Troubles With R34

[seanisonfire]

Hey guys

I've got a 4 door r34 which was imported from japan about 6 months ago and I have spent plenty of money to try and get it pretty quick!

Mods are as follows:

Garret gt3076r turbo

800cc denso injectors

Link g4 ecu

Xforce 3.5 inch exhaust

Greddy fmic

Slitfire coilpacks

Walbro in tank fuel pump

H/duty clutch

Now all this work was done at a tuner and they tuned it to 356hp@19psi. It wasn't a very good tune coz the motor was apparently on it's way out so they pulled heaps of timing out of the tune!

So now I have taken my car to a new tuner who has a very good name to try and get some more hp and a better tune! But they did a pressure test on the engine and found I was losing pressure through my 5th cylinder!

So I purchased a low km engine through these guys and decided to do some more work while the engine is out!

New mod list:

Low km neo rb25

Larger rear housing on turbo

Tial 44mm external wastegate

Now my problems have just started.. The tuner has had my car for almost 3 weeks now and can't seem to tune it properly.. Has only managed to get the car to 230hp@15psi.

He has been working with the old tune from the other tuner and trying to modify it to get it right but no luck! The car seems to spool up nice but plateus around 5000rpm. And one minute the car is running lean.. The next it's rich!! Should he be starting from scratch with a new tune seeing as though it's a new engine in the car? Or does this sound like another problem?? L

[GTSBoy]

Is fuel pressure properly under control? If the regulator isn't the same one between engines, (ie moved your injectors to the new engine's rail) then that would be a leading contender. I'd be looking at the fuel reg for a start, and testing the pump out, even if it is new.

Seeing as you've put a different wastegate in, you'd do well to make sure that that is closed when it is supposed to be and open when it is supposed to be.

[seanisonfire]

I don't have an aftermarket fpr.. The tuner reckons I don't need one?

[GTSBoy]

Yeah, so that's the point. How is the original one doing? They do die you know. Also, the pump might be crappy. Might have sucked something into the inlet or some other hassle that means it can't deliver enough pressure all the time. When a car is on the dyno being tuned, especially if the tuner is having trouble getting consistency, then it should have a fuel pressure gauge plumbed into the line and visible to the tuner so he an see what's happening with that whenever the car starts to misbehave. Also offers the possibility of saving an engine from blowing up on the dyno.

[DVS JEZ]

Did he compressiin test the new motor?

Tell him to check if the intake to the turbo is sucking shut.

Check that the vtc is working. Do a run with it on and a run with it off