208 CLK320 cabriolet, 2012 A207 E350 cabriolet, 2011 X204 GLK350 4matic
As samaritrey said, I would definitely look into getting it scanned with STAR. Even so a full ECU reset if you can. Not sure if it would work or not, but it is worth a try.
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Joined: Dec 2008
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From: MD
2007 C230 and 1985 Monte SS
Here is the key.
It looks like there may be a strand or three out of place in the inductor/coil. Here is another picture of a (slightly different) key.
But then this one looks similar to mine...
The two pins on the top of the end ohm out at nearly zero. They are both isolated from the pin on the other end (by the IR transmitter). Trying to ohm the coil itself showed an open circuit no matter where I held the leads.
I don't see any other obvious clues.
Edit: The car behaves the same still. I doubt the coil windings are the issue. I was touching them with my multimeter leads, so if that was the intermittent issue, I'm sure it would have become permanent.
It looks like there may be a strand or three out of place in the inductor/coil. Here is another picture of a (slightly different) key.
But then this one looks similar to mine...
The two pins on the top of the end ohm out at nearly zero. They are both isolated from the pin on the other end (by the IR transmitter). Trying to ohm the coil itself showed an open circuit no matter where I held the leads.
I don't see any other obvious clues.
Edit: The car behaves the same still. I doubt the coil windings are the issue. I was touching them with my multimeter leads, so if that was the intermittent issue, I'm sure it would have become permanent.
Last edited by SickSpeedMonte; Nov 14, 2013 at 07:57 PM.
Thread Starter
Super Member
Joined: Dec 2008
Posts: 526
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From: MD
2007 C230 and 1985 Monte SS
The MB has been on the back burner for a little while, but I did call the indy shop and they said that they did scan it with STAR. They were getting an "intermittent immobilizer authorization failure".
I guess the next step is a new key... but for some reason I would be really surprised if that worked.
I guess the next step is a new key... but for some reason I would be really surprised if that worked.
