Hey guys,

Had an engine swapped in my 1.4 8v 6n, to another exact same AEX engine..

The engine turns over, but the guy who is doing it for me, says the ECU needs resetting, as the immobiliser chip in the key is stopping the fuel pump from working, so they can't start it.

I've had a quick search, and I've been told just leaving the battery disconnected for 10mins will reset it.. I can get it done with diagnostics but at a price, and I'm on a very tight budget, and I'm not sure what to do!

Any thought/tips/help would be greatly apreciated as I have to let the guy know what I want done tonight!

Cheers guy

(1996 1.4 8v AEX 6n)

Edited 3 March, 201115 yr by tommybaker

ttt.. I hate bumping my own stuff up, sorry!!

where is your old ecu?

unless he changed the ecu i don't see why the immo would be the problem.

i think something has not been reconnected (easily done)

The old ECU is in the car with the new engine.

And maybe? what could it be.

Thanks guys

did you change either...

the ecu

the immobilizer

the transponder ring

the key

if non of these were changed then it is not you immobilizer that is the issue (well as long as it was all working before the swap?). if any of these were changed then the rest of them have to be changed with them, but you wouldn't need to of changed any of them if you were just swapping the lumps over. if any of these have been swapped then just swapping them back to the original one for the car would be fine.

Edited 27 January, 201115 yr by McLOVIN

nope!

literally it was just the cylinder head and engine block that was replaced! I thought It would have been a straight swap as it was all working fine before!?

well it shouldn't be the immob giving you the hassle then mate and don't listen to any one that tries to tell you that unplugging the batty on a 6n resets the ecu, it's bullshit.

my advice is to just double check that every thing is plugged in properly, are you getting dash board lights when you turn the ignition on?

Thanks a lot man, really appreciate all this..

and I'm not sure, I haven't seen it for myself, as he only managed to get this far this evening!

I'll mention this to him, but he's gonna get his mate to run diagnostics and see what it is in the morning! and let me know how much his mate's gonna charge..

Thanks again, I'll keep you updated!

Does it turn over? Does it fire up at all?

Immo prob is always start, run for less than a sec then stop.

Check the earth connection front of the gearbox, check the earth connection from coil to head, check coil is plugged in, check the dizzy is set correctly, check ht leads go to right cylinders

did you change either...

the ecu

the immobilizer

the transponder ring

the key

if non of these were changed then it is not you immobilizer that is the issue (well as long as it was all working before the swap?). if any of these were changed then the rest of them have to be changed with them, but you wouldn't need to of changed any of them if you were just swapping the lumps over. if any of these have been swapped then just swapping them back to the original one for the car would be fine.

Dash clocks as well

did you change either...

the ecu

the immobilizer

the transponder ring

the key

if non of these were changed then it is not you immobilizer that is the issue (well as long as it was all working before the swap?). if any of these were changed then the rest of them have to be changed with them, but you wouldn't need to of changed any of them if you were just swapping the lumps over. if any of these have been swapped then just swapping them back to the original one for the car would be fine.

Dash clocks as well

nah clocks don't mean nothing on the 6n mate

Immobilizer pin key is held in the dash clocks - ecu reads that as part of immob interogation (or so I thought - happy to be proven wrong - I know you can pull the pin code out of the clocks to add transponder keys on a 6N)

I ended up paying the guy to sort it out with VAG-COM, cost me £70 which was a lot cheaper than it should have been as he said he took hours doings it..

It starts up now, but the oil light is on, even though it's been reset and had new oil/flush through.. I've heard it's common in Vws? I don't really know.

Since then, it's gone and come back from the garage having freshly painted pannels and a shiny new 16bumper But now she won't even start up!!

They said it worked wednesday when they moved it, but thursday morning when they tried getting it on the truck.. nothing.

It's home now, and it still wont start. you turn the key and nothing happens. the handbrake light just stays on and the clocks go black. something to do with the immobiliser again maybe? I'm not sure. Also the Airbag light now stays on!! :(

I'm not really sure what to do now, as it's like she's completely dead :( any help with this, again would be greatly appreciated as I really can't afford to keep going back and forth from the garage!

Cheers guys,

Tommy

you've paid them to sort it and they haven't... take it back and get them to do what they've been paid to do!

Immobilizer pin key is held in the dash clocks -

no there is a seperate immo unit on a 6n, its a little black box about 3" square next to the steering column

my guess is that one of the engine or chassis earth straps is loose, seeing as the engine has been out a good place to start is the ones that attach to the engine block, iirc one goes from the battery - terminal to the gearbox, and one goes from the back of the engine block(timing belt end) to the chassis rail

Edited 11 February, 201115 yr by SkodaBoy

Cheers guys, I will ring up the guy who did it for me and get him to get in contact with the fella responsible.

and I will have a proper look tomorrow, hopefully it's just something simple like that!

thanks again for the help.

Immobilizer pin key is held in the dash clocks -

no there is a seperate immo unit on a 6n, its a little black box about 3" square next to the steering column

yep as skoda boy says. i'm running a 6n engine and part of the loom in my mk3 (with full immob set up) and i haven't had any issues with not having the 6n clocks fitted to the car

back on topic... is your battery dead? because that kida sounds like what your discribing mate, maybe they left some thing turned on on the wednesday night or some thing?

Doesn't seem to be!? all the lights, head unit and openair roof work? I have been busy working his weekend so haven't had a chance to have a proper look unfortunately. I'll keep you guys updated this week.

thakns again!

my oil light and so on is still on on mine and all i have done it the head . the hand breake light is on to . dont know why they are on tho i cheecked all the ground leads to the head and all was good .

Yo! I've been saving the pennies so I could get this sorted, ended up calling my insurance company who sent out a local breakdown guy to have a look..

Turns out you guys were right, the gearbox hadn't been grounded properly, and the alternator isn't charging the battery enough, so even if it were grounded the battery wouldn't have enough juice to start the engine!

Really pleased things are getting on the way now, and it's booked in for its MOT on thursday, as well as an idle speed reset, change of alternator and they're gonna earth everything properly!

Thanks for all your help on here guys, I would be no where near getting this sorted if it wasn't for all your input! Will be great to be back on the road, and I have some major plans which may include some 13x8.5" banded steels.. I'll keep you guys updated!

thanks again!

Tommy

excellent, thanks for coming back to let us know you resolved the problem

Glad its all sorted mate, these problems are the ones where you look back and think "how did I not spot that to start with"

Simple solutions you over look thinking the problem has to be some thing complex, we've all been there

i'm actually quite dissapointed that a 'garage' could not have diagnosed this problem before it left thier premisis.

it's funny how 99% of simple electrical problems are blamed on the engine ecu, ironically it's probably the least problematic component in the entire car!