AAN starts and stops immediately

[Stefen]

A friend and I are building a buggy and chose the UrS4 AAN engine as a powerplant. The engine came with a loom and ECU. After pouring over the manuals and wiring diagrams, we are at the stage now that the engine starts, but stops immedately.

The fuel pump is wired straight to the battery, and since it sparks and fires all the 3 main cam and flywheel sensors must be working, so I'm unsure about what to look at next...

Any help would be greatly appreciated.

Thanks

[veneto rs2]

I'm probably naive but......

Immobilizer?

[Stefen]

It does sound like the immoboliser, but can anyone confirm that this engine has one? I have searched the manual and wiring diagrams but have seen no mention of an immoboliser.

[GazzaG60]

part of the pump process is priming, cranking and the run.

does the engine stop if you hold gas,
compression?

also presuming the sensors are good is risky.

you may have a sync issue. it may not be aware of where no1 tdc is.

[S2central.net]

I'll bet its an IMMO ECU - what is the part number on the cover and where you at Stefen ?

[spink]

What year was the car the engine/ecu came out of? I understand later S4s were immobilsed.If you post up the part number of the ecu we will be able to tell if it is immobilised or not

pah,Paul was quicker

[Stefen]

does the engine stop if you hold gas, compression?

If we give it some throtte it will very briefly begin to rev up, but then cuts out. I haven't checked compression in the cylinders.

The part number - I'll be able to get it tonight for you, I'm in Dungannon. Where abouts are you?

[Stefen]

I understand it was one of the later S4s, which would probably indicate then that it is most likley the immobiliser. I'll get that part number ASAP.

If it is the immobiliser what are the options then? Reflashing the ECU? ECU, coil and key combo? Earlier ECU?

[S2central.net]

You can't reflash the ECU... but I can get you running with non IMMO chips in the ECU - and a hoof more bhp and torque too if you wish...

[S2central.net]

I have a multi-channel scope and a bunch of other stuff if you need help debugging this one (if it turns out not to be an immo ECU).

[GazzaG60]

will vagcom not tell you if its an immo ECU.

pauls your man for those type of things for sure

[Stefen]

Looks like this will be sorted one way or the other then. I like the sound of more bhp and torque... Every cloud...

[S2central.net]

there's lots of ECU variants for AAN - some S4, some S6, some immo, some manual and some automatic.

AFAIK - the only ones that are NOT immo end have part numbers that end with AA or A

[S2central.net]

@Stefen - have you wired up the OBD plugs to get VAGCOM working ? - as Gazza says - that will report the ECU part number if that is easier than ripping things apart to see the ECU label on its cover.

[Stefen]

The OBD plugs aren't wired up, this is something I should do as undoubtedly there will be other issues in the future. Having VAGCOM would be good, persumabally I can download it and it's just a matter of buying a USB to OBD plug lead?
The ECU is sitting loose on the side of the buggy, so it's just a matter of a quick photo.