R33 Skyline Start Up Problems In The Morning

[Ben C34]

Have you checked the tps is adjusted correctly? ecu codes? temp sensor?

as suggested above?

[tripsteady]

Have you checked the tps is adjusted correctly? ecu codes? temp sensor?

as suggested above?

will try

[zoomzoom]

If you have a consult cable, or feel like buying one of ebay, you would be able to create a log of all available sensors while you start the car and let it run (or die out).

That should give some useful info as to what is going on.

[tripsteady]

If you have a consult cable, or feel like buying one of ebay, you would be able to create a log of all available sensors while you start the car and let it run (or die out).

That should give some useful info as to what is going on.

how much is it?

how do you use it?

do you need anything else beside laptop and cable?

what software is used?

[zoomzoom]

I use an ECUtalk consult which is about $100 on ebay. There are cheaper ones though I can't comment on their quality.

You plug the consult connector in the consult port near the fuses on the drivers side, you plug the USB into a windows laptop.

Theres a few freeware programs which can then read the consult port as a COM port. Apart from reading codes and realtime sensor info, you can create a log which writes all the selected sensors into a table format about 30 times per second.

More info here: http://www.ecutalk.com/interface.aspx

[tripsteady]

Ok, so some new info

I didn't start the car for 4 complete days....assuming that of course it would be extremely cold and obviously have the cold start issue. I took my camera out to record for my mechanic so was looking forward to it having the cold start problem...for once lol

This is the weird part...after sitting for 4 days....it started absolutely perfectly. No hesitation , nothing. This has happened before when I hadn't started the car for 3 days....

Don't know if this will help anyone but it seems if I don't start the car for between 24-48 hours it has this issue , but less then 24 hours or over 48 hours of not starting , it starts perfectly.

Weird...im stumped....maybe more knowledgeable folk can chip in.

[tripsteady]

Ok, so some new info

I didn't start the car for 4 complete days....assuming that of course it would be extremely cold and obviously have the cold start issue. I took my camera out to record for my mechanic so was looking forward to it having the cold start problem...for once lol

This is the weird part...after sitting for 4 days....it started absolutely perfectly. No hesitation , nothing. This has happened before when I hadn't started the car for 3 days....

Don't know if this will help anyone but it seems if I don't start the car for between 24-48 hours it has this issue , but less then 24 hours or over 48 hours of not starting , it starts perfectly.

Weird...im stumped....maybe more knowledgeable folk can chip in.

FYI I have confirmed this. If I start the car after it sits for between 18 hours and 30 hours it has issues starting. Before or after this amount of time has passed it fires up perfectly. Tried a few times and same result every time. This could narrow our search greatly.

[MatthewT85]

i dont know if this will help.

but i had the cold start issues way back when this was started, on stock ecu, i never found a fix for it.

i changed to a Power FC and tuned

and then had a diff prob, whether its from the same issue or not i dont know.

but what would happen is it wouldnt start first go would splutter and die, then be fine next start This is cold start btw.

then when i would be lazy and put the clutch in but not down change it would rev hunt but not stall.

also hot starting would give the same rev bounce.

i had looked around trying to find others having the issue and noticed there is a sensor check on the Power FC looked at it and noticed my TPS was at 0.35v

which is low anywhere from 0.45-0.5v is what you should be aiming for.

so today i adjusted it and it has been near perfect!!! fingers crossed

so maybe you guys might want to check it out.

Like i said it may have no relevence to these issues, ive forgotten the specifics of everyone posting, just my own.

If you guys are running stock ecus you can still check the voltage just need a multimeter, there are a few threads around, you may just need to find the correct wire....

hope it helps

[Ben C34]

I suggested that at the top of of this page.....

[MatthewT85]

ha well i clearly skipped it, well it works

[dyl33]

Anyone still experiencing this shit in 2020 lol 

Starts then cuts out. Restart runs rough, tap accelerator revs pick up then runs fine.

[GTSBoy]

Usually a dirty IACV.

[dyl33]

1 minute ago, GTSBoy said:

Usually a dirty IACV.

That's the Aac valve right? I cleaned that once before wasn't really that dirty and cleaned it 2 weeks ago just to double check was still fairly clean. Never mad a differance ?

[GTSBoy]

No, AAC and IACV are two different things, unless you have a Neo, in which case they are two different things inside the one unit.

IACV is the Idle Air Control Valve. It is the motorised valve controlled by the ECU to control the idle speed to a set point.

AAC is the Auxiliary Air Control. It is a thermostatic valve that is open when cold. In earlier cars it is electrically heated so it starts open to provide lots of air for a fast idle when cold, and then closes and the idle speed control then falls back on the ECU & IACV. On the Neo, the AAC is heated by coolant.

Both can be dirty and stuck open/closed/anywhere.

The IACV is far more likely to be dirty and stuck than the AAC.

You would need to look for some pictures of both (use a manual, not Google image search, because most such photos of such valves are mislabelled and you could continue your wrongness, or convert your rightness to wrongness just as easily as it actually helping. FWIW, the AAC is a quite big thing with a hose in and a hose out. The IACV is bolted directly onto the plenum and has what looks like a motor on it.

[dyl33]

I thought the aac/iacv are the same thing on the back of the intake manifold? There's a cold start valve under intake manifold?

Edited April 15, 2020 by dyl33

[GTSBoy]

1 hour ago, dyl33 said:

There's a cold start valve under intake manifold?

Actually, I done f**ked up. It's the RB20 and the 26 that have the separate AAC under the manifold. The vanilla RB25 has the combined unit (but not the same combined unit as the Neo). The AAC is still electrically heated. The IACV is the stepper motor driven one. There's plenty of threads on these on here.

[dyl33]

So what could be wrong with it? Aac appears to operate normal cold or hot via ecutalk. Idles and drives perfectly 

[KiwiRS4T]

14 minutes ago, dyl33 said:

So what could be wrong with it? Aac appears to operate normal cold or hot via ecutalk. Idles and drives perfectly 

Well did you do what was suggested as a cause back in the thread - check the TPS setting?

And of course my favourite try unplugging the ecu water temp sensor. If it starts better that way (and don't turn the engine off again but keep driving) then you need to replace that sensor (its the one with two wires - the single wire one goes to the gauge).

Other than that check that the fuel is priming properly.

[dyl33]

Yeah man checked tps 0.45 closed. 

Never tryed the temp sensor because i thought i can see it working correctly in ecutalk but might give it ago.

[dyl33]

Also cleaned the cold start valve last night which was spotless anyway so doubt that'll make a differance.