Bogging Down After Burping The Throttle

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Sayten

Registered
Did a bunch of work to my busa engine and now it idles great and will run but if i hit the throttle to fast instead of rolling on it, it starts bogging down but it only does this at the lower RPMs. I have a after market Fuel Pressure Regulator and it sits around 45psi so i know its getting the fuel it needs. ive been at this for some time and i cant think of what it could be.
Gen 1 Busa with gen 2 ECU and flywheel

changed the plugs
checked the jets

any other suggestions?
 
Is it hesitation, then picks up or does it feel like it will stall, if you continue to hold the throttle open? Did it start doing it after changing the ecu or was it running fine, then started doing it? Have you checked the TPS adjustment and carried out a throttle body sync?
 
Sayten said:
Did a bunch of work to my busa engine and now it idles great and will run but if i hit the throttle to fast instead of rolling on it, it starts bogging down but it only does this at the lower RPMs. I have a after market Fuel Pressure Regulator and it sits around 45psi so i know its getting the fuel it needs. ive been at this for some time and i cant think of what it could be.
Gen 1 Busa with gen 2 ECU and flywheel

changed the plugs
checked the jets

any other suggestions?
Click to expand...

I didn't know fuel injected bikes had jets? Did you mean injectors?
 
David Offor said:
Is it hesitation, then picks up or does it feel like it will stall, if you continue to hold the throttle open? Did it start doing it after changing the ecu or was it running fine, then started doing it? Have you checked the TPS adjustment and carried out a throttle body sync?
Click to expand...

its will die if i hold it open to long. but i can gradually bring up the rpms and then punch it and not have any problems
 
this also happened after i had the wiring harness rebuilt ecu changed out and i put a new collector onto the exhaust bc the old one was beat to crap.
 
u absolutely sure its getting fuel under load? do a deep search on ure problem on here... what did u do to the motor? vacuum leaks????
 
Not sure if this will help, but I will throw it out there.
I had an 84 Firebird that I swapped in a 350. Threw on a Holley 780 DP and it would bog and die for a sec, then run like a raped ape. I could roll on and all was great. Switched the 780 to a 600 and it ran perfect. Turned out I was pushing way too much fuel. Worked at high rpms, but would seriously bog put at low rpms.
I wonder if the ecu was programmed wrong, wrong (too high) fuel pressure, or maybe u really can't add a gen 2 ecu to a gen1. Hmmm.
GL,
Troy
 
ali123 said:
u absolutely sure its getting fuel under load? do a deep search on ure problem on here... what did u do to the motor? vacuum leaks????
Click to expand...

under load meaning when i burp the throttle real quick or at a constant? bc i can run this thing fine after i pass about 35mph but anything before that i cant just punch it. i did rebuild my exhaust the OEM collector was super beat so i put a different one on and went from dual exhaust to a single but i couldnt tell you if it started before or after the exhaust bc i did all this while it was tore down and hadnt ran it sense before i made all the changes other then that no changes to the motor at all not a single thing.

i'm pretty sure i dont have any leaks but i could just put new lines on just in case.
 
Getn off said:
Not sure if this will help, but I will throw it out there.
I had an 84 Firebird that I swapped in a 350. Threw on a Holley 780 DP and it would bog and die for a sec, then run like a raped ape. I could roll on and all was great. Switched the 780 to a 600 and it ran perfect. Turned out I was pushing way too much fuel. Worked at high rpms, but would seriously bog put at low rpms.
I wonder if the ecu was programmed wrong, wrong (too high) fuel pressure, or maybe u really can't add a gen 2 ecu to a gen1. Hmmm.
GL,
Troy
Click to expand...

the gen 2 ECU works fine if it didnt the motor would run at all. could be the programming wish i new ha.
 
well i feel like an idiot. its not a gen 2 ECU, i upgraded from a 16bit to a 32 bit ecu that is all. i think i confused myself with the bit change relating to a gen change and the ECU is a 06 and Gen 2 wasnt till 08 my apologies yall.

side note, should i get a PC and see if that helps with anything, and if so which one?
 
If the aftermarket fuel pressure regulator is negatively impacting the amount of fuel delivered, a PC should help but you'd also need to tune for proper AFR. You could check AFR with a AFR gauge and if it is off at lower rpms, PC5 and AutoTune or bring to a tuner and flash/dynotune. If you're racing, you might want to consider the secondary module PC5. I always hear secondary injectors are not necessary to tune except maybe for turbo. There is now a PC5 that includes ignition module capability if that's of any use to you.
 
It’s better to find the actual fault, than putting a plaster/PC on the problem, otherwise you will start causing more issues and the masked problem, might get worse.
Have you eliminated the TPS as a possible fault or the ckps (crankshaft position sensor).
 
David Offor said:
It’s better to find the actual fault, than putting a plaster/PC on the problem, otherwise you will start causing more issues and the masked problem, might get worse.
Have you eliminated the TPS as a possible fault or the ckps (crankshaft position sensor).
Click to expand...

No I haven't. How do I do that? Bit new to all this.
 
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