Armchair diagnostics on boost issues anyone?

[Nick Mann]

Last weekend Jason very kindly tried to make my car quicker. However, no matter what he does to the ECU settings for the boost solenoid, we couldn't make more than approx 0.5bar boost.
He left the ecu flashed with settings that "should see well over 1.0 bar" and left me to it.
Since then I have twice had close to 1.0 bar of boost, both times in low gears when the car and the morning were cold. As soon as the car is hot it won't boost over .5 bar again.

I have boost leak checked it recently and it was all fine. I have also checked the plumbing to the solenoids etc and that was good. So now I guess I have two possible solutions in my head - dodgy wiring/connection to the boost solenoid and/or dodgy boost solenoid. Are any of those more likely in peoples heads, or does anyone have any other suggestions?

[foxdie]

Here's what I have done in terms of mapping, I pulled down his original ROM (7202 Auto-box Non-TCL), made a backup copy of it (always do) and then tried by upping the target load to as far as 125% (with the 40% load adder left as-is), setting the wastegate duty cycle as high as 75% and upping the boost cut limit to around 180%.

Just to make it known, no I didn't just set them straight to these high values (I'm fully aware that's foolhardy) and yes I updated both sets of high octane tables for target load and wastegate duty to the same values. The above values are aimed at those who have upgraded their fuel, intake and exhaust systems, don't just blind copy them into your ROMs people

When this didn't work, we also tried using the same settings on Kens 1.3 ROM, again we couldn't make more than 0.5 bar boost.

We did a few EvoScan logs to test the ROMs, one such log can be found here; http://is.gd/yOOpyq

(All testing was done on away from public roads).

[Wodjno]

My 1st thoughts would be to put the ECU back to standard settings or another stock ECU in. If this doesn't solve the issue, then the issue is not with the remap.. I am guessing this issue did not exist before the remap ? If it is still there, then pull the fault codes if you haven't already. It could be a fail safe mode if it's sensing issues with maybe the MAF or Standard boost solenoid. Again, if you have a spare solenoid or even a basic bleed valve that you can use to negate an issue with the solenoid. Same with the MAF..

Wodj

[foxdie]

I have a spare 7202 ECU I can test with, won't be until the 22nd though, although from the logs you can see the ECU is attempting to keep the wastegate fully closed at WOT until the higher RPMs.

[Nick Mann]

TBH Wodj, I suspect the issue has always been there - I was very down on power at the rolling road day, where my boost was a bit low. They put it down to a failed cat, but I now suspect that the smell they thought was the cat was a slight leak from the t/c seal hitting the downpipes.
It was because of the lowish boost and the low power that I checked for boost leaks and the assorted solenoid pipework.
I was only getting approx 0.5 bar in the couple of days before Jason tried to up the boost, but the gauge was only fitted in the last couple of days before Jason tried to up the boost!

[Eurospec]

You still got the red ended restrictor pipe off the big feed into the throttle body?

Cheers,

Ben.

[Nick Mann]

Yep. All the piping looks stock at the moment. Except for the boost gauge line, which is coming from the back of the plenum, teed off the dump valve control pipe.

[Nick Mann]

I can't work out why the red pipe being missing would stop me making boost? Or could it be blocked? But either would lead to a low pressure at the wastegate actuators wouldn't it? Therefore I should make more boost?

[The Vee]

Have you cheched the wastegates are being held closed ok. When my EBC was turned off (which I didn't know at the time ) I was only making about .2 bar. Adjusted the wastegate actuaters and boost was much improved - infact when the EBC is on it makes higher boosting so much easier now.

[scott.mohekey]

The hose with the red end on it has a restrictor pill inside it that reduces the amount of boost the waste gates see.

[Kenneth]

It doesn't reduce how much boost the wastegate sees, but the fill rate of the pipe work behind the pill. The standard solenoid bleeds pressure off the wastegate line, if the wastegate line is being fed without the restrictor, the solenoid cannot bleed pressure off fast enough to have any real effect on boost.

So check that the red pipe is there and that it does indeed have the restrictor in it (you can feel it easy enough).

Then try removing the restrictor in the boost solenoid which increases the amount the solenoid can bleed.

Lastly, get a 3 port solenoid. If you have a spare fuel pressure solenoid, you can use the solenoid body from the boost solenoid and the rest of the fuel pressure solenoid to get an OEM fitting 3 port. They work great

[Davezj]

This is my thought's on it, from you last last post, nick.

With the wastegate boost pipe disconnected you will be making the max boost the turbos can make.
If you constantly pressurise the the boost pipe to the wastegate actuators the wastegate will be open all the time and you will make the minimum boost possible.
The only reasons i can think of you are not making as much boost as you think are,
1. Turbos are knackered.
2. Boost leak.
3. Boost gauge is not reading the correct boost pressure.
4. Something else is stopping the boost build (not sure what that could be).

Now I am not saying point 1 or 2 are occurring, so that leaves 3 and 4.
3 is an interesting one, a a friend of mine had an ebc and an analogue fitted, the analogue gauge only ever read up to 6 psi but the ebc read up to 12 psi. The Analogue gauge was not plumbed in quite right, it was connected via a T piece that was too restrictive, the hole in the T piece was too small. I replaced this with another T piece and all was well with the boost again.
Again I am not saying this is your issue, as you know all about gauges and boost pipework. So that just leaves point 4.
4. As I said above I am not sure what it is, but you can narrow it down by doing a few test.
Discorrect the wastegate boost pipe and see if you make more boost than 0.5 bar. It should make at least 1.0 bar. This would suggest the turbos are ok and the boost pipework is ok. But not necessarily leak tight. I have a boost leak tester if you want to give it a pressure test it should only take 10mins to do. But if that show you have no leaks then,
That leaves the boost control to check out.

You could fit an MBC as a temp measure to prove it is the boost solenoid that is the issue, by bypassing the factory one completely.
If it does not boost properly with the MBC fitted then it is probable not the factory boost solenoid.
What it is I don't know.

[Nick Mann]

My theory is that the boost solenoid is not bleeding anything, so I am getting actuator spring pressure boost, approx 0.5 bar. The red restrictor pipe makes a kind of sense. And I like the FPR solenoid solution - as I have a spare one of those!! All good ideas - keep 'em coming!

[foxdie]

Providing you don't break it (again ), you can borrow my boost solenoid to rule out yours being faulty.

Also, can we connect 3-port boost solenoids to our cars direct? I know R-Spec sell one for Evo's that is directly drivable from our ECUs without any additional circuitry, if it means responsive and reliable boost control on our cars I'd be tempted to buy one too.

[exevoowner]

check all pipes as i had the oppisite to this and found leaking pipe to gauge that someone fitted with too many joints in it removed bend and all fine,could you have blocked ports on solenoid ?????????????

[foxdie]

check all pipes as i had the oppisite to this and found leaking pipe to gauge that someone fitted with too many joints in it removed bend and all fine,could you have blocked ports on solenoid ?????????????

Actually, this is a good point. When I had a HKS EVC III on my previous VR-4 it used to be very sluggish in boost response, I disassembled the solenoid and found it caked in an oily sludge.

It's entirely conceivable that this has happened to the stock solenoid, if that's the case cleaning it out and maybe fitting an oil catch can would help?

[lathiat]

The first port of call in my book would be to get evoscan hooked up and log Wastegate Duty Cycle (WGDC). Then you can see whether or not it's actually trying to bleed pressure or not. It's possible you are getting false knock or other things causing it to pull the WGDC right in despite the tune.

If the WGDC logs correctly then i'd go with plumbing your boost gauge into the wastegate line then you can monitor that and see whats happening there. Might be worth checking both wastegates are both correctly plumbed in too. It's easy to confuse that pipework. For example it could be a faulty solenoid as you suggest and that'l be clear from the vacuum line.. that'd be my first hardware guess.

TL;DR; Log WGDC to check the ECU is outputting to the solenoid correctly, if it is, then your guess of solenoid/wiring sounds likely to me.

[Nick Mann]

WGDC is what it should be on the logs. Jason set it to 100& and 75% and that was what the logs were showing. But no change in boost.

The sludge will be checked along with the solenoid when I get the chance. Assuming the solenoid is working I will then remove the solenoids restrictor pill and check the red pipes pill is still there. If everything is then still no good, I will remove the pipe from the solenoid to the wastegates - that should see silly boost. If not I'll have to think about wastegates/actuators, if so then I'll have to start physically measuring the voltage to the solenoid.

Thanks for the ideas everybody! When I get a chance to do all that I'll post up the results....

[scott.mohekey]

Taylor was having the same problem, and it turned out he didn't have the hose with the red end and restrictor pill. He fixed it by putting one in that I had lying around.

[Adie]

This sounds like it could be the same issue I'm having. I don't have the car with atm but could someone please take a picture of where about this restrictor pill should be?