NEW LEADS now not starting ?????

Brett928S2 · **Posted:** Sun Apr 05, 2015 7:46 pm

Hi All

Put a new set of plugs and a brand new set of 928 Motorsports blue leads on my car today.......

All working fine before...now NOT starting... grrrr....

Timing light shows flashing from both coil leads.... connected a spare plug to one of new leads ...sparking ok....

pulled maf, sprayed ether into hole...still nothing, cracked fuel pipe at front end of fuel rail...high pressure sprays ok when ignition on....

rechecked leads on correct positions on both dizzy caps...all ok....

Anyone got any bright ideas before i jump off a bridge ...lol ??????

Only thing i can think of is to put old leads back on

Unless ?????

All the best Brett

Greggers · **Posted:** Sun Apr 05, 2015 9:57 pm

I'd probably put the old plugs back in for starters (excuse the non-intentional pun...) then go one by one with plugs and leads...

G

Brett928S2 · **Posted:** Sun Apr 05, 2015 10:27 pm

Hi

The new plugs are brand new NGKs... not even trying to fire on one or two... the chance of 8 being faulty is slim....

I am stumped lol ....

All the best Brett

Greggers · **Posted:** Sun Apr 05, 2015 10:41 pm

So unless the ECU has spontaneously fried itself, you've only changed two factors - leads and plugs. I was forgetting you have another four to look at! Seriously though, it should only be one or the other - shouldn't it?

Brett928S2 · **Posted:** Sun Apr 05, 2015 10:52 pm

Greggers wrote:

So unless the ECU has spontaneously fried itself, you've only changed two factors - leads and plugs. I was forgetting you have another four to look at! Seriously though, it should only be one or the other - shouldn't it?

Hi

I am suspecting that possibly I knocked off something (sensor etc) when removing the airfilter casing.... which is needed to change the two rear plugs....maybe lol....

All the best Brett

Brett928S2 · **Posted:** Sun Apr 05, 2015 11:03 pm

Hi

Thinking about it....I suspect the injectors are NOT opening, even though I have high pressure fuel at both fuel rails,,,,

So I will have a very good look to see if somehow I managed to disconnect a sensor or wire to a sensor tomorrow...

All the best Brett

stratfordshark · **Posted:** Sun Apr 05, 2015 11:21 pm

Are you certain the pump runs? You said fuel sprayed out with ignition on, but this could be residual pressure in lines. The pump doesn't run when ignition on, but only after itreceives signal via ezk that the engine is cranking.

Brett928S2 · **Posted:** Sun Apr 05, 2015 11:42 pm

stratfordshark wrote:

Are you certain the pump runs? You said fuel sprayed out with ignition on, but this could be residual pressure in lines. The pump doesn't run when ignition on, but only after itreceives signal via ezk that the engine is cranking.

Hi Adrian

I "assumed" it did lol...will check in am....

But it was all running fine until i did the leads/plugs etc all at the engine end....

Is there a sensor that I could have damaged or knocked near the top/bottom of air filter casing (which were both removed to get at back 2 plugs) ..?

All the best Brett

stratfordshark · **Posted:** Mon Apr 06, 2015 6:57 pm

I'm not the man to rely on here as the S2s seem very mysterious compared with S4 I know better.

But the only critical sensor I can think of near air filter is the crank position sensor, whose connector is underneath the lower air box housing. If there is no crank signal then the fuel pump will not run.

Brett928S2 · **Posted:** Mon Apr 06, 2015 7:42 pm

stratfordshark wrote:

I'm not the man to rely on here as the S2s seem very mysterious compared with S4 I know better.

But the only critical sensor I can think of near air filter is the crank position sensor, whose connector is underneath the lower air box housing. If there is no crank signal then the fuel pump will not run.

Hi Adrian

Looked at crank sensor...all seems fine....

Car off to Paul A tomorrow I think

Desperate for it to be running for a family event next Sunday....

Always happens at the wrong time lol...

All the best Brett

Greggers · **Posted:** Mon Apr 06, 2015 9:47 pm

So is it not running if you put all the old stuff back on..??

Brett928S2 · **Posted:** Mon Apr 06, 2015 9:59 pm

Greggers wrote:

So is it not running if you put all the old stuff back on..??

Hi

Nope, exactly the same....turns over fine but no start...

All the best Brett

stratfordshark · **Posted:** Mon Apr 06, 2015 10:40 pm

Brett reviewing your tests so far, I think you could be right about injectors not firing.

On 928 the injectors are on parallel, so if you have a short in injector harness then none will fire. You may have inadvertently damaged injector wire when trying to yank out a plug boot or routing the new leads?

You can get set of "noid lights" to test injector pulse/harness. Choose the one suitable for our injectors and plug it into any of the injector 2pin leads. If it flashes the harness is fine, if not you need to examine harness for split in insulation, probably close to plug where it is exposed

Brett928S2 · **Posted:** Mon Apr 06, 2015 11:04 pm

stratfordshark wrote:

Brett reviewing your tests so far, I think you could be right about injectors not firing.

On 928 the injectors are on parallel, so if you have a short in injector harness then none will fire. You may have inadvertently damaged injector wire when trying to yank out a plug boot or routing the new leads?

You can get set of "noid lights" to test injector pulse/harness. Choose the one suitable for our injectors and plug it into any of the injector 2pin leads. If it flashes the harness is fine, if not you need to examine harness for split in insulation, probably close to plug where it is exposed

Hi Adrian

Damn you got my hopes up then ..lol, and thanks for the ideas...

Good thought though....i hadnt thought of it...

But on my 16 valve the injectors and their relevant plugs/harnesses are on the OUTER side of the spider legs....

Plugs and leads on the INNER side...

I did just go out and check though, but all injectors/plugs/harnesses seem ok and undamaged etc ...

Oh well, speak to Paul tomorrow i think

All the best Brett

stratfordshark · **Posted:** Tue Apr 07, 2015 7:55 am

Well I did say anything pre S4 was closed book to me!

Hope Paul sorts it quickly Brett. Please let me know what problem was - I'm baffled unless coincidentally relay or LH ecu failed same time as plug change, but as you say far more likely related to something you disturbed changing leads.

Cheers

Adrian

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