Mk3 ABF no power

[Leon27]

As said already, check the fault codes as there are a lot of things that can make the ABF feel slow. If you don't have access to a scanner right now then off the top of my head you could check..
Aside from cambelt timing is the cam to cam timing alright?
Vac hoses not pinched or collapsed to ECU, Fuel pressure reg and PCV valve?
PCV valve working
Throttle position sensor wiring broken up around exhaust manifold?
Oxygen sensor working
Compression test
Got the right plugs in it
Does the car rev past 5k rpm
Manifolds don't have air leaks

Don't know much about the differences between the Seat and VW ABF's - think it's only the lifters that are lighter.

[Boufon]

Thank you, that's quite a list!

Cam to cam has occurred to us, we'll check that next.
Vac hose & wiring to throttle sensor are all A-OK.
FPR is good but what is the PCV valve please?
Oxygen sensor swapped for another from a running car.
Haven't tested compression, plugs are brand new iridium set.
Yes it revs fine- 7-8k on the 8v clocks.
Been right round with brake cleaner looking for air leaks & no joy.

Thanks Leon, I'll try the bits I haven't yet asap.

Keep 'em coming please this is all good stuff!

[Leon27]

PCV is basically the crankcase breather - you should see a pipe from the block going into a black plastic square unit (PCV) infront of the inlet manifold. It also has a pipe going into the main air intake pipe before the throttle.
Any fault codes thrown up?

[VW BUSH]

Coil pack

[Boufon]

Thanks,
I have a spare PCV - I'll try it!

I don't have diagnostics but we're waiting to borrow a friends again.
There were no fault codes when we first got it going but that was before we took it for a run.
Coil pack was working fine on the 8v & as far as I can gather they are the same for both models.

I'll try to get the diagnostics this weekend & then check cam to cam & ther bits.
Thanks for the help & I'll keep you posted!

Cheers,
Ross.

[Ess_Three]

The ECU was from a seat cupra ABF - anyone know if that had different injectors or fuel pump/pressure regulator?

ECU is the same, as are injectors and FPR.
SW code in the ECU is sometimes a higher revision on the SEAT...but it makes no difference to power.

Cam to cam timing or cam to crank timing, most likely at fault, if it's running on all cylinders.
Cam to cam is really easy to get one tooth out - the markings are crap!

[Boufon]

Right - I have a conclusion for those interested:

The Seat ECU was the problem.
Despite me hearing of various people who are running a VW engine on a Seat ECU or vice versa, It hasn't worked in mine.

I have now Fitted a VW ECU with a different Imob box, coil reader & key chip. I had a guy come out & code them for me & all the problems are gone. Only trouble is I will now have to pay to have the whole thing remapped to make the most of the mods I've added!

The issues this swap has solved were:
Overfuelling/ incorrect ignition timing from ECU? - 1) Exhaust hot to the tailpie within a minute or so. 2) Exhaust manifold glowing to near white after a 6mile journey below 40mph & 3k revs. 3) Very fuely smell from exhaust at idle.

No power - As mentioned before the car just had nothing to give. (Less than when it was an 8V!)

Trying to pinpoint a reason, the only things I can think are,
Was it to do with the TSR remapping on the Seat ECU? The cars both had high lift cams, full stainless exhausts with 4 branch manifolds, lightened flywheels etc so I would have thought it would suit.
Was it to do with the engine bay loom? ie if you fit a seat engine into a vw or vice versa & retain the Bay & Engine looms these match the ECU & all you would do is plug in the fuel rail, sensors etc. If its just the ecu which is changed then perhaps the pins are different which would not match the loom & maybe send signals down the wrong wires??

Anyway its done now but thought people might want an update.

Thanks to all those who contibuted ideas & any further nuggets of wisdom will be read with interest.
Ross.