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[MaxV6]

Okay,  we have a ghost in the machine on our daughter's Mk4 astra ......   

clearly i'm going to need to beer token persuade someone with a tech2 to come and look at it,.....

it started cutting out on my daughter while running,    so needed attention,  we read codes when she had to be recovered by green flag...... 

,   and initially it said EGR and absolute barometric pressure in manifold...   then in the garage, it came up with throttle position sensor fault....

 

EGR,  changed that,    still iffy, but different codes.... 

 then MAF... changed......   code changed again..... 

then Cam sensor....   changed....   ran okay for 10 minutes,   then hiccuped and EM light came back on,  and   code changed again..... 


this is getting bloody stupid....



HELP?? 

[MaxV6]

Oh, and it has a new battery as well.......   !!!   

[freecall666]

Oh, and it has a new battery as well.......   !!!

mrk4 is ecotec engine, they use the same engine as 2.0l engine, which mod is is it 1.8 2.0 2.2?

[MaxV6]

1.6 SE   


(2001  8 valve 1.6 Auto Astra Envoy,  )

[freecall666]

1.6 SE   


(2001  8 valve 1.6 Auto Astra Envoy,  )

oh all one's ive seen have eco tec type engine, but it dose sound like cam sensor fault, can throw up randam codes, dose engine still go into limp mode?

[Marks DTM Calib]

Willy nilly part changing, never good.!

So, you say its a MAF based setup yet it throws a MAP type fault code, alarm bells are ringing for me!

[MaxV6]

Err ,  to be honest Mark,   i may have got the precise lettering wrong....    whatever it is, it's the airflow sensor on the inlet side....   

[mantahatch]

Mk4's can suffer from bad earth connections in an around the engine. cheap and free to do. Diagnostic machines do not always offer the best results  in fact on occasions can be downright wrong  Proper tech 2 on son.s Astra 2.0 SRi said EGR changed no different. Then it said something else I cant remember it was replaced and guess what no difference. Finally in desparation I drove it for a week to get my years of amatuer mechanics to feel for the problem. One old CTS fitted and bingo all working nicely again. Tech 2 did not even mention CTS

This was not an amatuer using the tech2 either. If it had been me using it I could understand, sometimes you just need to hear it and drive it to realise what is happening.


Edit: CTS coolant temparature sensor.

[Marks DTM Calib]

Tech 2 is a tool, it gives access to symptom information and nothing else, it does not give a definative diagnosis 

If tech 2 was used and the diagnosis was wrong then its operator error and nothing else 

[cem_devecioglu]

most codes given by code readers are irrelevant as those codes are the end result..
 
ignition and fuel components are also beyond their scope.. 
 
and sometimes there are no codes stored for the faulty sensor 
 
so back to will nilly part changing

[MaxV6]

the garage (local non franchised) used generic code reader , not proper tech 2,
 i thought perhaps being able to read live data on the right machine,   might give a clue,
 likewise our resident tech 2 equipped chaps have vast experience in DIY mechanics that i lack, or more precisely, i lack recent up to date experience,   the last time i even thought I knew what the hell i was doing was on essex V6 lumps and Pintos .     nigh on  30 years ago....    (although actually, also the straight 6 sennie was not unfamiliar territory in some respects....    )   

 I understand basic principles,   but lack the experience of being able to "get a feel" for what ails it....    from my perspective ,  even if it was running perfect , it would still sound and feel like it was missing....   being 2 cylinders short of being a proper engine....   

and i'm not well equipped with mechanicky tools.....     anything you like for electronics,  building , luthiery , but spanners and sockets and stuff are not amongst my list of "fully equipped"  things....   a few basics, that's it....

[Radar]

Agree with previous comments made about earthing -
In the end we put another earthing strip in the engine connected one side to the top of the shock area and the other into a relay box.

[TheBoy]

Mk4's can suffer from bad earth connections in an around the engine. cheap and free to do. Diagnostic machines do not always offer the best results  in fact on occasions can be downright wrong  Proper tech 2 on son.s Astra 2.0 SRi said EGR changed no different. Then it said something else I cant remember it was replaced and guess what no difference. Finally in desparation I drove it for a week to get my years of amatuer mechanics to feel for the problem. One old CTS fitted and bingo all working nicely again. Tech 2 did not even mention CTS

This was not an amatuer using the tech2 either. If it had been me using it I could understand, sometimes you just need to hear it and drive it to realise what is happening.


Edit: CTS coolant temparature sensor.

As Mr DTM says, any idiot can plug in a machine and read a code, and then change a part based on that part being mentioned in the fault code.

The skill is interpreating the codes and live data to ascertain what could be causing the symptoms BEFORE changing any parts.

[MaxV6]

Having got a list of faults , and the order they came in , it appears to be a choice between earthing issues or ECU failure , or a combination of them , apparently there's some question of earth breakdown in the ECU , I believe a direct good earth to a specific pin in the ECU is a possible fix , already changed CTS

[Brikhead]

it started cutting out while running...

...it appears to be a choice between earthing issues or ECU failure...

Done a few Astras now for different customers, symptoms are the car will usually be o.k. when first started but as it warms up it will cut out, you can then confirm ECU failure by wiggling gently applying pressure to the wiring connectors on the ECU whilst attempting to start, that usually allows the car to be started.
I use a company in Cannock to repair failed Vx. e.c.u.'s but it costs around £200.