Hi all,

Background:

Car: JDM STI-7 - 26 kms on the tach

Mods: ScoobySport turbo back zorst no cats, walbro uprated fuel pump, mail in remapped ecu by ScoobySport running 1.20 - 1.25 max boost in 4th gear mapped for 98 RON fuel, estimated 330 bhp by delta dash road dyno outside ambient temp 33' C


Problem: I have been running the above setup for about 12 months or more never noticed a problem. Two days ago I was driving home from work with less than a 1/4 tank of gas and for the first time I heard det....

I am 99.99% sure it is det.....sounds exactly like little nails being dropped in a tin can. It happens at higher revs and I can 'feel' the car is not quite as fast....the little nails are like a noise in the background but has to be det that I can hear and friends have heard as well....

I did a delta dash log and noticed that even when driving around very very easy under 3500 rpms the DD registered -6 degrees knock correction at some point ??? I did a DD run in 3rd gear and can't seem to see anything strange but then again I am no expert...

I filled up with gas thinking maybe the low gas tank was causing problems but its still detting......

Questions:

How many gallons of gas does the fuel lines, fuel filter etc hold ? I am hoping that maybe the crappy fuel is still in the lines and still causing the det, only done about 70 kms since fillup and still detting, perhaps still bad fuel in the lines filter etc ?

Why would the car be detting all of a sudden when everything has been fine ? I have checked hoses etc and can't see any problems.....what should I be looking for ?

Any guesses what could be causing the problem ?

I have the two DD logs in 3rd gear and can email them to someone if they would be kind enough to have a look and see if anything looks strange...

Please help me out guys as there are no Subaru or real tunning specialist here so I need help ...thanks...

Pat and Pete from ScoobySport.....any ideas ? never had a problem with your setup till now.....would you like to see the DD log ?

Guys I can run any DD logs you would like to see with any parameters you want me to log...

Please help me out as I have no idea what to do...

Have I done any major damage by running the car hard the few times to hear the det (probably about 6 - 10 times).....I am currently driving it very very easy below 4k rpms with zero boost just to get around, will this hurt her anymore ?

Cheers,
R

 

Failing MAF sensor?

 

Hi,


Anything I can do to test this ? Is there something I can look for on a DD log to see this, any other tests ?

I guess it could be this but I have heard that the STI-7 MAFs are very rugged and almost none have been replaced.

Cheers,
R

 

Should read that I have 26,000 KMS on the tach not 26

 

Any KnockLink activity?

LoFi

 

Are you using standard plugs ?

 

Hi guys,

No knock link

I am using standard plugs yes. Been replaced about 8,000 kms ago as they were ruined by bad octane booster...

cheers,
Ray

 

bttt

 

I'd get a knocklink or det cans on it to be sure of what you are hearing

 

When you experience -6 deg of knock correction I would realy only drive VERY VERY easy with the car until you find the cause!!!

The MAF's of the WRX from MY01 also fail! I've seen 2 already who had to be replaced........

P.S. you could send me the DD logs, but I can only look from tommorow morning when I am in my shop.

mark@ems-tuning.nl

Mark.

 

Mark, can you explain the relationship between DET and a failing MAF? The limit of my knowledge, which is very limited is that a failing MAF makes the car run lean, which is why many people use a Lambdalink to monitor air/fuel ratio. I'd like to learn something new.

LoFi

 

Hi Piers

A failing MAF generally reads lower than the correct airflow level. This has a twofold effect, one is the obvious one that less fuel is added and the car runs lean (hotter) secondly, the mass air flow is the primary load with regard to ignition advance. If the load reads low then the ignition will be more advanced.
Lean and over advanced - guaranteed to cause a problem on a scoob

Andy

 

MAF sensors on the new age car are also prone to failure. For the reasons Andy said above it can be catastrophic for an engine.

Not 100% sure on how you would test one though?

Are you running standard induction?

Nathan..

 

if you email me the logs I'll take a look at them, sure you are seeing minus 6 degrees and not just 6 ? pats not in the Uk at the mo so I would be glad to help out if I can

bob (rbr@brdevelopments.com)

 

Hi all,

Yes ! 100% sure it was - 6 degrees knock correction and this was just 1/2 throttle max 5,000 rpms !!! BUT crazy thing was when I ran the DD logs in 3rd gear I did not see any negative knock correction ???? I saw the - 6 knock correction in the minmum column in the DD log after driving very easy around ???

Any MAF tests out there guys ???

Cheers,
Ray

 

Thank you all for the help. I am still not sure what is cuasing the det. I am going to run some more logs and see if anything strange pops out at me. I will also compare these logs to some older ones before I noticed the problem. If you have any ideas please throw them out there.

Thanks again and I will keep you all posted after more runs are complete.

Cheers,
Ray

 

Razor2001,

Get a knocklink fitted asap.

I'm no mechanic but I fitted my knocklink at the weekend, and it was fairly easy.

I too was concerned about potential det, but the knocklink shows nothing but 2 green lights on full chat...

 

Hi Mark,

I am trying to find a USA supplier for the knockLink as shipping from UK will be expensive and we also pay duty on freight and invoice cost (42% duty) !

Cheers,
Ray

 

http://sandstallion.com/link.html under the ancilliaries section.

Steve

 

Doesn't Delta Dash log MAF voltages? You could then compare DD logs with someone who knows their MAF is healthy...

 

Send me a PM with your telephone number & I'll call Pat right now.....or ring me on
01702 389277, I'm on this number for an hour or so.....

 

Thanks Andy,

So whilst there are two effects in either case this would be picked up via a lambdalink as you cannot have one effect without the other?

Piers LoFi

by the way TD05 works a treat (although 'some' modifications required to get it to fit). Thanks for getting it to me in time.

 

Ray, looked at the logs and not enough info, as per mail enable ALL logging items in DD and the do some more runs.

cheers

bob

 

Thanks Bob,

New DD runs have been sent :-)

Let me know if you need anything else. BIG thanks again to you and all who are trying to help

Cheers,
Ray

 

XtremeScoobies did you want my tel# ?

Cheers,
Ray

 

Sorry guys,

Actually it was - 6 degrees of timing on the minimum column of DD not - 6 degrees of knock correction....sorry for the mistake ! Not sure how this affects peoples thoughts so far though ?

Cheers,
Ray

 

bttt

 

Update:

I have had a couple of pros look over my maps and no one can seem to find anything 'jumping' out at them ?? Is it possible I am hearing something else and not det ? Is there anything else that would make this background, tiny nails dropping in a tin can sound on revs over 5,500 or so rpms ??

Cheers,
Ray

PS: I should have a knocklink installed in a few weeks...they guy is telling me to buy a subaru sensor rather than the link or bosch one, he says the subaru sensor is tuned for the subaru block and it's unique frequency sounds and that different engine types give off drifferent frequencies etc and that is why the subaru sensor is better ....any truth to this or usual salesman crapola ?

 

Bosch sensor is the best you can get AFAIK.

Nathan..

 

I agree with Nathan, get the Bosch sensor.