Strange Starting Problems

[240zrb]

Hi

I have been searching for a couple of hours, but don't seem to find anything like the problem I'm having....

Rb25det, 3" turbo back, Apexi filter, Freddy intake, otherwise original.

Doesn't matter hot or cold engine, it takes a few (2-3-4-5) tries to get it to start. This problem only started a couple of weeks ago, earlier it always started first try.

The strange thing is once it's running, it's all smooth, idle and rev, no noticeble problems at all.

Fuelpump is priming, diagnoses gave 55, no visual sparks around coilpacks (tested in total darkness), new temp sensor did nothing.

Plugs bcpr6es-11, fuelpump and fuelfilter is just a couple of months old (and not that many miles on them).

Any advise would be appreciated!

Thanx:-)

[nuclear_skyline]

Has the cranking speed / frequency changed at all?

[R.3.2.G.T.R]

how old is your battery? Perhaps swap with another to check if it fixes the issue

also when u say takes a couple of attempts to start, what sort of noise does the car make during this time?

[240zrb]

Cranking speed appears unchanged, by the sound of it it's all good.

Battery is less than a year old, measured 13.2V (14.1v at idle). Oh, and noise is just your normal noise, engine cranking. No coughing or sputtering.

Edited September 29, 2010 by 240zrb

[-_-StRyDeR-_-]

got a fuel pressure gauge?

[240zrb]

No, I haven't got a fuel pressure gauge. But that could be a good point to check. I'll see if I can borrow a gauge.

Still, it pulls strong idle to redline (well, haven't tried redline but up to 5-6000). So, could it be fuel pressure..? pump is walbro, straight wire battery - relay - pump

[SiR_RB]

My gtr has started to do this recently too. After I put in bcpr7es spark plugs it would only do it when u go to restart the car when hot. Plenty of cranking then when it does start revs r very low so u tap the throttle and it picks up and idles perfect.

My cold start was perfect up until yesterday, now that's gone shit too

I thought it might of been those plugs so I put my old iridiums back in but same problem

Cars got sard fuel pump, nismo 600cc injectors, -7 turbos, and nistune...only been road tuned

Any ideas on what it could be??? Driving me nuts !

[UWISSH!]

funny that u guys mention this as i have a similar problem with my r33 gtr.

sum days it starts perfect and other days it wont, have to crank it 2 or 3 times before it wants to start and have to hit the accelerator aswell to get revs up.

is there anyway it could be a starter motor or alternator related problem?

it gives me the shits, ill start it and drive to work then at the eend of the day it sum times doesnt want to start again.

i also changed the battery and that didnt help

[DVS JEZ]

Guys is there any black smoke once it starts? As if its too rich?

[SiR_RB]

No smoke

It's weird how it's just started to happen from no where :s

[DVS JEZ]

I will check it out when we tune it in 2 weeks or so

[240zrb]

I still haven't figured out this, but in my case I have discovered: If I just touch the gas pedal just a tiny tiny bit, and crank, it fires right up:-) So, I haven't tryed too hard finding the real solution to this problem. If I don't put pressure on the pedal it takes x tries to fire it up, and the same happens if I try to pump / half pedal / full pedal...

[Adriano]

Maybe check your tps, it could be faulty causing clear flood on cranking

[DVS JEZ]

As above. Try checking and adjusting the tps.

How high does ur car normally idle?

[240zrb]

Thanx for the advice:-)

It idles at about 800 I think (hard to remember, haven't had it running for months)

I'll try checking the TPS, but not for a couple of months... I live in the northern most part of Norway, and it's freaking cold at the moment (well, now it's just -15 celsius, we've had a couple of weeks with -25-30 celsius. But I'm not firing the 25 untill it's + something.

And I need to hook up a diagnose plug, as it was not in the wiring I got with the engine. Engine vent into a 240z and I didn't think I would a plug, but now I need one for the Nistune:-)

Edited February 21, 2011 by 240zrb

[DVS JEZ]

If te temps are that cold maybe u should try a hotter spark plug. But u need to be wary of preignition under sustained wide open throttle

[240zrb]

It's just a summer car, as in only out on the streets during summer, but I'll keep your advice in mind:-) Thanx.

A pic if anyone wanna see the old Datsun with the new heart (and some plastic surgery...):

http://forums.hybridz.org/index.php/gallery/image/24342-73-240z-rb25det/

[DVS JEZ]

Looks tough 

[wolverine]

I imagine the fix is in the cold fuel enrichment tables. Colder weather is is going to make it hard for fuel to vapourise.

[tridentt150v]

I know its normal for Norway, but I can't get over those -20' temps........I get a -4' frosty morning in winter and swear and curse and vow to move north to a warmer climate.

Well I guess you don't have to worry about +40' days at least.

And apologies for OT.

PS as DVS said your car looks tough