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Showing results for tags 'Rich'.
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RB20 runs rich and sloppy then leans out under boost
GabeDiaZ27 posted a topic in Nissan RB ForumOK, So heres what im dealing with right now. My rb20 is having some weird issues running, Idle is good at a 14.7 AFR but under load/driving is where I get problems. Upon initial acceleration or low rpm`s the engine has little power and runs like its missing a cylinder or two with afr`s dipping into the 10`s then as boost comes on it runs normal for a bit like it should with afr`s towards 12-13`s and as the rpm`s raise and I hit full boost it will sputter and pop as it leans all the way out untill my wideband cant go any higher (18+ afr`s). So far I have checked everything manually and also through nistune and I still cant figure it out. Here is my current setup: Stock RB20DET and stock turbo Z32 MAF Nistune chipped ECU RB26 444CC injectors (and resistor wired into the harness) Walbro 255 fuel pump Nismo FPR AEM Wideband I have checked the timing and its at 15 deg. Fuel pump has good power and ground. All injectors are opening/closing. All coilpacks work (I pulled them with the plugs and spun the CAS to double check). ECU dosent pull any codes. Fuel pressure isn`t dropping off. TPS voltage is good. Plugs look good and are gapped to the reccomended .8, The MAF readings look linear and accurate from what I can tell through nistune. If I go into nistune and bump up the fuel it just runs richer in the lower rpm`s and still leans out and pops. The only things left I can think of is a bad MAF, Low voltage to the pump under boost, A bad ignitor for the coilpacks, or possibly a bad CAS or something. Any help would be greatly appreciated because I dont know what else I should check at this point lol.
Help. what is wrong with this tune.
MerloZ posted a topic in MegaSquirtHello, Can anyone smarter than me take a look at this tune and tell me what is wrong with it for my build. I have a pretty much stock 82 l28et stock injectors DIY wiring harness i put together. iac sensor 240sx 65mm throttle body and tps DIY trigger wheel single coil lc2 wideband (not wired to ms2) walbro 255 lph inline fuel pump no other sensors are connected to the MS2 Ive been messing around with some other peoples tunes and came up with this. This started the previously warm car yesterday and i set my timing on the car with this project. its set to around 19 btdc because it was running so rough. The car was running very rich and was backfiring with every change in throttle. i assume the ignition settings might be wrong and the fuel map is too rich. ive scaled down the fuel map and it didnt seem to change much at all. could their possibly be other more hidden settings that i also have to change. Today i tried to start it and it just kept flooding itself no matter what spark settings i change or if i scale down the fuel map. Im new to this type of stuff so any help is apreciated. ive been researching so much and tried so many things but nothing is working. thankyou.
High fuel pressure on boost
Timecode posted a topic in Nissan L6 ForumI'm experiencing a slight rich issue and need the groups help. Its an l28et running a JWT 550 kit in a 71 240z. Using the stock l28et fuel rail, Aeromotive FPR with psi gauge, upgraded to bigger fuel line (still using the oem return line), and an unknown in tank pump. Prior owner says its a 300zx turbo pump, but I have yet to drop the tank. I have seen it go to 65 psi with no pressure drop at all. 11.5 AFR until boost crosses the 10 psi mark, then fuel pressure shoots up 5 psi too much (relative to boost )and stays that way. At idle, fuel psi is correct. Cruising, it's correct. The problem shows up only after 10 psi of boost, thats when my AFR's go to 9.5-10.5. Myself and other can't see any smoke from the tail pipe during acceleration. I believe there is an restriction thats not allowing the fuel to return fast enough. Maybe the oem fuel rail? I don't see any pinches in the rail that would cause such a thing. Maybe its my setup. Any ideas where the restriction might be?
Mikuni Tuning - The Wideband May Fool You.
inline6 posted a topic in Fuel DeliveryI've been doing some tuning of my Mikuni 44 set up as of late with the assistance of a wide band o2 sensor, and I have learned a few things that may be helpful to some others. Generally, I recommend determining these in the order listed: Pilot Screws: One bit from Honsowetz in the How to Modify Your Nissan Datsun OHC Engine which is a very specific instruction: run your pilot screws 1.5 turns out. I have mine set at 1.5 dead on, and the engine likes the 57.5 pilots at that setting. AFRs are where they should be for idle and low speed operation. The engine runs well in both of these conditions. Mains (Fuel Jets) and Air Correction (Air Jets): This bit came from TonyD... and that is stay out of the pump nozzles when trying to determine what the engine wants for main and air jets. Accelerator pedal movement may engage the pump circuit and if it does, this will throw fuel into the mix from that circuit. This will "mask" what is happening with the main circuit and you won't know what is what. According to the Mikuni manual, accel pumps are in play from 0 to 30% of throttle. So use inputs like 50% or 100% and ignore where the 0-30% is most likely occurring. Since the pump circuit has a known volume... and the duration of the fuel "injection" from the nozzle is specific to each nozzle, you could time the length of the injection duration if you are so inclined. Then you could ignore that time duration (from throttle open) in your Wideband AFR (Air Fuel Ratio) plots. Pump Nozzles: This one came from my engine builder. Know that sometimes wideband o2 sensors/loggers may show you rich readings when actually the engine is lean. This can occur when there is any engine misfire condition. The rich reading is resulting from a chain event of the flame going out too early, and the subsequent passing of remaining unburnt mixture through to the sensor. When you open the throttle quickly, if the engine is sluggish, but doesn't misfire, and your wideband shows rich, you are rich. However, if the engine misfires, and your wideband shows rich, you could be lean. Regarding this last one, I think that is what I am currently experiencing. I will be testing that theory out soon. As I have changed the pump nozzles from 50 to 45 to 40, I am fairly certain that I have been experiencing a more prevalent misfire when applying large throttle inputs (I haven't been doing much full throttle yet and there has been a fair amount of time involved from when I swapped nozzles one to the next to the last). I was going smaller and smaller because of the rich readings I was getting on the wideband when "throwing large throttle inputs" at the engine. Last tuning session, I was getting a large amount of misfire for the first couple of seconds of full throttle... even when in first gear. I am going to switch back to the 50's next and see if that situation improves.