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

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.

__________________
Ben
1987 190d 2.5Turbo

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

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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.

__________________
1996 C280 289K Traded
1997 E420 167K Traded
2001 S430 240K Traded
2010 E550 4matic 80K
2000 GMC Jimmy 198K Gone to Boneyard
2003 Camry LE 196K
2011 Mazda3 i Sport 31K

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

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

__________________
Robert Fini

'12 ML350 BlueTec, 100k
'06 E320CDI (x2)
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 70k
'97 C36AMG, 319k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)

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

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?

__________________
Robert Fini

'12 ML350 BlueTec, 100k
'06 E320CDI (x2)
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 70k
'97 C36AMG, 319k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)

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.

__________________
1996 C280 289K Traded
1997 E420 167K Traded
2001 S430 240K Traded
2010 E550 4matic 80K
2000 GMC Jimmy 198K Gone to Boneyard
2003 Camry LE 196K
2011 Mazda3 i Sport 31K

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

Steve, just noticed, if the start is authorized the result is no fuel injection. The pump might still run, but the injectors don't squirt.

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Gilly, thank for your expertise!
You are correct about the ring around the igntion switch. Mine is an 06/96. The 97 models have the sensors.
Now, you hit on something.
I have the driveside door that will not lock or unlock, thought it was the actuator, but now think it could be something else. Any ideas?
I had trouble with the car again yesterday, but I tried putting the key in, and I know this will sound silly, so as to scrape the top and over right side of the ignition entrance as I insert it. Low and behold, it started! Tried it again and it continues to work!
Now my question is, since this is an electronic switch, could it be the ignition connections inside the switch?
I also can, on rare occasions, get my dash to come up and work if I turn the key in right manner. This seems to be related to the ignition as well.
I have found ignition switches on Ebay, don't know what they are, exactly, but would a replacement of the 7 pin switch be a possible solution?http://cgi.ebay.com/Mercedes-Benz-Ignition-Switch-240D-280CE-280E-300D-300E-/170463511640?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3AC280&hash=item27b06ac458
Your assistance is greatly appreciated!
Steve Dale

Steve, I don't think that's the right style switch. It could be suspect, if it is the style I think it is, I've posted to several people aout the suspicion I always have of this style switch.
My immediate reaction is that there is I believe an electrical switch in by the door lock which I would also be suspicious of, especially if you have a problem with the drivers door lock anyways. This switch is what would signal the DAS to let the car start.

__________________
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Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)

So, Gully, what is this sensor in the door? Can it be replaced?
My mechanic is quite sufficient if I can get the right part. I will also check with the Benz house to see about the ignition switch and what is in the door. Can u tell me what a DAS is?
Thank u for Ur diligence in this matter. I truly love this car and other then this issue it is in wonderful condirion. I have taken great care with this car and want to continue to drive it. Your assistance is so appreciated.
Steve Dale

Sorry, Gilly. Stupid phone.
I also need to add that the door will lock and unlock via the trunk, so the actuator appears to be working. Let me know if their is an electronic sensor or something of that nature inside the door.
Thanks again
Steve Dale