Snowy_RA

Hello can anyone suggest anything please,

I have a 1994 WRX RA 260ps one with Z5 ecu always run on Optimax and Booster. To do a quick history recap - it came with only mods HKS induction Kit, Blitz mid/rear section 1 cat removed, boost gauge. At this point I had it Rolling Roaded and was told it was running fine. I added ScoobyECU(15.5psi) some months later and had it Rolling Roaded again and got told the car was detting.
I then took it to a specialist mapper who got his det cans on, plugged his laptop into an ECU output port under my dash and off we went. After 2 sessions he couldent work out why my car was detting as everything seemed to be fine on his laptop data. So I decided it would be left to me to work out the solution by replacing stuff (The worst and most expensive way).

I then had added H&S downpipe decat, DAWES device and a Knocklink. Sure enough Im getting red lights in spikes on the gauge randomly in 3rd 4th and 5th with the horrible ckkk ckkk sound from the engine when Ive got the window down (I can audibly hear the det now as I hear the sound when the gauge lights up).

It doesnt matter what map im using (standard or ScoobyECU) how much booster I add to fuel or what boost I have car set to on DAWES from 0.5 bar to 1.1 bar it dets randomly regardless, and when I say randomly I can nail car around for 5 mins and get no more than 1 green on Knocklink then suddenly it will start spiking upto the red light 2-3 times in each gear while getting that horrible det noise.

So today I did 2 things, the first I had a uprated fuel pump fitted to the car, hoping that this is the culprit. Nope its exactly the same as before, the second thing I did today is remove the MAF sensor (its the green label one) and let the elements steep in White Spirit for 1 hour, I then carefully cleaned it with a paint brush and cotten wool buds, then performed an ECU reset and its exactly the same, getting random det.

I have been told the green label MAF sensor fitted to my model is one of the better MAF's types out there and that particular one hardly ever breaks.

So im totally ****** off as you probably can imagine!

Can anyone suggest anything else that might be causing det that I can replace or clean etc!

Your input is appreciated.

Snowy

Snowy_RA

Bump

Dark Blue Mark

Are the fuel lines / injectors clean?

MB

Roojai

IS the engine original? Perhaps someone has changed the engine and unwittingly put a higher compression ration engine in that is more prone to DET. But at 0.5bar should not be a problem.
Do you have an AFR meter?
Perhaps it's done loads of miles and has major carbon build up.
Dodgy MAF sensor is a possibility, and AFR meter should help to determine this.
Spark plugs - have you got 7's and are they set to 0.7mm or less?

Roojai

z5??

cong

yep coil pack, spark plugs, get the main culprit out the are your injectors working hows the timing are you using ocatane booster your, you not getting any boost leeks are you, there could be anything wrong the people at the garage should of told you what it could be, go to a specialist

NotoriousREV

What condition is the intercooler in? It may be heatsoak if it's fine at first then starts to det?

Snowy_RA

First Id like to say thanks for the replies, very helpful

When I had the pump replaced and uprated they changed the filter as well.
I will put some RedX or other injector cleaner in to see if it helps.

Certainly cant rule this one out, tonight I set the DAWES back to .6 bar and drove back from work - didnt get more than 2 green the whole Journey - will leave it like this, see what its like tommorrow, however as Ive mentioned its like Jekyll and Hyde.

Nope but will consider getting one of these.

Understood, will wait on the AFR results.

Yep

I think the coil packs need changing as I get some hesitation in 1st and second gear but it not really bad.. but hints at this being a problem. Am 99%
sure no boost leaks. I have every faith in garage and mapper my car is simply acting oddly I think

Well it looked bad when I got the car but I spent 4 hours and about 20 toothpicks and straightened all the vains out on it, its about as good as you would expect for a 10year old intercooler


Thanks for the replies, gonna try injector cleaner and leaving it on .6 bar for a few days to see how it gets on. If the problem resurfaces I will get an AFR meter fitted.

Thanks

Darbo_wrx

sounds abit like a sensor on its way out and making the ecu add more advance when its not needed
if its running perfect for 5 mins at full chat then suddenly starts detting?
does it ever stop detting once the detting starts? as in runs for 5 mins ok detts for a min then ok for 5 mins more???

i would
1) borrow someone elses ecu for a day to illiminate ecu probs-i have one you could lend if you are near lancaster
2)talk to a expert mapper type to find out if there is a sensor that could make the ecu advance the ignition timing if it went faulty/intermitent

put the boost back up to 1 bar as it should be able to run at that and fix problems around it
if its perfect with the low 0.6 boost then it could be just intercooler heatsoak-next time you get the det check your water spray system works and keep activating the waterspray to see if you can make the det go away-this is probly step 1 if you havent already done it

Darbo

GrantyBoy

ditch the induction kit, that might help.

Snowy_RA

Ive been running the car on 0.7 bar of boost last 2 days - Im getting no more than 2 green on Knocklink. Previously when I dropped the boost down it must have been another factor causing the det (bad fuel), dirty MAF but its definately not Detting any more. This leads me to 1 of 2 conclusions.

I didnt mention this earlier but this is exactly one of the things the Mapper mentioned in passing while testing the car. This coupled with you saying the same thing made me re-test the low boost scenario. is now looking like a strong possibility.

OR

something like my intercooler is knackered.. heat soak... as mentioned.

Well things are looking better thanks to your input, cheers guys for helping
me solve this one (or at least know how to stop it).

Thanks

Snowy

Roojai

I also read once that a dodgy cam sensor could effect the timing and cause DET, but I guess this would show up as a fault.

If your intercooler, injectors, fuel pump, spark plugs, MAF, lambda etc are ok then it might be related to timing. Can you get the map on your scoobyecu adjusted and get the timing retarded a bit.