Scan and post any saved codes you have.
Borrow a scanner, if needed, if you dont own one.
Your local autoparts shop should have a proper one to lend to you.

edit: forgot to ask.
when you use the keyfob to access the vehicle,on the mirror, do you see the flashing green and red lights, when you activate the keyfob?

reset -

 

The car is located quite a distance from where I live and it will be a while before I can get access to it again. It's at a cousin's house (who has passed away) and I was trying to get it started so I could bring it home. I had a few tools with me because I didn't expect it to start right up after sitting about 4-5 years. I wanted to check fuel pressure while I was there but I didn't find the Schrader valve to attach my pressure gauge. I didn't have my Foxwell NT630 Plus scanner with me when I was trying to get it started. I'm not sure if the Foxwell will work on it. What do you think?

Anyway, seeing the flashing red and green lights on the outside of the rearview mirror while my wife was trying to crank the engine is what prompted me to read the owners manual and replace the fob batteries. After replacing the batteries in the fob it would lock and unlock the doors so I assumed everything was fine. I didn't know to look at the lights on the inside of the mirror while engaging the starter to see if they were flashing. I'm not familiar with a car that will allow the starter to engage with the security system activated so I didn't think about the security system being the problem until I started reading here on the forum.

Thank you for the link to the YouTube video. The next time I get to work on the car I will make sure the key fob is synchronized as described in the video and watch for the flashing light lights on the mirror when trying to start the engine. I will also try to read the OBD2 codes with my scanner. Thanks for all your help! I appreciate it.

 

I have an autel MD802 for my 97 but it only reads 9 modules
Not sure if the Foxwell NT630 plus will work 100% - does it have the 38pin cable with it?
I now use a C4 star diagnostics. The other scanners for the latter models.

To clarify, the flashing red and green is alternating lights? while cranking? indicates immobilizer issue.
Try resyncing the keyfob.
Your fob is a bladed key with one button?

 

Foxwell doesn't have the 38 pin cable with it. Only standard ODB2 connection. It works well with GM products but don't know about Mercedes. I'm going to need a repair manual in .pdf format to get up to speed on this Mercedes. Can you recommend a place to get one at a good price for a '96 c220 like mine?

It is the folding blade fob with one big button. Red and green lights were alternating before changing fob batteries. I didn't look for that after I changed batteries when cranking. I didn't know I should do that. I did notice hearing doors lock and unlock when I pushed the button but I didn't notice the lights to see if they were flashing or not. I'm just now trying to figure all that out. I will try resyncing when I get another chance to work on it.

Do you know what all the immobilizer shuts off on this model is in security mode? Fuel pump? Injectors? Spark? I don't hear the fuel pump run to prime the fuel each time I turn the key on before starting like on GM products but that might be because the fuel pump is stuck from sitting so long without being run. Thanks for the help.

 

Spray starter fluid into intake to check spark. Motor should run briefly. Sitting that long, fuel is no good. Lines will have to be flushed in addition to changing pump and filter. Foxwell NT530 Pro comes with 38 pin adapter for $210 on ebay. Not sure about MY 1996, that is right around the time OBD2 came into being.

 

Sam, Thanks for the reply. I'm sure you are right about the bad gas. I didn't have any starting fluid when I tried to get it running. I did have some WD-40 that I squirted into the intake and it seemed to sputter a time or two but it didn't try to run on it. The gas gauge showed the tank was empty. I added four gallons of fresh fuel but the gauge didn't move. Fuel lines are probably still full of bad gas and it all will have to drained out, including what I added to the tank. If I can get the fuel pump running I can pump the bad gas out of the lines. At this point I don't know if the security system is keeping the pump from running or the pump has stuck from sitting there with the bad gas in it. I will know more the next time I get a chance to work on it. That will be several days from now. I'll report back what I find.

 

Thanks for all the help. I was able to start the car and drive it home even though it was running poorly and the check engine light came on.

The problem with the fuel pump not running was the immobilizer system. I tried several things to disable the immobilizer. Finally to disable the immobilizer and get the engine to start, I had to close all the doors - then use the key from the outside to lock the doors - and then use the key to unlock the doors. After just a few tries with it sputtering and dying it finally started up and kept running. I never shut it off again until I got it home.

I still have work to do to get it to run like it should. I took a sample of gas through the Shrader valve. The sample was about 1/3 cup of gas. After 10 minutes there was a Nickle size bubble of water in the bottom of the container that had separated from the gas. That is a lot of water for just 1/3 cup of gas.

Now I have to figure out how to get the old gas out of the tank. I would like to siphon it out with a hose but I can't get the hose to go down the filler pipe. Does the tank have a drain plug? Thanks!

 

DIsconnect fuel line and use external autmotive fuel pump to pump out gas from tank. Or siphon.

Try replacing fuel pump relay.

 

I want to siphon the gas out with a hose so I can get the water out below the pickup for the fuel pump but the hose won't go all the way in. Any tips on what I can do that will allow the hose to go into the tank?

 

Is the hose getting caught on something or bottoming out without reaching the bottom of the tank? If it's getting caught, you can try using a fuel filler funnel and then feed the hose through the funnel if the hole is big enough.

Otherwise you'd have to disconnect the fuel hose on the bottom of the tank that goes to the fuel pump.

 

You might also want to replace your fuel hoses while you’re at it if they are original. And don’t use auto parts store fuel hose, I made that mistake (it cracked and started leaking after only 1 year). Get hose from the dealer. Unless it’s the big hose coming from the fuel tank with the big bolt then aftermarket is ok. I believe the OEM brand is Cohline.

 

Thanks for the illustration of of the fuel system components. It's very helpful. I will remove the hose to drain that tank as suggested. Also, thanks for the tip about the fuel hoses. I was intending to replace them when I drain the old fuel from the tank. I'm new to Mercedes and I appreciate the help.

 

I'm assuming your problem is resolved. But for others who stumble upon this thread if they have a similar problem, there is a procedure to follow if the battery in the fob goes bad or is removed. This is described in the owner's manual but not obvious. Once a good battery is installed in the fob you must point it at the mirror and click the fob twice, then within 30 sec you need to insert the key into the ignition switch and turn it to the #2 position (on/run). That action resets the anti-theft function.