1998 s14 with Sr20det black top - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

GX3 · 07-21-2018, 06:53 PM

Hey I’m new to this website and I was hoping some one could help me with my s14 black top.

I just got this car two weeks ago and I notice this issue it had. Every time I came to a complete stop my car would bog out/ cut off as well when I turn the car on if it’s cold it idles perfect, but once it start warming up to it’s normal temp rpms start to drop and if you floor it the car cuts off. Also the car has no power what so ever on first and second gear it takes it a while to build up speed.

I’ve tried changing the coolent sensor, changed spark plugs, messed with the tps, messed with the maf, checked for leaks idk what els to check...?

Kingtal0n · 07-21-2018, 07:41 PM

boost leaks, check leaking bypass,

GX3 · 07-21-2018, 08:11 PM

Hey kingtal0n I’ve actually tried that as well and no leaks but some people have told me as well to check if I have the right ecu for my blacktop but I wouldn’t know where to lock up if I do have the right one

Kingtal0n · 07-21-2018, 09:21 PM

1. compression test
2. pressure test
3. timing test
whats the wideband say....

....4. get a wideband

GX3 · 07-22-2018, 10:59 AM

Quote:

Originally Posted by Kingtal0n

1. compression test
2. pressure test
3. timing test
whats the wideband say....

....4. get a wideband

Yeah that’s going to be my next step to get a wideband and if doesn’t work I’ll post the numbers it was making. Thanks

rellik27 · 07-22-2018, 08:34 AM

Is the blow off valve recirculated?

GX3 · 07-22-2018, 10:57 AM

Quote:

Originally Posted by rellik27

Is the blow off valve recirculated?

No it’s not recirculated

Kingtal0n · 07-22-2018, 11:10 AM

these engines are remarkably simple.

Fuel goes
maf -> ecu -> injectors

spark goes
cas -> ecu -> coils

The only places to really screw up here are
1. timing
2. maf related (boost / pressure leak or incorrect maf, placement, position, recirculation interference, all of that stuff)

and of course there is always
3. general misc. (wrong ecu/leaking injectors/wiring related/bad fuel pump/etc) but these are more apparent

GX3 · 07-22-2018, 11:20 AM

Quote:

Originally Posted by Kingtal0n

these engines are remarkably simple.

Fuel goes
maf -> ecu -> injectors

spark goes
cas -> ecu -> coils

The only places to really screw up here are
1. timing
2. maf related (boost / pressure leak or incorrect maf)

and of course there is always
3. general misc. (wrong ecu/leaking injectors/wiring related/bad fuel pump/etc) but these are more apparent

Thanks I really appreciate it I’ll get working today and checking all of that out and see what I can find.

GX3 · 07-22-2018, 11:28 AM

Quote:

Originally Posted by Kingtal0n

these engines are remarkably simple.

Fuel goes
maf -> ecu -> injectors

spark goes
cas -> ecu -> coils

The only places to really screw up here are
1. timing
2. maf related (boost / pressure leak or incorrect maf)

and of course there is always
3. general misc. (wrong ecu/leaking injectors/wiring related/bad fuel pump/etc) but these are more apparent

One last thing how can I find out what ecu is the correct one for my black top

Kingtal0n · 07-22-2018, 12:57 PM

1998 Notchtop with VTC Engine uses black "NA" ECU
1995-1996.5 uses red "WC" ECU
1996.5-1997 uses black "WC" ECU

iirc Both WC Ecu share a harness, but the NA ECU will NOT Plug into WC harness. So you can not possible have the wrong ECU since it wouldn't plug into the harness (apparently

)

wurley · 07-22-2018, 02:24 PM

also make sure the maf is an adequate distance away from the turbo.

rellik27 · 07-22-2018, 05:28 PM

recirculate it, it messes up your maf readings. Thats probably why your car shuts off when you come to a stop. Try that first before you waste money, could solve your other problems.

shobotan · 07-23-2018, 12:36 AM

Add to the list
Check the IACV - they can get clogged up with carbon residue.
Dismantle & clean and you should get a stable idle.

Check if the O2 sensor is still working this can affect idle quality when the car is warmed up.

07-21-2018, 06:53 PM	#1
GX3 Join Date: Jul 2018 Location: Houston Age: 26 Posts: 8 Trader Rating: (0) Feedback Score: 0 reviews	1998 s14 with Sr20det black top Hey I’m new to this website and I was hoping some one could help me with my s14 black top. I just got this car two weeks ago and I notice this issue it had. Every time I came to a complete stop my car would bog out/ cut off as well when I turn the car on if it’s cold it idles perfect, but once it start warming up to it’s normal temp rpms start to drop and if you floor it the car cuts off. Also the car has no power what so ever on first and second gear it takes it a while to build up speed. I’ve tried changing the coolent sensor, changed spark plugs, messed with the tps, messed with the maf, checked for leaks idk what els to check...?

07-22-2018, 11:10 AM	#8
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	these engines are remarkably simple. Fuel goes maf -> ecu -> injectors spark goes cas -> ecu -> coils The only places to really screw up here are 1. timing 2. maf related (boost / pressure leak or incorrect maf, placement, position, recirculation interference, all of that stuff) and of course there is always 3. general misc. (wrong ecu/leaking injectors/wiring related/bad fuel pump/etc) but these are more apparent Last edited by Kingtal0n; 07-22-2018 at 02:49 PM..

07-22-2018, 12:57 PM	#11
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	1998 Notchtop with VTC Engine uses black "NA" ECU 1995-1996.5 uses red "WC" ECU 1996.5-1997 uses black "WC" ECU iirc Both WC Ecu share a harness, but the NA ECU will NOT Plug into WC harness. So you can not possible have the wrong ECU since it wouldn't plug into the harness (apparently ) Last edited by Kingtal0n; 07-22-2018 at 02:50 PM..

07-22-2018, 02:24 PM	#12
wurley Zilvia Junkie Join Date: Dec 2012 Location: Wa Posts: 355 Trader Rating: (16) Feedback Score: 16 reviews	also make sure the maf is an adequate distance away from the turbo. __________________ @hiddenkouki WTB: FRONT S14 SILVIA Q'S SEATS purple zebra)

07-23-2018, 12:36 AM	#14
shobotan Join Date: Jan 2011 Location: Emerald City, Straya Posts: 23 Trader Rating: (0) Feedback Score: 0 reviews	Add to the list Check the IACV - they can get clogged up with carbon residue. Dismantle & clean and you should get a stable idle. Check if the O2 sensor is still working this can affect idle quality when the car is warmed up. __________________ MECHANICAL INJURNEER

07-21-2018, 07:41 PM	#2
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	boost leaks, check leaking bypass,

07-21-2018, 08:11 PM	#3
GX3 Join Date: Jul 2018 Location: Houston Age: 26 Posts: 8 Trader Rating: (0) Feedback Score: 0 reviews	Hey kingtal0n I’ve actually tried that as well and no leaks but some people have told me as well to check if I have the right ecu for my blacktop but I wouldn’t know where to lock up if I do have the right one

07-21-2018, 09:21 PM	#4
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	1. compression test 2. pressure test 3. timing test whats the wideband say.... ....4. get a wideband

07-22-2018, 08:34 AM	#6
rellik27 Zilvia Member Join Date: Jul 2008 Location: the bottom Posts: 254 Trader Rating: (4) Feedback Score: 4 reviews	Is the blow off valve recirculated?

07-22-2018, 05:28 PM	#13
rellik27 Zilvia Member Join Date: Jul 2008 Location: the bottom Posts: 254 Trader Rating: (4) Feedback Score: 4 reviews	recirculate it, it messes up your maf readings. Thats probably why your car shuts off when you come to a stop. Try that first before you waste money, could solve your other problems.

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