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Hey all,

So i have an r34 gtt.

 

Z32 AFM, Xspurts 725cc injectors, bosch o44 fuel pump, Nistune.

 

Turbo, cooler, exhaust bla bla bla.

 

Problem is cold start is shit, idle is a little rough, and one the cars warms up, it has quite a nasty stumble low in the revs under slight load.

 

Everything else is great, just gets annoying when cruising around.

 

AFM is good, no vacuum leaks, no apparent leaks.

 

Ive had it retuend multiple times, and cant seem to shake it...

 

Im thinking injectors, but i wanna know what others may think before i rip them out and replace them,

 

All my parts are less than 12 months old, and its driving me nuts.

 

Any help would be awsome.

Cheers, Cam

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Ive got the same issue as you. Cold start is ruining my driving experience. Ive got the same parts as you, except I have 555cc Nismo injectors, Z32 copy and a Power FC.

This morning after driving 10-15 minutes home from work i decided to check my hand controller. Even though i have no idea if all the figures are working in harmony together i did find the "Ign Tmng" to be quite erratic. Even after the time amount id travelled the Ign Tmng was changing from 12-17. I dont know if this is a desired value. The sputter was felt exactly the moment when values of Ign Tmng changed.

 

Here is the video i captured:

 

 

maybe someone could jump in and lend some advice

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^^ Problem might be the fake Z32 afm, have heard they can cause bad running. Has the op with the r34 got a genuine Z32 or fake ?

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Even if the AFM looks to be fine it could be stuffed, happened to my old silvia till the point it wasnt driveable took the AFM off everything seemed perfectly fine, replaced it with another Z32 and the car ran perfectly.

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manifold leak..

 

I think that the timing is moving around because the TPS idle condition is on.. meaning that the ecu is in closed loop using the timing to control the idle speed..which it should be.. when the engine is hot... however when it is cold it should not be doing that and accessing a fixed timing figure from the ecu maps.. if the setup of the TPS is incorrect it can be that the tps idle position / voltage is still on under light acceleration.. this caps the timing and makes it stumble..

 

if the timing is excessively bouncing around normally it is a mani leak and the ecu goes crazy with timing values trying to stabilise the idle. but only when hot..

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I got it retuned and the cold start issue is better. Ive still got wierd ign tmng changes that occurs randomly at idle. Car drives great at acceleration though. Another issue has creapt out of no where. Occassionaly when i go from any gear to neutral the revs jumps (1500 - 800) 3-4 times before settling at 950 rpm. any ideas?

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boost/vac leak, and have you checked the tps?

 

 

-dan

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Nissan Silvia is one of the most favorite and most popular car who had the king of all the cars due to his auto parts. Many providers are looking for dissertation help online that will help him to choose the right forums about the technical issue.

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