[Macca52]

I started MCTUFF today to prep for a run tomorrow and it ran for 10 seconds then stalled.
I have no spark at plugs and fairly weak spark out of coil. I cannot remove my dissy cap as it is too close to the firewall.There is a module of some sort below the coil.Can any body tell me if there is a module inside the distributor
I have power at the injectors so I believe the crank angle sensor is ok.

Macca

[fordem]

Macca52 wrote:

I have power at the injectors so I believe the crank angle sensor is ok.

Where's the logic behind this? Seriously, what does "power at the injectors" have to do with the crank angle sensor?

Based on my knowledge of the GTI EFI system, you switch the ignition on and the ECU energizes the FI main relay and that applies +12v power to the injectors - the ECU then grounds the injectors to fire them - you could completely unplug the distributor and still have power to the injectors, what you would not have is the injector drive pulse.

The module in the distributor is the crank angle sensor, if it's defective there will be no spark at the coil and no injector pulse at the injectors, the module below the coil is most likely the ignitor (it may depend on who installed what, where), if that's defective, there will be no spark at the coil, you have spark, albeit weak at the coil and no spark at the plugs - should you not also have a weak spark at the plugs?

[Macca52]

Fordem, while I thank you for your response, If I were an expert mechanic I would not be asking for help. I was led to believe that if the injector power pulses while cranking then the crank angle sensor is ok. I am hoping to eliminate the c.a.s. as the source of the problem.

[fordem]

There's no shame in asking for help - but the question doesn't make sense to me.

On this, as well as most other EFI systems, "power at the injector" and "injector pulses" are two different things - it's important to recognize the difference. On this EFI system, you can have power at the injector without having injector pulses, but, yes if you have injector pulses whilst cranking, the CAS is most likely not the source of the problem.

Do you have a "NOID" light (injector test light) - plug it in place of any one injector and crank the engine, if it flashes, you're good - if you don't have a NOID light, you can use a dash warning light bulb (low oil pressure light, high beam indicator light).