Crank, no start. Not getting enough fuel

[TMunson]

Hi, I just completed a head gasket replacement on my 1994 e320 m104. Put everything back together and it wouldn't start. I have narrowed it down to lack of fuel. If i cover the air intake in front of the MAF sensor, it turns over and tries to start but fails, or starts but immediately stalls out. if i hit the gas pedal and allow more air in it stalls. if i dont cover the air intake it doesnt really even fire. it tried really hard to start with carb cleaner in the intake. the more i prime the injectors before turning over the more it tries to start so I'm thinking theres a problem with fuel pressure or something that worked fine before the job now needs replacement. (fuel pump/filer, fp relay, ovp, some kind of electrical or cpu component of the fuel control regulator?) Cam and crank sensors are connected... What else could be causing this issue?

 

[Steve@Avantgarde]

Have you actually measured the fuel pressure being delivered from the electric pump?

 

[TMunson]

Have you actually measured the fuel pressure being delivered from the electric pump?

I don't have the pressure gauge to test it, and didn't think testing the line's psi with my finger would be accurate enough. Would ordering the equipment to do that test that be my next logical step?

 

[mioba]

Was it working before the HG change. If so you might have missed connecting something back up.

 

[mattkh]

I don't have the pressure gauge to test it, and didn't think testing the line's psi with my finger would be accurate enough. Would ordering the equipment to do that test that be my next logical step?

Jump the fuel pump relay, then try to start it.

 

[Steve@Avantgarde]

Engines dont run for a couple of different reasons.

1. Loss of fuel pressure.
2. Spark (if its not a diesel)
3. Battery power/electrical failure.
4. Loss of compression.


Use that as your guide to diagnose your fault and you will be half way there.

 

[TMunson]

Can confirm the issue is lack of fuel pressure. zero fuel pressure in the fuel rail

 

[TMunson]

Yes everything was working before the hg change. job lasted less than a week so it doubtful something failed in that time period. going to grab a multi meter next and start following some leads, test fuel pump, fuses etc.

 

[mattkh]

Could something have happened to the injectors while the head was off...?

 

[TMunson]

Could something have happened to the injectors while the head was off...?

considering check for injector pulse. not sure if the cam shaft or crank position sensor have a signal that turns on the ground to signal injectors or how exactly that works. may have to buy more tools as i dont think i have access to tool to test wave lengths

 

[TMunson]

so i got the fuel pump relay out, jumpered 30 to 87. it had hot lead to it but still no fuel pressure. fuses in ovp checked and working.

 

[mattkh]

I take it, you do hear the fuel pump buzzing.

 

[TMunson]

Fuel lines were reversed. intake was on outflow and visa versa. Car runs

 

[mattkh]

Brilliant news. Easily done.

 

[Steve@Avantgarde]

Fuel pressure!! Great news its sorted.