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Old 08-23-2006, 12:25 AM   #1
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Default Bucking at full throttle? what do I do

I installed the greddy turbo system and very carefully searched the forum for installation(to make sure I did it right) and problems. but I dont' see anyone else with this problem.

car
1992 1.6
greddy turbo and intercooler.

thats it
here is the problem.

the car runs fine idles fin and everything all they way up to 4000rpm.

once I step on the gas (floor it) past 4000rpm the car startes to jerk like riding a wild bull. (yes really that bad, and yes I have ridden a bull before). any ideas what is going on? or a link to where on this forum someone else had this problem?

my thought was not enough fuel, but then again I know nothing about cars.

Please help me.
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Old 08-23-2006, 12:27 AM   #2
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Did this just start happening? How long have you owned the car?
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Old 08-23-2006, 12:29 AM   #3
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I had a garage rebuild the engine. the engine ran perfect until I put in the greddy.

I put 400miles on the greddy to break it in then took it out today to run it and this happened
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Old 08-23-2006, 12:30 AM   #4
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and I put about 20,000 on the car after the rebuild
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Old 08-23-2006, 01:11 AM   #5
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Install a saddle and hang on!!!!!!!!!!!!


Double check all your piping clamps- a blown off pipe might cause it), and spark plugs, loss of spark would cause it.
What plugs and gap are you running? Could be flameout??
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Old 08-23-2006, 01:14 AM   #6
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running ngk ir 35 gap checked all the pipes and tubes and connections and everything
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Old 08-23-2006, 01:17 AM   #7
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the bucking is so bad there is no way I would be able to control anything
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Old 08-23-2006, 01:38 AM   #8
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Make sure the AFPR is hooked up correctly. I think this can happen if you have the lines reversed. This is happening just as you are entering boost right?

When it happens can you see a black cloud of smoke belched from the exhaust? Did you do a check of the stock fuel pump to make sure it was healthy? New fuel filter?
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Old 08-23-2006, 02:06 AM   #9
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I had the stock fuel pump checked I put in an another inline fuel pump and put in a new fuel filter.

i checked the afpr lines and they are hooked up according to the manuel and I did a seached and they are also as stated in one of the instalaiton posts on here

any other ideas?
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Old 08-23-2006, 03:28 AM   #10
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What fuel pump, what AFPR and how much boost? Do you know what your fuel pressures are?
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Old 08-23-2006, 03:54 AM   #11
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zex inline fuel booster

the vortec thing that comes with greddy

and no I don't know

stock boost so i assume 5 but i get like 1-2 psi (if I am lucky) and it starts bucking
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Old 08-23-2006, 04:53 AM   #12
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You are probly overfueling your system with that zex booster. Take it out! The stock fuel pump produces enough fuel for the greddy kit up to about 6psi.
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Old 08-23-2006, 05:06 AM   #13
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Sounds like when you hit the Rev limiter on an NA, has the Rev limiter been droped to 4k?
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Old 08-23-2006, 05:12 AM   #14
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How in the world could that happen with just a basic greddy kit?
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Old 08-23-2006, 06:11 AM   #15
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how does it happen I have no idea I am dumb when it comes to cars.


could it be the slipping (clutch grabing and releasing)?

just curious because when it happens the car revs high then jerks and sone on

Last edited by chowser2; 08-23-2006 at 06:29 AM.
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Old 08-23-2006, 09:44 AM   #16
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I bet you $5 your fuel lines to the FMU are backwards or wrong.

The line from the back of the fuel rail (firewall) runs into the offset fitting of the FMU. Then the center fitting runs backs to the hardline.
The line to the front of the fuel rail (radiator) should still be connected straight to the other hard line.
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Old 08-23-2006, 10:17 AM   #17
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if it's not the fuel lines, i would consider the injectors. sounds like you are losing one as the load/demand increases.
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Old 08-23-2006, 11:32 AM   #18
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overly rich, or too lean. I would get some NGK ZFR6f-11 plugs and gap them down to .028 to make sure spark isnt getting blown out. I still think its a fuel issue though.
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Old 08-24-2006, 02:57 AM   #19
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Look on my pages under two sections ... Greddy Install and Vortech AFPR. Can run a complete check on the fuel system to include the AFPR in about 10 minutes. Can decide if that is the problem or not.
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Old 08-24-2006, 04:10 AM   #20
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did you check your timing? try setting your base timing to 6 degrees.
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