GAZZUZZ:
Fanex where are you?

fanex:

lagos VI or Ikeja.

Imike:
i have a problem with my 2005 pajero GDI. i ve been searching for a good auto mechanic all to no avail. the car begins to jerk once it reaches 100km/hr. the fuel pump has been changed, as well as the throttle cable and neck, it then developed another problem. you can contact me through my no if you can help. please only if you can help. MODS please help a brother in need. pls push to front page. 08085236231

mayor2013:
l

Was the throttle head and eyes changed as well

GAZZUZZ:
Fanex where are you?

Imike:
i have a problem with my 2005 pajero GDI. i ve been searching for a good auto mechanic all to no avail. the car begins to jerk once it reaches 100km/hr. the fuel pump has been changed, as well as the throttle cable and neck, it then developed another problem. you can contact me through my no if you can help. please only if you can help. MODS please help a brother in need. pls push to front page. 08085236231

Imike:
i have a problem with my 2005 pajero GDI. i ve been searching for a good auto mechanic all to no avail. the car begins to jerk once it reaches 100km/hr. the fuel pump has been changed, as well as the throttle cable and neck, it then developed another problem. you can contact me through my no if you can help. please only if you can help. MODS please help a brother in need. pls push to front page. 08085236231

While there are a number of vehicle manufacturers that produce GDI engines the most common that I come into contact with are the Mitsubishi models, so for that reason I will focus on them for this article.

GDI or Gasoline Direct Injection is another step in the ongoing search for a more efficient use of the petrol that your car uses. It is simply an engine where the petrol is injected directly into the cylinder as opposed to the more common petrol injected car where petrol is injected into the air flow prior to it reaching the cylinder. Characteristics of the Mitsubishi GDI are the vertical inlet manifold, the rather odd piston design (see photo)and the design of the new "swirl" fuel injectors, named so because of the vortex type of spray pattern as fuel is injected into the combustion chamber. The airflow from the manifold into the cylinder produces a swirling effect in the cylinder which tumbles in the opposite direction than other engine designs and by injecting fuel at a very late stage of compression, into the bowl on top of the piston, a richer mixture can be concentrated around the spark plug to allow for proper ignition.


Mitsubishi GDI Swirl Injectors
This means that the GDI engine can, under certain "low load" conditions operate on an air/fuel ratio of about 40:1 rather than the more common 14:1. Under heavier loads fuel is injected once during the intake cycle which cools the incoming air and then again at the late stage of compression which results in a richer air/fuel mixture for more power.

Fuel delivery is another difference for the GDI, there is a standard type electric fuel pump immersed in the fuel tank just like most other fuel injected cars, but this pump instead of delivering fuel to the injectors, delivers it to a mechanical pump on the side of the engine which then increases the pressure from 45psi to approx 750psi and that is the pressure that is delivered to the injectors.


The unusual piston crown
on a Mitsubishi GDI piston
There is also an unusually high compression ratio with GDI cars 12.5:1 is common with Mitsubishi, this means that it is vital to use a higher octane fuel to avoid pre-ignition in the combustion chamber which can cause severe damage to the engine over time.

Mitsubishi claims that their GDI engines can burn fuel 35% to 40% more efficiently than engines with the more common MPFI (Multi Point Fuel Injection) systems and at the same time get an increase in power output by about 10%.

GAZZUZZ:



THANK U GAZZUZ


The unusual piston crown on a gdi engine.
[img]http://critchauto.co.nz/myworksite/images/GDI-Piston.jpg[/img]


From all the long stories iv posted it seems you have a fuel pressure problem on the mechanical pump on the side of the engine. I'm not a fan of blind diagnosis but I'll advice you scan vehicle and check fuel pressure using a fuel pressure testing device to avoid throwing unnecessary parts at the problem.

Good luck.


://critchauto.co.nz/myworksite/Techdocs/techdoc2.html

Sorry add http in front of the link for the source iv been having to many spambot bans all week.