R33 Problem After Highway Driving

[Kane_R32]

So my mate has a R33 RB25det manual.

Mods include 3inch cat back and turbo timer. Standard boost without going through the solonoid (7psi?).

Everything else its stock mechanical wise.

He rang me today and said once he got of the m7 doing the 100km/h speed limit when he back off in gear, very loud pops can be heard.

So I intially thought it might have been the normal popping sometimes associated with a bigger exhaust.

These are loud crisp pops and sound to be in sync. I mean pop...pop...pop... not pop......popopopop.........pop. Sort of thing.

Also now when starting the car it will stall unless the pedal is held for 5 seconds and then the car gains idle to 800-950rpm.

No check light has come on yet. Checked all vacuum lines, not leaks and everything seems to be in good working order visually.

Any thoughts?

[defari]

mine is similar except mine doesnt stall and the pops aren't in 'sync'.... when i get off the gas say at 6-7000rpm and revs drop to about 4000 it makes a loud pop + flame then a few little pops... i think its just the big exhaust (3inch straight through into 4inch muffler) + mine is running a tad bit rich hence the flamage..

edit: car is a series 2 r33

Edited November 3, 2009 by defari

[Kane_R32]

Yeh this is deffinately not the over rich sound poping.

If you drive in 2nd @ 60 and back off the whole way on deacel its pops the same loudness like. Same sort of pop noise and its crisp not a rich sounding pop pop.

[defari]

so its more like a backfire sorta sound?

[Kane_R32]

so its more like a backfire sorta sound?

Not the usualy deep backfire but more a pop.

I'll try find an audio.

[Dorigecko]

Check fuel pump and lines. if you gotta feed it to get the revs back so it doesn't die, and it's backfiring (usually a sound associated with not getting fuel - bare in mind it IS an rb25det with standard computer), then it sounds to be a fuel issue. fuel pump, lines, AFM could also be outta whack.

[blind_elk]

Backfire is generally excess fuel getting into the exhaust and being ignited by the heat. Since the injectors shut down at full decell, it must be a leaking injector feeding fuel during decell. Get the injectors cleaned.

It may also be that the injectors are not shutting down, and that is usually a result of the TPS getting out of whack and not sending the "throttle closed" signal to the ECU. Check the TPS for 0 ohms at "throttle closed".

[Ultimategtr]

What BOV is he using?

[Kane_R32]

stock bov.

strangely enough, today he reports no issue.

heat related?

[Granthem]

needs moar limiter...

[Luke_GTS-T]

needs moar limiter...

please explain...

[Kane_R32]

OK quick ecutalk scan showed:

tps: .12v @ idle, 4.3v 100% throttle

afm: 1.2v @ idle - forgot 100%

02 is deffinatley stuffed. it sometimes adjusts from .20 to .40 but mainly sits on .00

Would the ecu see this as lean or would it ignore if tps and afm read full throttle.