Nissan Sunny Petrol Issue

[salal777]

i have a 2000 B14 nissan sunny. its engine changed from 1400cc EFI to a GA15DE 1500cc EFI. i have removed the cng.
problem is that as i accelerate, at around 2-3k rpms the engine lags the rpms drop and the car is held back for a while before openly accelerating again. the problem occurs when the tank has good enough level of fuel, the engine holding back is minimal but still takes the joy out of driving. it gets worse as the fuel level drops, and gets to a point where its hard to even get the car going in traffic. also at times wen the car is on a small incline, it starts up and then dies again as if theres no fuel at all.

i have installed a new fuel pump of thai/china origin about 2 days ago. and the problem is still there. as of now the car is parked on level ground. i started it and it stayed on for about 10 seconds then rpm dropped, engine stopped and now wont start like it has no petrol. it doesnt have much right now but i know it has atleast 6liters. im thinking of cleaning out the tank and checking all fuel lines incase that solves the problem. otherwise im clueless!

what could be the issue here?

[salal777]

abit of additional information, while going on motorway at speeds of 120 and above, the engine pulls back as if the fuel is cut off. the speed drops to about 100 and an explosion or a small fire cracker kind of sound comes from the engine bay. right after that sound, the engine frees up again and the car is able to accelerate again. anyone know whats up?

[sufian_noshad]

Did you change the fuel lines as well or not?
Coz once you upgrade to bigger capacity engine it requires more fuel as well and a car which came with a smaller engine from factory would require larger capacity fuel lines. Your car will keep going through the fuel pumps, as it has to keep working hard pushing that fuel to the engine through those narrow fuel lines.

[ashbal]

your ecu needs remapping or the engine isnt wired properly....the back explosion happens due to this

[ashbal]

when the car is still...does the small explosion happen when you press the pedal completely?if yes then its the eu issue either its not wired properly or it needs to be remapped

[salal777]

no the backfire or shooting or other kind of sound doesnt happen while car is parked. it also doesnt happen while in regular city driving. only happens at high speeds of 120 and above.

the narrow fuel lines could be the issue, that makes sense since the car originally came with a 1.4 and now it has 1.5.
i will look into cleaning out the tank as well as changing/checking the lines. by the way is change of fuel lines a big and or expensive job? will i need to get parts from a good shop in the city or are fuel lines readily available in other small areas? i do most car work in the village after getting required parts from the city.

[hornblower]

This post was flagged by the community and is temporarily hidden.

[SER_GTR]

Is You CEL(Check Engine Light ) Wired And Working????

The Problem You Mention Can Be Clogged Fuel Filter To Dead Or Weak Fuel Pump To Clogged Injectors....Fuel Tanks With No Baffles Do That...(Carb Cars To Efi Conversion Cars...) Strange For EFI Car Do That...

GA14DE Fuel Lines Will Work Fine On This....Along With Fuel Pump And All.....

[ashbal]

no the backfire or shooting or other kind of sound doesnt happen while car is parked. it also doesnt happen while in regular city driving. only happens at high speeds of 120 and above.

the narrow fuel lines could be the issue, that makes sense since the car originally came with a 1.4 and now it has 1.5.
i will look into cleaning out the tank as well as changing/checking the lines. by the way is change of fuel lines a big and or expensive job? will i need to get parts from a good shop in the city or are fuel lines readily available in other small areas? i do most car work in the village after getting required parts from the city.

People use the same fuel lines for 2000cc engines even if the orignal was for 1300cc ...urs difference is of a 100cc and for surely this is not the issue

[salal777]

the injectors have been replaced and checked. fuel pump is new so even if its not of very good origin it should still work atleast the first few days. if the fuel lines work same for ga14 and ga15 then thats fine too.
the only thing which i havent yet checked at all is the fuel filter, which after all could be the problem. the car has been run on cng mostly so i will have the petrol tank and fuel filter checked out.

the fact that the engine holds back and lags and then frees up leads me to think that theres probably gunk in the tank and the fuel filter. thats choking the supply.
CEL lights up while starting the car but idk i doubt its wired to light up when a problem arises.

[salal777]

wow. so i just checked out under the bonnet and there is no fuel filter at all. talk about cutting corners in Pakistan. at some point in time, the car has had its filtration system by passed idont know when.

i was thinking the filter might need changing, but there isnt a filter in the 1st place so now it has me worried that there might be a more expensive issue such as clogged injectors.

[jalaldurrani1985]

I had a same issue but I had pakistani engine in my car. I changed. Its computer ,throtal and wiring with japnes and now my car is fit.