ECMlink Loss of spool & mid range power (before & after logs included)

[soldave]

Haven't got on the gas in a couple of months in my car, but finally got around to it today. First run it just felt a little sluggish for some reason. so I turned round, plugged in ECMLink and did a logged run.

Both runs were from 2,000rpm at WOT. Injector duty is way down, boost is way down, torque and hp figures are much lower. and strangely in the new log I'm getting quite a bit of knock around 5,000rpm which I wasn't before. The only change I've made to the engine since the earlier log was replacing some worn out injector seals (that were leaking badly) with brand new viton ones. And I've done a tiny bit of map smoothing, but nothing severe.

I'm gonna go with a boost leak test this weekend I think, as well as check my XS Power wastegate (surely they couldn't go wrong!). The logs don't seem to show anything to me that might be wrong.

Can anyone else spot anything that sets alarm bells ringing?

 

[soldave]

Met up with by far the most knowledgable guy, car-wise, on the island. Checked the turbo for shaft play today and it checked out perfectly. Also did a relative compression test on the engine using a computerised oscilloscope and the engine's in perfect condition. Checked the coils using the same oscilloscope and saw that one coil was slightly weakened (amperage wasn't building up linearly, and it hit the 7.5amp limiter at the coil, signifying it going out), but the plugs and everything else in the ignition system checked out ok. So that's the engine and ignition confirmed good. I'll need a new coil pack at some point soon, but that can't be causing the problem I'm having.

He then looked at the logs I'd got, and specifically what happened when boost started to build. In the most recent log, the boost curve is pretty much a straight line, and boost is not ramping up as it did before. It's just slowly but steadily building up, as it would do if one or more wastegates were opening up before they were supposed to (due to a poor spring, maybe?). It could be the boost controller, but you can see after boost has built up it oscillates, which probably shows the controller solenoid is working to limit the boost.

So I'm thinking I'll order a pair of 1bar springs, replace them and go from there.

 

[soldave]

Just for the record I did a boost leak today. Didn't spray any soapy water around as a boost leak this big was going to be audible. Pressurized the system to 1.2bar and no leaks whatsoever, so as expected that side of it is good.

 

[snowborder714]

You changed a fair amount, so I'm not positive what might be the cause. I see the after log is running higher timing (2° at the 4k RPM) but also richer. That might contribute to the slight loss of spool?

Either way, you still have a lot of tuning to do. Is this something you know you still need to accomplish or are you looking for help with that as well?

 

[soldave]

Well it might be "slight" in your books, but I've lost 5psi at 4,800rpm, and now the boost doesn't ramp up in a curve as in the before log. It now just comes on very slowly and steadily, and the boost curve has become a straight line. Would just changing timing affect the whole shape of the boost curve?

AFRs are about where I want them to be. Any leaner and I start to get knock (the temperature and humidity is a killer here) and I'm only on pump gas (no E85 in the country). If I can get the spool back to where it was and remove the knock at 5,000rpm (probably again due to the increased temperature since the first round of testing) then I'll probably be good. Note that intake air temps were 8-9C higher at 4,800rpm; no small amount.

 

[snowborder714]

Your airflow is off though (in regards to more tuning being needed). If you look at WBFactor during your pull (or just display AFRatioEst and your wideband), you'll see they vary a good bit. These should be as identical as possible.

I would suggest getting everything in order and then we can start playing with timing and/or AFR's at the onset of boost to see how much we can gain back.

 

[soldave]

So you're meaning play with my SD VE tables?

 

[snowborder714]

Yup. There's an SD WOT tuning link in this sticky that you can use to make things easier.
http://www.dsmtuners.com/forums/ecmlink-tuning-help/443307-helpful-links.html

 

[soldave]

Thanks for the link.

But surely I need to find out why the boost curve has changed so dramatically before I start tuning again, right? If not then once I get back to where I was the tune will have to be re-done.

I have also tried throwing my old maps onto the car and have a similar slow spool without any ramping up. So I'm almost certain it's not the tune itself, but the fact the boost curve has changed so dramatically is a sign that something else is at fault.

I have new wastegate springs coming in the next few days anyway so I'll see if that has any effect, but will read that SD link later