Please help! C280 wont start
 

Install a new EGR and EGR pipe to the newer one on my 95 C280. Once completed, I notice the idle was not as usual. During the process of removing/installing the EGR pipe, I had to pull the injector rail and loosen the Intake Mani. When reinstalling the injector rail, I noticed that the seals looked dry but just put some oil on them. Drove the car for a week without improvements.

Thinking the seals was causing my unsteady idle, I ordered a set of upper and lower injector seals. Replaced all the injector seals, let the system prime and attempted to start the car. Car would not start! Got out and looked under the hood to find gas everywhere. The upper seal on Cyl 4 was spilling gas everywhere and all over the garage floor. Cleaned up everything and changed the seal with an extra one purchased.

Now, the car starts for 2 seconds and then stops. Will not start again for 3-5 mins, but only runs for 2 secs. Pulled and tested the spark plugs; they are dry and have spark. Tested at the fuel pressure relief valve and it squirted across the room. Got spark, got fuel, got air = No Start!! What should I try next??

Update:

Checked the fuel relay & fuse = good.

Checked the OVP relay & fuse = good.

Checked EGR valve operation = good..

Still trying to find the source of the problem..

Anyone have other suggestions?? Please help..

Not sure on this, but it almost sounds like an " Anti - Theft " device kicking in.
Can you monitor the fuelpump ( turn key on,listen, start car, listen ) and see if the pump turns off ? :confused:

Thanks Manny for your reply...

Just tried it.. Yes, I can hear the fuel pump come on.. but not if it turns off..

Now, Im resetting the alarm by locking/unlocking drivers door using the key. No start!! :(

Im at my whits-end here!!

Can you put a 12 v. testlight on the fuelpump circuit, to see if the power stays there after starting ?

Where is the fuelpump circuit? The fuse, relay or somewhere else?

Feel the relay with your hand.
Have somebody turn the key on.
You should feel the relay klick in.
Start the engine & see if you feel the relay kicking out.

okay... we might be getting somewhere now!! :)

Turn the key to on position: Feel the click twice..
Start the engine: Feel it click again.. motor stops!! :(

Im guessing its turning off the pump as you described...
I then reset the ECU (removing negative battery post)
Performed test above and same result...

How do I clear this? Whats next?

Maybe have a closer look at the relays ( OVP & fuelpump )?
I've heard soooooo many stories here about cracked solderjoints inside of relays, etc.
Could be worth taking it apart & inspecting it ( burned contacts, cracked solderjoints ).
At this point I don't want to tell you to " jumper " anything.

LOL!! Manny, guess what Im doing right now?? I have a fuel relay open looking for burned connections... I will also look for cracked solders too..

Ive also checked in my box of extra relays (I usually buy extra relays found online on-sale/ebay)... I couldnt find a fuel one though. Its probably this one :)

okay... Found the spare gas relay... I was in a packaged box..

Installed the new relay... But same problem: starts, runs for 2 sec, dies :(

How can I figure out what triggering this?

Boy, we're really getting to the " bottom of the pit " here. :D
On most vehicles, not specifically M-B's, there is a signal ( either tachometer or oilpressure ) that keeps the relay in.
Sorry I can't be more specific or more help. :(
Just looked at my Haynes Manual & see the trigger wire comes from the ECU. ( Not too helpful ).
If you want to try something temporarily, you could jump power from terminal 30 to 87 & see if the engine stays running.
http://img.eautopartscatalog.com/live/P202067087MEY.JPG

Terminal 30 is always hot. As me how I know??
Big time spark between 30 & 87 with car off...
But 85 & 86 activates the relay..but will not keep the engine running..

BTW, all of the connections inside of my fuel pump relay were fine; no burns or solder cracks...

Any other suggestions? Im going crazy here. Changed the injector seals and engine runs only 2 seconds! Why?

Ideas?

Put a FP gauge on the fuel rail test port and monitor the pressure when the car stalls.