Hi All,

I am hoping someone out there can help me. Over the last few weeks my 97 STiV3 has had all the symptons of faulty air flow meter and faulty Oxy sensor,
these conclusions were arrived at from the fault codes issued on a diagnostic check.
However after replacing the above with new or borrowed replacements the problem still exsisted.
With the help of Chris at Power Engineering we discovered that due to a dodgy ground the ECU was only getting 9.2volts instead of the 13.8 it should have so as a temporary fix we ran a seperate earth from the ECU to a suitable grounding point underneath the dash and hey presto, problem solved,
back to 13.8 volts.
My problem is this, despite looking at all the wiring diagrams we could find we cannot locate the specific grounding location for the ECU on this model STi.
We have located all the grounds we can and cleaned and greased them after cleaning but without the seperate earth we fitted the problem still exsists.
I realise that the temporary cure will be probably be Ok for ever and a day but would really like to cure the root cause of the problem as I would not be surprised if the ECU ground is not the only one at this location therefore further probs could come in the future.
Any answers or help in this matter would be most appreciated.

Ralph

 

The original earths on scoobs are generally regarded as being less than perfect, and, as it seems you've found out, deteriorate over time. Several people on here have done earthing mods to their cars which, amongst other things, include what you've done. I'm no expert, and only follow the advice of people on here who I've come to regard as knowledgeable, however, from what they say, you'd be better off running seperate earths direct from the battery to various locations on the body and engine, such as strut tops, block/inlet manifolds, alternator, and the ecu, which you've obviously already done. I did this on my MY00, not because there was any specific problem, but as a preventative measure against something along the lines of what you've experienced. If you do this, imo, it's a cheap solution to your problem, and would save you the trouble of searching for the original earthing fault. Plus, of course, with this method you are giving clean, fresh grounding points to all the other sensors etc, possibly saving future grief. Hope this helps.

 

for a how to for location of earthing I used Ozzy's site. My car had some problems that were driving me round the bend. I tried his advice - he even give you what and where to get the stuff from.

Ozzy's website - Click here!

Hope this helps,
Marky

 

you could email this chap sorted me out no problem
"Kevin Strachan" <kevstrachan@firenet.uk.com>

 

what were the symptoms you were experiencing to make you go down this route.

 

Hi Mate,

The original problem was typical of air flow meter ie; eratic idle, big flat spots until on boost when it sorted itsel out and an even more than usual thirst for fuel.
As i said borrowed an air flow meter from a car I knew was working but made no difference, then i got an error code which said oxy sensor so I changed it,
fine for a couple of days until on my way to Japfest last week, did not get there as I turned around and came home.
Went to PE this week and did a few power runs and such like which revealed amongst other things that the oxy sensor was not working again which then lead us down the path we finally took.

Ralph

 

thanks think its best to sort all my earths out before problems arise.

 

Hi All,
Thanks to everybody that took time to answer, looks like I'll be doing the same as Carlegacy and spending a few hours running some new earths and cleaning all the originals for good measure.
I actually spoke to someone after I posted this thread and he said he had exactly the same symptoms on a car exactly the same age and after running all new earths all his problems ended and have remained that way.

Ralph

 

See here regarding the earth mods that I can do or you can use this to do it yourself.

http://kevuk.com/earthkits/index.php...c6bde399d7e6c2

Might have one left but i'm gonna make up a new batch in the next few weeks anyway.

 

I have just signed up to your site and want a kit - please see my psot

 

IMHO good preventative medecine. But then again I would say that since I brought it up years ago <and was laughed at by a few peeps - knowledgeable ones too>

PS I am sure I wasn't the first to bring it up either