uxon

TLDR:
My car started having trouble with hitting full boost after last service (new spark plugs, oil, filters). From logs it showed up that my target boost is lower than it used to and its max value is different on every pull. I attach current and old logs. What can cause that?

Long version:
The car is 04 WRX with PPP ecu. Apart from the ecu, the only non oem parts in engine are ppp silicone y-pipe and decated uppipe (from sti).
After last visit to a shop I have noticed some problems with boost (I have a boost gauge). It seems that it is spooling a little later than it used to and for sure it is not getting the same full boost. It always has hit about 1.25bar of boost and now I am seeing 1-1.1.
There is a small chance that the boost was behaving that way before last visit to the shop (I am driving mainly around town on daily basis and I noticed the behavior on highway couple days after getting the car back).
The car went to the shop for 2 main reasons:
- it was a first service after engine rebuilt (so change oil and check if everything works fine);
- after engine rebuilt I started getting misfires on multiple cylinders when engine is cold;
The shop told me that everything with engine is fine (they made some logs with ecutek). They also changed the spark plugs (they said that my plugs were not OK) for new ones to address the problem with misfires (which did not fix it, I am still getting misfires couple minutes after cold start, every 2-3 days).
I have logged my car. I attach the logs from 3 pulls. All of them done during the same run (same petrol, weather, etc.). All pulls were done on 3rd gear of my short STI P1 4.44 transmission.
3 runs 3rd gear boost problems.csv
One interesting thing that I notice here is that on every pull, the max Target Boost value is different (1.061, 1.149, 1.044 bar). It doesn't seem normal to me. Where this difference might come from?
My IAM is 16 and learning table is full of 0's (which is a bit strange to me because usually I used to have some values there).

Also I have found some old logs, 2 years old, with:
- stock catted uppipe and leaky uppipe gasket;
- on the old engine (completely ok, but with about 100k miles)
- with GFB blow off valve (now changed for a second hand stock valve);
- without egt probe in exhaust maniflod (possible leak?).
Unfortunatelly not all important parameters are logged, but it should give some comparison. To be fair, the pull was probably done on higher gear (4th) and on longer tranny (stock wrx tranny).
4romraiderlog_20160704_220508.csv
As you can see, the target boost used to be stable 1.237bar and max manifold pressure gets around 1.25bar and boost comes on much faster.
2
What do you think about my current target boost fluctuations? Do you see anything more that looks strange? Why am I not getting as much boost as I used to? Do I need to log anything more?
A leak (either pre turbo or on intake) should not affect target bosst, right? I would have large boost error then?

uxon

I have investigated the issue further. Now (after ecu reset?) I see normal Target Boost value (1.237 bar). Is it possible that ecu somehow learned that it cannot hit the target boost and lowered its expectations?
So the target boost is 1.237, but I am not hitting it at any time. I see tops of about 1.1-1.15 and it shows up pretty high (3800rpm). I usually see 1bar of boost not earlier than 3600 bar. Also, max boost that I noticed at 3000rpm is 0.6 bar.

I looked for boost leaks in the intake by spraying isopropylic alcohol spray in as much spots as I could manage and I didn't find any possible leaks.

Also, I tried to remove the pipe from T-shaped connector that goes from turbo solenoid. With this pipe disconnected (so one end going to atmosphere instead of to solenoid) my boost comes on about 300rpm faster (3rd gear: 1bar at 3300rpm, 1.237 - target - at 3550 and I managed to hit 1.36 bar between 3750-4300rpm and took my foot of the gas pedal, because I didn't want to break anything). Is this exepriment useful, can we have any useful conclusions from it? Is this behavior OK?

Anyone?

davoid

wastegate actuation? Maybe try flushing out all those boost control pipes. Also I sometimes see stuff about a restrictor, pill which I've never delved properly into.

scooby kid

iTrader: (6)

Get some carb cleaner and clean your boost solenoid out and make sure your restrictor pill is still in the pipe , maybe on rebuild they took it out by swapping pipes etc ? Clean or replace the maff to this can cause havoc if honest if your car is still on 2004 maff I’d replace it any how. But your miss fire is key to start pal , this could be a coil pack breaking down your car won’t reach full boost if ones playing up could be lambda could also be maff. Also best to do logs in 4th gear this is the most load.
My car is mapped to 1.45 yet 2nd and 3rd only see 1.2/3bar as the load is less only 4th & 5th see 1.45.

keep us posted tho I’d like to hear your findings

uxon

Cheers for the input
I think that restrictor is in the place (I could feel it by hand) - if it was not, would have problem with getting abything above 0,5bar.
I may clean the solenoid. I did it once, but as I remember it correctly, I just sprayed into it, without opening and closing it. Can I do this cycle of opening and closing on the car (some kind of test mode)?
MAF seems to be quite expensive for a blind shot
Another log that Ive taken is with completely detached turbo actuator (operating at atmospheric pressure): [attachment=0]3,4 gear with detached actuator hose.ods[/attachment]
One thing to notice is that target boost is fluctuating here again, but I don't see a direct connection between it and the temps. I mean 91-93C is normal operating temperature and IAT about 35C also seems pretty OK to me.
About the boost, with the actuator disconnected, at 4th gear I see: 0.6b@3000, 1b@3300, 1.2b@3400, 1.5b@3700. When I noticed 1.5b at my gauge I immediatelly put my foot off, as I didn't want to break anything. Do these numbers look ok to you for ej205 with straight sti uppipe and all the rest of exhaust stock (2 cats) and with PPP map?

scooby kid

iTrader: (6)

Looks late boosting, have you checked your inlet pipe isn’t split where it clamps on the turbo . Very very common issue . This causes similar troubles

scooby kid

iTrader: (6)

Td04 should be on full boost by 3k

uxon

My Turbo Inlet Pipe is nearly new (half a year old), at that time I also have changed most of the vacuum hoses, PCV valve, put new Dump Valve gasket, changed uppipe to decatted sti version with new gaskets. Also all of the gaskets that come in a full gasket set for engine rebuilt are fresh.

By full boost you mean 1.25bar@3000rpm? Are you sure that this is achievable with stock catted downpipe and a third cat in place?

Somebody told me that the lower target boost might be connected with compensations for IAT, coolant temperature or atmosperic pressure.
Today my outdoor temps were significantly lower (20C) than during previous week (30-35C). I did some quick logging during my commute. IAT is of course lower, from my observations my typical IAT temps during my daily commute are +3-5C more than the outdoor temp (if there is no traffic jams). What is more interesting, the coolant temp. is significantly lower. In last days, after warmup it was oscilating between 90-96C, while today it was oscilating between 81-90C. But maybe my commute isn't long enough to fully warm the engine (10kms or 6-7 miles). Under these conditions, my Target boost had the proper 1.237bar value. I also was able to get the boost a little sooner (0.7 bar@3000rpm @4th gear), but still I was not able to get more than 1.1-1.15 of boost.

uxon

I cleaned the BCS yesterday and reset the ECU. Today I had a test drive and, at least on a short distance, there is improvement in spoolup. On 4th and 5th I see now 0.9-0.95bar@3000rpm which is great
My max boost hasn't improved though. I still strugle to go above 1.15bar (vs 1.237 target). I have compared directly my log from today with the 2 years old log and I noticed some things. The pulls were pretty similar, starting from 2kish rpm with similar IAT, the old log on 4th@3.9 gearbox (probably, the new one on 5th@4.44 gearbox. Comparing directly logged values at ~3000rpm:

So despite of getting more boost at 3000rpm, I have more ignition, less airflow and less engine load. Is the Engine load (g/rev) calcualted directly from MAF values? If yes, then maybe my MAF is showing a little lower than it should. Could this cause me not hitting the target boost? On the other hand my learning view looks ok (no more than 5% anywhere).

uxon

So I cleaned my MAF but it didn't changed anything. I decided to buy a new denso maf. After installing it, I see a little more g/s (up to 10-15 more in higher rpm), but the numbers are very close to what I see in my 2 year old log. And unfortunatelly it didn't change anything in regard to my boost.

I see 2 problems now:

1. I see target boost fluctuations, which are connected with coolant temperature. Basicaly any time my coolant temp raises above 90C, my target boost is compensated. The higher the temp, the lower target boost gets (0,973 bar @ 96C). This is probably how PPP map is constructed.
http://www.romraider.com/forum/viewt...105014#p105014
Does WRX GD has single coolant temeperature sensor? Is the temperature that I log identical to what ECU sees?

2. Even if my target boost is not lowered, I still struggle to reach it. What is worth mentioning, the max value that I am able to reach, changes a bit between pulls. For example, I do one pull and get up to 1,18-1,2bar of boost. A couple of minutes later, doing a pull on the same gear (and nearly identical conditions) I cannot go above 1,1-1,15. I see similar thing about my spool up. Usually at 3rd gear I am able to get up to 0,6bar@3000rpm, but sometimes I manage to get close to 0,75bar@3000rpm.

Any ideas?

uxon

It seems that I am able to reach full boost, but only sometimes... Apart from the target boost coolant temp. compensation, I see some significant inconsistence in my pulls. I have a clear example, 2 pulls from the last night. In both cases car was fully warmed (1h hour of driving before that):
https://docs.google.com/spreadsheets...it?usp=sharing

In the first pull, I got 0,7bar@3000, 1bar@3240, 1,2bar@3500.
In the second pull, half an hour later during the same drive, I got 0,55bar@3000, 1bar@3600 and I am unable to reach target boost, even though I started the pull from lower rpms.
In both cases:
- coolant temeperature was below 80C
- target boost was ok (1,237bar)
The main difference was in ambient temps (first pull was outside city, second one in a city) and because of that IAT was a bit higher in the second pull (17C vs 26C). But still, 26C is quite low, right? I uderstand that when tmic gets heatsoaked up to 50-60C the car is getting weaker, but 26C should not be the case..
The other difference that I can read from my logs is that during my first pull, at similar rpms my Total Timing is lower than in the second pull. But this is probably because at the same rmps I am getting more boost, right?
As you can see my car changes the way it pulls very dynamically, from pull to pull. Why? What else can I check?