openecu.org

I've recently jumped into re-tuning my 05LGT. I'm no stranger to ECU tuning in general, as I've modified my 1st gen Integra's ECU a number of times. However, this is my first shot at an OBD-2 ECU.

The problem I'm having is with low boost and oddly low WDC (logged). My Initial duty cycle is now at 85% with a max at 90% (high, I know but I started out lower but couldn't hit targets).

In looking at the logs for 3rd gear pull, the WDC starts out at 86.67% at 2100RPM (good so far) but begins tapering DOWN to 30.2%@2722-3372RPM. After 3372RPM i starts rising (slowly) to 85% by 5500RPM. Nowhere in my maps does it have anything as low as 30.2% and it's killing my boost to 10PSI max (turbo doesn't recover well after WDC begins rising again). It does seem to learn around the low WDC somewhat, but it will probably take a long time to get to the desired 70-90% to achieve target boost of ~17psi. The wierd thing is that the boost is pretty flat once it hits 10psi.

This doesn't feel like a boost leak, as I've already had the vacuum line under the intercooler blow off. It idles great and is smooth over the rev range, just not as powerful as with the MBC set at 16PSI.

I wanted to go back to ECU control to get around the goofy overboosting that comes with a MBC and to allow more fine control over boost.

The only difference over the stock map is that I used the A2WC522N as the base code then made my changes. My ECU is probably a pre-521N map base, so this was a considerable upgrade.

I also have non-Zero entries in the Low Speed Boost Compensation tables, per the OSECU Stage 1 map. I haven't tried it without any entries in those tables to see if that quells the problem, but I don't see why that would cause a problem.

I've attached a graph showing WDC and boost in a 3rd gear pull. Any ideas? Do I just have to wait for it to learn?

Can you post your ROM?

Here's the rom.. Although, now I tried the a2wc522nPERFrv494oct.hex from osecuroms.org and it killed my ECU.. Er HC (CAN Error), no communication, no start despite a successful flash. Hopefully Colby can resurrect it for me.

Well, it looks ok at a glance, but I would start by reverting back to a completely stock calibration.

Was that log on a warm engine?

Freon wrote:Well, it looks ok at a glance, but I would start by reverting back to a completely stock calibration.

Was that log on a warm engine?

That part of the log was when the engine had long reached temp. It is perplexing. I'll experiment more when I get my ECU back up and running.

I'm having the same problem - did you find the solution?

Not yet. It appears that the ECU is learning up to target boost, but extremely slowly. I'm going to change the map to allow larger adjustments when the boost error is high.

The 522N is an manual tranmission rom. You do have an MT, right?

Everyone seems to be having this problem.

groff on legacygt.com reverted back to 510N. He got better WGDC (no longer pegged at 30.2) but it's still way below initial WGDC target.

racerdavenow is also having this problem. However, his car came stock with 521N so I don't know if reverting to 510N for him would be okay or not (there's two extra DTC codes plus possibly other stuff).

Hopefully, we can get to the bottom of this shortly.

I would try modifying the "wastegate duty A (rpm)" table, which is an alternate initial wg duty. This table is also compensated by the usual WG compensation tables (except it uses a different IAT compensation - D, IIRC).

Just Wastegate Duty A (RPM)?

Not B or C as well? As Mike said, I have 522N on right now and it's pegging the WGDC at 30.2 between 2200-3400.

I current have the following on Wastegate Duty A (RPM), Wastegate Duty B (RPM), and Wastegate Duty C (RPM):

2000 -- 45.0
2800 -- 45.0
3600 -- 47.5
4400 -- 50.0
5200 -- 50.0

And it's still pegging like I mentioned earlier.

--Dave

A for MTs, B/C for ATs. There might be something else going on here. I'll take a look at it when I get a chance.

I would suggest using the rom that was originally on the car for those with this issue to rule out a mid-year hardware change.

EDIT: try bumping up the wg duty (rpm) table(s) up to 60%-70% to see if it has any impact at all.

Ok... I'll start with jacking up the 2 lower WGDC values to 70 or so.

My car came with 521N, so I thought the only real change for 522N was to fix the cruise control from randomly turning itself off (with no codes thrown). I did experience that.

521n to 522n would probably not be a problem. I seem to remember Cobb having different AP maps for 2005 and 2005.5 LGTs, which might mean that later revisions may not be designed for earlier models.

merchgod wrote:I seem to remember Cobb having different AP maps for 2005 and 2005.5 LGTs, which might mean that later revisions may not be designed for earlier models.

The opposite is true.
http://www.thel7.com/TSB/11-75-05.pdf