Help needed, Engine won´t start running

[lvjost]

Hi guys. It´s been a while since I postet here for the last time as german winter season forced me to get my GTR some winter sleep. By 1st may my accreditation re-newed and so I wanted to make the first 2007 ride. Unfortunately I didn´t get very far. To be honest, I haven´t even left my garage :-( .Now I´m seeking help from you guys:

My Engine doesn´t start running. Facts about my GTR:
2004 LS6 5,7, Original GM-ECU re-programmed by THE german specialist for LS-KitCar-Engines,
4 lambda probes, original GM cats...... Engine already worked very well for over 2875 miles
in 2006 without bigger complications. Car was jacked up and connected to a charger over the last
winter months. No big work done on the car exept changing the AirFilter and therefore once
unplugged the MAF Sensor...

The status is as following:
When turning the key, the ECU starts the fuelpump (one can hear it) and the fuelpump builds up
pressure. Tanks are full, pre-filter is fully new and apparently flew through by fuel.
When pressing the fuel line between two fingers at the input of the engine fuel rail and turning the key,
one can also feel fuel running through...So I don´t think, that the engine doesn´t get
fuel.....

The starter motor also works well as it is able to fully turn the engine..But afterwards the engine
doesn´t start up and rpm falls down to 0 immediately. Pushing the gas-pedal (I´ve got the fly-by-
wire throttle) doesn´t have any effect! But when turing ignition on and pushing gas-pedal,
one can hear (and see) the throttle (resp. its´ potentiometer)moving...So no error there!

Furthermore I connected a OBD reader and read out the error codes. Only 2 are displayed: P0452 and
again P0452 with a additional comment. I checked it and LS6 Error Code-List says, that this code
is synonym for EVAP System, low pressure.... I don´t have an EVAP installed so this is understandable...
And the engine worked well the whole last year with this set-up......No other error codes.....

I´ve checked all Engine-Loom-Fuses (they´re o.k.), checked, un- and re-plugged many connections of
the engine-loom as f.e. the MAF, MAP, Throttle etc. everything seems tight, closed, connected and
o.k. . The alarm system I have has not been initiated and set up since my built in 2005/2006, so it can´t
have any effect on the engine start....

After checking all these things, testing etc. I am at my wits' end! Does anybody have a clue, what
more to test, what to look after, how to proceed etc. . Maybe some of the real ultima sages like
steve_d, jeff_schwarz, lucky_p or GTWayne may have a idea about it ?!?!

Thanks alot.

Regards

Lutz

[steve_d]

First thing you do not mention is if you have sparks at the plugs.

Does the engine have a cold start injector? If so can you remove it and connect it to one of the main injector cables to see if you are getting an injector pulse. Or can you smell excess fuel in the exhaust.

I'm a little concerned about the alarm/immobiliser. You say it has not been commissioned but if connected to the car electrics there are a number of circuits it will disable. During the winter it may have had a glitch and reset itself into a disable mode.

Fuel and spark are the fundamentals. Having pressure in the fuel rail is the first step but does not tell that the injectors are firing. I'm not sure if you can see the injector pulses with a test meter.

Steve

[boosted ls1]

steve_d said:

First thing you do not mention is if you have sparks at the plugs.

Fuel and spark are the fundamentals. Having pressure in the fuel rail is the first step but does not tell that the injectors are firing. I'm not sure if you can see the injector pulses with a test meter.

Steve

What he said. You should be able to feel the injectors working with your hand and smell fuel in the exhaust pipe even when only cranking.

I'm surprised the pcm hasn't shown a more useful error code?

Boosted.

[luckyp]

lvjost said:

. . Maybe some of the real ultima sages like
steve_d, jeff_schwarz, lucky_p or GTWayne may have a idea about it ?!?!

I'm flattered....but I must apologise if I have deceived you.

You are best off....with the Proff

Lucky

[lvjost]

steve, boosted,

Thanks for your quick replys....I see it the way, you see it. The two most important things are
fuel and sparks...Fuel seems to be o.k., but sparks ????

How can I "test", feel or smth. if the coils are "firing" ? Supposed the problem is, that there´s
no sparks which ignite the injected fuel..What kind of sources of error are imaginable ?
No or insufficient power supply, damaged spark plugs, error in the ECU ...????

Unfortunately I don´t know how to proceed know, as I don´t know how to test if the spark plugs
are working....How does one test them ?

What would you gyus do in my situation ?

REgards Lutz

[boosted ls1]

lvjost said:

steve, boosted, How can I "test", feel or smth. if the coils are "firing" ? Supposed the problem is, that there´s
no sparks which ignite the injected fuel..What kind of sources of error are imaginable ?
No or insufficient power supply, damaged spark plugs, error in the ECU ...????

Unfortunately I don´t know how to proceed know, as I don´t know how to test if the spark plugs
are working....How does one test them ?


REgards Lutz

If this was me I'd unplug a plug lead from the plug and fit a spare plug into the lead. Crank the engine once and you should see a spark at the plug. You want to see a bright fat spark, not something dim and orange. If you haven't got sparks let us know. Have you still got healthy cranking speed, nice and fast? If not the spark at the plugs will be weak. Put the battery on charge overnight. Oh, I see you've already charged the battery. Your plugs should smell of fuel.

Also, you say it switches off when off cranking, ie goes to 0? This could also mean be zero power to the plugs and injectors. I'd check the relays (give them a tap incase they're stuck inside).

Oh, if the engine isn't capable of measuring air then maybe it won't inject fuel. I'd have a close look at the MAF connector again.

Boosted.

Edited by boosted ls1 on Saturday 5th May 16:13

Edited to say definately go back to the MAF sensor, apparantly it's a known fault!

Edited by boosted ls1 on Sunday 6th May 20:42

[peterpsg]

How old is the fuel?

Petrol goes off after a while, and the Ultima tanks aren't extactly air tight, so if the fuel is from last season, I'd drain it, and replace it with new stuff...

my £0.02...

[steve_d]

Fuel first have you tried what boosted suggested 'feeling' the injectors to see if you can feel them pulsing or vibrating? Did not know you could do this so will have to try it next time I have the bonnet up on my Range Rover.

Sparks.
Do you have coil packs with leads going to each plug or the 'coil-on-plug' type?

If leads then pull one of off a plug and lay it on a metal part of the engine so there is about 4-5mm gap from the lead contact to the earthed metal part of the engine. Do not hold it or you could get a nasty shock. Turn the engine over and see if you get a spark jump across from lead to engine. Should be nice and fat and make a loud crack.

If it is a coil-on-plug type then remove coil and plug. Refit the coil to the plug and again lay it on the engine to see if it sparks when turning over.

If none of them spark then you are back to ECU or immobiliser problems for which you will need to get an expert in particularly if the ecu is not giving fault codes.

Steve

[tuxman]

something to check is the cranking voltage ,when Dave Walker fitted my emerald systen he could not get it to start as the cranking voltage was very low he put this down to a crap battery ,had to set the ecu to work on lower voltage is the battrey ok ? should get a goos 12v when cranking . simon

[crafty]

Have you fixed it yet?