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[Jimbo27]

I have a 2001 Opel Omega V6 auto stationwagon and it goes fine except that every 2 months or so it just won't start. The last garage got it going simply by re-tensioning the ECU terminals and it went sweetly for two months after that. Now, exactly the same, no spark but battery is fine.

As it happened at home (luckily) I was hoping to get a mobile mechanic to re-tension the ECU terminals or even have a go at it myself, seeing as it did not take long for it to be remedied last time.

As an aside the Engine warning light kept coming on and the previous mechanic thought it was a faulty knock sensor, got a new one sent from Australia, was a total waste of time and money. In the end the mechanic simply disconnected the Engine warning light bulb as there was no fault detected with the engine and so on.

Anyway, where is the ECU located and how are the terminals re-tensioned?

All help appreciated.

[Mv8.com]

What engine? 3.2/3.0/2.5/2.6 in the uk...?


And, not sure what you mean by tensioned 

[Kevin Wood]

I can't recall us ever seeing a car where the ECU connections were problematic.

Sounds like you need to get the engine codes read and take it from there.

[Jimbo27]

It's a 2.5 V6, seems to have come to NZ from Japan.

The previous mechanic's e-mail read this:

There was no actual fault found, but the engine started going after the engine ECU terminals were re-tensioned.

[Jimbo27]

I just read this on another forum

2.5 V6 models a nightmare, CATS fail wholesale (cats need back pressure testing plus testing with four gas analyzer).  Engines are prone to cylinder head failure between bores (they do not pressurerise coolant as a rule, so leakdown test thru plug ports, only conclusive method of diagnosis).  Cambelt replacement vile job, most small independent garages just won't do it.  Avoid any form of major electronic diagnosis like the plague, motion sensor faultcodes common, even when sensors show perfect waveform on scope and are working perfectly with host wiring in excellent shape.  Piezo knock sensors on engine block suffer from bad earths and component failure (very difficult to get to and backprobe to prove function with scope).

[dbug]

I just read this on another forum

2.5 V6 models a nightmare, CATS fail wholesale (cats need back pressure testing plus testing with four gas analyzer).  Engines are prone to cylinder head failure between bores (they do not pressurerise coolant as a rule, so leakdown test thru plug ports, only conclusive method of diagnosis).  Cambelt replacement vile job, most small independent garages just won't do it.  Avoid any form of major electronic diagnosis like the plague, motion sensor faultcodes common, even when sensors show perfect waveform on scope and are working perfectly with host wiring in excellent shape.  Piezo knock sensors on engine block suffer from bad earths and component failure (very difficult to get to and backprobe to prove function with scope).

We talking about an Omega 2.5 V6?

Cats rarely fail, cylinder head failure extremely rare, cambelt repolacement not a difficult job, agree crank sensors are problematical (reroute them away from exhaust), knock sensors robust unless you trap the wires.  What forum was that?

And anyone who "re-tensions" ecu terminals is strange to say the least.
We tend to tighten up loose items 

[jb]

your symptoms are classic crank sensor failure - make you replace with genuine gm part

[feeutfo]

I just read this on another forum

2.5 V6 models a nightmare, CATS fail wholesale (cats need back pressure testing plus testing with four gas analyzer).  Engines are prone to cylinder head failure between bores (they do not pressurerise coolant as a rule, so leakdown test thru plug ports, only conclusive method of diagnosis).  Cambelt replacement vile job, most small independent garages just won't do it.  Avoid any form of major electronic diagnosis like the plague, motion sensor faultcodes common, even when sensors show perfect waveform on scope and are working perfectly with host wiring in excellent shape.  Piezo knock sensors on engine block suffer from bad earths and component failure (very difficult to get to and backprobe to prove function with scope).

Ignore that load of rubbish mate. Mis informed clap trap. Almost every myth ever told about the omega is in that paragraph.

[feeutfo]

It's a 2.5 V6, seems to have come to NZ from Japan.

The previous mechanic's e-mail read this:

There was no actual fault found, but the engine started going after the engine ECU terminals were re-tensioned.

As others have quite cleverly seen through the fog, and got to the actual symptoms the car is displaying, crank sensor does fit the description. Turning on the key with no firing.

Try the paper clip test as described in code reading in maintanance guides. If you get code 19 that will confirm it, but the code isn't always displayed until the failure mode is quite advanced.

I suspect what ever previous mechanics where doing to rectify the fault at the time was pure coincidence, and the car started randomly regardless. They just happened to be working on the ecu when it started next turn of the key. Ecu issues are almost unheard of on here.

[Jimbo27]

Thanks guys, yeah it turns over fine, just won't spark up.

I guess the ECU tampering was only a short-term solution and maybe replacing the crank sensor is the long-term one.

Does anyone know roughly what it is likely to cost to replace it?

[Lazydocker]

You need to replace the Engine Management Light and read the codes with the Paperclip Test. As said, it's classic Crank Sensor symptoms 

There's a guide in the maintenance section and it takes about 10-15 minutes to do, perhaps as long as half an hour if you're working slowly

[feeutfo]

Link in my signiature.

Read the codes.


Link\/

[TheBoy]

The garage removing the dash bulb are clearly a bunch of retards. Best avoid that place in the future.

As others say, replace dash bulb, and do a paperclip test, then we can see whats what. Remember, if the bulb comes on when driving, there is a fault, and the ECU will store it.


As for "retensioning ECU terminals", that sounds like BS to me...

[omegod]

Crank sensor has led many of us on a merry dance especially as it magically resolves itself when it wants to ...just after you have replaced/fiddled with a completely unrelated component. No start/cutting out = no fuel or goosed crank sensor

[TheBoy]

Surely I'm not the only V6 owner who carries a crank sensor in the boot