North American Turbocoupe Organization



88TC code 41
Glenn Briglio Offline
Junior Member
#1
88 tc completely stock except for K&N air filter in stock air cleaner housing. Engine running rough after going into closed loop.Put a new denso 234-3002 o2 sensor in.Changed mass air flow sensor(used).New motorcraft spark plugs.Definetely runs better.Eliminated problem of stalling randomly and idle flucuating when put into neutral.Code 41 is only code at this time.Also gas mileage has gone down by 4-5 mpg.
Turbo all the time. 88 Turbocoupe 5spd, 84 SVO 5spd,2012 Ford F150 Ecoboost (automatic yuck),2008 Chevy HHR SS 5 speed, 2 Margay offset go karts 5hp B&S. 97 Yamaha GP1200,05 Yamaha VX110,98 Yamaha XL1200, 98 Yamaha XL760, 97 Yamaha GP1200, 99 Kawasaki Ultra 150, 97 Kawasaki 750 SS/Xi, ,2000 Yamaha Superjet jetskis.
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John B Offline
Member
#2
Glenn Briglio Wrote:88 tc completely stock except for K&N air filter in stock air cleaner housing. Engine running rough after going into closed loop.Put a new denso 234-3002 o2 sensor in.Changed mass air flow sensor(used).New motorcraft spark plugs.Definetely runs better.Eliminated problem of stalling randomly and idle flucuating when put into neutral.Code 41 is only code at this time.Also gas mileage has gone down by 4-5 mpg.

I'd continue with the ignition tune up stuff; I.e cap and rotor, spark plug wires, etc. Also check for exhaust leaks around the manifold, turbo before the downpipe. I just got done with this as it was causing me some problems. When was the last time you changed the PCV?
88 Turbo Coupe: Front mount intercooler, MGW short throw shifter, full coilover conversion, tubular control arms front and rear, svo front brakes, vacuum assist brake swap, manual steering swap, GT35R turbo with external gate, pimpx ecu, 60lb injectors, 3 core aluminum radiator, Boport 1.5 cam, gutted upper, corbeau fixed back seats, and the list goes on.
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Pete D Offline
Administrator
#3
Which part of the EEC tests did the code 41 occur in, KOEO/CM or KOER? It makes a difference with codes 41 & 42.
Pete Dunham


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Jeff K Offline
Administrator
#4
^^^^ +1

My guess is a vacuum leak. Carefully inspect all vac lines and IC couplings. Consider a "poor mans smoke test" using a cigar or pressurize the intake to look for leaks.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
11 Crown Vic Interceptor
14 Toyota Camry (wifes car)
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Glenn Briglio Offline
Junior Member
#5
Jeff K Wrote:^^^^ +1

My guess is a vacuum leak. Carefully inspect all vac lines and IC couplings. Consider a "poor mans smoke test" using a cigar or pressurize the intake to look for leaks.
Did a smoke test at friends repair shop. Nothing
Turbo all the time. 88 Turbocoupe 5spd, 84 SVO 5spd,2012 Ford F150 Ecoboost (automatic yuck),2008 Chevy HHR SS 5 speed, 2 Margay offset go karts 5hp B&S. 97 Yamaha GP1200,05 Yamaha VX110,98 Yamaha XL1200, 98 Yamaha XL760, 97 Yamaha GP1200, 99 Kawasaki Ultra 150, 97 Kawasaki 750 SS/Xi, ,2000 Yamaha Superjet jetskis.
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Glenn Briglio Offline
Junior Member
#6
Pete D Wrote:Which part of the EEC tests did the code 41 occur in, KOEO/CM or KOER? It makes a difference with codes 41 & 42.
Test done with KOEO snap on tester.
Turbo all the time. 88 Turbocoupe 5spd, 84 SVO 5spd,2012 Ford F150 Ecoboost (automatic yuck),2008 Chevy HHR SS 5 speed, 2 Margay offset go karts 5hp B&S. 97 Yamaha GP1200,05 Yamaha VX110,98 Yamaha XL1200, 98 Yamaha XL760, 97 Yamaha GP1200, 99 Kawasaki Ultra 150, 97 Kawasaki 750 SS/Xi, ,2000 Yamaha Superjet jetskis.
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Pete D Offline
Administrator
#7
What, if anything, might have been done to the car maintenance wise just before the problem started?

Have you run the fuel system diagnostics: http://turbotbird.com/techinfo/Fuel_Syst...ostics.htm
Pete Dunham


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Jeff K Offline
Administrator
#8
Another possibility ifs a failing / out of calibration VAM. CHeck the VAM output voltage (BK/W wire to W/BK wire) at 1000 RM hot idle. Volts should be around .5 V to .8 V or so. Also be sure the VAM isnt gunked up and the flapper door is not sticking. Do you have a spare VAM you can try?
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
11 Crown Vic Interceptor
14 Toyota Camry (wifes car)
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Glenn Briglio Offline
Junior Member
#9
Pete D Wrote:What, if anything, might have been done to the car maintenance wise just before the problem started?

Have you run the fuel system diagnostics: http://turbotbird.com/techinfo/Fuel_Syst...ostics.htm
Nothing done before problem started. Will do fuel system checks.
Turbo all the time. 88 Turbocoupe 5spd, 84 SVO 5spd,2012 Ford F150 Ecoboost (automatic yuck),2008 Chevy HHR SS 5 speed, 2 Margay offset go karts 5hp B&S. 97 Yamaha GP1200,05 Yamaha VX110,98 Yamaha XL1200, 98 Yamaha XL760, 97 Yamaha GP1200, 99 Kawasaki Ultra 150, 97 Kawasaki 750 SS/Xi, ,2000 Yamaha Superjet jetskis.
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Glenn Briglio Offline
Junior Member
#10
Jeff K Wrote:Another possibility ifs a failing / out of calibration VAM. CHeck the VAM output voltage (BK/W wire to W/BK wire) at 1000 RM hot idle. Volts should be around .5 V to .8 V or so. Also be sure the VAM isnt gunked up and the flapper door is not sticking. Do you have a spare VAM you can try?
I will check vam settings.No don't have another vam. The original was definetely a problem.New (used) vam seems to operate correctly.
Turbo all the time. 88 Turbocoupe 5spd, 84 SVO 5spd,2012 Ford F150 Ecoboost (automatic yuck),2008 Chevy HHR SS 5 speed, 2 Margay offset go karts 5hp B&S. 97 Yamaha GP1200,05 Yamaha VX110,98 Yamaha XL1200, 98 Yamaha XL760, 97 Yamaha GP1200, 99 Kawasaki Ultra 150, 97 Kawasaki 750 SS/Xi, ,2000 Yamaha Superjet jetskis.
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