ECU advice

manisinghb

manisinghb

manisinghb

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Joined
12 Apr 2009
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627
Hi guys,

A few months ago (well almost a year ago to be precise), I posted about my 2002 Vectra B having some pick up/power problems.

http://forums.overclockers.co.uk/showthread.php?t=18217607


YES, I still have the problem and the final verdict was: ECU gone! In the op you can see that MOOGLEYS advised me to go check Vauxhall as they should re-program it for £80. But I just wanted some advice before I carry out more work and it turns out to be non-sensical.

So anyone with some knowledge of ECU's gone bad and my options? The op describes the problems my car has but just to narrow it down:

1. No pick up AT ALL
2. Struggles to maintain speed, especially above 65-70 mph
3. Occassionally misfires
4. The ABS (and rarely the Airbag) lights come on and off on the instrument panel
5. Increased fuel consumption
6. Overall sluggish performance

edit: 7. an engine management type light also pops up now and again on the instrument panel (image of car with spanner going through it)
 
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Utterly impossible to tell without seeing diagnostic oscilloscope output traces from the various sensors feeding from the ECU..
You'd have to be looking at cam, crank, injector and coil drive outputs before you could condem the ECU.
 
Scubascorpion said:
Utterly impossible to tell without seeing diagnostic oscilloscope output traces from the various sensors feeding from the ECU..
You'd have to be looking at cam, crank, injector and coil drive outputs before you could condem the ECU.
Click to expand...

I suppose Vauxhall would be best to take this to and get this done from then?
They quoted me about £52.34 for a tech 2 diagnostics...
 
I have a distaste for anything dealer related to be honest.
Fair enough if they have a master tech there who knows his square wave from his inductance loop but I wouldn't trust a dealer as far as I could throw one.
A good quality diagnostics specific independent garage would be my first port of call.
Something like -http://www.allautodiagnostics.co.uk/ for example, although I don't know where you are based.
 
jon.bda said:
Get it done...better than randomly swapping out parts it 'may' be...
:)
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Yup u see I have taken the car to 3/4 different mechanics all of whom can't suss the problem and want to carry out a 'trial ad error' on the vehicle. I'd rather just get straight to the problem rather then having to keep visiting mechanics everywhere. I don't know why they can't get the fault codes though, they are all experienced and well established technicians where I have been. I've come to conclude the situation as a deep underlying problem only the manufacturer could deal with.

Anyway I'm gonna bite the bullet and see what their diagnosis comes out with, I too have alway been reluctant to deal with dealers but it seems my best bet now...
 
Having now read the other thread I would be very reluctant to do that tech 2 diagnostics, as by the sounds of it you are paying £50 for them to plug a code reader in, read off the codes and then clear them. Which takes all of five minutes.

If it involves further investigation afterwards which hasn't been mentioned then fair enough.

On a related note, MIL (ECU) codes only give you possible clues as to the issue at hand. They can be quite spurious at times and lead you right up the garden path if you don't investigate things properly. (X causes Y effect etc etc)
 
Can you not get cheap diagnostics cables/readers off ebay? I paid £10 for a vagcom cable and downloaded a cracked copy of vagcom off the net. It's great for any VAG car.

ECU's very rarely go wrong, check earths first.
 
Scubascorpion said:
Having now read the other thread I would be very reluctant to do that tech 2 diagnostics, as by the sounds of it you are paying £50 for them to plug a code reader in, read off the codes and then clear them. Which takes all of five minutes.
Click to expand...

But Tech 2 diagnostics is not just a crappy code reader off fleabay is it...
 
jon.bda said:
But Tech 2 diagnostics is not just a crappy code reader off fleabay is it...
Click to expand...

Codes are codes, whether it is read by my £5k Snap-On one or a £20 Ebay special.
If they are not going to do more than just read and delete them, then that isn't worth £50 in my book!
 
Scubascorpion said:
Codes are codes, whether it is read by my £5k Snap-On one or a £20 Ebay special.
If they are not going to do more than just read and delete them, then that isn't worth £50 in my book!
Click to expand...

If they are going to get a spotty 16 y/o to just clear the codes fair enough, what Snap-On you got...
 
I'd say more than half of ECU faults diagnosed are wrong. My first car had an exchange ECU when I bought it as a non-runner, it really needed a fuel pump.

With ECU faults you'll tend to see:
- Total loss, no response whatsoever and ECU fault light on dash.
- Driver failure, coil or injector driver failure if the drivers are in the ECU.
- Very rarely a signal input failure, can no longer read a signal.

The last one will usually set the fault light.

You need the diagnostic to see what errors have been logged and what the ECU thinks all the signals say. If something shows up there you need to understand and examine the signal. You need to confirm that the sensor is working.

Do also consider what powers this sensor, fuses and wiring included. For potential dividers, what other sensors are on the same supply? There's usually two or three 5V supplies from the ECU that power a multitude of sensors, sometimes there are some insane combinations in the design (yes DTA, I mean you!)
 
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Vauxhall should read the codes then delete all the codes stored, re-set it to stock then take it for a run and re read the codes and compare the results. They will more than likely just read the codes and take an educated guess.
 
You guys are giving me some very valuable input here, and it's making me wonder whether to even get it sorted now...

One thing I forgot to mention in the OP here (I will edit it in now) is that an engine management type of light does show up on the instrument panel now and again (image of a car with spanner going through it..?)

As far as I am aware, the £50 is only for a tech 2 diagnostics, nothing more nothing less, lady on the phone said it will take 30 minutes (don't know if that's a sales line or if they will be as thorough as Moogley's last procedural comment)... She also said it would be best if I left the car with them for a day...
 
Catalytic converter in the exhaust, if it collapses it can restrict the gasflow greatly causing some of the symptoms you describe - not saying thats it, just that its worth checking. :)
 
i dont see any mention of you having changed or cleaned anything on it, so i dont know how you can point the finger at the ecu :confused:
you have a misfire and that points to the spark side of it, so plugs, leads, coilpack. tech2 will not tell you if the leads or coilpack is arcing to the head.
the misfire will also have damaged the lambda partially or fully and its old anyway.
 
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