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-   -   why won't it fire??? (http://www.haynes.co.uk/forums/showthread.php?t=4277)

aerosam 15th May 2010 09:44 PM

why won't it fire???
 
Ok for those not in the know, my car has a BMW M60 3.0L V8 installed.

Tried to get it running today - and failed.

After several hours going over the wiring with a multimeter I can surmise the following.

the starter is cranking the engine
the fuel injectors are working
the spark plugs are firing
the fuel pump is pumping
there is fuel in the tank

I am getting fuel vapour ejected from the exhaust ports, and the (very) occasional cough of life. WHY WON'T IT JUST START!!!!

Have I missed something obvious?

les g 15th May 2010 09:48 PM

Sam
you got air fuel and sparks..its gotta go...............
unless the sparks are happening at the wrong time or in the wrong place.
or the fuel is squirting at the wrong time.
plug leads on wrong or timing out somehow i guess..
cheers les g
nah dont think its fuel as the fuel would sit on the inlet valve and the engine would try to fire
just like as if you had put a capful down the manifold
really does sound like an ignition/timing problem

aerosam 15th May 2010 10:14 PM

Tomorrow I'm gonna remove and clean all the plugs.

I'm also wondering if I have plumbed the fuel system right. - Am I right in my thinking that the fuel should be pumped into the fuel rail, with the fuel pressure regulator at the outlet end?

Timing really isn't an issue, I should have mentioned before that it's fully ecu controlled with 8 individual coil packs mounted directly to the plugs. Thanks for your answer Les, don't mean to p1ss all over it, but I don't want you to think I ignored it either.

RAYLEE29 16th May 2010 11:32 AM

Hi, just because the ign is controlled by an ecu doesnt mean the timings actually right could be out of phase i s there a phase sensor on it? or is it a lost spark system?
yes it is normal to have a regulator on the exit/return side of the fuel rail.
chuck some fuel in the intake if it fires its fuel if it doesnt its ignition
as the meerkat says simples init
Ray:)
of course this assumes cam timing is correct and you have compression.

Bonzo 16th May 2010 12:12 PM

Quote:

Originally Posted by RAYLEE29 (Post 38284)
Hi, just because the ign is controlled by an ecu doesnt mean the timings actually right could be out of phase i s there a phase sensor on it? or is it a lost spark system?
yes it is normal to have a regulator on the exit/return side of the fuel rail.
chuck some fuel in the intake if it fires its fuel if it doesnt its ignition
as the meerkat says simples init
Ray:)
of course this assumes cam timing is correct and you have compression.

My thoughts persactly ;) :)

flyerncle 16th May 2010 12:13 PM

Make sure all the earth's required are fitted,a lot of injection systems switch earth to turn things on and off.

aerosam 16th May 2010 02:27 PM

Quote:

Originally Posted by RAYLEE29 (Post 38284)
Hi, just because the ign is controlled by an ecu doesnt mean the timings actually right could be out of phase i s there a phase sensor on it? or is it a lost spark system?
yes it is normal to have a regulator on the exit/return side of the fuel rail.
chuck some fuel in the intake if it fires its fuel if it doesnt its ignition
as the meerkat says simples init
Ray:)
of course this assumes cam timing is correct and you have compression.

Hi Raylee, yeah cam timing should be ok, it ran fine in the donor, is chain driven and hasn't been touched. Definitely got compression too.

not a wasted/lost spark system - what does a phase sensor look like and where should I look for it? I know I have a crank position sensor mouned next to a toothed wheel on the crankshaft - is that it?

aerosam 16th May 2010 02:32 PM

Quote:

Originally Posted by flyerncle (Post 38288)
Make sure all the earth's required are fitted,a lot of injection systems switch earth to turn things on and off.

yep will do - heading up the garage just as soon as the F1 finishes.

aerosam 16th May 2010 04:18 PM

IT WORKS! WOO HOO!!!! GOT IT RUNNING!!!!

Duly video'ed and currently being uploaded for your viewing pleasure.

Man what a noise!!!!

On cloud 9 right now, and kinda deaf. It caught me out the first time it started and I didn't have my ear defenders on.

Bonzo 16th May 2010 04:42 PM

Well done :cool: :cool:

I guess you found out why it wouldn't start yesterday, what was the problem ?

Imagine that you are well pleased that it is up & running :) :)

RAYLEE29 16th May 2010 05:39 PM

Glad you got it going Good feeling init
so what was the problem? or did it just go this time? sometimes you gotta leave it be and try again the next day lets the engine/plugs dry out and the battery recover
Ray:)
oh yes the ecu needs to know what cycle the engine is on tdc is not enough unless its wasted spark you should find a sensor on the cam or on a cossie its in the distibutor for instance
personally know nothing about bmw v8s but all engines need the same basic things :)

twinturbo 16th May 2010 08:11 PM

my guess is dirty plugs

TT

aerosam 16th May 2010 10:33 PM

Quote:

Originally Posted by twinturbo (Post 38317)
my guess is dirty plugs

TT

Spot on TT!

I only took 1 out when I was checking for sparks, when I removed the other 7, 5 of them were severely crudded up. It still didn't go straight away, but after cranking it then leaving it for a while several times over, first 1 cylinder would fire, then 2 then 3, and when i got 4 it just went!

Yeah, still DEAD CHUFFED.

aerosam 16th May 2010 10:37 PM

Quote:

Originally Posted by RAYLEE29 (Post 38313)
Glad you got it going Good feeling init
so what was the problem? or did it just go this time? sometimes you gotta leave it be and try again the next day lets the engine/plugs dry out and the battery recover
Ray:)
oh yes the ecu needs to know what cycle the engine is on tdc is not enough unless its wasted spark you should find a sensor on the cam or on a cossie its in the distibutor for instance
personally know nothing about bmw v8s but all engines need the same basic things :)

Crackin feeling Ray, absolutely brilliant.

it has a cam position sensor on the drivers side inlet cam, i'm guessing that's it?

There's a vid on my blog, click below! :D

twinturbo 16th May 2010 10:40 PM

that sounds like it's gona scare the local cats, and the ones in the next county too!!!

Bonzo 17th May 2010 08:36 AM

Awesome
 
That engine sounds awesome Sam :) :)

Definately going to be singing a sweet song once the silencers are fitted :cool:

No finer sound than a V8 purring away :cool:


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