Suspected dirty injectors... what to do?? GOT NEW INJECTORS!

[MMamdouh]

I use STP too but my mech said to me that the cleaners start working after 3 days.

tryed STP, cyclo and GUNK injector cleaners... non of them did anything substantial to solve the issue.

MMamdouh

[MMamdouh]

Check fuel pressure regulator. Sometimes they like to "put" some fuel in underpressure pipe just to the intake manifold. Disconnect this pipe and look if there is no fuel leaking...

didn't get what am i supposed to do here...

do you mean to take off the fuel return line from the FPR with the engine off and fuel system under full pressure and see if some fuel is actually going out of the FPR pipe??

what if fuel does return and what if it doesn't??

MMamdouh

[klonek78]

Check fuel pressure regulator. Sometimes they like to "put" some fuel in underpressure pipe just to the intake manifold. Disconnect this pipe and look if there is no fuel leaking...

didn't get what am i supposed to do here...

do you mean to take off the fuel return line from the FPR with the engine off and fuel system under full pressure and see if some fuel is actually going out of the FPR pipe??

what if fuel does return and what if it doesn't??

MMamdouh

Not fuel return line, but line connecting FPR with intake manifold.

[pollito]

the injectors i got brand new are officially leaking... DAMN!

my mechanic told me that this type of injectors are known for leaking problems and he offered a solution... he gave me a set of different kind of injectors to try out and if i do like them i can buy them.


at a first glance i see that they are a different design than the ones i already got but still the same size... fitment was not an issue at all, after an initial test the car was a bit more responsive and the only startup test i did so far was a success.

on the diagnostic side i see that this injector is not a multi point fuel injector... it is a single point as it has only one port, the ones we got as OEM got 6 fine ports and thus it is MPFI, i recon it is because of our crappy fuel lots of fine size shit gets past the fuel filter and start to accumilate inside the fine ports of the injector and cause it to leak when closed due to improper sealing.

this single point injector got one big port - compared to the ones we got as OEM - and thus fine dirt will pass through the port and not clog the port... or at least this is what i think.

will keep you all posted.

MMamdouh

MPFI refers to having injectors in more places than just a single spot on your intake track, not how the injector iteself works. Almost all cars today are MPFI, which denotes how the injectors fire directly into the intake port.

[MMamdouh]

MPFI refers to having injectors in more places than just a single spot on your intake track, not how the injector iteself works. Almost all cars today are MPFI, which denotes how the injectors fire directly into the intake port.

then how come the lanos is MPFI when it have only one injector per cyl.??

MMamdouh

[MMamdouh]

so far the startup tests are OK... their is a little bogging out in 1st and 2nd gears when the revs are low and throttler is lightly applied... could be a little air leak from the injectors O ring as i think they are a bit smaller than the OEM ones... will check and see.

MMamdouh

[klonek78]

MPFI refers to having injectors in more places than just a single spot on your intake track, not how the injector iteself works. Almost all cars today are MPFI, which denotes how the injectors fire directly into the intake port.

then how come the lanos is MPFI when it have only one injector per cyl.??

MMamdouh

MPFI (Multi Point Fuel Injection) means that you have one injector per each cylinder - nothing more.
SPI (Single Point Injection) means that you have only ONE injector (near throttle body) per all cylinders.

[MMamdouh]

MPFI (Multi Point Fuel Injection) means that you have one injector per each cylinder - nothing more.
SPI (Single Point Injection) means that you have only ONE injector (near throttle body) per all cylinders.

you mean TBI (throttle body injection)?... i have seen some daewoos and Ibizas with TBI system and i think our system is more effecent eh?

also why does our injectors got 6 fine ports while others got one big port? is that got to do with spray pattern or so?

does this mean that both injector work in a MPFI system as single point injection is a TBI system?

MMamdouh

[MMamdouh]

according to what is mentioned in this article i just swaped GM injectors with BOSCH injectors:
http://www.teamlorenz.com/1990_lotus_se.htm



now i got to figure out the flow rate of both injectors to know what kinda flow am i running now.

MMamdouh

[MMamdouh]

i measured the resistance in the stock injectors and they were at 13 ohms so we are using high impedance injectors... right?

MMamdouh

[MMamdouh]

Check fuel pressure regulator. Sometimes they like to "put" some fuel in underpressure pipe just to the intake manifold. Disconnect this pipe and look if there is no fuel leaking...

didn't get what am i supposed to do here...

do you mean to take off the fuel return line from the FPR with the engine off and fuel system under full pressure and see if some fuel is actually going out of the FPR pipe??

what if fuel does return and what if it doesn't??

MMamdouh

Not fuel return line, but line connecting FPR with intake manifold.

did the test and no fuel came off the return line of the FPR.

MMamdouh

[klonek78]

MPFI (Multi Point Fuel Injection) means that you have one injector per each cylinder - nothing more.
SPI (Single Point Injection) means that you have only ONE injector (near throttle body) per all cylinders.

you mean TBI (throttle body injection)?... i have seen some daewoos and Ibizas with TBI system and i think our system is more effecent eh?

also why does our injectors got 6 fine ports while others got one big port? is that got to do with spray pattern or so?

does this mean that both injector work in a MPFI system as single point injection is a TBI system?

MMamdouh

Number of holes depends on injector placement and fuel pressure od fuel rail but the most important is flow rate at specified pressure.

You have right with SPI=TBI.

MPFI can be found for ex. in C20NE engines. Each cylider has its own injector but they works all together at the same time.

Also exists semi-SFI and SFI (sequential fuel injection). Semi-SFI can be found in ex Nubira X20SED - injectors works here in pairs. SFI can be found in T20SED - each injectors works alone (at same time) in sequence.

[klonek78]

did the test and no fuel came off the return line of the FPR.

MMamdouh

Did you disconnected fuel return line?? and there was no fuel??

Again!
Disconnect "air" line/pipe that connects FPR with intake manifold.
Start the engine and look at FPR in there is no gasoline leak.

[MMamdouh]

OH... i did the test with the engine off but i have spooled the fuel pump, will do it again with the engine running at idle.

MMamdouh

[klonek78]

OH... i did the test with the engine off but i have spooled the fuel pump, will do it again with the engine running at idle.

MMamdouh

But do not disconnect fuel return line - only this one I was written about.