Hot Start Stumble

[WogsRus]

Hi all

got another question.

I had reacently installed a new high pressure WALBRO GSS342 pump, as mine was dying. So now i have noticed that when the car is HOT, and you go to start it, it does this funny stumble, like when not all the cylinders start at once, then all fire up.

The car starts first time everytime, but does the above.

ANY IDEAS.

Didn't notice this with the old pump?

[mad082]

are you letting the pump prime, or just turning it straight on. you may need to turn the key to "on" for a second, then to start.

[Link]

Alternator problem maybe?

[WogsRus]

YEP, DEFFINATLY PRIMES, PUMP FITTED WITH AN ANTI DRAIN VALVE

[mad082]

was it only after you did the pump? did you do any other mods at the time?

[WogsRus]

adjustable fuel pressure rewg is on, but on bypass, so no pressure, using stock for now. SAFC II in but left at zero values.

That's all

[skylinecouple]

I have EXACTLY the same problem.Though mine has to be primed up to three times.I asked the tuner about it and he confessed he removed the flow back device cause it reduces the bosch 910 HP rating from 350hp to 250hp.Now I have to buy a new pump to get the higher HP rating and still have the anti flow back device.

However, you said yours has the valve in it so did you do it yourself or did someone do it for you? If it was someone else then double check.

[WazR32GTSt]

mate, i like to call it the "R32 syndrome"...

if you did a search you would find that this is a VERY common idiosyncrasy that many rb20 owners find they have with hot starts

it is benign - try not to worry about it!

[WogsRus]

lol, exept mine is the R33 syndrome.

Yeah it's a bit funny, i will sorght it out. I have a funny fealing it's teh fuel pump, as it is not direct wired, will sought that out ASAP and get back to you.

"skylinecouple" I do all the work myself, as much as i can, i don't trust other nimwits to screw up my car. If it is major, then it goes to a workshop i know well.

As far as i know, all WALBRO pumps have an antidrain valve fitted, mine did. you can get inline ones and put them in the tank, only cost about $30 from bosch

[WazR32GTSt]

ok to give you more info on the fact that this is normal...

this has happened to my car since i bought it 3.5 years ago...

what have i changed/cleaned to try to fix it?

- AFM

- fuel filter + hoses (also have changed to a walbro fuel pump with the problem still there)

- IAC valve

- AAC valve

- O2 sensor

- base timing

- battery

- spark plugs

- coils

that's all i can think of... pretty much changed or cleaned every sensor with no luck. running the car with nissan datascan reveals no problems either...

so if you find the problem, tell us all and make about 1500 skyline owners very happy

[SuAvE-1]

I have the same problem, some times it does it when the car is cold. Sometimes it does it when the car is warm, sometimes not. I am running everything stock except for boost controller, AAC valve out of a GTS-4 93' model, adj fuel pressure reg and walbro gss342 pump. These problems came once i installed the pump and reg.

I can resolve the problem very quickly by simply touching the slightest of touches on the acclerator. perhaps this has something to do with it. I will investigate in a few weeks time.

[WogsRus]

Well i am working on it. I will wire the pump in to direct feed on the weekend, and also stuff arround with the fuel reg. I will check the TP sensor ro ensure it is calibrated ok, and go from there.

It's one of those weird things.

I also changed my ECU temp sensor, which made a bit of differance, but now when the car is COLD, the rpm go up and then down and then up and stay at 1300rpm till she is warm.

BLODY CARS. LOL.

[WazR32GTSt]

maybe its something to do with fuel vaccum when the car is off?

my fuel cap doesn't go "pssh" when i open it.. i have always thought there might be somewhere that is making the fuel tank lose vaccum and maybe this hinders the start?

[WogsRus]

could be, but i reaealed mine over the weekend, and it is nice and air tight, makes a nice phsssss sound when you open it.

Still does it though.LOL.

[No Crust Racing]

Not sure if this is the same but my 33 had a problem where it simple wouldn't start when hot, it turned out to be a bad earth to the Cam Angle Sensor, fixed it no worries. Just something to consider

[WogsRus]

thanks mate, will look into that.

[WazR32GTSt]

no luck... i have an earthing kit installed and mine still does it