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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?

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https://www.sau.com.au/forums/topic/133783-hot-start-stumble/
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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.

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

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 :D

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.

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.

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