No start condition due to fuel

MCUPKA

MEMBER
1985 MERCEDES BENZ 380SE
V8
180,000 MILES

Good afternoon. I have an 85 Mercedes SE with no start condition due to fuel. Just replaced pump, filter and relay but still will not start. I jumped pins 7 and 8 and pump runs but vehicle will not start. Also pump runs while cranking engine. I put starter fluid down the intake and car starts right up for a couple of seconds. I also pulled the lines off of fuel distributor and bypassed the relay which made fuel squirt out of the ports. To be honest I am at a loss. Don't know if my fuel distributor is bad and locked in closed position and I have no knowledge of how to test it. Also don't know of other parts in fuel system that can cause my issue. Please help.

4 Replies

KASEKENNY

MECHANIC
18,907 POSTS

Hi,

Thanks for the question. Sounds like you have a fuel pressure/delivery issue. Clearly, you confirmed it was not getting fuel to the cylinders because it starts with starter fluid, so good thinking with that.

The only thing I need you to clarify is where you pulled the lines off of the distributor. The reason is, we need to find how far the fuel is getting in the system. Basically, were does it stop?

I included the fuel pressure specs and then where the regulator is. Please see the info at the bottom where the valve is matched to the distributor but if you have not inspected this and replaced the o-rings to ensure there is no leak, I would suggest you do this. However, start with getting a fuel pressure reading and see if you even have good pressure. My guess will be that you don't in which case, I would go to the regulator, then the distributor itself if you don't see anything there.

Let me know what you find and we can go from there if needed.

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Friday, April 19th, 2019 AT 2:07 PM

MCUPKA

MEMBER
2 POSTS

Thank you for your response. I unplugged the fuel lines on top of the distributor and also what appear to be some sort of regulators. There are two of them connected to the distributor. Pictures are below. After bypassing fuel relay I was able to get fuel out of all connections that I removed. I have heard that when fuel comes out the top of the distributor when lines are removed then it means that the piston is stuck. Not sure if this is true and to be honest that doesn't make sense. Fuel needs to go through there to access the cylinders anyway. I will check for fuel pressure and respond with the results. Where is the best place to get the fuel pressure reading? I am used to taking it at the fuel rail with a service port but don't see one on this motor. Thanks again for your help.

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Friday, April 19th, 2019 AT 9:34 PM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

This system is difficult to get a fuel pressure reading on. 9 times out of 10 the fuel distributors go bad, we replaced them all the time back in the day. I would search eBay to try and find a rebuilt unit and install it. Please let us know what you find. We are interested to see what it is.

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Monday, April 22nd, 2019 AT 4:50 PM

KASEKENNY

MECHANIC
18,907 POSTS

Agree with Ken. You would need to fashion a connection that has a “T” in it on a fuel line past the pressurized supply. Most of the time the OEM has a special tool made just for this. However, I don’t know of one and don’t see anything in the manual on a procedure. I am sure you could call a dealer and talk to a seasoned tech that was working on these back then. But again I think Ken is right to just find a rebuilt one and swap it out.

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Monday, April 22nd, 2019 AT 5:44 PM