10 second buick problems

[Corvettekiller]

Okay, I am 16 years old and I am just now getting into the full complexity of these cars. I have a 1986 Grand National that should run around 10.50. It runs perfect on the street but last week I took it to test and tune at the track and it threw the check engine light as i was pulling off the trailer but i went ahead and ran it and it wouldnt push over 70mph. It showed the mass airflow and the iac so i replaced the maf unit and it was running perfect on the street again. I took it to the track last night and it was like the fuel shut off at 65mph and it ran a 16. Terrible. The check engine light came back on on the return road. It threw codes 21 and 24 which is tps and wheel speed sensor I believe.
Should i try to replace them, or what could be the problem? Any help at all would be appreciated as i am still learning about these cars. If you need any more info about the car then just ask me. Thank you.

 

[87_we4]

Make a list of all your mods to start with.

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[rmar]

Make a list of all your mods to start with.

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X2
Add forget the strip until everything is sorted out.

 

[Corvettekiller]

TE61 turbo running 18 psi of boost with 3 inch terry Houston downpipe, Revolution X Roller Cam Kit 210/215, TRW Forged pistons, block is 30 over, decked, and honed, stock rockers with TA Performance Hardened rocker shafts, powerlogger with 3 bar map, LC1 wideband O2 and a Translator with 4" GM MAF with integrated IAC sensor and has a Art Carr non lockup 3400 stall torque converter. Im sure there is other stuff but I don't know off the top of my head.

 

[rmar]

Late night reading. I should say required reading if you own one of these cars.
http://www.vortexbuicks-etc.com
http://www.gnttype.org

 

[87_we4]

Didn't see anything about what fuel pump, hotwire, regulator. What's your afr when its doing it? Post your log from power logger

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[Phoneguy]

What makes you think that this car will run mid 10's ?

At 18 psi you will be lucky to run a mid 12.

What fuel are you running? Fuel pressure ? Do you get a 1:1 rise in fuel pressure with boost? What is the A/F ratio? Timing ?

Bryan

 

[ZNix]

Stock heads?

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[Corvettekiller]

Yes stock heads. I turned the boost down from 22psi untill i can get my cooling mist kit installed. It began to knock occasionly at WOT.

 

[Corvettekiller]

The fuel pressure at idle is 41 psi. It has a hotwired XP fuel pump.

 

[ZNix]

You are going to blow this thing up running 22 psi on 93 octane! You are getting so much KR. Thats why u are running so slow. You are lucky its not in pieces atm!! Scanmaster?!?!

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[Shawn N]

What's the TPS voltage at idle in closed loop and again at wot? 21 error code is voltage over .50v idle or over 4.80v at wot. Your car needs to be in the .42v to .46v range at idle and 4.40v to 4.60v wot. Anything out of range will cause the car to run erratic like you are describing.

 

[87_we4]

What chip are you running? Is your fuel pressure rising 1to1

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[blackgn1]

I agree with everyone's post. A 10 second run isn't easy. I would look at doing a leakdown test. You may have hurt the motor already. You most likely had lot of knock with your boost and octane.

 

[Corvettekiller]

The previous owner had it set at 22 and i tuned it down. I have been running 116 i buy from the track.

 

[Corvettekiller]

The tps closed is at .42 and at wot is 4.48 and yea the fuel pressure is rising 1/1 with the boost

 

[Shawn N]

The tps closed is at .42 and at wot is 4.48 and yea the fuel pressure is rising 1/1 with the boost

You should not be setting off the SES 21 with those numbers. Is there something tied in with the TPS harness like a voltage booster?

 

[blackgn1]

Good to hear you had 116. I would trouble shoot everything.

 

[87_we4]

With those mods I dont see that car being anywhere near 10.50

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[Corvettekiller]

The car has made a 11.08 pass before so i guess technically not 10 but its almost there. That was sorta my goal. But the car just feels overall slower even before it threw the codes.