car falls on its face under boost

[green97gstspyder]

Here is my issue the car ran fine without building any boost and now that I fixed those issues when it builds boost it loses all power. logs are posted below. I was thinking fuel cut but I am not sure exactly what that feels like since this is my first turbo car. this seems to occur around 4000rpms when my hx35 spools. I am also running a tial waste gate with a large green and small red spring

 

[habitatguy187]

Just do a boost leak test to make sure. I usually check my car at least 3 or 4 times a year.

 

[green97gstspyder]

Found some small leaks and fixed those but now i have a big one on the throttle body shaft. Goes to 20 psi and drops rapidly. I just ordered mil spec seals. Hopefully this will help with tuning

 

[My1GLaser]

You haven't touched your fuel sliders at all! You are running stock AFR maps which are about 9.5:1. Your front O2 suggests this also. Basically you are pig rich. Do you have a WB? If so, then target around 11:1 to start and see how that works. Without a WB you are going to have to tune with the front O2 and knock threshold which isn't quite as easy. Shoot for .90V on the front O2 and see how that works.

Also, 6* of timing isn't going to get you anywhere fast! You have a lot of tuning to do!!! I would shoot for at least 15* personally...

 

[green97gstspyder]

Should i do 15 degrees at idle or slowly build up to that? Wb is on my next main thing to buy. Ive got almost 7k in this build so im a little over budget and still need tires. Im trying to get by for now so i can drive it safely and get the final tweaks later when my wallet heals .

Doesnt the front o2 fluctuate up and down? How do i get it to stay at. 90v?

 

[My1GLaser]

When you swapped a 6 bolt did you rebuild it or are there still stock CR pistons in there? If you are on stock 1g CR then you should load a 1G timing map and adjust from there. I will be more help if that's the case, cause I don't know what the 2g curve looks like without doing some research. That would also explain why it falls on its face so bad. 2Gs are 8.5:1. 1Gs are 7.8:1. A 2g curve in a 1g has to be like a mule pullling a cart!!!

When I say shoot for 15* I mean total ignition timing advance, just so we are clear. (not as in add 15* with the sliders) So 15* on the DSMLink graph is what you should be seeing. Personally, I would go more aggressive, but it depends on how old your front O2 & knock sensor are and what fuel you are running. It will be critical that they are functioning well.

Your front O2 only oscillates during closed loop operation. Once certain conditions are met, you switch to open loop and the front O2 reads a constant voltage. Look at the Front O2 voltage in the log. I would pull all the sliders down about -5-10% and see if that gets you there. You will probably need more. I think I remember pulling as much as 15% to get the AFR I wanted when I ran V2 back in the day....

 

[habitatguy187]

Look at the Front O2 voltage in the log. I would pull all the sliders down about -5-10% and see if that gets you there. You will probably need more. I think I remember pulling as much as 15% to get the AFR I wanted when I ran V2 back in the day....

OP said he still has a huge boost leak, which will also cause him to run rich. He needs to fix all leaks before going and pulling fuel out from a WOT tune.

Found some small leaks and fixed those but now i have a big one on the throttle body shaft. Goes to 20 psi and drops rapidly. I just ordered mil spec seals. Hopefully this will help with tuning

This will definitely help. Under boost you're leaking out air that the ecu has already read AND already added fuel for, throwing off your a/f ratio.

 

[green97gstspyder]

When you swapped a 6 bolt did you rebuild it or are there still stock CR pistons in there? If you are on stock 1g CR then you should load a 1G timing map and adjust from there. I will be more help if that's the case, cause I don't know what the 2g curve looks like without doing some research. That would also explain why it falls on its face so bad. 2Gs are 8.5:1. 1Gs are 7.8:1. A 2g curve in a 1g has to be like a mule pullling a cart!!!

When I say shoot for 15* I mean total ignition timing advance, just so we are clear. (not as in add 15* with the sliders) So 15* on the DSMLink graph is what you should be seeing. Personally, I would go more aggressive, but it depends on how old your front O2 & knock sensor are and what fuel you are running. It will be critical that they are functioning well.

Your front O2 only oscillates during closed loop operation. Once certain conditions are met, you switch to open loop and the front O2 reads a constant voltage. Look at the Front O2 voltage in the log. I would pull all the sliders down about -5-10% and see if that gets you there. You will probably need more. I think I remember pulling as much as 15% to get the AFR I wanted when I ran V2 back in the day....

The 6 bolt i swapped in has forged rods and pistons but i forget the cr on them.

As far as timing goes at what rpm should it reach 15 degrees? If i remember i am around 7 at idle right now and it jumps to 19 or maybe even in the twenties in the upper rpms. I do understand what you meant by total timing but thanks for the heads up though

 

[My1GLaser]

Definitely try and determine the CR.

How fast does it leak? Time it. I shoot for only 1 psi drop every second at the max. That's above 30 psi. 20 psi and below it drops 1 psi every 3 seconds on my car. Nevertheless, you are still running stock fuel maps which are around 9.5:1.

As for timing, I shoot for peak timing shortly after peak torque(peak cyl pressure). My HX hits peak torque around 5k. So I'm at 21* by 5.5 k and up it another two degrees by redline. I don't dip below 18* even thru the peak torque area. But I'm running 60% E85.

 

[green97gstspyder]

It leaks rapidly 23 psi in probably 20 seconds or less. Im running on pump gas no e85. Im thinking the cr is close to 8.5 to one. Whats your timing at idle? Would moving the sliders help with the fuel map.

 

[My1GLaser]

Like I said, if it leaks 1 psi per second then that's not a bad leak IMO. At 20 psi and below, I target 1 psi drop every 2 seconds. I BLT to 40 psi and it drops 1 psi per 1-1.5 seconds, so at 20 and below I am golden.

Some of the leak can be going past the pcv valve and into the VC and pressurizing the crankcase or coming out the breather hose side of the VC. It can also go past an open intake valve and into the cylinder and past the rings. Air also pushes past the oil seal in the turbo and down the return into the oil pan and you can sometimes hear oil gurgling. All this is normal, but still makes the pressure drop. It also depends on if the car is cold or at operating temp. I do compression tests and BLT at operating temp as much as possible. I would put one of these http://www.usplastic.com/catalog/item.aspx?itemid=23369&clickid=redirect between the PCV and intake!

Moving the fuel sliders will change the fuel map. IIRC, they are only active at WOT, so your closed loop operation would still be stockish.

20-25 psi on an HX35 and 8.5:1 CR and pump gas should be a good combo. Some people run a modified Evo timing map in that situation. I have always run a modified 1G map, even on pump gas at 28 psi on my 18g. I still targeted 18-19* timing back then with no knock, but my car loves timing even with 9:1 CR.

My timing at idle is around 20-21*. It dips to 17 & peaks at 24 as it fluctuates. I honestly never look at that though...

 

[green97gstspyder]

My main issue with my blt was i couldnt build above 23psi as all air was rushing out the shaft seals. I will post back as soon as i get those in and try to move some stuff around on link. I hope they'll be here by tomorrow.

 

[green97gstspyder]

Ive gotten my boost leaks sealed up except for the lines that go onto the top of the throttle body. I put zip ties on there which helped some but there is a small leak. It takes a little over a min to loose 30lbs.

Just waiting on new air filter now to mess with the tune.

 

[KeelesKustome]

I'll explain if needed.

Otherwise close your sparkplug gap either .019-.023

If your BL's are fixed this should fix yor driveability. I've been their.

Also buy a wideband immediately to protect your $7,000 investment. Otherwise don't boost. (that was the best advice ever given to me as well.)

 

[green97gstspyder]

Ok will do i believe plug gap is around. 030 right now. Ill close them up to around .020. Is this for high boost applications?

What o2 sensor is recommended. Ill most likely run it as the rear sensor. What's involved to wire it in? Will i need the gauge or can i get just the sensor?

 

[talon2gbuyer]

Most widebands come with the harness (at least my lc1 did) and you plug and play, others you need to splice into the ecu pin so your ecu can work with the more accurate numbers the wideband gives. Also plug gap should be around 25-27 but .020 is ideal enough. Our cars aren't all that picky as long as the gap isn't .032 or above, then it starts running like crap.

 

[green97gstspyder]

Where did you get your wideband from and is the harness year model specific or does it work on multiple cars??

 

[KeelesKustome]

I also run the lc1 anilog gauge, also wired into ecu for logs runs.

the kit i baught and have no issues.

EXTREME PSI : Your #1 Source for In Stock Performance Parts

Depending on your battery strength and ignition age, with alot of airflow your will experience spark blowout, it feels identical to fuel cut, or it will just fall on it's face and pick back up like a hickup. tighten that gap to make sure it's not your problem. I run a .017 gap and have no idle issues. I need to purchase a amplifier for my situation to run a larger gap. It's a hit or miss with any car, as they are all different.

If you have no more problems widen up your gap .01 degree and make a pass and drive it for a day, if all is well keep repeating the process, untill you have blowout and go back to previous for the best running gap.

 

[green97gstspyder]

today I took it for a drive and it is boosting fine and not cutting out. the shaft seals are no longer leaking and plug gap is around .022 and it drives ok. when this turbo spools up it really pulls. I am going to try to get a wideband here in a week or so but i couldnt wait that long to see what i could get the logs to look like. after playing with the biss screw and the timing sliders and deadtime this is where i am at driving on the first log. the first good bit of this log is sitting in the driveway waiting to warm up and i had to move the biss screw a little. i even did a maf comp adjust as well. i am just posting the second log to be able to view where the final settings were when driving under the first log after i changed some things since i forgot to reset the capture before i left the driveway. i am a little concerned on the afr. what is a good way to try to bring it down some so i can drive this without hurting it until i get the wideband?

 

[inspire]

More than likely it is because of one of the 4 following reasons.

1. Boost Leak
2. O2 Sensor Bad
3. Mass Air Flow Sensor
4. Non Recirculated Blow Off Valve

Boost Leak: My car when it had a boost leak was misfiring at idle I also lost almost all power under boost. Car was very hesitate under heavy throttle.

02 Sensor: My car that was one of the first things to go wrong with the car when I bought it. Took it on highway to get into it a little bit and the car felt like it hit a brick wall under boost. Plugged in the scanner and found the exact code. Fixed it, ran like a champ.

Mass Air Flow Sensor: Faulted Mass sends improper readings to the ecu under acceleration. Car reads something is not right and it fuel cuts to prevent damage. Feels like car is going nowhere under heavy acceleration and at top of power band.

Open Vented Blow Off Valve: Air is escaping, acting as a giant boost leak. Mass picks up the lack of air from the Ecus configuration and sends it into a safe mode. Recirculate the valve, or pay the penalties.

Hope something in this could help. Best of luck!