Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Big_Al]

hi guys ,
               this is my 3rd V6   Omega , the previous 2 always started as soon as the engine was turned but not this one .

It always goes 2nd turn but not first       It makes no difference if you hold on the starter,  just won't seem to fire up on the first turn .

Something that I noticed during recent plenum & injector bridge removal was that when I depressed the small valve  to depressurize the fuel line , there was nothing coming out .When I have done this on my previous V6 omegas , i'm sure  fuel shot out  into the rag I was holding to catch it.

Seems  like no fuel pressure on this one 

I have stripped down several times over the past few weeks while trying to sort another issue (oil leak) & it's always the same  . . . no fuel escaping 

Just wondering if this is causing  the not starting on first turn issue ?

The previous owner told me it has always done this but sometimes it will start first time for a while , then go back to 2nd time start

Any ideas  or suggestions to what could be causing it ?

TIA     Al 

[amba]

My understanding is when engine is switched off fuel pressure is retained in the fuel line and regulator so on the next start up fule is available emmediately for the injectors and hence fires up first time.

Can,t imagine it is the fuel pump at fault as that would just continue feeding fuel along the fuel line whilst running so suppose it is possible the fuel regulator is not holding pressure when you stop eningine and causing fuel to flow back along the fuel line.This could be also why when you have done you numerous top end strip downs you have not experienced fuel escaping under pressure.

Just to confirm when I have needed to depressurized fuel line it has had either shown a good excape of fuel if I havent done it the correct way by pushing the small center pin on the valve.

Sounds to me like fuel is not holding pressure but my only suggestion at present would be the fuel regulator if it does have a one way valve this might not be functioning correctly if at all.

Possibly others will be able to shed a bit more light on how the regulator functions.

[TheBoy]

Leaky injector?

[cem_devecioglu]

when this happens ?  engine hot or cold..
 
if it happens only when hot, injectors leaking.. if it happens also when cold solution more complicated..
 
try to measure the fuel line pressure after the car stopped

[Andy H]

For the pressure to be retained when the pump stops there must be a non-return valve in the line. I'm guessing that it is integral with the fuel pump 

[Big_Al]

when this happens ?  engine hot or cold..
 
if it happens only when hot, injectors leaking.. if it happens also when cold solution more complicated..
 
try to measure the fuel line pressure after the car stopped

Both from cold & hot . Not really a problem  as it always goes 2nd turn 



Even if the the engine is just turned over one revolution on the first try  ,it always goes 2nd turn  . . instantly . . .  .weird  eh?

[amba]

That does seem to point to a drop in fuel pressure and on cranking even only if just once you are in effect getting the fuel pressure back to normal.

[cem_devecioglu]

simplest solution.. park near an oof members healthy omega.. and try fuel pump, regulator and injectors from it .. one by one at a time..
 
and also try pressing the accelerator ..

[Big_Al]

simplest solution.. park near an oof members healthy omega.. and try fuel pump, regulator and injectors from it .. one by one at a time..
 
and also try pressing the accelerator ..

Tried that  Cem  . . .   still the same 


Not sure what occurs here    does fuel pressure up just by turning on ignition?   or does the engine need to turn to do that ?


Saying that , have also tried just turning on ignition for 10 or so seconds & then cranking  . . . .  .same result , won't start first turn 

[Andy H]

simplest solution.. park near an oof members healthy omega.. and try fuel pump, regulator and injectors from it .. one by one at a time..
 
and also try pressing the accelerator ..

Tried that  Cem  . . .   still the same 


Not sure what occurs here    does fuel pressure up just by turning on ignition?   or does the engine need to turn to do that ?


Saying that , have also tried just turning on ignition for 10 or so seconds & then cranking  . . . .  .same result , won't start first turn 

The ECU runs the pump when it gets a signal from the crank sensor to say that the engine is turning over. If the engine isn't turning then the pump won't run.

[Big_Al]

simplest solution.. park near an oof members healthy omega.. and try fuel pump, regulator and injectors from it .. one by one at a time..
 
and also try pressing the accelerator ..

Tried that  Cem  . . .   still the same 


Not sure what occurs here    does fuel pressure up just by turning on ignition?   or does the engine need to turn to do that ?


Saying that , have also tried just turning on ignition for 10 or so seconds & then cranking  . . . .  .same result , won't start first turn 

The ECU runs the pump when it gets a signal from the crank sensor to say that the engine is turning over. If the engine isn't turning then the pump won't run.

now I know . .   Thanks 

[Big_Al]

Update on this one . Now i'm using the car  . ..    Car will now start first time after initial start in the morning .

Seems that if it is left more than 3-4 hours then 2nd turn will start it .

Looks like some form of pressure loss over that time period          TB suggested a leaky injector

This is not a real problem  . . . it alway goes 2nd turn anyway  . . .  just that  I like things put right 

[dbug]

I always suspected a leaky injector Al, but never quite got round to sorting it.  Was easier to accept it would always start 2nd time without fail! HTH