Hesitation @ WOT - 3000GT/Stealth International Message Center

chask · 04-10-2008, 04:23 PM

checked:
.Gap= .28
.MAF= Tried three different MAF sensors
.New walbro 255 external fuel pump
.MSD wires
.NGK BCP7ES spark plugs
.no leaky caps on ecu.

what could be the problem? only does it at WOT.

btw...
running 8:1 comp
9b's
360cc injectors
no boost leaks

what do you guys think?

red3000gtvr4 · 04-10-2008, 05:27 PM

Are you running stock BOV? thats what the problem was with my hesitation issues.. i replaced it with an RFL fixed it for a while but they came back again..

Sean3S · 04-10-2008, 08:16 PM

Other obvious stuff.... coils? PTU?

cap93 · 04-10-2008, 08:22 PM

Replacing the coils solved that problem for me.

a2j · 04-10-2008, 08:26 PM

hesitation @ what rpms? all of them or at the top?

DigiiManDan3KGT · 04-11-2008, 12:56 AM

I helped chask tonight but the problem still isnt fixed.

We didnt read this so we missed out on changing the Coils and PTU.

checked:
.Gap= tried .32
.MSD wires Changed to Digiimans wires that were working fine
.NGK BCP7ES spark plugs, They were all white and lean.
.no leaky caps on ecu. Changed to digiimans ECU nothing..
Took Digiimans Fuel rail, injectors, & fuel Pressure regulator - nothing..
Disconnected the SAFC - No change.
Added fuel to the SAFC to compensate - No change
Turned the boost down to 6psi -no change.

When the car sits for 2 hours we can drive it and make 1-2 pulls with out it Studdering & running a normal AFR. Once it heats up the wideband is showing the car allmost constantly running lean in closed loop mode. It will start creeping up 14- 15- 16 then 20 while WOT and it breaks up. Digiimans data logger didnt record any knock when this happened though. Once its heated up the wide band at idel just sits at 13.2 and doesnt cycle. Cruise is at 14 but if you start to create a load on the engine the AFR goes up, not down. Soon as the car saw any boost it would hesitate. RPMS didnt really matter because we slowly crept up the rpm band with out putting a load on the engine and it wouldnt break up. The problem would get progressively worse as we kept driving the car. Chask drove home and once he did about 30-40 miles the car would Idel rich at a light and stall but soon as i hit the gass it would jump way lean. We unpluged the MAF to see if the Wideband was reading rich & lean correctly. With the Maf unpluged the wideband sat at 10.0 AFR.

DigiiManDan3KGT · 04-11-2008, 05:47 AM

Added:

Fuel filter was completely bypassed to see if it was holding fuel back.
Made sure fuel pump was hotwired.

lawdogg · 04-11-2008, 06:07 AM

Surprisingly this same thing was happening on a friend's RT/TT. It wound up that the air filter was the problem! He swapped the stock intake back on and the hesitation completely disappeared.

DigiiManDan3KGT · 04-11-2008, 08:22 AM

he has tried 3 diffenent maf sensors.

a2j · 04-12-2008, 09:20 PM

so was anything done with coil packs or wires?

04-10-2008, 04:23 PM	#1 (permalink)
chask Forum Member Join Date: Aug 2005 Location: west palm beach Drives: 3000GT-TT Trader Rating: (1)	Hesitation @ WOT checked: .Gap= .28 .MAF= Tried three different MAF sensors .New walbro 255 external fuel pump .MSD wires .NGK BCP7ES spark plugs .no leaky caps on ecu. what could be the problem? only does it at WOT. btw... running 8:1 comp 9b's 360cc injectors no boost leaks what do you guys think? __________________ Recent Video: http://www.3si.org/forum/f60/small-v...my-car-416800/ Last edited by chask : 04-10-2008 at 04:33 PM.

04-10-2008, 05:27 PM	#2 (permalink)
red3000gtvr4 Forum Member Join Date: Feb 2008 Location: Portland OR Drives: 92 VR4 Trader Rating: (0)	Re: Hesitation @ WOT Are you running stock BOV? thats what the problem was with my hesitation issues.. i replaced it with an RFL fixed it for a while but they came back again..

04-10-2008, 08:16 PM	#3 (permalink)
Sean3S Verified Asian Join Date: Aug 2001 Location: Sugar Land, TX Drives: 94 TT Trader Rating: (35)	Re: Hesitation @ WOT Other obvious stuff.... coils? PTU? __________________ '94 RT/TT 13T's \| PTE FMIC - PPE Pipes \| 560's \| Supra FP w/ 8ga Hotwire \| MAF-T 1.37 & LT1 Blow-Through \| E-Manage Blue w/ Boomslang Harness \| HKS DLI \| Stillen Downpipe \| Gutted Rear Pre-cat \| Borla Catback \| Tial BOV \| AEM FPR & Rob Beck Adapter \| DejonTool Intake Pipes \| PWR Radiator w/ IPS Pipes \| FAL Fans \| MP Motor Mounts \| 99 Lash Adjusters \| Clevite 77 Rod & Main Bearings \| Leatherseats.com Dk. Graphite w/ Red Center Seats \| Sparco Flash 5 Black w/ Red Alcantara \| Spec Stg. 2 Clutch & 3SX Clutch Line \| 3SX Crank Pulley \| Bob's SS Shifter & All Solid Bushings \| NGK Coppers & MSD Wires \| eK2 EGR Blockoffs \| eK2 Fuel Line Loop \| PST 1 Pc. CFDS \| Volk LE37T \| Falken FK452 \| Tein S-Tech Springs \| Adj. Rear Control Arms \| Slotted Rotors w/ Hawk HPS Pads \| GReddy Profec B \| AEM UEGO WB \| GReddy PWH Boost, EGT, GReddy OP, FP, Temp \| Hybrid Logger \| McColluch 5300K HIDs \| Shaved '99 Bumper & Turns \| VIS Hood 295.7 AWHP / 310.3 TQ @ 1 Bar - BPU @ TX04 Collecting Dust - CM Oil Filter, Setrab Oil Cooler, Snow Stage 2 Meth, Brake Lines, Megan Coilovers Some Day - ABS Delete, Ducting WTB - ek2 Harness Cover (above the fuel rails)

04-10-2008, 08:22 PM	#4 (permalink)
cap93 Forum Member Join Date: Oct 2005 Location: Bel Air, MD Drives: 93 VR4 Trader Rating: (0)	Re: Hesitation @ WOT Replacing the coils solved that problem for me.

04-11-2008, 12:56 AM	#6 (permalink)
DigiiManDan3KGT 2 Time Member of SBC Join Date: Dec 2003 Location: Jupiter, Florida Drives: 80Gig WesternDigital Trader Rating: (7)	Re: Hesitation @ WOT I helped chask tonight but the problem still isnt fixed. We didnt read this so we missed out on changing the Coils and PTU. checked: .Gap= tried .32 .MSD wires Changed to Digiimans wires that were working fine .NGK BCP7ES spark plugs, They were all white and lean. .no leaky caps on ecu. Changed to digiimans ECU nothing.. Took Digiimans Fuel rail, injectors, & fuel Pressure regulator - nothing.. Disconnected the SAFC - No change. Added fuel to the SAFC to compensate - No change Turned the boost down to 6psi -no change. When the car sits for 2 hours we can drive it and make 1-2 pulls with out it Studdering & running a normal AFR. Once it heats up the wideband is showing the car allmost constantly running lean in closed loop mode. It will start creeping up 14- 15- 16 then 20 while WOT and it breaks up. Digiimans data logger didnt record any knock when this happened though. Once its heated up the wide band at idel just sits at 13.2 and doesnt cycle. Cruise is at 14 but if you start to create a load on the engine the AFR goes up, not down. Soon as the car saw any boost it would hesitate. RPMS didnt really matter because we slowly crept up the rpm band with out putting a load on the engine and it wouldnt break up. The problem would get progressively worse as we kept driving the car. Chask drove home and once he did about 30-40 miles the car would Idel rich at a light and stall but soon as i hit the gass it would jump way lean. We unpluged the MAF to see if the Wideband was reading rich & lean correctly. With the Maf unpluged the wideband sat at 10.0 AFR. __________________ Green 1995 3000GT FWD-TT 8:1 // ATX to MTX // NA to TT // Completed in 2005 // Purchased 11/12/02 White 1999 3000GT Black Dash/Tan Leather Interior // SOHC // MTX // Stock Daily Driver Purchased 7/25/07 Red.._1992 Stealth RT/TT Twin Turbo AWD // Project Car for AWD // Purchased 05/19/08 <-- Click Here Join FL3S

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04-11-2008, 05:47 AM	#7 (permalink)
DigiiManDan3KGT 2 Time Member of SBC Join Date: Dec 2003 Location: Jupiter, Florida Drives: 80Gig WesternDigital Trader Rating: (7)	Re: Hesitation @ WOT Added: Fuel filter was completely bypassed to see if it was holding fuel back. Made sure fuel pump was hotwired.

04-11-2008, 06:07 AM	#8 (permalink)
lawdogg Here for the tuna. Join Date: Jul 2003 Location: Williamsport, PA Drives: The Speed Limit Trader Rating: (60)	Re: Hesitation @ WOT Surprisingly this same thing was happening on a friend's RT/TT. It wound up that the air filter was the problem! He swapped the stock intake back on and the hesitation completely disappeared. __________________ 2002 WJ -- 1994 VR-4 -- --Canon Rebel XTi Green Cars FTW

04-11-2008, 08:22 AM	#9 (permalink)
DigiiManDan3KGT 2 Time Member of SBC Join Date: Dec 2003 Location: Jupiter, Florida Drives: 80Gig WesternDigital Trader Rating: (7)	Re: Hesitation @ WOT he has tried 3 diffenent maf sensors.

04-12-2008, 09:20 PM	#10 (permalink)
a2j Driving While Ukrainian Join Date: May 2007 Location: WI Drives: Red Car Trader Rating: (4)	Re: Hesitation @ WOT so was anything done with coil packs or wires?