96 C280 wont start - PeachParts Mercedes-Benz Forum

steve dale · #1 04-05-2011, 12:06 PM

I am needing some advice.
I own a 1996 C280 with 214,000 miles.
I am having a small problem in starting it. It fires but won't start. The fuel pump has been replaced along with coils, wires and plugs. I have just purshased a new fuel relay. In addition to it not starting, the rearview mirror lights flash, alternating. When it does start, the fuel pump buzzes.
My question, is this a bad fuel pump, a crank shaft sensor or something else?
In addition, I replaced the OVC recently.
Thank you for your advice.
Steve Dale

1996 C280
2001 E430

benhogan · #2 04-05-2011, 01:44 PM

think FAST

F- are you getting FUEL? disconnect the fuel line connecting to the fuel rail, crank the engine, if fuel comes out, then your fuel pump is probably ok. OR you could check fuel flow at the injectors by pulling them and watching for the spray.

A- are you getting Air? is the air filter clogged?

S- are you getting Spark? use a $5 spark tester to check for spark.

T- is the Timing set properly? check for proper operation of the crank position sensor or something related to timing.

Your no start problem is one of those.

Gilly · #3 04-05-2011, 07:42 PM

To me "firing" and "starting" are the same thing. You mena it cranks but won't start, or.....???

Steve M · #4 04-08-2011, 08:51 AM

This probably won't help, but if I recall correctly, the red and green lights alternating on the mirror mean that the security system won't let the car start. This will happen if you get in the car, and use the remote key to lock the doors. You have to wait ten minutes to start the car if you do this. Maybe your security system is on when it shouldn't be.

steve dale · #5 04-19-2011, 12:38 PM

Thanks for your input. I seem to remember something to that extent, also.
Would you know how or what to check to see if this is the problem? I dont use the remote, the key is old and the the infrared sensor is out. My driverside door will not open with the key, I believe the actuator is out. I lock and unlock the car via the trunk. I did notice a sound coming from the right rear, which i believe to be the cars vacuum system for locks. If you can add any other information, I would appreciate it.
Thanks
Steve Dale

RobertFini · #6 04-19-2011, 12:57 PM

Regarding getting into the car using the key in the trunk and possible security system intervention, I've been doing this for years with my 1997 C36 without problems since the remote transmitter battery died.

I would think that security system intervention would prohibit the car from cranking at all, but I could be wrong.

Best Regards,
Rob

steve dale · #7 04-19-2011, 01:40 PM

I have been doing the same for years, also. That makes me think the issue is crankshaft and camshaft sensors. Could this be a reason for the flashing security light, alternating?
Thanks for your input
Steve Dale

1985 190E (RIP)
1989 190E (RIP)
1996 C280 214,000
2001 E430 133,000

RobertFini · #8 04-20-2011, 08:20 PM

I doubt a bad crank or cam sensor would result in any kind of flashing/alternating security indicators.

When the crankshaft sensor on my wife's 1999 E320 went bad, the car just wouldn't start. It cranked just fine, but no fire and no blinky lights.

It could be that you've got two separate and unrelated issues. I would recommend disregarding the blinky lights and chasing after the starting problem in a methodical manner (rather than continuing to just throw parts at it).

Are you getting any codes out of the computer?

Steve M · #9 04-21-2011, 09:25 AM

Steve-

I don't recall for sure what happens when you turn the key while the lights are blinking. This happened 8 years ago the day my daughter got her drivers license. She drove by herself for the first time. When she got back in the car she immediately locked the doors like her Mom told her to. The only way she had ever locked a car was with the remote, so that's how she did it. The car wouldn't start. I came out with a can of gas, but the car started with no problem. She had this problem every day for a week until we figured it out.

I thought it cranked. She doesn't remember. I just tried the same thing in the 97 E420 and the car unlocks itself and starts just fine, with no alternating blinking lights, so they may have changed that system after 96.

The sound you hear from the right rear is the electric vacuum pump that tends to run when there is a vacuum leak - I learned this when one of the climate control vacuum diaphragms stopped working. I tore the whole dash out to get to it. I don't know how the locks work, but if you can seal off the vacuum line that's leaking you might stop that pump from burning out someday (it cost $474 a couple of years ago).

You said you unlock your car from the trunk - how do you lock it? You don't have a passenger door keyhole, do you?

The suggestion that this blinking light thing may be unrelated to a real starting problem sounds completely reasonable. I wonder if these could all be related to a computer problem, maybe related to battery condition or something like that? That vacuum pump would start to run right away, I think, so it may be drawing on the battery at the worst possible moment.

Poking around the forums, I've found threads about a 1996 C280 and a 1995 C220 with no start, cranking and flashing lights- both resolved by replacing K40 relay. Maybe worth looking at.

steve dale · #10 05-12-2011, 02:31 PM

Thanks for the input, gentlemen.
I have continued to have the same problem. My mechanic replaced both sensors and we still have the problem. It will start, but not turn over. The lights continue to flash.
In addition, the codes we get are from a Snap-On reader, they indicate air temp at 312, without any air flowing and water temp at 416, without the engine on.
He checked the injectors and they are not pulsing, although it is getting fuel.
We think it is a computer issue, but now are running out of ideas.
I wonder about a new key. The old one no longer sends a signal.
In answer to your question about unlocking the car thru the trunk, yes, I unlock and lock the car via the trunk, with no major issues, still does that today.
I have changed all relays and sensors I know off. This K40 relay, I have no idae about. If you would, inform me what this is.
Any other ideas would be greatly appreciated.
Thanks

#11 05-14-2011, 11:52 AM

I am kind of confused on your statement. You say it will start but won't turn over? Not sure what that means?? Not for sure if it would help or not, but have you tried disconnecting DC from it. Then reconnecting DC to see if it will start.

steve dale · #12 06-12-2011, 10:16 AM

Well, my mechanic replaced both sensors and the car has started without any problems since late April. It is now mid June and the same problem has returned.
The security lights continue to flash alternatingly, it will start, but not turnover. I can tell whether it will turnover when I turn the key to the 2 position and I can hear the fuel pump kick in, then I can continue to turn the key and the car will start.
Surprisingly, this situation has happened multiple times this week. Once it took and hour before it kicked over, another 30 minutes and this morning I quite after 10 minutes, out of frustration.
As I have mentioned, the sensors, fuel relay, ovc relay, fuel pump, plugs, wires, coils, battery, starter, fuel filter, mass air sensor have all been replaced in the last year.
I am open for suggestions.
It pulls no codes and Benz techs don't know what the issue is without forcing me into bankruptcy.
I appreciate your input on this matter.
Steve Dale

SocksE420 · #13 06-12-2011, 01:43 PM

I had the same problem with the same car - somehow I compressed key fob while trying to start the car and this somehow disabled the ignition (assume it is an anti theft device). As I recall, the fix was to lock the car with key and then unlock it. If that doesn't work, locking and unlocking the car with fob vice the key worked on my 85 Porsche.
Socks E420

Gilly · #14 06-12-2011, 04:16 PM

I was going to mention this same sort of thing as well. IIRC the alternate flashing red and green lights means that there is no start authorization. Either that or the battery in the key is weak, but also IIRC the battery is not required to get start authorization, so a bit confusing, although I think I do have a training manual for the older DAS systems so could look it up.
IN the meantime, do you have a second key you can switch to as a test? Could also be a problem with DAS on the car, like the DAS module or transponder ring (antenna ring) around the key, if this style has that.
Gilly

Gilly · #15 06-12-2011, 04:37 PM

(Found my training guide)
All 96 Mercedes used DAS2 immobilizer.
The alternate red/green lights do signal an unauthorized start attempt.
The engine control module is disabled in an unauthorized attempt. Since the control system is ME-SFI, I am unsure what is disabled, but would have to be spark or injection or both, the fuel pump might still operate as you've noticed.
The system is set whenever the car is locked, either with the remote or key blade (I know you said the remote is inop).
There is no antenna on the ignition lock, what I mentioned before about that is wrong, that came a year later.
DAS is controled by the remote central locking control module (RCL). If this proves to be the problem it will need to be purchased new, as the RCL is "mated" to the engine control module, you can't just buy a used one.
I don't know if it could one of the unlock switches in the car causing this? It would be "interesting" to find out if the remote central locking working (new working key) would fix the problem or not.
If someone with a shop computer (probably a dealer) could monitor the system, this should give some idea of why the start process is being disabled by DAS, or there might be codes stored telling where the problem is. Some of the security functions on the car can only be accessed by a dealer, you can ask the dealer if they can simply do a "quick test" of the control modules on the car and ask for a printout. The problem possibly could be with the drivers door lock not working properly, would be my first guess.