JDS Performance
10-28-2010, 07:09 PM
240sx S13 Hatchback Stock Hesitation - Bucking - Slow Throttle Issues
I am writing this to help anyone with the same issues I had with a customers car.
Ok lets start with what we got
1993 240sx SE Hatchback - 5 Speed - KA24DE - Completely stock
Ok issues
When idling everything is fine
When driving under normal conditions with engine warm fine - until you punch the throttle
Then it has slow throttle and starts to buck and has hesitation
When engine is cold its way worse - but say deal
No error codes thrown
Ok what I was told has been done by Nissan & a ASE shop
Nissan ran a diagnostics check - stated MAFS was bad
Shop installed new "Nissan" fuel pump
Shop replaced gas tank with used one that has been cleaned out
Shop installed new fuel filter
Shop installed a remanned MAFS
Owners cousin did a full tune up - plugs, wires, dizzy cap & rotor button
Car was given back to owner and stated everything checked out and was running great - which was not the case at all
Owner contacted me stating I would be the last to try and fix it - as he was tired of the games and wasted money
So I went to work
Pulled plugs to check them - good/normal
Replaced MAFS with known working one - no change
Replaced ECU with known working one - no change
New O2 sensor - no change
New engine temp sensor (ECU) - no change
TPS calibrated - no dead spots - so good
Fuel pump ohmed out per FSM - so good
Unplugged each injector 1 at a time and that cylinder responded - so good
Unplugged each plug wire 1 at a time and that cylinder responded - so good
Checked MAFS wiring with multimeter per FSM - good
Checked/set timing - was retarded quite a bit - but did not fix the issue
While engine idled - pinched fuel line to engine and engine stalled - so good
Conclusion
I suspected either a really big vacuum leak or something wrong with the fuel system - but the fuel pump was new Nissan pump so assumed it would be good - hell its a expensive Nissan part - WRONG!!!!
I installed a walbro fuel pump today - and viola - fixed!
So dont ever think just because you got a new part installed and it didn't fix the issue your ok with that part - as even Nissan parts are prone to failure!
I am writing this to help anyone with the same issues I had with a customers car.
Ok lets start with what we got
1993 240sx SE Hatchback - 5 Speed - KA24DE - Completely stock
Ok issues
When idling everything is fine
When driving under normal conditions with engine warm fine - until you punch the throttle
Then it has slow throttle and starts to buck and has hesitation
When engine is cold its way worse - but say deal
No error codes thrown
Ok what I was told has been done by Nissan & a ASE shop
Nissan ran a diagnostics check - stated MAFS was bad
Shop installed new "Nissan" fuel pump
Shop replaced gas tank with used one that has been cleaned out
Shop installed new fuel filter
Shop installed a remanned MAFS
Owners cousin did a full tune up - plugs, wires, dizzy cap & rotor button
Car was given back to owner and stated everything checked out and was running great - which was not the case at all
Owner contacted me stating I would be the last to try and fix it - as he was tired of the games and wasted money
So I went to work
Pulled plugs to check them - good/normal
Replaced MAFS with known working one - no change
Replaced ECU with known working one - no change
New O2 sensor - no change
New engine temp sensor (ECU) - no change
TPS calibrated - no dead spots - so good
Fuel pump ohmed out per FSM - so good
Unplugged each injector 1 at a time and that cylinder responded - so good
Unplugged each plug wire 1 at a time and that cylinder responded - so good
Checked MAFS wiring with multimeter per FSM - good
Checked/set timing - was retarded quite a bit - but did not fix the issue
While engine idled - pinched fuel line to engine and engine stalled - so good
Conclusion
I suspected either a really big vacuum leak or something wrong with the fuel system - but the fuel pump was new Nissan pump so assumed it would be good - hell its a expensive Nissan part - WRONG!!!!
I installed a walbro fuel pump today - and viola - fixed!
So dont ever think just because you got a new part installed and it didn't fix the issue your ok with that part - as even Nissan parts are prone to failure!