ECMlink LinkV3: BoostEst and boost gauge not equal {attached log}

[MY1GDSM]

I think he was referring to a stock rear O2 sensor, which would be used for emissions rather than engine control.

If they had one... .

 

[Calan]

I'm saying test pipe to cat back because my wb is in rear o2 location, right after this flange.

Gotcha.

Still looks like there is a small exhaust leak somewhere between the front O2 sensor and your wideband though.

If they had one... .

Huh? You lost me.

EDIT:

Oh wait... "they" = op I take it?

 

[razrman8]

I posted that picture to show where it was, note the slight carbon mark. It was minuscule, but I could definitely see it throwing off readings. I understand what you are saying. I never understood why my wb would read so lean at idle, but during cruising be alright.

I'm in the process of fixing any exhaust leak that there is, leaving no room for error.

FOR TUNING? The rear o2 is the wideband and the only thing that realy matters as far as any real tuning IMHO... and the reason I asked. Yes the front o2 is controlling the car. But it seems for the most part to be cycling hence why I asked again if there was a leak before the W/b

If you take a look at the log you can see where at cruise the W/b and N/b o2 are switching at the same point this is not happening at idle.

Calan The raw voltage looks about right so I would think that the Wideband is reading right...

OP there are a few more things I don't see in the log that would be good to keep track of

LTFT low
LTFT mid
LTFT High (yes I know 2g's don't have one But you can turn on it's function)
Battery
ISCPosition
Baro
LrnIdleadjust
TPS Delta

I'll be sure to get these values captured for further examination.

That 500hz spike in your log is probably an anomaly. That airflow point is close to where you would be switching into open loop, so the MAFComp tool probably just picked up one or two random values in that area. I would zero it back out until you get more data at that point.

Will definitely be zeroing that out.

 

[razrman8]

Bigger than I expected.

 

[Calan]

I never understood why my wb would read so lean at idle, but during cruising be alright.

Part of that was probably airflow calibration, but the exhaust leak definitely makes a difference.

When pulses are moving through the exhaust pipe, fresh air will actually get pulled in through leaks between pulses. This is what screws with your wideband; O2 sensors measure oxygen content (duh , so when fresh air gets pulled into the stream in front of them they read a lean condition.

How much air gets pulled in is dependent on a lot of factors, including the velocity of the pulses moving through the pipe, temperature, expansion rate, etc. The effect it has is also controversial and debatable, but it can definitely cause problems.

Bigger than I expected.

A few inches in front of the wideband sensor? Yeah, that should do it.

 

[MY1GDSM]

Figured so... .

 

[Calan]

Keenan, go back and read the last paragraph of post #23.

I'm going to make it bold for future readers of this thread. We tell people this all the time, and like clockwork, we get the same type of reply: "Boost leak test is perfect, no boost/vac leaks anywhere. I also checked everything 3 times and there are zero exhaust leaks"

And then we tell them to go check again.

 

[razrman8]

Okay, okay, you got me. But DON'T think I was just saying it was not leaking. I had just put these new gaskets on last week and thought they had sealed. In my defense, was on the top side. Nonetheless, there's no way this thing will be able to leak after I'm done with it.

 

[Calan]

Common mistake that we've all made. We all tend to assume too much, and it just doesn't work in this case.

"No boost or exhaust leaks" has to mean "Zero boost or exhaust leaks...nadda...zilch...none.".

 

[razrman8]

Chyeah. Definitely got that now.



To anyone in the future reading this thread, until you've taken apart your exhaust, or at least examined all angles of view possible, don't assume you have no exhaust leaks. Prime example, gaskets were changed last week and there were leaks. Be 100% sure, then check again.

 

[Calan]

Same goes for boost/vac leaks...even more so.

That little breather that everyone likes to hang off the end of the VC causes more problems than just a film of oil all over the engine bay.

 

[razrman8]

Haha. For sure. No doubt. I need a can

 

[boost97gst]

I gotta say, what really threw me in this thread was how to setup fuel trims. I had been using mafcomp AND deadtime. I opened your last log and saw 0 deadtime! And your combinedfts looked good?? Thats awesome. Im having problems similiar to yours and ended up nearly doubling my deadtime. Im going to retune using this method and zero it out and see what i come up with.

 

[snowborder714]

That's because the deadtime values were set in the InjBatteryAdj DA table.

 

[huafist]

I recommend this thread be stickied. Damn, craig, u are the man. Ive learned more in 3 pages than in hours of reading on link.

Agreed. Every car I've ever tuned has been SD, and the only DSM I ever tuned on ECMLink was in SD. I've never done a MAF car before, and the DSM I just picked up is running 'Link 2.5. Reading this thread has helped my understanding of it tremendously.

 

[boost97gst]

That's because the deadtime values were set in the InjBatteryAdj DA table.

hey, i have pte 1000cc, can i use that injbatteryadj settings in my DA? Cause it seems to work very well for this guy.

 

[Calan]

No, you'll need to find the values specific to your injectors.

 

[boost97gst]

craig, any chart to come up with those numbers? Theyre pte 1000s, actual flow is 940, global is iirc -52%
deadtime 440

 

[razrman8]

Alrighty Craig, here is the most recent idle log I have. Had a car meet down in the city tonight, so I tagged along my laptop and took some logs. This is an idle log after about 4-5 MAFComp adjustments. My fuel trims seem a little far away from 0. Fixing that leak definitely helped bring my WB and AFRest closer together. Kinda nice seeing a reading at idle.

 

[Calan]

craig, any chart to come up with those numbers? Theyre pte 1000s, actual flow is 940, global is iirc -52%
deadtime 440

Every individual set is different, but you might search through this thread and see if Tom has tested a set of those. That would give you some good starting values.

Start your own thread on it and maybe someone with a set of those injectors could provide you with what works well for them.

Alrighty Craig, here is the most recent idle log I have. Had a car meet down in the city tonight, so I tagged along my laptop and took some logs. This is an idle log after about 4-5 MAFComp adjustments. My fuel trims seem a little far away from 0. Fixing that leak definitely helped bring my WB and AFRest closer together. Kinda nice seeing a reading at idle.

That's actually not that bad. Trims could come down a tad, but you are fairly close. Definitely looks much better than it was.

Try raising the 0hz slider to about 28%, and drop the 50hz slider to 25%. You are idling at lower than 50hz, so there is probably a little overlap there.

BTW - Why is your car running so hot? Look at your coolant temp.

You should always log battery voltage, and you should add ISCPosition as well...although your idle looks pretty solid.

 

[razrman8]

Oh believe me, I know she runs hot. I no longer have the ac fan, exhaust melted it. So I am only running the main fan. To me, I don't think that it should get that hot with just one fan. But sitting and idling for a period of time, it doesn't like. I am going to check coolant levels tomorrow after it has cooled. If it's not that then its got me stumped, though I think it may be the level.

 

[Calan]

You're up around 230*, which would be pushing my comfort level...especially for any length of time. While idling that hot, temperatures can skyrocket in just a few seconds if something happens to a fan relay or something.

 

[razrman8]

Hell, they skyrocket now. I don't like it one bit either. Something has to be done to keep it cooler while idling. I am considering front bumper vents as well to keep the car cooler while cruising.

 

[Calan]

I would be making that temperature issue a priority. One of these days you'll be sitting in a parking lot and reviewing a log while idling, and when you start streaming again the coolant will suddenly be over 250* and climbing. Ask me how I know.

Knowing how to tune a car with a warped head is useless.

 

[razrman8]

Gahh!! Don't say that Craig! You're gonna put me under the curse!