m52 swap not starting

[HRH-squidlips_III]

hi all,
just finished my m52 swap and have a problem not starting if anyone can help it would be much appreciated
problem is the car starts but only using easy start
i guess this means its getting spark but not fuel
i pulled the line were it feeds into the fuel rail with the car cranking and gas is coming out, also tried bridging the fuel pump relay pins 30 and 87 the pump runs quite noticabley so its definitley working
replaced the tank, pump (cheap ebay pump) fuel lines and filter
as the car had sat for 15 years prior to me buying last year
the pump seems to be working more just after i stop cranking for a second or so
only doubts i have with the wiring are pin 7 e30 to pin21 e36 as there were two green wires on the c101 one thick one thin
i just spliced the two e30 ones together and joined to pin 21 wire
ews has been flashed out of ecu so no worries there
only other thing i can think of was a brn/red wire that had been spliced into e30 just before ecu going to pin 45 in ecu that,s supposed to be coolant temp sensor going back to a relay under the steering column that definitely don,t look factory
thanks dan

[Acaciastrain360]

Make sure the pump has enough pressure as standard e30 pumps aren’t powerful enough for m50/52, need a higher psi/bar pump for them

[Acaciastrain360]

I think m50/52 have a 3.5bar fuel regulator and the e30 pump only produces 3bar... also check that the fuel regulator isn’t buggered, maybe swap it with one you know works

[sale3x]

Maybe it will help you

[DanThe]

Nothing wrong with an E30 fuel pump on an M50 or M52 conversion, easy to work out if the injectors are getting the signal with an LED test light

[Brianmoooore]

i pulled the line were it feeds into the fuel rail with the car cranking and gas is coming out,

Did this pipe connect directly to the rail, or to the pressure regulator?

[sale3x]

My e30 m52 works normally with the original fuel pump.

[Acaciastrain360]

Oh mine are 2

[HRH-squidlips_III]

Nothing wrong with an E30 fuel pump on an M50 or M52 conversion, easy to work out if the injectors are getting the signal with an LED test light

thanks for the confirmation dan i,d read that some time ago
i don,t have led light at the moment i,ll see if i can find one tonight

[HRH-squidlips_III]

Maybe it will help you

thanks sale i used brianmoooore,s guide that he wrote up a few posts back to wire up the c101 x20

[HRH-squidlips_III]

i pulled the line were it feeds into the fuel rail with the car cranking and gas is coming out,

Did this pipe connect directly to the rail, or to the pressure regulator?

hard to tell brian i seems it goes into the fuel rail but the fpr is right on the rear of the fuel rail so i guess it could be either

thanks for your replies all i,m really hoping to get this car going this weekend as i been at this of on for a year now
again much apperciated dan

[Brianmoooore]

i pulled the line were it feeds into the fuel rail with the car cranking and gas is coming out,

Did this pipe connect directly to the rail, or to the pressure regulator?

hard to tell brian i seems it goes into the fuel rail but the fpr is right on the rear of the fuel rail so i guess it could be either

It'll give exactly your symptoms if it's wrong.

[HRH-squidlips_III]

makes sense brian fuel is getting there
does a bad fpr mean it,s not getting enough pressure to open the injectors

[Brianmoooore]

I'm not suspecting a bad FPR - I'm wondering whether you have the fuel feed pipe in the correct place.
It goes directly to the fuel rail, not the regulator. Is this how you have it?

[HRH-squidlips_III]

hi brian,
my fuel rail has feed and return on the end of the fuel rail i did not take note of what was feed or return when i removed it from the e38
(my names forest, forest gump)
so i looked online and found the feed goes to the fuel rail and return has a pipe thats on top of the fuel rail and comes back along to the same end fpr seems to be built into the end of the fuel rail right where the feed line is so it carn,t go into the fpr
i hope it is the fpr as i just orded a new one and a cam position sensor from bmw

[Brianmoooore]

I can assure you that one of the hoses connects directly to the fuel rail, and one connects to the outlet of the pressure regulator. The feed hose must connect directly to the rail, and the return hose to the regulator.
Fuel pressure is easy to check on a M52 - there's a Shrader valve on the rail (same as a tyre valve), so checking the pressure is as easy as checking that in your tyres.
Cheap fuel pressure gauges are available on the likes of ebay, for around £15 or so, or, at a push, a tyre pressure gauge could be used, but don't expect it to work for air afterwards.

[HRH-squidlips_III]

thanks for taking the time to explain brian
as you have described it i have had the fuel lines round the wrong way
i couldn,t find anything on the net about which way round they went but found a m54 one and assumed they wen,t the same way
thanks again brian saved me a lot of head scratching and money replacing even more parts

[Brianmoooore]

Does that mean it's running now?

[HRH-squidlips_III]

not yet brian i pulled the fuel rail last night thinking it would be the fuel pressure regulator and ordered a new one so no sense putting back together till tomorrow when the fpr comes
will report back asap
appreciate all your advice if you or anyone else for that matter needs advice/help in the carpentry arena
let me know been a chippie 27 years
carn,t wait till tomorrow
cheers dan

[Brianmoooore]

There has been one case on here where connecting the fuel lines the wrong way around did actually damage the pressure regulator, so if you've already bought one, you may as well use it.
Been loads of other cases, though, where it did no damage whatsoever.

[HRH-squidlips_III]

big thanks brian she lives and breathes
you spotted it straight away fuel pipes round the wrong way
just goes to show belive a 1/4 of what your hear and 1/2 of what you see on the net
next week i,ll get the exhaust done then shes all done
well for the time being anyway
thank you all for your help and advice very much apperciated

[Brianmoooore]