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Hesiataion problem

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mikelv

15+ Year Contributor
566
10
Jun 17, 2006
Columbus, Georgia
Well, first of I know, I know, there is over a billion posts about hesitstion.
I thank anyone in advance for there help here!

I am having strong hesitation problems at cruise. And I believe it to be caused by one of the following.

I am running very very rich, and I'm having trouble leaning out the car.
Also, I am running a Pre 95' Compressor Bypass Valve that is over "crushed". Not by much, but enough to probably do something here.

Would an over crushed valve cause a hesitation this bad?

The symptoms and condidtions:
Under normal operating condidtions, in all weather (20-85deg). While driving the car, with no more than 40% throttle...when I let of the gas, the car hesitates, and sputters. (Enough shock to send me forward.)
I'm trying to word this as best as possible so bare with me.
I decresed the boost pressure to only 10psi, and continued to have the same problem.
It happens at all rpm's. Basically, when I let off the gas, and when the excess pressure releases. The CBV also shutters.

Now, I've tried to search the FAQ's and such and stumbled upon some things about the BCS. I am wondering if my air/fuel mix is so bad, that it is closing the wastgate, or something to that effect. I do not have enough experience to really discuss this matter though.
Now, all engine electrical related components have been tested and are good. Its not a hesitation when trying to accelerate, it just happens at random, as either a mixture is bad, or when I let off air is having trouble releasing.

I am embarrased to say this, but I was running so rich, that there was excess gas in my oil. What is the consequences of this, and what in the hell do I need to do to lean this out. I am strongly under the impression that this hesitation is a bad air/fuel mix, and the ECU's last ditch effort to avoid damage, or something along those means. Either that or the CBV being to compressed and not able to release the excess air properly.

This is a 2G GSX with 26000 mi.
Honeycombs removed side, and bottom
I have Denso 720's
155lph
SAFC and DSMLINK which is killing me. Before you say I know the AFC needs to go bbye bye
1G CBV
Frank 3 and 40mm Ext. WG
All supporting mods
Anything else in question, please let me know!!!

As for DSMLINK before anyone asks. I am awaiting approval for access to the forums, am I am new to the program. As soon as I can, I will conatact help there. I have gone through the user's guide front to back many many times. The only major concern I've had with it is which LTFT do I use, or measure! There are LO MID HIGH, 1, 2, 3.....theres not one value that just say LTFT!!!! Anyway....

I'm very very sorry in advance for being vauge in any manner, I've read all pre post threads, and done extensive searching, so I'm doing everything possible not to waste anyone's time. I just am quite fustrated at this point. I am asking for some direction or guidance as to where I should take this, and I am apt to be more repsonsive as to what other symtoms or questions you might have of me to better solve my issue. Sorry this is so long, and thanks to all for help, and listening!!

Sincerely,
Mike

I also have some logs of cruise, and when this happens. I am willing to relay that information as to what settings I am currently using. I do not dare to venture to WOT as of yet, but I will try and relay what is going on, per my settings.

Thanks again!!
 
Well, first of I know, I know, there is over a billion posts about hesitstion.
I thank anyone in advance for there help here!

I am having strong hesitation problems at cruise. And I believe it to be caused by one of the following.

I am running very very rich, and I'm having trouble leaning out the car.
Also, I am running a Pre 95' Compressor Bypass Valve that is over "crushed". Not by much, but enough to probably do something here.

Would an over crushed valve cause a hesitation this bad?

The symptoms and condidtions:
Under normal operating condidtions, in all weather (20-85deg). While driving the car, with no more than 40% throttle...when I let of the gas, the car hesitates, and sputters. (Enough shock to send me forward.)
I'm trying to word this as best as possible so bare with me.
I decresed the boost pressure to only 10psi, and continued to have the same problem.
It happens at all rpm's. Basically, when I let off the gas, and when the excess pressure releases. The CBV also shutters.

Now, I've tried to search the FAQ's and such and stumbled upon some things about the BCS. I am wondering if my air/fuel mix is so bad, that it is closing the wastgate, or something to that effect. I do not have enough experience to really discuss this matter though.
Now, all engine electrical related components have been tested and are good. Its not a hesitation when trying to accelerate, it just happens at random, as either a mixture is bad, or when I let off air is having trouble releasing.

I am embarrased to say this, but I was running so rich, that there was excess gas in my oil. What is the consequences of this, and what in the hell do I need to do to lean this out. I am strongly under the impression that this hesitation is a bad air/fuel mix, and the ECU's last ditch effort to avoid detnotation, or something along those means. Either that or the CBV being to compressed and not able to release the excess air properly.

This is a 2G GXS with 26000 mi.
I have Denso 720's
155lph
SAFC and DSMLINK which is killing me. Before you say I know the AFC needs to go bbye bye
1G CBV
Frank 3 and 40mm Ext. WG
All supporting mods
Anything else in question, please let me know!!!

I'm very very sorry in advance for being vauge in any manner, I've read all pre post threads, and done extensive searching, so I'm doing everything possible not to waste anyone's time. I just am quite fustrated at this point. I am asking for some direction or guidance as to where I should take this, and I am apt to be more repsonsive as to what other symtoms or questions you might have of me to better solve my issue. Sorry this is so long, and thanks to all for help, and listening!!

Sincerely,
Mike

I also have some logs of cruise, and when this happens. I am willing to relay that information as to what settings I am currently using. I do not dare to venture to WOT as of yet, but I will try and relay what is going on, per my settings.

Thanks again!!

For fuel pump do you mean a 255 ? If so you need a fuel pressure regulator . Have you done a boost leak test ? http://vfaq.com/mods/ICtester.html .
 
Yeah, I read that article earlier and thought so myself.
No it's a 155lph with and 10 guaged hard wired. I also have a supra pump for it not installed.
I have an aeromotive AFPR not installed yet.

I also own a GST. I have been familiar with DSM's for about five years. I have only tuned my FWD with pocketlogger and the AFC though. This DSMLink is bran new to me, and it's killing me.

My GST has been totally done by me, and I have never had any issues as such. But then again, I have never used DSMLink or a 1G BOV. It uses a 255lph and a AFPR. It has 550's with the AFC, and it's quite simple.

Would what I'm thinking cause this. The BOV? Boost leak would cause an excessive hesitation? Would have to be severe? All IC piping is tight, and all connections are there, I just dont see it. But I will do this. I thought of that, and my mixtures were so out of wack I didn't believe this could be such.... This is what I plan to do.....I have purchased a new 1G CBV, a MBC, and something to check for leaks. It has to be the CBV....the sad thing is I do not recall this problem before I crushed it. But I'm not so sure.
I dunno maybe I'm just over fustrated, and burnt out, and needed a fresh pair of eyes!! I hate it when someone points out something so obvious that it makes me wanna just crawl up in a hole and die LOL.
Thanks for the help!
 
Now that was the issue with the program that I've been having as far as getting the settings proper.

Now, the battery was disconnected for storage, and the setting were lost, however, I zeroed out the fuel settings, and calculated for the global settings. I had them set for -37.5% global.

Adjustment = 450 / 720 - 1.0 = 0.625 - 1.0 = -0.375 or -37.5%

Now, as for airflow....something just isn't right.
Or maybe just both, because I'm having an issue trying to compensate for the piggyback AFC.

LO Settings:
+30% +22% +15% +10% +10% +5% +5% +5%
1K, 2K, 3K, 4K, 5K 5.5K 6K 7K respectively
 
Wow,
Thank you good sir, I will look over this in the morning.

Man, it's all there a wealth of knowledge. Thanks again, and if you ever need anything....anyone who replied let me know. I'm not one to turn and run.

Thanks to all for the references, I owe you all one, and let me know if you need anything.

Thanks a bunch,
Mike
 
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