matth76

If the MAF sensor has gone what would be the symptoms?

Scooby Dan

It will be worth waiting for ! Adam rebuilt my 2.5 nearly 2 years ago and it has been running over 450 bhp for the last 10k miles and hasn't missed a beat . Adam and Jamie at Autotecnica are top blokes and your car couldn't be in better hands.

matth76

Does anyone know if Duncan at Race Dynamix is in the south east over next few days? Unfortunately I've not been able to get hold of him. I'm not sure if my map needs a tweak or look at as another member recommended.

Do Subaru dealers still service and look at cars which have a custom remap (Im not talking about having anything done on warranty - engine problems, even sensors etc aren't covered under the 12 month warranty even on standard cars - not really sure what is actually covered lol) but just to do a diagnostic on my car? Thanks again guys. Autotecnica sounds good. I assume Buxton is quite a way from me unfortunately.

dpn

It just picked I up today, wow it feels great obviously haven't gone up to or over 4,000 rpm and I won't do for 4-500 miles yet. It feels so much better though and the exhaust is perfect for me not too loud but sound is awesome. Early days but It feels much tighter and so much more responsive. I'm going to get it mapped too, I'm not going as far as you have. I didn't replace the cranks. I just want it reliable. Adam said it would be good for 400bhp I'm not going to change the turbo at present either I'm going for around 360/400 hopefully. Who did you use to map yours? Oh it was over £2000 in total in the end. I don't really care though as I'm well chuffed with it!

dynamix

iTrader: (3)

Matt - am down in sussex on friday if any good to you. Could pop in first thing ...

As said it could be a million things and before you start panicing on rebuilds or the like it needs to be checked.

Gimme a shout on my mobile or pm or text or email etc

matth76

Hi Duncan thanks I really appreciate your help. Email sent

matth76

Ok a small update from Subaru. As mentioned my car was in at the local main dealer to diagnose the problem. The initial response is they could find nothing wrong. They did a full electronic diagnosis and scan and no faults were found nor any errors of any kind. Their test drive said it performed normally and they couldn't replicate the problem which was very strange as the symptoms were very clear for the last few days and permanently there. So clearly this is an intermittent problem. They are keeping it in over night to test it from cold in the morning. They may do further tests tomorrow to test the fuel pressure and change spark plugs but they'll let me know before any work is done. So it is good and bad. Bad that they haven't found out what the problem is and good that it is intermittent as I'd assume piston damage would be consistently there. So still a bit of a mystery. I'm not holding out hope they will get to the bottom of the issue. It could be a similar issue Greatgonzo that you had, where it is a simple case the timing has been knocked out and just needs a simple map adjustment. I doubt Subaru would have been testing parameters like that. Thanks again Duncan for offering to come and check my car. It looks like I will be needing to see you Friday unless Subaru solve the problem tomorrow. I'll email you either way.

Mrfastbaz

keep us posted interesting post hope its all sorted

matth76

Thanks. I will do. Just want my car back

dr jim

iTrader: (1)

Not one to jump to any conclusions but this bears all the symptoms of my cracked ringlands on my 08sti. Car went to 2 seprate dealers who couldnt find the problem. Every time the ECU reported no faults

Only when Subaru UK became involved they requested a snap shot of the ECU and after reviewing told the dealer to perform leakdown test of cylinders. This showed number 4 as leaking big time.

My understanding of it was the knock sensor dectects the cracks as knock and pulls the boost and igntion hence the jerkiness between 2000-3000 rpm and reduced boost.

Some days my car was fine the others not...

What i did see was a increase in oil consumption however the engne remained quiet and you would of thought there was nothing wrong with it mechanicaly.

I hope im wrong but this is my experiance of these symptoms,

If this piston is cracked bad you should be able to see smoke once you remove the oil filler cap with the engine running.

Hope you get it sorted without much agro

Jim

dynamix

iTrader: (3)

See you firday Matt.

greatgonzo

iTrader: (1)

I think op mentioned no use of any fluids ie oil or coolant, hope its a simple fault

dpn

Mine too Matt. Jims description is spot on with what i experienced. Same piston 4 was the offender. Some drives I didn't have any hesitation, other drives is was really obvious. There is a silver lining though as now the car is better than I've ever known it to be. I'm certainly no expert I can only relay what I've experienced. I hope it's not worst case senario. Keep us informed.

matth76

Hi guys, thanks for the replies. Subaru had my car in for two days, test driving it, fault scanning etc and couldn't find anything wrong with my car. So for the last four days since Subaru first took it in the car has been fine. Pressures all fine (not sure what pressures they tested), no fault codes what so ever, and drives perfectly. When I had the issue which seemed to last two or three days it never had any CEL light, temps all fine, fluids all fine it was just lumpy and hesitant, delayed response in power and about half the amount of power.. the issue has been gone for the last few days but could well come back (which is worrying), therefore Duncan's kindly taking time out to check it over . I'm hoping Duncan can see if something is out of balance which Subaru couldn't and I hope it's something very simple too but for now I'm loving having the car driving normally

I do know the issue started almost 5-10 mins after my wife filled the car with Tesco 99, could be coincidental but not sure if this was just a bad batch, as Tesco 99 has been known to be inconsistent although I always use it as its cheap, it could perhaps have affected my fuelling slightly or timing slightly and my map just needs a tweak, who knows. I filled up on Shell VP yesterday (5p more per litre but I may stick to this from now on to be safe). I'll wait to see what happens tomorrow with Duncan's checks.

Mrfastbaz

in my 57 plate sti type uk i nver use anything but shell v power.....

matth76

Big thanks to Duncan today for taking time out to check my car over. It's all fine, map wise and running ok. However it did have another "30 second" episode (same symptoms hesitant, delayed response in power /lack of power, especially low down) as I was pulling out from my work, especially noticable driving up a hill outside my work, and I thought oh no! (wish I had done a test drive Duncan as you would have picked it up as it was happening) but I think that could be because my ecu had been reset (would my ecu have been reset Duncan as this could explain it possibly?). But a couple of mins later it seemed to be fine again (just as it had rectified itself when it happened on the odd occasion before straight after leaving work).

Strangely though I did seem to hear a repetitive quiet clicking or ticking noise (car was cold), on idle, not revving, (car was cold so on idle it was around 1500rpm) before I pulled out of the car park Duncan, so not sure if my ecu is mistaking this noise for detting, when it is in fact something vibrating, heat sheild perhaps as it did sound more like a vibrating not engine noise as I got out and couldn't hear anything? I may have been hearing things though. It only lasted for a minute as I got out of the car and couldn't hear it. And havent heard it since, not even when it was cold this evening. I could have imagined it though but it was just prior to this bout of hesitancy. Car is all absolutely fine now though so I will just keep an eye on it.

But a big thanks to Duncan coming down and checking it over. I appreciate it.

dr jim

iTrader: (1)

As I said in my previous post I'm 99% sure you have a cracked piston, pay for a leakdown test, don't get a compression test as this won't always show the problem. The symptoms you are describing are classic ringlands failure....

matth76

Thanks Jim. I probably will if it happens again. How much are leakdown tests at most normally?

dr jim

iTrader: (1)

Depending on where you go a couple of hrs labour at most

dynamix

iTrader: (3)

Yes Matt the reset would do that c

matth76

Cheers. I'm hoping it wont come to that as my car's ecu had just been reset (I assume this is the case) which could account for the slight hesitancy, and it was only slight, and the continual 2-3 day issue I had last week was immediately (5-10mins literally) just after filling up on tesco fuel so it could have been a bad batch of fuel, and I have been using Tesco since I got the car which could account for the odd 30 sec bout like I had yesterday, over the last couple of weeks. But like you say it could also be something worse causing it ..but I like to stay positive Car is running fine at the moment and will assess it over the next week. I am going to invest in an OBD2 scanner from ebay to read fault codes though (if that is what its called). Do I need a separate "cable" as well or is that part of the odb2 scanner kit? Is there any particular scanner "model/product" number I need to purchase for my 2007 hawkeye car, or will any obd2 scanner which works on cars back to 2000 work on my car? And is there a function on it to reset the ecu normally as I need it to include this? I want to make sure its compatible with my car. Thanks for any help on this.

I've also see a small mobile device on tv (not much bigger than a USB stick but more of a square block shape) which you can plug in on a test drive, or importantly leave it plugged in, and it logs data, even over a longer period of time, so if it does occur on the odd occasion you can catch the data at that time.. especially for intermittent issues as the problem always disappears before you have time to plug in the main obd2 scanner. Does anyone know what this device might be called and how data on it could be read?

matth76

Thanks, yes I thought it might be the case. Im definitely sticking to V Power from now on. Just interestingly to see if the problem disappears, which I think last week was down to as it was straight after filling up at tesco.

Thanks again Duncan for coming down. Really appreciate it mate Definitely wanting more power now.. amazing how used to it you get.

matth76

Will a leakdown test definitely prove whether there is a cracked piston or ringlands failure, and importantly, if the test gives the all clear does that mean I definately do not have ringlands failure or a cracked piston and the problem (if there is one) is elsewhere, or can a result from a leak down test still be inconclusive? Generally what would be acceptable leakage percentage, ie indicate 99% all ok?

I haven't driven it much this week but I did drive it today and there was another bit of hesitancy (just for a split second when reaching 2500 revs, and then all fine again), and I do always appear to get a small amount of hesitancy leaving work, like I used to, especially going up a steepish hill outside my work, only revving up to about 2000-2500 max as the engine is cold, but then 30 secs later all fine. Seems to be a regular thing leaving work. Is this because the fuel pump is not primed or something as I've spoken to other people with turbo cars and they also experience this when cold for the first 30-60 secs ..does anyone else here? As said, no coolant loss, oil consumption is fine, no smoke, no noise, no engine light, nothing.

If it is the worst, ringlands failure or even a cracked piston, who is the most recommended engine rebuilder in south/south-east region (ie south of london)? Is an engine rebuild required just to change the piston rings/ringlands, or is it no extra labour to change pistons at same time if changing ringlands?

I've heard API are good. Does anyone use them, or recommend anyone else? I assume for a forged piston, head stud job (thicker head studs I'd assume would be a must to firmly prevent another issue from happening - ie head gasket), am I looking at ~£1500-2000 spend, ie enough to take power safely up to 400bhp? I'm not thinking the worst just yet but it is strange that my map is all fine, and no fault codes were found. My next call is to a specialist to see if they can perform a leak down test (to hopefully prove yes or no my engine is fine and the problem is elsewhere). Although all the spark plugs have to come out for the leak down test so I assume it is quite a large expensive job

New_scooby_04

iTrader: (4)

Hi Matt

When does the hesitation appear? Between 1800rpm and 2800 by any chance?

You may have a problem with Phantom knock, which is not unheard of in even std hawks.

Did the car hesitate when Duncan had the laptop plugged in? It would have been obvious to a mapper as the car would have just started pulling and then adding ignition for no apparent reason.

API are very good btw - they built my 470bhp Hawk. Getting that spec reliably costs a little more than two grand though....try putting a 1 in front of the 2 and you're a bit closer

I'm sure you could get the pistons replaced with pukka ones for around the 2k mark though (IF it comes to that!!). Might be worth giving David at APi a call for adivce on how to diagnose your problem.

Good luck.

greatgonzo

iTrader: (1)

Slowboy Racing are a good Subaru specialist, they are situated in Brands Hatch you could give Neil a ring for any advice (very helpful)

matth76

Thanks guys. No the car was fine when Duncan had the laptop plugged in. The hesitation is only intermittent (very intermittent barely happening once or twice a week) but normally happens every few days when I leave work and climb quite a steep hill to get out of our car park (but not revving it more than 1500-2500 revs, and the hesitation is only like a "delayed reaction" and then the power comes on but 30 secs later it is all fine. But it does not happen all the time leaving work. But oddly its never happened when I leave my house in the morning when it is really cold, but the road is all flat so not sure if the hill outside my work car park has something to do with it, making the car work a fraction slightly harder when cold (??).

I actually spoke to Neil at slowboy racing today and you're right he is very helpful and spent 5-10 mins on the phone taking time out to give good advice. I'll certainly be using him as he's only about an hour up the road. Basically he said it is very unlikely my hesitation problem is mechanical and nor a compression issue as the symptoms I have would be consistently there and they're definitely not. In fact the car is really good 99.9% of the time. It was only a couple of times leaving work and the briefest of split seconds yesterday during a drive when the car was warm, around the point the boost kicks in just under 3k rpm that there was a hint of hesitation but then it was all fine and didn't disrupt the acceleration as it was only a split second. The fact it is unlikely to be mechanical or a compression issue gave me a big sigh of relief. It is more likely he said to be a temperature or possibly sensor fault on it's way out but as the issue is very intermittent I need to wait until it gets to be consistent (if it does get worse that is as so far its only getting better!) so they can diagnose it, otherwise I could throw money at a problem which is barely there in the first place and still never find out exactly what is causing it. So sensible advice and very helpful. I will keep an eye on it and if it becomes more consistent I'll be taking it down to Slowboy for a look. Neil was very helpful answering all my questions and seems very knowledgable. I'm just so glad that it is unlikely to be compression or mechanical issue

jura11

iTrader: (7)

I can vouch for Neil's work,he's really helpful.


Jura

telemarker

Sorry to bring this back from the dead, but what was the final outcome?

matth76

From memory it was all fixed with a simple remap adjustment Sadly I no longer own the car. It was one of the best cars I have ever owned. I will be getting another Subaru one day! Family has to come first at mo.

telemarker

Thanks, I'm going to have to keep looking for my problem then ! 👾