Boost dropping from 25 psi to 12 psi on the 2-3 shift... need to help!

[turbov6joe]

Boost dropping from 25 psi to 12 psi on the 2-3 shift... need some help!

I'm still loosing boost on the 2-3 shift and can't seem to figure it out??? Basically it drops from 25 psi to around 12 psi then slowly climbs back up to 25 psi the rest of the pass. Someone suggested it might be the HD WG actuator, another thought it might be an overly rich condition due to my LOW EGT's (1350º's), and another thought it had something to due with the tranny taking SO long to make the 2-3 shift (stock/sloppy tranny), but why not on the 1-2? I'm using a new TE44 with a mildly hogged out 90º elbow and a 2.5" ATR DP. Do you think that it has something to do with the boost backing up in the elbow/DP at this high of a boost level? If I lower the boost to say 23 psi, the problem is much less pronounced if not at all. It only seems to act up at the 24 + psi level and higher??? Although not a huge problem, I am loosing a bit of ET and MPH while the boost is taking it's ever loving time to build back up to my set level... As a side note, I'm seeing just a small amount of KR (low single digits)on the 2-3 shift, but surely this is not enough for the ECM to pull out that much timing an thus cause the boost to drop off as it is??? Any other ideas at all?

TIA

 

[TurboBob]

what scantool are you using?

What chip are you running?

Bob

 

[turbov6joe]

Scanmaster 2.0

 

[TurboBob]

You didn't mention the chip you have, but the symptom sounds like MAF dropout.

Dropout can reset the wastgate dutycycle to zero, after which in has to climb back to it's programmed setting.

It can be seen on Direct Scan, so if you have access to DS thru a friend you can check it.

The quickest way to fix it would be to use a bleeder valve or other device to control boost.

It can also be programmed out in the chip. So you can contact your chip programmer for an update.

Bob

 

[turbov6joe]

I'm using a slightly modified Joe L. race chip. Funny thing you should mention the MAF. Last week at the track, the guy re-programming the chip noticed that the MAF seemed kinda low at idle (3-5 gps), but it would climb to 255 at WOT no problem. What exactly do you mean by MAF dropout??? If the MAF stays at 255 throughout a WOT pass, then this shouldn't be existant, correct? If there is indeed MAF dropout, why not in 1st or 2nd gears? If you could explain in detail what you know about this MAF dropout and how it effects the WG DC, I would be greatly appricitive.

 

[turbov6joe]

BTW, I forgot to mention that I am using a bleeder in conjunction with the WG solenoid, I have the bleeder right before the solenoid's "in" side. I seem to recall trying to take the WG solenoid out of the picture, using the bleeder only, and noticing no change.

 

[TurboBob]

If the MAF signal goes too high the internal counters in the ECM miscount and cause the MAF reading to drop very low for a split second. It's way too fast to catch on a ALDL scantool. It can be seen on DS.

High gear puts more load on the motor and draws more air, the reading may say 255 but the actual flow is much higher.

The dip in MAF reading resets the wastegate logic which then has to climb back to the programmed setting.

But, if you've run bleeder-only and still have the problem then it must be something else.

Regards,

TurboBob

 

[REDS HOT AIR]

that is backwards of the norm..

most have problems with boost jumping up on shifts..

really sounds like when the tranny slips between gears its floating the valves

 

[turbov6joe]

If it was floating the valves, wouldn't it do it on the 1-2 shift as well??? Before I crashed last night, I was thinking further into this little senario and came up with something else. I'm perty sure Joe L. has a 255 MAF lock programmed into this chip. If this is true, then shouldn't the MAF dropout idea be null and void as the ECM thinks it's at a perfect 255 throughout the pass?

 

[Ormand]

Valve Float..

You mentioned it taking a long time to make the 2-3 shift. That could be why it floats the valves on that shift, and not on the 1-2 shift. Should be able to see a difference in rmp with a Turbolink, or directscan file. That would also help you see what's causing the low EGTs.

 

[turbov6joe]

Ahh, good observation, I forgot that I mentioned that in my first post! Yes indeed the tranny takes longer on the 2-3 shift, but it has never taken long enough to hit the rev limiter or such. I think turbobob has hit something here. 1, I have a suspicious MAF sensor. 2, I had a lean pop on the last pass this happened.
3, I'm only using a Scanmaster, so I'm not seeing all the info I need to effectively diagnose this problem. My pop has a DS, I'll if I can sweet talk him into yanking the ECM and all for me to use to diagnose the situation. Looks as though my buddy (the chip's programmer) will be comming over today, maybe we can get this worked out then??? First we're gonna try leaning it out and getting the EGT up to where it needs to be. Then we'll play with the MAF stuff and see what happens. I hate to put the car to sleep for the winter knowing it's not in top running condition for the 2003 race season...I'm anal like that!
Turbobob, do you have a private email address you can send me?

 

[Eric Stage I]

Hey Joe,

No maf lock in that chip. Blm lock, yes.

Talk to you later,
Eric

 

[TurboBob]

turbobob231@bailey-eng.com

 

[REDS HOT AIR]

if you bypass the wastegate solenoid and use the bleeder by itself and it does it then you can forget the chip cause at that rpm you can be way untuned and its not going to drop boost like that.

thats why I mention floating the valves..what valve springs are on it..your sig dont say nothing so I take it they're stock

and get an rpm reading..

 

[turbov6joe]

Ok, here is the latest and greatest about my car. My buddy Eric programmed for me a 16 position thumbewheel with the JL chip on it. On each setting over #1 he has 5% fuel enrichment being trimmed out, I believe the total fueling started at 65% at WOT. I went out in the same state of tune with a static FP of 43 psi, alky on #6, and the boost set at 24-25 psi. On the first few passes the signs were good in that I did not notice the boost loss that I observed last week; seemed pretty solid! However, on settings #2-#5 the EGT still would not go over the high 13xxº mark??? Each time I clicked it to another leaner position, the KR would go up a few º's. If I tried to compensate for the KR by increasing the alky, the EGT's would get lower and the car would rich pop. If I run just race gas, with no alky, 25 psi and the same FP setting, the car pulls hard. If I run a 50/50 pump/race fuel mixture and use the alky, the car rich surges and runs like crap. SO, what is this telling me... With the OE injectors, alky, and a 50/50 fuel mix, 25 psi of boost, I can get the EGT's in the 1580º-1600º range with VERY little KR at all and the car runs like a banshee. Go 100% 114 fuel, no alky, OE injectors, and 25 psi, the car runs great then as well... With the 50's, alky, and a 50/50 mixture, the EGT's suck, the MPH is way down, and the car feels like crap. With that in mind, I will try to pull more fuel out with the thumbwheel chip and continue to tune the 50's untill I get it back in the 120 MPH range like it should be. If I can't get the 50's to run right, they're comming out, the OE squirters are going back in, and I'll run it with the alky 100% of the time! In the past I never had such problems with 50's running rich like they are. Maybe I don't have enough turbo for the 50's, maybe I have my head up my ass and am doing something totally stupid with the tuning, I don't know. But now the winter is here and I may not know what's up untill next spring. I may just throw the TTA on my trailer and put it on my buddy's dyno and try to get it tuned on that??? Thanks to all who shed their opinions...keep'em comming if you have any ideas.

 

[turbov6joe]

BTW, Red the springs are the original 14k mile pieces. I have some HD springs in a box ready to go in this winter when I do the rear main seal and timing chain.

 

[bruce]

Originally posted by turbov6joe
Ok, here is the latest and greatest about my car. My buddy Eric programmed for me a 16 position thumbewheel with the JL chip on it. On each setting over #1 he has 5% fuel enrichment being trimmed out, I believe the total fueling started at 65% at WOT. I went out in the same state of tune with a static FP of 43 psi, alky on #6, and the boost set at 24-25 psi. On the first few passes the signs were good in that I did not notice the boost loss that I observed last week; seemed pretty solid! However, on settings #2-#5 the EGT still would not go over the high 13xxº mark??? Each time I clicked it to another leaner position, the KR would go up a few º's. If I tried to compensate for the KR by increasing the alky, the EGT's would get lower and the car would rich pop. If I run just race gas, with no alky, 25 psi and the same FP setting, the car pulls hard. If I run a 50/50 pump/race fuel mixture and use the alky, the car rich surges and runs like crap. SO, what is this telling me... With the OE injectors, alky, and a 50/50 fuel mix, 25 psi of boost, I can get the EGT's in the 1580º-1600º range with VERY little KR at all and the car runs like a banshee. Go 100% 114 fuel, no alky, OE injectors, and 25 psi, the car runs great then as well... With the 50's, alky, and a 50/50 mixture, the EGT's suck, the MPH is way down, and the car feels like crap. With that in mind, I will try to pull more fuel out with the thumbwheel chip and continue to tune the 50's untill I get it back in the 120 MPH range like it should be. If I can't get the 50's to run right, they're comming out, the OE squirters are going back in, and I'll run it with the alky 100% of the time! In the past I never had such problems with 50's running rich like they are. Maybe I don't have enough turbo for the 50's, maybe I have my head up my ass and am doing something totally stupid with the tuning, I don't know. But now the winter is here and I may not know what's up untill next spring. I may just throw the TTA on my trailer and put it on my buddy's dyno and try to get it tuned on that??? Thanks to all who shed their opinions...keep'em comming if you have any ideas.

You've got your idea of tuning slightly messed up.
You tune for what makes the engine run best.
Looks like your trying to get numbers that you like.

I've got a stock turbo'd car running CORRECTLY using 55s.

If you want to get the car running CORRECTLY you need to start from scratch with the prom. Basing a chip on one that possibly has errors just perpetuates the errors.

Buy, a few sets of plugs.
Take a stock bin file, reset the injector constant, reduce the WOT timing to the 18d range, and then start tuning.

 

[Eric Stage I]

Joe, it sure sounds like the alcohol is dowsing your EGT. Instead of trimming fuel back, what happens if turn the alcohol down. Would you get knock? Maybe we have to get the fuel right with straight race gas first, then introduce the alcohol. Or, like Steve Yaklin says, add water to the alc to lean it out.

Eric

 

[turbov6joe]

Eric,
When I first put the 50's in I took the car to Heartland Park and made numerous passes. Initially I had the alky turned on and the car ran like ass. Each pass after that I turned the alky down a number or two untill it was completely off. Every time I turned it down a notch the car went considerbly faster. At the time I was running straight 114 and 24-25 psi with the converter locked. I agree that the alky is palying a huge part in creating my woes. After you dropped the chip off I went out on my private 1/4 mile strip and made about 10 passes. With the boost at 24 psi, the FP at 43 psi static, and the alky on setting #6, the car ran pretty decent with KR in the low single digits and the EGT in the lower 1300º-1350º range. I tried turning up the alky controller and the car ran worse as well as the EGT dropped. The problem was that when I lowered the alky under #6, the KR went up enough to scare me into turning the alky back up. Unfortunately I was running a 50/50 114/92 fuel mix, so the testing was sorta screwed. If my memory serves me right, at Heartland Park the EGT's were sorta where they needed to be. I agree I need to turn the alky off, dump about 6 gallons of 114 in the tank, and tune from there. I think what I'm trying to do is tune the car for both race and street (alky) at the same time...which obviously isn't getting me anywhere! BTW, the chip I used at HP was the original JL chip you started with. Anyhow, the weather has turned for the worse, and the streets will get too cold to play on, so I'll put'er down untill next year. I may however take it over the MC Racing to tune it on the dyno for a while. I'll prolly try 100% pump gas and the alky first, then pump that out, add some 114 into the tank and tune it with 100% race gas for a while. I think the most recent chip is pretty close to what I need. The only thing we might have to play with is the timing later on down the road. If the JC chip was a 19º chip, and the JL was a 24º chip, then we might be alright with the newest version being at 22º @ WOT. Anyhow, thanks for droppijg that off the other day. I'll let you know when I plan to tune it on the dyno. Have a great turkey day and we'll talk soon.

PS>> On my last pass some kids in a BB Chevelle pulled up to me and wanted to race...so, I gave in to the temptation and comenced to handing him his ass pretty bad The kids didn't believe it was only a 6 cylinder untill I popped the hood...Cold roads + cold tires + a 1 psi launch = about 100' of rubber for the world to see!

 

[stss96]

My T does the same exact thing, my car is mostly stock except for 36# bluetops and bolt ons. On the 2-3 shift boost will drop down to around 10 and then slowly build back up. I am running the stock turbo and about 23-24 lbs of boost on race gas. 02's were a little rich around 810 or so if i remember right.I was running a jay carter race chip. I still haven't figured out whats causing it either.