Noobie needs HELP!!!!!!

[redneck_ricer]

First off it's a 91 gts-t type m. Now when I first start the car dead cold the Rpms come up and it starts it's regular idle, 45 seconds in the idle begins to drop and will stall. I fire it up again 30 seconds later it stalls, if I tap the gas the rpms come back up and again 30 seconds later it will try to stall again. Now that'd not where the problem stops, while driving I have a slight hesitation and sever power loss. When I come to a light it will try to stall again. Please help would like to get this figured out before it comes off the road for the winter and I am very new to fuel injection so please explain short forms and roughly where to find these parts thanks alot

[Skym]

Sounds like TPS (located on side of throttle body) is not touching idle contact inside TPS (ECU doesn't switch to idle tables), as revs will drop below idle rpm (engine runs very rich) and engine stalls if not touching idle contact. TPS is used by ECU for transient throttle enrichment (similar to accelerator pump on carb engine), so affects amount of fuel injected into engine on top of what fuel map tells ECU to inject when accelerating. Hesitation, stalling out of the blue are other symtoms of faulty TPS.

When this starts happening, only option is to replace TPS, as it's faulty and out of spec. Also you'll probably find a TPS error code on ECU that needs to be cleared by pulling battery terminals off, stomping on brakes to remove any left over charge, reconnecting battery terminals (resets ECU).

Or buy this cable, software and clear error code via laptop -

http://www.blazt.biz/

[mitch32]

I'd say first check the code on the ecu. All nissan from our era have the same way of reading codes, go to the following website and do what is says, pull the code and find out whats going on. The location of the ecu is different then the website says, its beside the passengers left foot. http://www.nicoclub.com/archives/nis...iagnostic.html

Like Skym said its probably TPS

[redneck_ricer]

If it turns out to be the tps then how easy is it to replace? Any tuning to be done?? And where do I find a tps is there an interchange?

[Nismo_line]

try the fuel pump i was having a problem where i had a hard time starting the car and no power while driving i replaced fuel pump and solved me problem

[redneck_ricer]

Fuel pump is less then 6 months old

[Skym]

I guess a way to check if TPS is touching idle contact, is when you back off throttle fully while cruising, should hear engine tone change, car buck a little bit as ECU switches to idle tables.

TPS is new from Nissan parts department (Nissan dealership). TPS needs to be set, so it's touching idle contact. If you have Nistune for stock ECU (makes older stock ECU's reflashable via consult port, cable, laptop, tuning software, like most modern cars have) it's easy, as has button that light's up in tuning software when TPS is touching idle contact. If you don't have Nistune tuning software, need to go by voltages, multimeter.

This is correct TPS voltages for RB20DET engine -

DEPRESSED (WOT) : 4.02V
RELEASED (idle) : 0.44V
RANGE : 3.58V
SPEC : MORE3.0V

Note depressed is .02 above normal spec for TPS.

[RHDskyline]

so i can go into Nissan and get a new TPS through them


Im assuming if i replace mine on my rb25det, i can use my power fc to adust it???


I was having similar problems.

My problems were if i accelertated hard then stopped hard the car would (and still does sometimes) stoop really low in RPM's and the odd time die.

A buddy looked at it and noticed i had to openings in my throttle body. He capped those off and it was good for a bit, but now i notice it sometimes happening again and i would like to think its the TPS

[Skym]

TPS is common failure part (usually last's same km as 02 sensor, but depends on how you drive car). I've been through 2x TPS on my car so far. Nissan went fly by wire with year 2000+??? cars, which is supposedly a better setup. You can fit fly by wire setup with older Skylines, but need a Motec M600? ECU that has the fly by wire feature.

You'll need the part number of TPS (should be on housing of TPS) if their fast program on computer doesn't have the part number (diagrams with part numbers) for Skylines.

TPS should be able to be set by PowerFC, if it displays TPS voltage on hand controller.

[Prophetic]

I checked ECU and got 55; but this sounds exactly like the problem I'm having. Is it possible it just won't show up on ECU codes?

[redneck_ricer]

K update...... Checked LED and it's dark so I would say burnt out so I don't have a way to check..... Anybody got a scanner that would b willing to help???? Don't have the money to send it into a shop

[Skym]

Last TPS failure on my car had no error codes on ECU (voltage range? didn't drop enough to engage error code). Checked TPS voltage via multimeter at TPS plug.

[redneck_ricer]

K what wires do I test are they color coded?

[Skym]

Read this link -

http://www4.wave.co.nz/~lakewood/Skyline/ThrottleTPS.htm

[M13]

from personal experience, TPS doesn't affect the symptoms you described above.

I've ran my car w/o TPS and ran fine (slight hesitation at 1500rpm)

Then again my car has Nistune and has been tuned for all RPM range.