car bogging under boost

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01-21-2005, 09:30 AM

95turbo gxe

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car bogging under boost

For some reason when I start getting into boost the car goes to back fire and popping. It seems to cut the power by 50% or so some times worst than others. Well me a and Mtcookson got the safc hook up the other night thru the good old phone. (THANKS AGAIN FOR THE HELP!) But this problem with the popping happen a while back and then stopped and went away. But it came back like two before I hooked up the safc and still is going on. IV tryed another maf with no luck.

01-21-2005, 10:02 AM

mtcookson

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rpm's limited at all? say perhaps around 2,000 to 3,000 rpm?

01-21-2005, 10:04 AM

95turbo gxe

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nahh not realy anything after boost builds. Like starting at 2000 grand and up. Does it real bad in 5th.Cant seem to find a leak anywhere

01-21-2005, 10:24 AM

cardana24

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is your car tuned? I had this problem when my car was running too rich. Also just double check to make sure you SAFC is functioning. Bags gave me this advice to make sure it was working. Take it down to your lowest rpm setting and start pulling fuel....if the car starts to sputter/die then it is working properly. It sounds like you may just be running super rich

01-21-2005, 10:28 AM

mtcookson

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he shouldn't be considering he's running stock injectors with boost (180 cc). if anything i would think it would be super lean.

01-21-2005, 10:31 AM

Stephen Max

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Do you have any gauges besides a boost gauge? What's your fuel pressure and EGT?

01-21-2005, 10:41 AM

cardana24

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oh ok thanks, I was not familiar with his set up.

-do you and adjustable FPR?

-you may want to make sure you fuel filter is not clogged, and that your fuel pump is not flaking out....also how is your cat...could it be clogged?

Quote:

Originally Posted by mtcookson

he shouldn't be considering he's running stock injectors with boost (180 cc). if anything i would think it would be super lean.

01-21-2005, 11:15 AM

mtcookson

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pretty sure he's running the stock fuel system. might have a bigger fuel pump in there but i can't remember off hand for some reason. its a bit dangerous to be running boost on such small injectors but he's taking it pretty easy and hasn't noticed any detonation or anything yet. he's getting some larger injectors and they should be in soon.

he got the afc so he could turn the fuel up a bit for now and once he gets the larger injectors he'll be able to crank it down.

that's about as much as i know at the moment. (i probably am forgetting a bunch of stuff though)

01-21-2005, 11:37 AM

cardana24

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Well he could possibly be running rich....I would not think so but look at the guy that just dynoed on the 2.87 pulley with the stock fuel system....pig rich with no upgraded injectors, though they are not 180s. Also if he is not positvie that the AFC was set up properly then it could be causing a problem. When I got my SAFCII it was on an evo and his settings were still saved, so as soon as I cranked my car it ran like crap because it was set up for an evo.....just thoughts.

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01-21-2005, 11:43 AM

#10

mtcookson

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i had him wire it just like i did and did all of the settings identically (except for the fuel maps because i have 259 cc injectors).

actually... now that i think about it i think his tps isn't working right. he's not getting a reading on the afc for the throttle and i'm positive the wire he hooked it into is correct since its the same wire i'm using. most likely the tps is bad because i've had lots of trouble with the tps on these cars.

01-21-2005, 11:54 AM

#11

cardana24

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wow...sounds like it is not even working at all....I am actually suprised the car would run with out a functioning TPS. I can attest to car studdering under acceleration with the TPS not being set properly...it happend on my fourth gen.

01-21-2005, 12:10 PM

#12

subs1000w

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one of my friends unplugged my tps without me knowing right before we went to race and i still beat him i didnt notice a difference so i dont think its that

the booging could definitly be a rich condition like when i spray without the bottle being open the car just basicly loses all hp and just sputters

also could be a clogged cat thats happened to me also same type thing althought the car ran fine it was just down alot on topend hp

01-21-2005, 12:26 PM

#13

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I think the TPS on our cars only tells the ECU if it's at idle or not. I believe that's what Bernard and I discussed one night. GM's are variable between .40 to 5.0V so the ecu knows where the throttle position is.
Sounds like a ignition or fuel problem. Check for good spark and check all your grounds again.. CHeck fuel pressure too.
I ran 180cc's for awhile.. it's definatly not rich... I ran 60+psi of fuel pressure at idle and it still was lean!
Get some 370's and do the upcoming fuel rail mod that I'll be posting about and your fuel issues will be solved.
~Scott

01-21-2005, 10:56 PM

#14

mtcookson

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Actually the Maxima TPS is both variable and idle/wot. It goes between .40 or so up to probably 5 (can't remember the exact peak voltage). It also has an idle and wot switch I think mainly for the a/c shutoff at wot and other various things like that.

The Z's had an "on/off" type TPS.

01-22-2005, 06:49 PM

#15

subs1000w

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its .45-.55 at idle and 4V at wot

and my friend unpluged that on not the WOT switch which i beleave is 9v at idle and 12V at WOT

01-23-2005, 08:12 AM

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slimer

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this definitely sounds like a lean condition. I had it when my aux fuel pump wasnt switching on.

did you check your spark plugs to see if theyre white? if so, thats the culprit. time to upgrade fuel.

01-23-2005, 04:23 PM

#17

95turbo gxe

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hey whats guys sorry for not getting back on this thread.Thanks Mark you were right about most of the stuff except I dont have a bigger fuel pump. I havent test the tps yet But the other night on the way home it just went back to idel while I was going and the peddel became dead it would not cut off but it would not rev up at all. then after a few it went back to working

02-02-2005, 06:16 PM

#18

95turbo gxe

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Ok oK i got it. I guess I was running super rich Due to a whole in the intercooler coupler at the intercooler. I could not see it till I took it a part to do something eles. DAM INTAKE
LEAK

02-02-2005, 09:10 PM

#19

mtcookson

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i just love coupler leaks... i don't think mine has lasted longer than a few weeks before blowing a hole in it. damn i hate rubber... need to get my intercooler and silicone couplers on there really soon.