Weird dyno/tuning issue

[94Jettameowpsst]

Mods in profile are up to date

Well i had my car dynod today and found out i was rich beyond belief....well thats not my problem.

I made about 8 runs on the dyno to get everything straightened out but the thing im confused about is my IDC's. One of my passes i put down 306whp and 290ft/lbs BUT my idc's were at 107%. SO out of sheer curiousness i decided to up the boost, mind you i was only at 15-16psi prior. 19psi is what i made most power on but my idc's were like 120%, the boost estimate on dsmlink said i was at 27psi falling to 15 by redline, my airflow was at 47lb/min and boost gauge was at 19-21psi (creeping bad up top but holding steady).

Now am i really maxing out my injectors since adding fuel in link REALLY adds fuel or is it a misreading due to my own lack of calibration with my maft? End result at 19psi put down 347whp and 303ft/lbs with a very steady 12.2-12.5:1 afr.

Havent done a boost leak test in a long time but i think i may inquire on that tomorrow.

 

[spyderturbo007]

Mathematically, 650cc injectors can support 46.66lbs/min @ 100% IDC and 37.32lbs/min @ 80% IDC assuming a target AFR of 11:1 and 93 octane.

 

[94Jettameowpsst]

^This is true which is the part that doesnt make much sense to me. I did something a little bit ago that made my low end even out better than it was before....as far as numbers go on link my ltft low and mid are about .8-1% and my stft cycles from -.2 to 2%. I havent had a chance to do a pull but so far what i've done amounts to this

On the dyno, my deadtime was 330 and under airflow maf settings, they were all 0 except for the last 3 bars...those ones i had to up about 5-10%. Now, i changed my deadtime to 210 via the chart http://www.dsmtuners.com/forums/showthread.php?t=236893&highlight=Injector+dead+time
and upped the 50 slider in maf airflow to 20% (which is what made the numbers better).


Now with a lower deadtime in link (maft is set to stock injectors) would i technically have to remove even more fuel to be at the level that i was at before since its technically squirting even more fuel in? So it should theoretically lower my IDC's?

 

[CanadianTSi]

Deadtime changes very little at WOT, it is mainly used for Idle/Cruise and dialing in your Fuel Trims.

You have a Boost Leak, Or your MAF-T is not calibrated properly. Judging by the Fact you said Boostest was 27psi and you were only running 19 I would say your MAF-T needs a little calibration...

 

[94Jettameowpsst]

Deadtime changes very little at WOT, it is mainly used for Idle/Cruise and dialing in your Fuel Trims.

You have a Boost Leak, Or your MAF-T is not calibrated properly. Judging by the Fact you said Boostest was 27psi and you were only running 19 I would say your MAF-T needs a little calibration...

I havent had a chance yet today to see if i have a boost leak but what do i have to do as far as calibrating my maft? Would i have to move the airflow sliders under MAF Settings negative until it reaches the right airflow im seeing via my boost gauge? Or do i have to mess with the ve part of the thing.

 

[CanadianTSi]

Ya thats pretty much it, theres a guide in the DSMLink Wiki.

Just an FYI my 650's at 100% IDC put down 400awhp 350trq on a Mustang Dyno.

 

[94Jettameowpsst]

Yea i knew i shouldnt be maxing out my injectors just yet.

Well im not exactly a registered user on the link forums....long story, was just hoping for some information on here since everything that i do is just trial and error thus far....and its harder than i expected!

So for instance, if my boost is dropping by redline (via dsmlink) shouldnt i be having to go positive on the af sliders? Because thats what im doing and it helped slightly but no drastic improvement and its also increasing my airflow and duty cycle >:O. I guess its inevitable that i have to do a boost leak test although i dont have a compressor at the moment so its posing to be a slightly difficult task at the moment .

Well if i have a boost leak, once i fix it and such, i should just calibrate the maf according to what my boost gauge is saying? Geez i wish i had a map sensor >.<

 

[94Jettameowpsst]

I was just reading a little bit and everyone that i've read about that has a maft also has a gm3bar map sensor. Is it harder to calibrate the maft if you dont have one...or is it necessary to have the map sensor?

 

[94Jettameowpsst]

So, i did a boost leak test and fixed everything but my headgasket (its not leaking as bad as i thought). I sort of figured out how to dial in my maft from what canadiantsi said and according to my boost gauge im running 20-21 psi....my boost estimate on dsmlink now says im running 20.9-21.5psi (pretty dead on). This is where it becomes kinda weird.

Like i said im on my stock fpr w/ a walbro 255 pump and 650 injectors. Well i reset the deadtime to 210 like that link says and pulled a BUNCH of fuel (i mean like 25%)out of the entire rpm range but no matter what i do it knocks from 5000 and up. Now the weird part is my duty cycle at the previous boost setting (19psi) was only getting to 89-92% (which still doesnt make sense at 37lb/min of flow. At 21psi now i am only showing 40.7lb/min and my duty cycle is 102% wtf?!?


Im begging to think that these injectors just dont like going over 80% duty cycle because i've noticed that is where my problems begin. I just picked up a set of pte 880s today and am gonna put em in tomorrow to see if i get some better results.

But why am i flowing such low airflow at such "high" boost? I seen more flow out of my evo 3?!?

 

[Maglin]

It actually seems about right. If you are flowing around 40 lbs/min and 102% IDC is about right. When I was running a stock computer with EPROM and doing my own tuning with a Ostrich I was running 30 PSI seeing about 42 lbs/min and 66% IDC on 1000cc injectors @ 11.5:1 AFR. So it's in line with what I was seeing at the same flow rates. And as far as your turbo not flowing what you want it to. That is probably more to due with your current tune.

 

[dsm-onster]

I can vouch for that too. I was running 39.5ish lbs/min w/ my PTE 660s and 18g and I saw 95% + IDC. I was running 11.2:1 w/ my lm-1 at peak airflow and IDC. I've not seen many get more airflow than that on pump gas w/ 650s w/out lots of knock. I was running a smallish FMIC and water injection.

650s are good injecctors for an evo3 16g. But for any turbo that can maintain 30 psi to redlin w/ a decent set of cams, then you're going to fall short on fuel.

It is clear that you're seeing that injectors can't put out much more fuel flow at 100% IDC as at 80% IDC.

But why am i flowing such low airflow at such "high" boost? I seen more flow out of my evo 3?!?

20 psi and stock cams don't give many people 40 lbs/min especially on the stock block. when running a tdo5h turbine and 7 cm^2 housing. If you've been uncalibrated, then your evo3 16g flow numbers have been false.

I think you're doing good. Find the knock issue. In fact, post your dsmlink logs.

 

[94Jettameowpsst]

I would post my logs but my laptop i log on is from 1990 and i dont have a connection to the computer....seriously, its old haha

Okay. Today i finally put my aeromotive fpr on and set it to 40 psi w/ the vaccum line on and installed my pte 880s. Im assuming, since i have basically NO boost leaks (seriously it held 30 psi for like 5-10 minutes) my maft is calibrated with the 420 deadtime and -41 global and my ltft lo, mid, and stft all about 0. Wtf.


This is all i have to say is wtf.

A while back i changed my fuel filter and the gas that came out of it was black and a slimy texture....but when i took my car to the track there was little to no knock at all and was running upwards of 25psi on my current turbo with the stock maf. Since then, it seems like i've been having nothing but problems. Im going to change my filter tomorrow and if that doesnt help im just going to change my pump. (ill get into why i could think its one of those things in a second)

My duty cycle on 880s is 72% with 40lb/min at 22-23psi.....impossible....should be higher airflow and lower idcs


Well i tuned the hell out of this damn car for the past hour or so and i noticed something. Even tho my pump isnt rewired and im going off of o2 voltages there should be a noticable difference when i make a change....well it doesnt. If i zero it out my o2 volts are .96 till 5k then it drops to .94. (knocking from 5k up consistently) If i lean it out 15% the whole way to redline it knocks all over from 4500-5k up and my 02 voltages stay at .94........

Anyone think i have a bad filter or pump!?


Edit: I failed to mention i know the fuel pressure should be 43.5 or w/e psi and thats what i have it set to with the vaccum line connected.....for some reason, with it disconnected and the vaccum line plugged, it shows 50psi

 

[dsm-onster]

Nevermind the knock for now. set it back to where there's no knock (zero out the fuel sliders). OK, . . .

Have you logged boostest vs. your actual boost? Are both graphs VERY close to each other?

I would pull the MAFT off and put in your stock maf. Go out and retune your fuel trims w/ dead time. Your global for 880s should NOT be 41% but 49%. Per the DSMLink manual:

Adjustment = 450 / 880 – 1.0 = 0.511 – 1.0 = -0.489 or –49%​

Your raised fuel pressure will alter the required global setting even more. The wrong global is why you're seeing the high % IDC. The ecu thinks you have:

450 / X – 1.0 = -0.41
450 / X = -0.41 + 1
450 / 0.59 = 760cc​

You're getting a higher % idc because the ecu thinks you have 760s in the fuel rail.

You're getting rich knock likely. It's an odd beast. But, it's a possibility, considering you have 100 more CCs of fuel coming out of the injectors than the ecu is prepared for and your FPR is running at 50 psi base fuel pressure (you're supposed to adjust the fuel pressure to 43.5 psi w/ the the vacuum line disconnected and plugged). At the very least, you have a bad tune

You're suffering from having too many variables. I did the same thing. I dropped in 1000cc injectors and a blowthru GM MAFT at the same time. Nothing helped until I put my old 1g maf BACK in and started from square one. . .

Get the stock maf back in the car and dial in the fuel trims again w/ your deadtime adjustments. Then, swap in the MAFt and calibrate. You have to have either a map sensor or a wideband to calibrate the MAFt. It's cheaper to grab a gm 3 bar map sensor AND the calibration is more accurate.

FYI, and I'm sure you already know this, don't even bother looking at that stock narrowband o2 sensor voltage.

 

[94Jettameowpsst]

What should the fuel pressure be with the vac line connected then for refrence?

Btw, thanks for all the helpful responses, its greatly appreciated!

edit: I just went to advance to see if i could pick up a map sensor but according to http://dsmlinkwiki.redacresracing.com/default.aspx/DSMLink/ExternalSensorInput.html the map sensor isnt usable with the barometer pin on the 2g ecu?

Whats the part number on the sensor i should get and how do you wire it in....btw, i reset my base fp to 43ish (cant tell its between 40 and 45) and its around 38 plugged in...so im assuming thats correct.

 

[dsm-onster]

38 psi w/ the vacuum line connected and at idle seams a bit high. Even if you have low vacuum from a cam upgrade. Does your boost gauge display vacuum also? If so, what is your idle vacuum?

I'd say you have an intake manifold gasket leak but you did a boost leak test that checked out ok. It's possible the AFPR has gone bad or has a gasket leak. I've seen it happen. What I do to check the AFPR now is:

1. Reinstall the vacuum line to the AFPR.
2. Turn the key to the on position and go in dsmlink.
3. Activate the pump in dsmlink under the Miscellaneous window.
4. Run a boost leak test.
5. See if the fuel pressure rises w/ the intake manifold pressure 1:1.
6. check the AFPR body for boost leaks.

You can use you rear o2 sensor input for the map sensor.

 

[94Jettameowpsst]

So when i put in the gm map i just run the power wires to the rear o2 sensor input on the ecu....dont mean to restate what you just said but i just wanna make it crystal since i've never did this before And does the map have a boost source or something or is it all electronic?

I looked at it more closely and im more like 33-35psi w/ the line on. The way i have the gauge in since its tight makes it upside down so i just made a glance at it.

My gauge is 0-60 so i cant read vacuum but on link (i know its not accurate) says 25hg and on decel reads 29



Once again, i really appreciate all the help, it sucks not having anyone locally to explain your situation to! Also, i think i may just get a 255hp pump since it probably wont hurt since the 255lph thats in there now is atleast 4-5 years old. Now, even tho my fuel pressure is right, could i necessarily have the pressure but not the volume of fuel i need? I did what you said to do with teh stock maf then put the maft on and zeroed everything out and im still at 75% duty cycle at 38lb/min knockin from 5k and up....i hate this car! haha

 

[this_tsi_8urV8]

Are your A/F ratio's right???? 12.2-12.5??? That is on the lean side. Or did you mean 11's?

 

[94Jettameowpsst]

It was definitely 12.5:1 and richer.

I determined the source...the very source of all my problems in the past 3 days....and i can explain it in disbelief in 3 very scary, simple words:


















STOCK FUEL PUMP!!!! WTF

 

[DirtyBirdRacing]

Damn dude, bum deal. Definetly swap that out with a 255 HP.

Bill

 

[94Jettameowpsst]

Oh its already been changed and my idc dropped about 25% compared to what they were before. This is about the first time that i havent knocked from 5k and up and its fantastic! haha, it feels like a new car


Now secondly. I know you can calibrate the maft with a map or a wideband but if you do it with one or the other will both figures be accurate? If you calibrate it to be exact with the air fuel estimate will the boost estimate also be correct?

 

[playitlouddsm]

Boostest is only accurate at about 5500 rpms and up.

 

[dsm-onster]

Oh its already been changed and my idc dropped about 25% compared to what they were before. This is about the first time that i havent knocked from 5k and up and its fantastic! haha, it feels like a new car


Now secondly. I know you can calibrate the maft with a map or a wideband but if you do it with one or the other will both figures be accurate? If you calibrate it to be exact with the air fuel estimate will the boost estimate also be correct?

I didn't even notice that you were still running the stock fuel pump. . . A stock fuel pump could certainly cause a knock issue. And it looks like you've found the cause of that.

But, during WOT, how does the ecu know that you're fuel pump (stokc 190, 255, or twin 255s) is not flowing enough? It doesn't. Your %IDCs came down because of your retuning or something else.

Most dsmlink guys report that the GM MAP sensor calibrating method is more accurate. You want boostest to match actual boost. Some have calibrated w/ their wideband o2 and found that boostest was off from the actual boost curve. Both ways are good. And a wideband calibration should still put your airflow measurement w/ in a lb/min of actual.

 

[DirtyBirdRacing]

But, during WOT, how does the ecu know that you're fuel pump (stokc 190, 255, or twin 255s) is not flowing enough? It doesn't. Your %IDCs came down because of your retuning or something else.

The 255 will obviously pump more, but espically at higher rpm's. So since it would be able to keep the fuel flow truer to what is deisred at high rpm's wouldnt that lower your IDC, due to a higher flowrate at higher rpm at the fuel rail then the stock fuel pump could deliver. Like I know that the amount the injector flows is due to the pressure differential across the injector, the size of the injector and how long it is held open, but I would have to think that the flowrate of fuel from the pump would have to help it some. And wouldn't the ECU know this because of the 02 sensor reading a richer mixture or in other words the ECU would read the deisred mixture at a lower IDC. This makes sense to me, so please correct me if Im wrong.

Bill

 

[94Jettameowpsst]

I didn't even notice that you were still running the stock fuel pump. . . A stock fuel pump could certainly cause a knock issue. And it looks like you've found the cause of that.

But, during WOT, how does the ecu know that you're fuel pump (stokc 190, 255, or twin 255s) is not flowing enough? It doesn't. Your %IDCs came down because of your retuning or something else.

Most dsmlink guys report that the GM MAP sensor calibrating method is more accurate. You want boostest to match actual boost. Some have calibrated w/ their wideband o2 and found that boostest was off from the actual boost curve. Both ways are good. And a wideband calibration should still put your airflow measurement w/ in a lb/min of actual.

I didnt know i was on the stock fuel pump either! The previous owner, who has been pretty reputable to me atleast, said he didnt know when where or how but he thought there was a 255 in the car. So yea, but not only that, when i changed my fpr and took the return line off of the old stock one, how about it was dry in the rubber hose....like literally nothing came out of it when i pulled it off.


On a lighter note, i think i broke my first axle, drivers side, not even spinnin...just all of a sudden it made a rumbling sound followed by a brake pulsation sensation. Looked under the car and the inner cv boot looks to be twisted off so im assuming thus far, thats all that broke.....hopefully :<

 

[dsm-onster]

The 255 will obviously pump more, but espically at higher rpm's. So since it would be able to keep the fuel flow truer to what is deisred at high rpm's wouldnt that lower your IDC, due to a higher flowrate at higher rpm at the fuel rail then the stock fuel pump could deliver. Like I know that the amount the injector flows is due to the pressure differential across the injector, the size of the injector and how long it is held open, but I would have to think that the flowrate of fuel from the pump would have to help it some. And wouldn't the ECU know this because of the 02 sensor reading a richer mixture or in other words the ECU would read the deisred mixture at a lower IDC. This makes sense to me, so please correct me if Im wrong.

Bill

I'm talking openloop here. There is no o2 sensor feedback read by the ecu at wide open throttle from where 94Jettameowpsst is discussing his %IDC. A stock fuel pump can handle any closed loop operation, where the ecu can manipulate the %IDC based on feedback and adjust for things like poor fuel flow.