Same "hesitation/stutter" issue new log lower boost

[hisandherturbo]

Someone come up with something I / a lot of others hasn't seen yet!
TY
JOE

For those who are seeing this for the first time.........
CAS changed replaced
Fuel filter "removed for test"
Tried MSD DIS II and Stock ignition
Tried COP's and known good coil pack w/Magnacore wires
Every combintaion of the above 2
Added fuel, removed fuel (DSMLink)
Added timing removed timing (DSMLink) Base is 5*
Replaced plugs NGK BPR7ES gapped at .028 (even lowered to .025 to test)
Tried a different 3 1/2" MAF

Car was perfect before it sat for 10 months waiting on a new crank (lighter/knife edged) and PTT....... The only thing touched besides those 2 was a new altenator (stud for POS broke while pulling engine), also needed a new Power Transistor, for some reason it died while sitting.

 

[turboglenn]

I"m not sure how accurate teh AFR reading is in your log, but it seems like you're too lean under the onset of boost. Is that where you're having the hesitation? If it feels like the car is being held back when you lay into boost at first then i would say that you need a lot more fuel in that area. There's been a few times that i dialed in the highway cruise AFR's and even went a little lean in the first few psi of boost and then when i tried to take off on the street it would hesitate and feel like it was super low on power, for me it was just that there wasn't enough fuel being delivered under the on-set of boost. I knwo you've tried adding fuel, but maybe it wasn't enough.... Move the sliders way up in the areas where you're ahving issues. Even over fueling that spot will make it feel better than a lean condition if in fact that's what's going on.

I can't see TPs, but every spot from 3k to 5k looks to be too lean in the beggining of the log where there's the one solid pull ebfore it goes into cruise. I don't remember your previous posts enough to know what all is going on so fill me in a little if i'm way off track.

 

[hisandherturbo]

This was a 1st gear and 2nd gear WOT, 1st was ok, a little hesitation towards the top of the gear......... it feels exactly like it looks, RPM"s drop a lil, Injector duty drops, boost drops almost like taking your foot of the gas a lil, then back on then off a lil, etc

2nd gear was really bad

AFR...... if your looking at the AEM WB, then it's good....... the computer AFR........... nope.

I am on TT111 Leaded Race gas.

I never really go into "cruise" just the last couple secs I lay off the throttle all the way. (look at ThrotPOS)

RPM's don't matter.......... I could go mid throttle all the way to 6k or whatever, then punch it.......... same result. If I don't punch it.... no problem.

 

[hisandherturbo]

Hre's another log done today. Where the RPM's look shacky..... that's where the issues are.

 

[hisandherturbo]

NO ONE? Nothing?

 

[turboglenn]

The way the RPM's jump up and down under 99% throttle, it looks like you may be having issues with the signal from the cam/crnak angle sensor. There's no other reasons besides a bad CAS or interference in the signals from it, that would cause your RPM's to "drop" a few hundred under boost and then continue back to normal and drop again while TP is staying consistant (unless you were loosing grip on the road)..this trend seems to repeat in your latest log. Do you have a spare CAS to try or one you can borrow? (i'm ASSuming you're running a 6bolt with a 1g CAS sensor )

 

[hisandherturbo]

Yes, Yes and ALREADY TRIED IT...............

 

[hisandherturbo]

Well, after playing around with wiring I noticed something that I find strange and don't think is right. I was doing different continuity checks and noticed that on my kill switch, the 2 large poles, continuity only works in 1 direction............I would assume either direction (meaning, pos on 1 pole, neg on other, then switch around) it would work the same. I won't know until tomorrow after work when I get another alternator on it. Got my fingers crossed.

 

[hisandherturbo]

K, well that was never an issue like I hoped. Figued out why it was like that was cause I still had the 2ga wire connected and with my trunk open it was closing a circuit to turn on the dome lights. Once I pulled both wires off the kill switch acted normal or if the hatch was closed............. back to square one.
So, I put in the new alternator and still can't see more then around 13.3v. I thought I would try something, I pulled the 4 wire connector out of the alternator and nothing changed. So I am wondering what should have happened? I assumed something different should happen.
So I wondered if 1 of the 4 wires was messed up. the 2 that go into the ECU G (ignition) and FR (Field monitor?) and both wires were fine have continuity to the ECU. Pin 2 is the "sense" wire which goes to the motor fuse (Almost positive) and continuity is good, also pin 2 has battery volts present. The last pin, 3 is just to the battery light.
So what? ECU part that tells the internal voltage regulator what to do messed up? This is soo stupid!

 

[SBR Joe]

Log your STFT and raw airflow in Hz, see if the STFT's go crazy when it starts to "stutter." If they do, look at where it does and see what the Hz reading is at that point, then go to the airflow tables and add a few % at that Hz until it smoothes out.



Joe
SBR

 

[hisandherturbo]

Log your STFT and raw airflow in Hz, see if the STFT's go crazy when it starts to "stutter." If they do, look at where it does and see what the Hz reading is at that point, then go to the airflow tables and add a few % at that Hz until it smoothes out.



Joe
SBR

I can't remember forsure if I logged STFT or not, but Raw airflow is. And it isn't a tunning issue (at least not at this poiont). We have tried everything in Air/fuel/timing in both extreme directions, the problem doesn't change. It is either the issue I am having with charging, or there is something physically broke.

 

[SBR Joe]

I can't remember forsure if I logged STFT or not, but Raw airflow is. And it isn't a tunning issue (at least not at this poiont). We have tried everything in Air/fuel/timing in both extreme directions, the problem doesn't change. It is either the issue I am having with charging, or there is something physically broke.

Bad alternator, (i know you already replaced) but a bad CAS on my car did a funny stutter at 2500rpms consistently, etc. It could be a few things, chances are its something really stupid and an easy fix but it can be a bigger PITA finding those problems opposed to fixing a bigger one. Good luck.

Oh, also, maybe a stupid q but is the translator box dip switch on for the use of a 3.5 inch maf????


Joe
SBR

 

[hisandherturbo]

Bad alternator, (i know you already replaced) but a bad CAS on my car did a funny stutter at 2500rpms consistently, etc. It could be a few things, chances are its something really stupid and an easy fix but it can be a bigger PITA finding those problems opposed to fixing a bigger one. Good luck.

Oh, also, maybe a stupid q but is the translator box dip switch on for the use of a 3.5 inch maf????


Joe
SBR

4th alternator which have all tested good on a load testing machine.
CAS....... 3rd known good one. And it isn't a specific RPM, it can do it and has at any RPM, and may or may not even do it at all.
Yes, the MAF-T is for 3 1/2".
The only things that have changed on the car since last april when I did the 11.4's were the crank (better, lighter, Knife edged), PTT (replaced ACT 2600 complete set-up), also had to put a new alternator in (since I broke the B+ post taking it out), CAS (just wanted one with a connector instead of hard-wired), and my Power Transistor went out while the car sat for 10 months. Other then that the car is the same as it was for the years prior......... something happened in them 10 months it sat (been running again with these problems since early MARCH).

 

[SBR Joe]

4th alternator which have all tested good on a load testing machine.
CAS....... 3rd known good one. And it isn't a specific RPM, it can do it and has at any RPM, and may or may not even do it at all.
Yes, the MAF-T is for 3 1/2".
The only things that have changed on the car since last april when I did the 11.4's were the crank (better, lighter, Knife edged), PTT (replaced ACT 2600 complete set-up), also had to put a new alternator in (since I broke the B+ post taking it out), CAS (just wanted one with a connector instead of hard-wired), and my Power Transistor went out while the car sat for 10 months. Other then that the car is the same as it was for the years prior......... something happened in them 10 months it sat (been running again with these problems since early MARCH).

An exorcism maybe??? !



Joe
SBR

 

[hisandherturbo]

Well, thought it was a bad fuel pump...........
Well, of course that wasn't it........... At least we know the problem...... loosing fuel pressure. It maxes out at like 60psi but then by redline drops to 54ish (boost is at 25psi the whole time). Of course it should be at 68.5psi.
6an feed and return. I've already removed the fuel filter seeing if that was bad. I can turn the pressure up to 70psi (car off, just adjusting the FPR) don't see any leakes and it holds. No boost leaks that would make the 1:1 pressure drop.
I can only think back to voltage........ yes, it's re-wired, I am going to check the mutimeter on a pull see what that shows, other then voltage at the pump can't think of anything else.

 

[hisandherturbo]

Well, swapped out the relay........ guess what......... nothing.
I tried more pressure tests with and without fuel pressure. I can get fuel pressure to rise with boost during a pressure test to about 80(ish) psi. I can adjust the AFPR to 80 and it will hold. I even set base pressure to 60psi added 20psi of boost...... fuel pressure 80psi. I understand that during all of this fuel is not "being" used so it doesn't have to deliver as much fuel......... but come on. I can't see more then 60psi of fuel pressure under 25 psi of boost while driving (correct me if my math is wrong, but shouldn't I see 68.5psi of fuel pressure?)....... then it will slowly fall while boost still holds.

 

[hisandherturbo]

How's this sound............ Car sat for 10 months with the TT111 Leaded race gas sitting in the fuel lines (-6an). Lines got "yucky" clogging them a little bit. In clogging them the fuel pump is trying to work very very hard to keep up with the demand I am asking for it, draining my power..........
I am going to pull off the fuel lines and check it out, all 3 sections pump to filter, filter to rail, and then rail to AFPR. If in fact that is the issue, I am going to just go ahead and upgrade to -8an.

 

[hisandherturbo]

Picked up another alt relay and also a mitsu 90amp alt from the junkyard.......
Well, I think that helped/fixed my voltage issue, I am seeing 13.1-13.2 at WOT, which I think should be good. Fuel pressure still only goes to about 64 then falls to about 58 (@25psi of boost). Which is better, but still not right. I am looking at my logs and I do have a slight downward angle for my fuel settings, but I don't think that is really making a difference, it's the same settings I had when I last ran the car correct, which is when I did the 11.4's. Sooooooooo, there is still a fuel pressure dropping issue. I will continue to look at leaks........ even though the boost holds. Fuel pump/lines/leaks...... what else could make pressure drop? I am still probably going to try another set of injectors, but I couldn't see how clogged injectors would make pressure fall, you would think it would rise....... wouldn't you?

 

[Artago]

Any error codes thrown? Like P0300?

Tom

 

[hisandherturbo]

Well, no, I have DSMLink...... but whats that code for?

 

[Artago]

Random misfire.

 

[hisandherturbo]

, thought soo, yeah, this isn't random mis-fire. I mean, it kinda seems like it's misfiring....... obviously, it's being fuel starved. But it isn't the 7 bolt to 6 bolt swap random mis-fire. Besides, that happens all the time, when it happens not like my issue.

 

[Artago]

, thought soo, yeah, this isn't random mis-fire. I mean, it kinda seems like it's misfiring....... obviously, it's being fuel starved. But it isn't the 7 bolt to 6 bolt swap random mis-fire. Besides, that happens all the time, when it happens not like my issue.

I replaced my 7-bolt with another 7-bolt... got the random misfire.

I just thought I'd bring it up in case.

 

[hisandherturbo]

OK, ty, This is way beyond the "norm". Just like when I had 15psi lower compression in 1 cylinder for over a year and found out it was cause I had a bent rod.......... drove perfectly fine for that whole year and did many many passes down the track no issues. Only found it out cause I was doing something else to the motor.

 

[hisandherturbo]

Well, even after trying new injectors still nothing, fuel pressure just won't go up where it needs too. I can't get it to go higher then 64ish max (@ 25PSI or even higher boost). I dunno........ I'm getting really tired of wasting so much damn time with this.