Hi everyone,

after some help please still struggling with my Skoda. I tacked the fault down I think .

the injectors are not pulsing .

I have tested all wiring back to ecu and as far as I can tell it’s all good.

I have the 5 pin injector harness where the screw on connector goes.

I have 2.5 volts on the brown centre wire at the plug, then the same at each of the brown wires on the injector plugs.

I put a noid  light in one of the injectors plugs and got some one to crank it it pulsed for a few seconds . I thought happy days then did the rest no pulse went back to the one that did no pulse. Also viewed injectors in Vcds values are 0.0 when cranking no change I’m thinking ecu as I think that is what controls the injectors as they go straight to the ecu as far as I can tell.

car starts momentarily on easy start then stops once easy start is used up.

which is why I think it’s fuel.

finally not sure if this relevant to the not starting . The only fault vCDS is logging after cranking is I have glow plug 1-3-4 open circuit I have replaced plugs still faulty pitting glow plug harness in tomorrow.there are no other faults coming up in the control unit .🤷‍♀️

Any thoughts suggestions would be greatly appreciated 👍

What is your cranking RPM?

 

There was some stupid ECU coding on these vehicles whereby if the engine is not cranking fast enough the injectors will not be commanded, it may have been on he earlier vehicles, someone else will hopefully confirm.

 

The immobiliser will do the same initial firing then cut out, have you changed keys by any chance?

 

I'm sure in VCDS you can find a log of engine shut down events and causes.

Thanks for the reply JR.

I have monitored the cranking speed and checked camshaft speed and engine speed are both visible battery is 100 %
I had heard of the injectors not firing if engine speed is low.

no keys changed . 
the car ran fine then gradually got worse at starting . Changed camshaft sensor, maf sensor glow plugs glow plug timer relay,pretty much everything 😂

I have changed the ecu it was coded from my original car started 1st time I left it running for 20 mins thought great sorted.

switched it off to clear codes tried to start it won’t start that’s where I am am up to now.

is there any signals the ecu needs to receive to make the injectors fire I assume it needs camshaft and crank sensor signals they appear to be working on vCDS any others or anything else I should be testing .

thanks 

again 😁

Now if you had mentioned the ECU change before.....................................

 

Immobiliser data is exchanged between the ECU and the instrument cluster, if you swap an ECU the engine won't start, I cannot explain why yours ran initially for 30 minutes but what it is doing now is expected as far as my understanding goes.

 

I had my MK2 Octavia remapped with an exchange ECU, so as not to send mine to the UK for reprogramming, have the car off the road while waiting and the risk of loss in transit I opted for a pre-programmed "plug n play" ECU, this had the immobiliser function disabled or hacked so that it would work on my vehicle, my understanding being that without that hack the vehicle would not start because the ECU was not recognised.

 

Some spotty teenager behind a computer screen will be able to sort you out!

Now if you had mentioned the ECU change before.....................................

 

Immobiliser data is exchanged between the ECU and the instrument cluster, if you swap an ECU the engine won't start, I cannot explain why yours ran initially for 30 minutes but what it is doing now is expected as far as my understanding goes.

 

I had my MK2 Octavia remapped with an exchange ECU, so as not to send mine to the UK for reprogramming, have the car off the road while waiting and the risk of loss in transit I opted for a pre-programmed "plug n play" ECU, this had the immobiliser function disabled or hacked so that it would work on my vehicle, my understanding being that without that hack the vehicle would not start because the ECU was not recognised.

 

Some spotty teenager behind a computer screen will be able to sort you out!

 

If you have the original ECU then refit it, if you dont then take it up with whoever took yours in exchange and supposedly coded it.

 

That was the other reason I went for a preprogrammed ECU, had there been problems I could revert to the original.

Morning JR I sent my ecu as he wanted to clone the data from it onto the one he was supplying.like you at same time he did egr and dpf delete and remap and transferred the original security code.

I will update later with camshaft and engine speed as shown on vCDS..

We determined ecu as swapped with another known hood ecu not coded to my car. It ran for about 5 seconds then stopped because the immobilizer kicks in .

but I believe this is a known way to check.

I think I am going to send ecu back for him to check he says he can.

 

 Thanks 

 

simon

Good luck! It sounds like you are in the nightmare scenario that against my normal Chancer character I sought to avoid, that of the car not running and my old ECU having been reprogrammed & sold to someone else.

Morning JR I sent my ecu as he wanted to clone the data from it onto the one he was supplying.like you at same time he did egr and dpf delete and remap and transferred the original security code.

I will update later with camshaft and engine speed as shown on vCDS..

We determined ecu as swapped with another known hood ecu not coded to my car. It ran for about 5 seconds then stopped because the immobilizer kicks in .

but I believe this is a known way to check.

I think I am going to send ecu back for him to check he says he can.

 

 Thanks 

 

simon

Jr you are right car has been a nightmare to try and fix . Fitted new glow plug harness today still getting same fault codes glow plug 1-3-4 open circuit had new plugs loom and timer 😩🤪😜

I think it’s going to drive me mad one weird thing it did while cranking and testing today first few times I cranked no camshaft speed showing on vCDS tried again then I had 105 for camshaft sensor I replaced that with a new Febi one I am wondering if I should have fitted an oe one . I assume ecu needs cam and crank sensor signals to know when to trigger the injectors. The car originally ran well started first turn of key gradually got more difficult to start changed out parts vCDS indicated at fault camshaft sensor ,

glow plugs , glow plug timer relay, for open circuit on glow plug faults but that one has stayed even after fitting a new loom all the way to the big multi connector under the headlight. I have stripped all the wiring back to the battery continuity checked all wires no breaks chaffs or rubs can be seen..

I have sent the ecu back today I think I’m going to fit that and an ie cam sensor then I’m out if that dosnt fix it . If anyone wants it I’ll be selling as spares or repairs someone more clever than me can probably fix it it’s a nice car to good to break really and had had a load of new parts genuine egr valve, maf sensor cam sensor glow plugs glow plug timer relay and more.

I’ll post my outcome after fitting ecu .

 

 Thanks 

2 hours ago, Vstorm said:

I assume ecu needs cam and crank sensor signals to know when to trigger the injectors

The PD engine had a quick start feature where it would start in a maximum of one revolution if the cam sensor was working, it would take 2 revolutions otherwise to know what cylinder to fire on.

 

I'm not convinced the Common Rail engine does the same as it always cranks a little longer than the PD did.

Hey JR finally got car running again was the ecu. It would run for 1st startup but not restart once key off anyway the guys who did the ecu where really helpful they programmed with different software and now it starts first time. I only have one fault now fault code 008825 P2279 leak in air intake system mil on at 2036rpm . It smoked a bit under load then went into limp and a high pitch screaming whistling noise high pitch. I cleared codes drove it gently no issue or noise . I would like to test the pcb valve what is the best way to determine illuminate it as I can’t see any leaks on the air inlet side. Im thinking pull pipe off air inlet let it vent and block hole in air inlet drive it up road if fault not there refit it if fault comes back pcb faulty what do you think 🤔 👍

Any advice greatly received I’m hoping if I get that fixed car will finally run properly