Help needed. Engine wont run

Well, I'm at my limit of what to do here now :sadlike:
Got those wiring diagrams thank very much aragorn but I'm getting out of my depth now.
Took ecu out last night and inspected circuit board, no sign of anything, no dry joints, no bad smells, nothing. Everything on the board is pretty much surface mount anyway. Therewere some connector plugs accesible from inside the ecu box, pulled these apart and connected back up, all looked ok. re-fitted it all... still the same :crying:
I don't know what to do now. My nearest auto electrician is over 30 miles away and I cant get the car there and he's booked up solid for Feb anyway. My boss has reached the end of his patience with me being constantly late for work for the last 3 weeks and now my job is under threat.
Aragorn you mentioned about by passing the fuel pump relay? I've had a look and not sure what to connect where? I'm worried about doing this because if the ecu is trying to shut down for what ever reason and it can't, would I not do some damage?
Gutted, totally gutted.....
 
If the ECU is shutting down then the bypass wont do anything, the car will still stop.

As i said up there, you need to get some test lights or even a volt meter onto the ECU power connections and see if they are staying constant when the thing stops. The wiring diagram tells you the pin numbers so you can pick them up either at the ECU itself, or at the multiplugs that go down into the car (the ones you replugged)

Cant you borrow a car or arrange a lift to work in the mean time?
 
nah, been trying for weeks to borrow a car now and no one can help and the one other lad near me has a car full. It takes me 3hrs on the bus to work and similar home so not getting in till nearly 8 in the eve, obviously its pitch dark by than so I'm not having much luck being able to sort anything. I've taken everything you've said on board Kev but it's difficult for me...
Si.
 
Its certainly seems one of the only options left right now but it would have to be so cheap that I may just be inheriting another nightmare lol
Just been thinking about this fault and am wondering under what condtions the ecu would want to shut down the engine, are there many circumstances?? I know the immo would do this but its not an immo fault although could it be related to that circuit?
grasping at straws now I know
 
the only real reason i could see is that the crank sensor input has stopped giving a reading.

The fact that vagcom drops out tells me its either a power supply fault/wiring, or an ECU issue.
 
Thanks for the clear thinking pal, things seem to be narrowing down a bit. I know I need to get the meter out (which I'm not very good with) but I think this going to have to wait until Saturday now for some daylight hrs. Should vagcomn still talk to the car with the fuel relay disengaged? I'm wondering if I should be including the ignition switch in my thoughts here, although I know the common fault with that is the return spring and problems with the lights. Can I rule out the instrument cluster too do you think?
Sorry for all the questions pal but I'm just trying to get this narrowed down as far as possible
Thanks
 
Ignition switch is a maybe for sure, but you need to find out if the ECU is actually losing power.

Cluster i would doubt could cause any issues.

Vagcom usually talks to the ECU with that relay de-engergised. If you turn the ignition on and dont start the engine, bar the prime cycle the relay is off, and vagcom works fine like this.
 
Hmmm, switched live to ecu a candidate for sure then
 
Ok I managed to test for voltages all the way to ecu plugs and all seems fine and constant. However I've managed to recreate the fault by tapping on the ecu case. Every time I tap on it everything seems to reset, engine cuts out or dies and picks up again slowly, fuel pump relay re-primes and the throttle body whines for a few seconds. I can wiggle on ecu plugs and wires and it's ok, its only when In tap on the metal ecu case it does it. So I think I can say I've an ecu problem? I took the board out the case and spent a couple of hrs with a big magnifying glass going over the board but cant see any dry joints or anything else.

Big ask here, does anyone have an ecu I can borrow or buy? Does the ecu contain any of the immobiliser or can it just be swapped ok? How specific is the ecu to the car? Part number is 8D0 907 558 DA
The pins on the ecu plugs all look ok but I suppose I cant rule out a connection issue between the plug and ecu because I couldnt test through from the plug to the board.
I have paypal so any payment not an issue.
Failing this I guess BBA Reman is the best option?
Thanks Si.
 
ECU immo is tied to the clocks unfortunately, so simply swapping it in isnt going to work. If you have an analog clock coding the new ECU is supposed to be pretty easy, if its digital its a dealer only or perhaps a good auto-locksmith job, unless you disable the immo on the ECU itself.

The 558DA ecu is specific to A4 TQS's as they're the only B5 DBC model with 180hp. You could use any two plug DBC ECU, but obviously fitting an AEB one will drop your power to 150hp. I guess a remap would sort that though.

I wouldnt bother trying to repair it, just get a replacement in there.

AUDI A6 1.8T 1998 ENGINE ECU 4B0907557B on eBay (end time 20-Feb-11 17:54:14 GMT)

Something like that along with suitable immo coding or deletion would get you rolling again.
 
Oh great, this just gets worse doesn't it :crying:
My nearest Audi dealer is 30 miles away and are absolutly crap. It took 2 phone calls to them once to even acknoledge a 1.8t tqs ever existed!.
I suppose you cant reply here about removing the immo but is there a way to delete it? PM me if ya like.
Dealer re coding, remaps, this is all starting to sound very expensive! Wondering if its all worth it. I just cant think what to do.
Why do you not think its worth sending for testing/repair aragorn? coz it looks a more logical solution at the moment to me. Are you saying you doubt they'd be able to do it? BBA Remans website looks ok and they seem to be able to do plenty of stuff
Si.
 
Finding an intermittent fault on a board full of SMD's isnt going to be particularly easy...

I'll drop you a PM about the immo.
 
I've got your PM many thanks. I've taken your advice and bought that ecu plus what you've told me about in the PM. I know its not going to be perfect but as you say it should get me mobile which is paramount atm. I think an AJL ecu is going to be hard to find and I just dont have the time to hang about waiting. I'll post a wanted ad and see what happens, fingers crossed eh.
Can you see any issues I might have fitting this A6 1.8t ecu? I'm almost sure the throttle body will want re-setting and I know I'm going to be missing some hp but anything else?
Si.
 
It lives!!! ... although in a slightly different way
Only done 25 mls but ok so far. Fitted the A6 1.8t ecu from aragorns post above and it works with a bit of immo foolery :sly:
Ecu fault eh, who would have thought it? I don't feel bad for not finding this sooner coz it was the last thing I expected to be a fail.
Trouble is, is that it feels sooo sloooow I guess because it doesn't have the Sports map for 180. Where's me boost gone? Plant me foot down @ 2500k and there's nowt there. Acceleration climbs smoothly but there's no 'kick' to it :faint:
But I'm mobile again and that's the main thing for now and all thanks to aragorn, without his help I would never have done this. You are a very clever and knowledgeable chap my friend, thank you for sticking with me on this and taking the time to help me, I certainly owe ya pal :applaus:
I have just sourced the correct 558DA ecu and am working to get it coded correctly. Immo 3 seems a bitch but I think I'm on to something other than the dealer option :eyebrows:
Also the idle is a bit bouncy for a few seconds on starting up and when clutching at a stop. I thought the drive would have sorted it but I'm hoping a throttle alignment might fix it. Trouble is Vagcom wont talk to the ecu now without me taking it all out again. (I was lazy and just wanted it working again Kev lol)
Anyway, onwards and upwards eh.
 
Good stuff mate, glad you got it going!

Let me know how you get on with IMMO3 coding, i'm interested in alternatives to the dealer myself.

If your struggling, get someone to remove the immo chip from the old ECU and solder it into the new one!!
 
Last edited:
Thanks mate. I don't just owe you a beer, I owe you a whole night out on me!

aragorn said:
If your struggling, get someone to remove the immo chip from the old ECU and solder it into the new one!!
Click to expand...
Really? , interesting.... I thought it was 'soft' never thought about it being on a chip. which one is it, you know?
Also, have you any idea if the engine performance I've described is normal, should I be getting boost kicking in at some point or is a standard 1.8t more subtle than that. I've tried planting my foot at various rpm's and nothing happens apart from, it just accelerates. I can hear the turbo spool but it just wont launch if ya know what I mean.

aragorn also said:
Let me know how you get on with IMMO3 coding, i'm interested in alternatives to the dealer myself.
Click to expand...
I'll message ya when I know more but if what you've said above is possible, this could be the way to go.
Cheers again pal. I'll message ya next time I'm up Blackpool way which is fairly often if ya fancy a pint ok
Si.
 
If you take a photo of the broken ECU board (both sides) i'll point out the IMMO chip for you.

Performance is hard to quantify, but remember your not only down 30hp, but a whole wodge of torque is missing from the midrange as you're only making 8psi of boost rather than 12. Your also quite a bit heavier than a FWD 150hp A4, so its only expected that the performance is going to be rather poor.

I guess its possible theres a fault and its in limp mode, which would only give you 4psi, but without vagcom access you cant tell that :p
 
Don't think it's in limp mode, it seems to accelerate fine and the rpm's don't seem limited in any way, guess I just need to get used to it. On the plus side my mpg has increased noticeably so if I drive round like this for a while I should recover my repair costs lol
I'll try to get a couple of pics in the week aragorn. There's a guy who reckons he can delete the immo entirely with no problems even though its immo3 and it won't effect vagom use etc but he wants £70 to do it, so I'm exploring other ways first.
 
The car wont do anything noticeable in limp mode, it'll just only boost to 4psi. Its worth checking, because there may be a fault code left over from the old car?

Give mark (byzan a4) a shout, i'm sure he played around with IMMO delete flashes and baught a chip writer etc. Theres a guide floating around the net that tells you which bytes you need to change in the flash data, i cant find it right now though.
 
Some further reading suggests vag tacho can read the SKC from both the dash board and the cluster, so this may also be something to look at.
 
That link that Byzan posted has just fried my brain lol It's all going over my head a bit. I'm tempted just to pay the ebay guy to do it, here's a link to it, what do you think?? Immo remove
Here's pics of the board so you can show me where the immo chip is Kev but tbh I don't think I've got the tools (or the balls) for it

Top.JPG


Bottom.JPG


Sorry for the image size!, cant seem to reduce them lol
 
Tyhat generic immo remover won't be able to do it. They couldn't do mine anyway. They are using a bit of software that reads the info out, patches the bytes required and flashes it back.

Unfortunatly ME5 cannot be done that way
 
Just to add, your ECU been chipped?

As that socket on the bottom left is not normal

Immo chip is on the front pic, about a wtr way up on right, 8 pins and will be 24c02
 
I think youre best bet is the SOIC clip i mentioned above and an EEPROM reader.

Mark, you recon the SOIC Clip will attach to your EEPROM reader/writer easily?

I cant actaully see the SOIC chip on those pics, i was under the impression it was on the underside of the ECU, but its not... Its a small 8 pin thing, and theres two of them on the top of the board so maybe its one of those?

Also, are you aware that ECU has been remapped?
 
First off, no I wasn't aware it had been remapped. I wasn't told when I bought the car and there's no paperwork about it so I've no idea about it at all. Maybe that's why the car seems so slow now lol I've not driven another AJL so I didn't have any base line re performance.
I've no idea about these SOIC clips and EEPROM readers, feel out of my depth with it and not sure how to go about it all. I now have the correct 558 DA ecu so do you think it would be worth having a go at swapping the immo chips over?
I've emailed that guy in the link a couple of times and clearly stated its from a 2000 car and has immo3 and he assures me that he he can delete the immo no problem so I just don't really know what to do for the best now.
Maybe it's worth getting the knackered ecu sent off for test/repair if its mapped?
 
I suspect the fault with your OLD ECU is the soldering on the remap chip has gone bad.

The idea behind the SOIC clip is that instead of trying to desolder the rom, you can just leave it on the board and read/write it in situ.

I'd defo go down that route, rather than deleting the immo completely, security etc.

Might also be worth getting someone to rework the soldering on the remap chip?
 
Well I've re read that thread a few times now and I get the idea of it and what you're saying about the clip to connect the reader/writer to the chip on the board but I really don't know what kit I would need, how much it would cost and even if I could do it. it sounds a bit scary. Do you know of any one who could do it at all?

I could perhaps try to re flow the joints where that piggy back board joins the main pcb. This remap thing has added another dimension to the hassles now hasnt it. What to do about that I wonder? can it be de soldered and put on my new board when/if I get it sorted? but if that's the cause of the problem then....
Is there anyway of finding out who's re map it is?
I'm sorry for all the q's but my head is once again pickled...
Si.
 
iv used them a few times
bit slow but cant fault there work
 
Ok I've found the test clip on ebay HERE not much I know but it's a start. I presume I need a loom, a reader/writer and some software?? but now I'm stuck.
 
NineNails said:
Well I've re read that thread a few times now and I get the idea of it and what you're saying about the clip to connect the reader/writer to the chip on the board but I really don't know what kit I would need, how much it would cost and even if I could do it. it sounds a bit scary. Do you know of any one who could do it at all?

I could perhaps try to re flow the joints where that piggy back board joins the main pcb. This remap thing has added another dimension to the hassles now hasnt it. What to do about that I wonder? can it be de soldered and put on my new board when/if I get it sorted? but if that's the cause of the problem then....
Is there anyway of finding out who's re map it is?
I'm sorry for all the q's but my head is once again pickled...
Si.
Click to expand...


Mark has a reader/writer but no clip, drop him a PM and work something out!

Tektronix do a kit with the clip, some wire and a mini board that plugs into marks programmer.
 
You must log in or register to reply here.

Similar threads

AUDI@WRC
URGENT HELP NEEDED !! center display wont turn off !!
Replies
19
Views
2K
rasA4
rasA4
audi-a6
a6 2.7t.... help needed (s4 engine)
Replies
43
Views
6K
audi-a6
audi-a6
L
Aircon Fixing Help & Exhaust/Engine Advice Needed Please!
Replies
25
Views
1K
LanciaNut69
L
Bradderz_1988
Help needed with ETKA !
Replies
8
Views
2K
B5NUT
B5NUT
B
Help needed :(
Replies
2
Views
528
AlexA4Avant
AlexA4Avant
Top
Back