Way too much boost!

[Grimster]

Ok got my maf-t installed and figured before I do anything new I'd get a little data logging on a nice trip around town today.

Since my last logging I've installed a 3 Bar map (the 2 bar pegged out under boost), a new Walbro 340 and hotwire kit, and the translator and 3" LS1 maf.

Anyway here's a screenshot it pretty much sums it up:

Yep something like 25psi (WTF?) boost I feel lucky I'm not bringing most of the motor home in the trunk.

Here's the logfile in case you have the PLC software and want to view it, remember to set it for 3 bar map:

http://www.dixiesys.com/LogFile11290701.dat

I have 60# injectors and a fresh Turbotweak chip tuned for 91 as my next thing to do I just wanted to make one change at a time so if something messes up I know what likely caused it rather than making 2 or 3 changes at once and not knowing for sure what messed it up.

Does the chip control the wastegate or do I need to set something to get that boost to something saner say, 12psi max until I get the injectors swapped?

 

[johnnyttype]

wow, did it just start this? maybe a boost line popped off the compressor, wastegate, or the y shaped tee? have had that happen to me a few times!

my boost solenoid is not hooked up anymore, i run a qboost controller instead to control the boost. hth

i believe the chip does control the solenoids duty cycle.

 

[Grimster]

No it's been doing this, I just recently gained the ability to log boost above 14 or 15 psi and found that it was boosting to THIS level. Basically a PO installed an upgraded turbo (TE44 supposedly) and not much else so I'm slowly tuning it and upgrading all the other bits that should be upgraded to support "more than stock" boost/etc. Working my way from the gas tank to the exhaust (if necessary).

 

[johnnyttype]

what kinda wastegate actuator do u have on the turbo? adjustable? if adjustable, the longer u make the rod the less boost u will see, given there is not a leak somewhere in the boost lines plumbing.

 

[notacarlo]

Do you have a mechanical boost gauge? What does it say?

 

[Grimster]

what kinda wastegate actuator do u have on the turbo? adjustable? if adjustable, the longer u make the rod the less boost u will see, given there is not a leak somewhere in the boost lines plumbing.

I guess it's the stock one? Not sure actually.

Do you have a mechanical boost gauge? What does it say?

I have one but it isn't installed yet I did the 5 volt source improvement for the MAP sensor so it has a better 5 volt source which is supposed to help its accuracy quite a bit (I hear). I'll see if I can get the pillar pod and boost and knock gauge installed soon.

 

[Grimster]

Welp it took all afternoon but I swapped out the injectors and put in the new TT chip, I only drove it up the road and back and it seemed to run fine, no sign of gas leaks.

I got into the boost enough to light up my stock boost gauge (with the 3 bar it only lights up at around 7psi) and I saw not a hint of knock retard on the scanmaster. I'll get a logged run in it tomorrow and see how it looks now.

I didn't mention (in this thread at least, I've mentioned it before), the chip it had is an "ANS Stage 1" apparently it's some old as hell chip from a company no longer in business and I've had a couple folks say it was running far far too much timing. I'm betting the injectors and the fresh TT chip will solve a lot of problems and kill more than a few of my gremlins.

 

[Grimster]

Fun day, took it out for a test drive and started smelling gas, it was literally spewing from the FPR, apparently I didn't put it in "just so" and I cinched the o-ring and cut it pretty bad once it warmed up and got soft it quit holding back the pressure and started doing it's own imitation of a sprinkler system.

Had to get my wife to bring my tools and my other FPR that had a good o-ring on it for some quick parking lot fixit.

Anyway here's a few screencaps of the parts where I got on it, it's better but still boosting way too high, guess the ecu doesn't control that like I thought? Time to dig into learning how the boost is controlled and setting my boost way down, I'll try and max it at 15 and work my way up from there if it seems safe. I've got a basic boost controller here on my desk guess I better get it in.

Faith's Stuff :: 87 Grand National :: afternchipandinjectors1
Faith's Stuff :: 87 Grand National :: afternchipandinjectors2
Faith's Stuff :: 87 Grand National :: afternchipandinjectors3

Here's the powerlogger dat files if you want to look it over:

http://www.dixiesys.com/LogFile12020701.dat
http://www.dixiesys.com/LogFile12020702.dat
http://www.dixiesys.com/LogFile12020703.dat

 

[johnnyttype]

the boost is def. too high still. i did the same thing with a fuel pressure reg. o-ring before, cut it and spewed fuel everywhere!

im still thinkin somethings wrong with the vacuum/boost lines connected to the turbo or wastegate out of adjustment. if u want u can take some photos of the turbo/wastegate setup and the vacuum lines coming off those and post them, see i anything is out of the ordinary.

an adj. wastegate should have a jam nut and threaded portion on it, is this what u have?

 

[Grimster]

Yes that sounds like what I have on it. I'll get pictures of the wastegate today, is there any way to "test" the wastegate maybe hooking up some compressed air hoses to it with the ignition on or something?

 

[johnnyttype]

Yes that sounds like what I have on it. I'll get pictures of the wastegate today, is there any way to "test" the wastegate maybe hooking up some compressed air hoses to it with the ignition on or something?

ive never really tested mine but if u were going to i would imagine u would leave the wastegate arm connected to the exhaust elbow on the downpipe and then unhook the boost/vacuum line goin to the nipple on the wastegate. then hook compressed air up to the nipple and gradually increase the pressure until u see the wastegate arm move towards the passenger side fender. this would tell u the needed pressure to open the wastegate and approx. ur max boost.

an easier way to check would be to just remove the small e-clip on the end of the wastegate arm, pull the arm off of the exhaust elbow, and see how much preload the arm has, meaning the distance the arm traveled once removed. since urs is adjustable, hold the flapper shut and wind the wastegate out so u will only have an 1/8" of preload on the wastegate arm when hooked up. this will set the boost at either 13psi or 18psi depending on the type of wastegate, it could be a high boost which has a stronger spring in it.

i hope this makes since for ya, alittle lengthy. :smile:

 

[johnnyttype]

heck i got spare time, here's a pic that may help crap i spelled actuator wrong...oh well!

 

[Grimster]

I just took my cover off and my setup looks pretty much like this.

Should I be able to move the wastegate arm by hand opening the flapper? I can't at least I gave it a bit of a push and it didn't move I didn't, like, manhandle it either.

If I take the clip off and lengthen the arm by turning the end of it around a few turns it should lower boost?

Are we talking "2 or 3 turns" or "a dozen" to appreciably lower boost levels?

Edit: I took the clip off and lengthened the rod about 1/8 inch (more than 1/8 but not much) so that I just barely had to give it a little pull to put it on the flapper. I gave it another try, and yes I can pull the arm out with a good stout pull pull . Gonna go make a quick test drive and see if this has affected my max boost in any way.

 

[Grimster]

So I looked at the hoses, the hose comes out of the turbo, goes to a "y" one hose goes to the solenoid up on the valve cover, and one goes to the wastegate actuator.

So what exactly does the solenoid DO? It can't "control" boost or the wastegate in any way I can see? Does the solenoid bleed off pressure until it's engaged so that the wastegate actuator "sees" no boost until a preset point? Maybe I just have a bad solenoid? Could I simply cap off the tube going to it and see how my boost looks?

Further edit: the hose going from the Y to the solenoid? Split, at the top by the elbow going into the solenoid, and at the bottom by the Y too, totally dry rotted. Possibly the solution to my overboost mystery?

Oh here's a pic edit:

 

[johnnyttype]

that split would almost undoubtly cause the over boost. the way the system works is that the compressor of the turbo sends a pressure signal out which goes to the "Y", then it splits and goes to the wastegate and boost solenoid. from there the pressure may either be bled off by the boost solenoid via the program in ur chip. the more air bled off by the solenoid or pressure bled off, the more pressure will be needed to over come the wastegate and stop the increasing boost pressuer. for example, if the wastegate was set to 14psi and the solenoid did not bleed any pressure, 14psi will be ur limit. if it did bleed pressure, depending on how much, it could be upwards to 20+ psi.

i have a manual boost controller on my car which takes the place of the solenoid. so my vac. line from the "Y" goes to the manual bleeder valve, rather than the solenoid.

hope all this helps, i would replace that split line, sounds like wastegate should be set lower now, generally one full turn on the rod=1psi. take the car for a test drive and ease into it, dont want to join the blown head gasket club if all is well u should boost about 14 or so psi! let me know how it goes!

 

[Grimster]

Just replaced that tube and took her out for a spin, didn't see over about 11 or 12 psi, I had adjusted my wastegate arm as far as it could go while giving literally a pinch of pressure on the flapper, which was a good 5 or 6 turns on the arm, but better lower boost than way way too high!

I am simply amazed this car isn't blown the hell up already, the guy I bought it from I don't think had a clue he was overboosting like this, there was no logging/gauges/etc, beyond what came on it from the factory when I got it. Probably a good thing it was an older fella who probably didn't romp on it too much!

 

[johnnyttype]

awesome, now just move up like 1 or 2 turns at a time til u get the desired boost. careful though when adjusting cause turbos get hot!!!

my friends uncle has a real 87 GNX along with a bunch of other expensive cars and i noticed his boost line had popped off, so i took it upon myself to put it back on for him...most likely it will pop back off again since it is most likely dry rotted, but i figured id save a head gasket or two!

 

[Grimster]

Yeah I finally got a chance to hammer it, I've yet to put the gas to the floor on it, I -knew- something wasn't right on it and have babied it since I brought it home. Got on a nice flat and straight side road with no traffic on it, stopped and just floored it, it built to about 11 or so psi (my logging computer DIED else I'd have a nice log), it started spinning, got a little sideways as it took off with authority, quit spinning around 30 and I let off around 60.

I did see a little knock retard show up on the scanmaster, I don't have an adjustable FPR so it could be I'm seeing a little fuel pressure dropping to cause that(?), I'll get logs and get it all dialed in soon I hope.

Yeah I'll slowly increase the wastegate, and most likely use a MBC but tomorrow's another day, one step at a time, one change at a time, do too much too fast and if it starts acting up you won't know what broked it.

 

[johnnyttype]

Yeah I finally got a chance to hammer it, I've yet to put the gas to the floor on it, I -knew- something wasn't right on it and have babied it since I brought it home. Got on a nice flat and straight side road with no traffic on it, stopped and just floored it, it built to about 11 or so psi (my logging computer DIED else I'd have a nice log), it started spinning, got a little sideways as it took off with authority, quit spinning around 30 and I let off around 60.

I did see a little knock retard show up on the scanmaster, I don't have an adjustable FPR so it could be I'm seeing a little fuel pressure dropping to cause that(?), I'll get logs and get it all dialed in soon I hope.

Yeah I'll slowly increase the wastegate, and most likely use a MBC but tomorrow's another day, one step at a time, one change at a time, do too much too fast and if it starts acting up you won't know what broked it.

the knock could be due to the tire spin, these cars for some reason do not like tire spin, or it could be somethin else causing it to go off like a bad mount or banging exhaust.

def. take one step at a time, can save the headaches! have fun and keep postin if ya got moe questions:smile:

 

[Grimster]

Got a little logging done today, here's a quick screenshot:

Boost stayed right in the mid/upper 14's, I see some knock retard but I wonder if it's false knock, since that second spike is after I'd let off the throttle and it was starting to slow back down?

Here's the log:
http://www.dixiesys.com/QuickSave.12070701.dat

Oh the new updates for the PowerLogger software really make it a lot better, kudos for the improvements to the software!