engine swap M42 (M44) General Fuel Rail Question

[DaveBMX]

Hi guys

 

I have no fuel coming from my injectors but they are working and i have fuel pressure and have bled the rail using the built in schrader valve. when taking out the injectors no fuel ran out of the holes. could this be because i have the fuel inlet and return on the wrong way round? 

 

im assuming in a  generic rail with fuel return that the pressure regulator acts like a one way valve back to the fuel tank releasing any extra pressure it sees therefore if fuel is being sent into the return it cant make it to the injectors?

 

 

regards

 

 

Dave

[Honolulu]

fuel rail backward cause problems? yeah it could.  Methinks if you understand the function of the fuel pressure regulator (and you seem to have an idea) you'd know it could be an issue.  Are you really asking this question, or trying to get at something else?

 

So let's look at the rest of the message:  If you "bled the rail" then you must have had pressure in it... and presence of fuel suggests the pump is upstream of the rail (good).  Pressure in the rail also implies the presence of fuel which could leak from the injectors when removed.

 

How do you really know the injectors are working?  Bench testing would establish that they *could* work in installed in a properly working car.  Are the injectors really, actually getting signal from the ECU?  If not, then ....

[ar_kid]

I’d tee into the line feeding the fuel rail and put a pressure gauge on it, you're looking for around 40psi.
What fuel pump are you running & if external where is it mounted? If internal make sure it is a high pressure pump and not just for header volume

Rgrds

[DaveBMX]

thanks guys its my first experience with fuel injection and i didnt want to remove the whole manifold as i have used silicon. i thought the valve might have been on the return side of the rail so it was pressurised but the rest of the rail not. that would be the problem with tieing in a pressure guage to the feed line as it would be pressurised by the pump up till the non return valve (if thats what it is) so would show the pressure to be correct.

 

Im sorry im very new to the injection side of things so grasping it slowly. I ran 1.5v across the injectors and the solenoids click open and shut but they could be faulty or blocked like your hinting at honolulu. I spent a couple of hours tracing the signals last night using a meter as i suspected like you that they werent getting ecu signal.

 

thanks ar_kid this is the pump

 

http://www.ebay.co.uk/itm/APS-Universal-External-In-Line-Fuel-Injection-Pump-Bosch-0580464070-Replacement-/400524708163?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5d41220943

 

i have it mounted with an injection inline filter just above the tank. when i pulled the hose off the pump i got hit in the face by some serious high velocity fuel haha! and it had been off for quite a while!

 

 

regards

 

Dave

[M3M3M3]

 for FI, pressure regulator should be DOWNSTREAM from the injectors.  tank>pump>filter>rail>regulator>tank.  

 

 

when the engine is turning over with the starter, you should be able to hear the injectors opening with a stethescope or screwdriver.  if they are not, you have an ECU or wiring problem.

 

post pics of  your rail and regulator.

[nbcbird]

The topic of NOT using silicon products around carburetors has been discussed before--I would think the same caveat would apply to injection systems (just so you are aware).  

[DaveBMX]

thanks mlytle! i will post some pics of all the bits tonight!

 

hi nbcbird i have read things on the subject and im on the fence. I can say though that my plan has only to us the silicon until the whole car is up and running and then once settled in move over to th oem gaskets

 

 

regards

 

Dave

[DaveBMX]

It lives!! or did for 30 seconds haha. thanks guys had the fuel rail the right way round just dont think i gave it enough of a chance.

 

should i write up a bit of an m44 guide? i think more will happen now with the m42 supply drying up so might help someone in the future?

 

 

 

regards

 

Dave