help with idle spark, LE5 turbo

[noorjSS]

Hey guys, I just turbocharged my 2.4 and I'm having trouble with the idle. The advance at idle jumps like crazy, maybe I'm missing a table for idle spark modifier somewhere. Thanks for any advice.

Heres a log of just idle.

[cobaltssoverbooster]

can u further describe whats happening at idle?

[noorjSS]

yeah its very jumpy, both lambda and speed and the exhaust blips alot. It is caused by the spark jumping like crazy from high to low. after doing more reading I think it is possibly a vacuum leak. I zeroed the idle adaptive spark control tables and the idle pinned at 1500 slightly rich but didnt jump or blip at all. So i'm thinking that the computer is trying to adjust for the high idle caused by the extra air by going crazy with the spark control. Could this be true?

next step is finding the vac leak if this is. I already disconnected tb/manifold/injectors and cleaned/oiled the gaskets but that didn't help. Also sprayed a little carb cleaner in those areas but it didnt make the idle change at all...

[Freakotec]

Try re-enabling closed loop control and changing all of your timing areas at idle to match like the screen shot I attached and see if that helps at all. This tune also isn't a full maf tune like you're running which could also effect things, but either way as you can see in my graph, I have a steady and solid 15* of timing at idle across the board with no big jumps.... and a fantastically lazy o2 sensor.. lol

[noorjSS]

Thanks man! I'll give that a shot.

I am still kind of thinking it is something mechanical though. I had installed the 60# injectors and went E85 while the car was still NA so I would have less tuning to do when the turbo went on, therefore the tune was good and really shouldn't have changed anything at idle.

edit: just a question, why would you change the DOD tables? I thought it was disabled on our cars anyways

[cobaltssoverbooster]

if you change and and for "some reason" it gets looked at then its what you want it to be.

[noorjSS]

so a new intake manifold gasket didn't end up helping anything. intake manifold vacuum is at a steady 20 inhg unless the timing is making it stumble. does this mean it could not have a vac leak?

[noorjSS]

turbolog1.hpl

Here is another log with a small drive around the parking lot. I've got another idea, could the MAF be in a bad spot? The maf readings are jumping around like crazy, maybe this is what is causing the fueling blips and the following shitty idle. I took the manifold off again and cleaned the shit out of all the gaskets, still no difference.

My other question is would it be alright to start tuning non idle areas? I just don't want to end up tuning over a vacuum leak.

[cobaltssoverbooster]

did you change the map sensor by any chance when you installed the turbo?
full maf with no closed loop control...what are you trying to do man? if the maf is enabled you need to have closed loop enabled or disable the maf completely and go speed density.
if you were trying to blend the maf and ve then you don't quite have the concept of the two modes figured out yet. once you understand the two modes you will understand exactly why what you have going on there isnt really working for you.

[noorjSS]

I did change the map but I suspected a vac leak there so I switched back to the stock map. full map open loop is how you tune the maf, am I incorrect? this is how I was taught. I can put it back in closed loop though.

[cobaltssoverbooster]

if closed loop is off there will be no fuel trim correction based off of the 02 sensor. you have to turn closed loop on and get the 02 sensor reporting in order to get trim values for adjusting the maf.
ill look into an old post and link it when i find it

[noorjSS]

Oh yeah I understand that, when the tune is finished I will also be running in closed loop MAF. But until I get the proper maf calibration values I was under the impression that closed loop could incorrectly skew those maf calibration values, therefore I am tuning the MAF in open loop.

So could those erratic MAF readings be a sign of an inconsistent vacuum leak? This would make sense to me because this vacuum leak would be causing the rich/lean spikes, which would then create the inconsistent idle speed and subsequent adaptive idle timing changes. So in other words:

Vacuum leak--->MAF readings jumping/erratic--->crazy rich/lean spikes at idle--->highly varying idle speed--->adaptive idle making crazy changes to spark timing both positive and negative--->shitty idle

correct?

Really just need this car to start working again

[noorjSS]

switched manifolds last night to a saab with a better gasket, still nothing. put rtv on the stock intake manifold to try to seal it better, still nothing.

I'm running out of ideas

[noorjSS]

Last night I tried another manifold again, and ended up blocking the factory pcv port on the head going into the intake manifold. So one of my friends told me to try just start tuning, that the maf being so far off could cause this. I started maf tuning and it did start to get better, but I'm still not sure if I'm tuning over a vac leak or not. Here is a recent log

turbo2.hpl

I swear I had done 5-6 iterations of the maf previously and it wasnt anywhere close to this, maybe that pcv check valve was bad

[cobaltssoverbooster]

if your really concerned about a vacuum leak buy a can of parts clean or a propane torch.
Vacuum search Method 1 (parts clean): parts clean is flammable so stay away from the header and turbine housing while its running. put the straw in the sprayer and let the car sit at just off idle so it smooths out. start your scanner with the computer near the engine bay so you can watch the 02 sensor signal. spray cleaner around the manifold gaskets 1 at a time and if there is a leak the vacuum in the intake will suck the cleaner in and burn it. you will hear a slight exhaust tone change and it should rev up some. you can verify the leak in the scanner as it will distort the 02 signal since it fuel added that wasnt commanded by the ecu. its an old school method and works well.

Vacuum search Method 2 (propane torch): propane is violent so spraying around the exhaust is not as dangerous but still highly not recommended. assemble your torch and let your car run as stated in method 1. start your scanner with the computer near the engine bay so you can watch the 02 sensor signal. turn your torch on to a steady slow flow to make the tank last and not be wasted. (*DO NOT LIGHT THE TORCH*) as stated before put the nozzle as close to the gasket surface as possible and follow the entire gasket around 1 gasket at a time. the engine will suck the propane in and burn it causing a slight rev and tone change. you can verify the leak in the scanner as it will distort the 02 signal as stated before. method 2 has been around just as long but not every one has a portable propane torch laying around. (*if you have a map gas torch i strongly advise to NOT use map gas as a substitute for propane as it burns hotter and more violently than propane.)

if you perform either or both methods and you hear no change or see no 02 sensor changes as you go around the gaskets then your tune is the problem.

if you revert back to tuning i would suggest disabling evap when base tuning as it can add fuel vapor when active and you will be adjusting for vapors being present instead of what only the motor requires. we do this on the lnf too helps steady results.

[noorjSS]

sorry but I'm not familiar with the evap table. I can just unplug is and cap the vacuum line correct?

Thanks for all your help man, I appreciate it

[cobaltssoverbooster]

disconnect the solenoid and set the code that pops up to "do not report". this will prevent that solenoid from working and ecu from thinking about it.

[noorjSS]

thanks man, mind looking at another log once I get it dialed in a little more? lol

[cobaltssoverbooster]

You would get more results posting it here for the community to look at. If you post I will be one of many to review

[noorjSS]

So I know the LE5 can't be push nearly as hard as the LSJ or LNF engine, both from higher compression and thinner/less supported cylinder walls. My question is does a 10psi tune with 12* ramping to 17* of timing up top (E85) with a .82 lambda PE sound "safe"?

I know every engine is different, and I will not be able to get any completely "solid" answers but I would just like opinions on the subject of the LE5's strength