Warning - long post !

Had my 05 sti ppp remapped not long ago(2 month) by a reputable tuner I worked with before. This was after I had ported headers and uppipe fitted, so it accommodates it. Now, for about 1 month I was fully happy, well worth it, until a month ago, when strange things started to happen.
Hesitation/ rattle, hold back under load in higher gears was the symptom, this started to happen after I hit by mistake the fuel cut. Since I live in holland it is not easy for me to just jump back for a good tuner, so I waited till I could go to local specialist, meanwhile I tried to drive it off boost, but still pushed it a few times just checking if by any chance my problem got miraculously solved, which it wasn't.
Finally after 3 weeks I got to local tuner(who turns out to be very knowledgeable and nice guy) and we see from ecutek log that it is detting as hell, multiplier was at 13 and timing very low(I think 8 or 9 can't remember exactly), and it was running very lean. After I took another fuel tank(the best around here) and ecu reset, started to run a bit better, less detting, but was still doing it in 5th and 6th and even in 4th a bit, timing didn't go up, only multiplier to max(16). Acceleration was still jerky.
What I need to point out that I used esso 98 for the original mapping and outside temp was about 8 maybe 10 degrees, also at that point I have no doubts car was running det free.
Now this fuel should be similar quality, the best 98 here, and outside was lately over 20 and when we were doing the logging it was 32 degrees.

Now I had no choice but ask local tuner for a remap, to make car running det free, so that is what he did, during mapping he said the car is still dettting a lot and he could not raise timing as it should be normally, but could still raise it to 13, if I recall correctly. He lowered boost from 1.5 to about 1.45 and made fuel mix richer, and now car is running smoothly and without det.

Now why did this happen ??? I must point out car was inspected by different mechanics and found nothing wrong mechanically.

Local mapper told me I am very lucky I have the 05sti 2 l engine es the new 2.5 would have been in pieces already!! He also told me that maybe I got a contaminated fuel and that cause the whole issue, but for now we don't know. In any case, car is now running safe, but not fantasticly powerful, in fact is less torque than it had before I had the headers and remap, so obviously I am pretty unhappy. After spending a lot. When it will get colder, I can go back to local mapper and try to optimize it, but till then this is it. Also, how do I know that my engine didn't get damaged ??? What if now I go on holiday and just blows after 3 weeks of detting...
Supposedly I should be still happy for the fact that my engine is not blown....

There are a few things I have to point out:
1. I am not trying to blame anybody, but learn from the problem, and I am only looking for constructive answers
2. Looking for advice on what could have been the issue
3. How can one tell if engine is still strong or is damaged ? should I get a knock sensor ?
4. Is there a fuel cleaner and or injector cleaner I can pop in the fuel tank just to be safe ?

Thank you for reading it.

 

to check for engine damage you could use a boroscope to see the insides, have you uprated the fuel pump? it could be that this is failing and therefore not supplying as much fuel as it was when mapped hence running lean), If you can get logs from the original tuner (if the logs exist) and compare them to the new logs then someone may be able to give a better diagnosis

 

first thing i did to my classic was fit a knocklink. absolutely paranoid about det. you can up performance on any car by advancing the timing and leaning out the engine, i see it all the time at the garage where i get my work done. a little knowledge is a dangerous thing and the sh1te that people spout on car forums and people think it is true beggars belief. a case of monkey see, monkey do. then the gurning afterwards when the engine calves itself, the recrimination, denials and a great deal of money spent on repairs.

Nothing short of splitting the block apart will tell you if you have damaged your engine. visual inspection is the only way i would do it. if you wanted to be really sure tou could have the parts inspected for micro fractures but that is taking things way beyond what you need to do.

 

I had ppp, so yes fuel pressure is good. I asked the delta dash logs, but no reply yet.... I will ask for the after map loggs too, hope he still has it.

To check with boroscope, I need somebody who can do that, should I look for local engine builders ?

 

Well, that is exactly what I try now to avoid: spending even more.
Taking the engine apart for inspection, how much time would that take a professional ?

 

BTW, Esso Supreme is more towards 97 RON, not 98. So a full c.2 RON down on the likes of V-Power or Tesco 99.

 

engine out 1/2 day. heads off,check valves, springs, check piston crowns, rings, split block, remove pistons, check rods and bearings, check bores for damage, repair/replace parts as necessary and rebuild, then put back in car. someone better than me could give you a better estimate of time, but at least a 2 or 3 days to do it properly, maybe even longer.

 

The OP is from Holland - the fuel is different there.

To the OP - is the fuel pump on its way out?

Lots of things can happen that would just weaken the car slightly, dropping down to 13 advance multiplier is showing that the ecu is doing its job correctly and protecting it (that level isnt too bad tbh although not ideal) - I would say the engine would be fine. as I say it could be fuel pump, air filter clogging up, slight split in inlet hose to turbo etc etc

 

thx for the explanation!

 

Sorry - only skim read.

 

Thx for the reply. Indeed fuel is different here, and uk esso 98 is actually very good fuel, compared to what we have here.
Fuel pump is working well, that was the first thing we looked at.
Yes ecu fortunately was doing its job. Air filter was replaced after first signs of trouble with brand new. As for split hoses, I was told all looks good, also I think during mapping would have been visible ?

edited to say that when I was driving it off boost it jumped back to 16, but as soon as on full load the it took back and the log in ecutek showed around 3 harsh drops

 

Splits in the inlet hose post maf can cause dramatic leaning out and can develop over a period of time. You wouldnt necessarily see in initial mapping as it would be part of the mapping process to make the fueling right, but if the split widens (as they do) the effect will get worse.

 

I had similar issues on my MY05 JDM Sti recently and we just could not find the problem .... but eventually we did after I had changed all sorts of things and we started to think it might be the fuel pressure regulator ...

The long and the short of it is that as we looked down the right hand end of the engine towards the fuel regulator .. we found that a small vacuum pipe had inexplicably come off from the rear of the manifold on the right. (I think it came from/went to the fuel regulator)

We re-connected it ... we could see the car re-learned its fueling adjustments on the laptop we had plugged in (or something like that) and it then transformed into the car I remember when it was mapped ... and I am 'in love' again !

Perhaps worth a quick check ? Certainly I understand your frustrations and so wish you the best of luck with a speedy resolution

 

good shout that

 

Just seen this ... we checked for these splits/leaks too and apparently they can be so small that it is very hard to see them. The way my mapper / engineer checked was to spray carb cleaner all round the air intake parts and joints whilst the engine was running and being monitored by a laptop to see whether there were any 'unusual movements' in the figures as the cleaner effectively got sucked into any hole that was there and affected the measurements.

As you'll have guessed I am not a tecky .. and so my point is simply that leaks can be very hard to spot .. and you probably need someone that knows what they are doing to check for them properly.

As i said above .. good luck with it

Chris

 

Very interesting, many thanks for the writeup !! I forgot to mention that I have replaced the maf sensor with a brand new one but made no difference(I left in the new anyway)

Yesterday I left my car at a local tuner to have Defi's installed so that at least I see smth, and I have also asked them to take off intercooler and look at plugs and all hoses. they will also do a compression test on the cylinders that can indicate also the state of the engine.
I am going on long holiday with the car in a few days and I am very tempted to buy the ecutek enthusiast software so that I can monitor myself what is going on if I feel smth is wrong. Only issue is that I spent twice my original budget already

 

I am sure there is free ECU monitoring s/w 'out there'

 

I think nothing as good though. I won't get it now anyway, but it is now on top of my list after holiday

 

If your car was running 99 Ron fuel when it was mapped ie. UK Shell V-Power or UK Tesco 99 then it has to continue to run on that fuel or the equivalent by the use of NF Octane Booster or some other known Octane Booster that actually works.
I would have assumed you would have taken in to account different fuel qualities when you had the car mapped.
As regards the weak running I would expect there is a reason for this and as described above it could be a very small air leak on one of the pipes connected to the inlet manifold and particularly the pipe supplying signal to the fuel pressure regulator.
If you want to monitor air fuel ratio or Lambda that is fairly simple with a wide band Lambda guage but you need to know what you are looking at and you need to know what values you should have under different engine operating conditions.

 

thx for the reply Harvey. Fuel was esso 98. Hope to get to the bottom of this very soon... with the fuel air ratio monitoring, like you said, I'd have no idea if values shown are correct, but also I want my dash to look as much standard as possible apart from defis.