Still no start - HELP!? - Page 2 - PeachParts Mercedes-Benz Forum

JEdwards · #16 08-10-2007, 12:41 PM

The car still does not start, it almost caught, but didn't, which is why I have no idea whats up with it.

saumil · #17 08-10-2007, 01:43 PM

O.K., now I understand. So it was just a guess that the engine was flooded, you really dont know if that was the case.

Do you know for sure that there is a spark on the spark plugs ?

Did you try the quick start fluid ? This would tell us a lot as to what type of problem you have.

Moneypit SEL · #18 08-10-2007, 01:58 PM

Quote:

Originally Posted by henrydupont

...also, maybe the injectors don't open up. you can check that with a voltmeter, is there power going to them or not?
[...]the 300e is junk. they have mechanical injection,

I'm curious. How, exactly, do you go about checking voltage at the mechanical injectors?

manny · #19 08-10-2007, 03:48 PM

Quote:

Originally Posted by Moneypit SEL

I'm curious. How, exactly, do you go about checking voltage at the mechanical injectors?

He's a diesel guy.

zcc · #20 08-10-2007, 04:28 PM

I would suspect the fuel distributor/EHA valve.

BTW, are you sure that you have enough fuel in the fuel tank?

bpaz_ph · #21 08-10-2007, 05:48 PM

Did anyone mess around with your fuel mix? You can also check if your IACV is stuck closed.

JEdwards · #22 08-10-2007, 06:20 PM

IACV? How do I go about checking that?

Yes, I have enough fuel, 1/2 a tank of 92 octane just before this happened.

Also, how do I go about checking the timing?

I don't believe anyone messed w/ the fuel mixture, however I had a guy get a sticker on the car about 2 weeks before this happened. I'm pretty sure it has nothing to do with the issue, but problems really started one day when I was on a long voyage and the coolant light came on (rad needed to be changed anyways). Since then, this problem materialized. Initially, the problem was just a rough idle that got progressively worst, then developed into a no-start scenario over a period of about 4 days - a week.

I know spark is reaching the spark plugs, because I pulled a spark plug out and plugged it in, ground it against the block and cranked the engine - plenty of spark came out. This is how I originally diagnosed the distributor rotor/cap issue.

Is there ever a case of the electrical components needing to reset, or are these relays pretty much plug and play?

JEdwards · #23 08-10-2007, 06:31 PM

I was just inspecting something else in the engine and happened to notice a large braided copper ground wire was completely severed in half. I don't know what it grounds, but its rather large, and come from down towards the block, the ground is screwed off with several other wires right near the coil-pack on the driver's side fender. Any idea what this is a ground for, and can I splice something like this (if so, what gauge wire should I use?)?

zcc · #24 08-10-2007, 07:23 PM

I don't know but try to change the fuel distribution first and see.

saumil · #25 08-10-2007, 09:18 PM

Looks like a fuel problem if the sparks are present. Check the coolant temp sensor. This sensor informs the ECU and ICU about the temp of the engine, if for some reason the ICU thinks that the engine is warm when it is really cold, the car will not start. This is the last sensor on the engine, towards the windshield. The resistance across the terminals should be between 2.5 and 3.5K when the engine is cold. Try connecting 10K across the wire connector terminals and see if the car starts.

Check the cold start valve. This valve should get close to 12V when you try to crank the car. If you get 12V when trying to start, check that the valve sprays some gas. If there is no gas, then the cold start valve is bad. If you dont get 12V when cranking, then your fuel pump relay is not sending the signal. I think, at one point MB updated their fuel pump relay to activate the cold start relay at a much higher temperature, maybe your relay is an older relay.

#26 08-10-2007, 09:25 PM

Quote:

Originally Posted by manny

He's a diesel guy.

yeah, one that makes fun of you gas burning fools

. wanna borrow my voltmeter?

rorypff · #27 08-11-2007, 05:27 AM

You mentioned the problem started after your coolant light came on - are you losing coolant? Check if you have oil in the coolant. Do a cylinder compression test to ensure you dont have a blown head gasket and to ensure there is equal compression between all cylinders.

I would definitely repair or replace the earth wire that is broken, can mess about with the electrics for sure.

JEdwards · #28 08-11-2007, 06:16 PM

I don't think the head gasket is the problem. The rad was junk (disintegrating fins where being blown at the engine, and tons more fell off when the rad was pulled). I have since replaced it. There isn't any coolant in the oil (I check this reg. because I'm terrified of that head gasket deal happening to me, but as I understand its more of a problem on the m104).

To test equal compression, how would I go about this? I'm relatively new to DIY repairs, but have been learning pretty fast (faster than I would like to be learning) on this car. I've got the engine layout down to a T after tearing apart a couple different engines in junkyards looking for replacement parts.

saumil · #29 08-12-2007, 12:48 AM

You need a compresson tester, it is like a pressure gauge and it comes with a threaded attachment, you remove all the plugs, remove the fuel relay, remove the wire from the coil to distributor, insert the threaded attachment of the compression tester instead of the plug one cyl at a time, and then crank the car. In one or two revolutions, the pressure should build up to a maximum level and stabilize. The minimum pressure in each cyl should be about 8.5 bar. The max diff between any two cyls should be 1.5 bars.

BUT, your problem is less likely to be compression related, check the basic things first. The car would start and run even if one cyl is not working, hust would run bad. Try spraying quick start fluid in the intake. Make sure you have sparks.