leaning out at high rpm in 4th gear
08-13-11, 02:58 AM
#1
leaning out at high rpm in 4th gear
I got some time to finally install the bnr stage 4 back in last week.
I bought a set of ID-1000 injectors and installed them in secondaries.
When I went to tune the injectors on the rtek, from the log, it shows that in 4th gear at 6k+ rpm starting at 8psi and ending at 10psi, it goes from 11.2afr and leans out all the way to 13afr at 7krpm at 10psi.
I have the fuel setting from 6-10psi 6k-8krpm enriched to its max 37% and its still leaning out. Duty cycle is at 69% when its leaning out.
3rd gear pull is more sensible in the afr but it has the rise in it that resembles the 4th gear pull.
The engine is a streetported S5 block. Stock fuel rails, stock fpr. only thing changed in the fuel system is the injectors 720prim 1000sec, a walbro255 and rewired fuel pump to supply constant 12v+
Is it because I have a stock FPR and need an aftermarket one, or do I just need bigger injectors? but according to the log, its only at 69% duty cycle.
I was going to run the turbo at 17 psi, but seeing how its leaning out at just 10 psi, I need to fix it somehow.
I bought a set of ID-1000 injectors and installed them in secondaries.
When I went to tune the injectors on the rtek, from the log, it shows that in 4th gear at 6k+ rpm starting at 8psi and ending at 10psi, it goes from 11.2afr and leans out all the way to 13afr at 7krpm at 10psi.
I have the fuel setting from 6-10psi 6k-8krpm enriched to its max 37% and its still leaning out. Duty cycle is at 69% when its leaning out.
3rd gear pull is more sensible in the afr but it has the rise in it that resembles the 4th gear pull.
The engine is a streetported S5 block. Stock fuel rails, stock fpr. only thing changed in the fuel system is the injectors 720prim 1000sec, a walbro255 and rewired fuel pump to supply constant 12v+
Is it because I have a stock FPR and need an aftermarket one, or do I just need bigger injectors? but according to the log, its only at 69% duty cycle.
I was going to run the turbo at 17 psi, but seeing how its leaning out at just 10 psi, I need to fix it somehow.
08-13-11, 08:35 AM
#2
i had the same problem wiht it running lean from 6k+ rpm, and low injector duty cycles even with correction maxed out. you could try readjusting the spring in your AFM. if you pop the cover off the AFM, you can see where you can adjust the tension on the AFM. loosen it up a few notches and retune. but I never actually tried this, i ended up going haltech instead when i was having this problem
08-14-11, 12:02 AM
#3
Is the afm @ 100% when this us happening? If so it may in fact be the afm's inability to meter air accurately past a certain cfm. You can swap to an s5 t2 (n370) or cosmo/20 (n390) afm and it should help.
What injector preset do you have selected?
What injector preset do you have selected?
08-14-11, 10:00 AM
#4
Afm is at 100%, even with the stock turbo, though im not sure if it is a 370 afm. The car is a gtus with a turbo swap, I will have to check. Its on the 720/720 preset. I was thinking of running on the 550/550, but with 37.5% taken out at idle, the afr is low 12 and stumbling from too rich.
08-15-11, 01:52 PM
#5
If its an n/a AFM (N350) THATS your problem. NickDTII had a similar problem in the rtek section and eventually figured out he had and n/a afm.
You can't adjust idle. Fuel corrections only apply to non-idle conditions as idle has its own closed loop map that digital tuning did not see fit to give us access to.
I have tried running the N390 AFM w/ 550/720 and it won't idle because the n390 bypasses more air and runs too lean. If I had 720 primaries (and the comp thought they were 550's) it would most likely idle....at least well enough for me to adjust it w/ the variable resistor and BAC. When I finish my hybrid I will run 720/1000 on the 550/720 or 550/550 setting and it should work (fingers crossed)
You can't adjust idle. Fuel corrections only apply to non-idle conditions as idle has its own closed loop map that digital tuning did not see fit to give us access to.
I have tried running the N390 AFM w/ 550/720 and it won't idle because the n390 bypasses more air and runs too lean. If I had 720 primaries (and the comp thought they were 550's) it would most likely idle....at least well enough for me to adjust it w/ the variable resistor and BAC. When I finish my hybrid I will run 720/1000 on the 550/720 or 550/550 setting and it should work (fingers crossed)
08-16-11, 01:36 AM
#6
yep, I am definitely running the n350 afm.
I guess I should try and get a cosmo n390 or a TII n370, off to search for one :P
I can adjust my idle afr fine on the S5 rtek 2.1.
I can lean it or richen it at 800rpm to make it stay steady.
I guess I should try and get a cosmo n390 or a TII n370, off to search for one :P
I can adjust my idle afr fine on the S5 rtek 2.1.
I can lean it or richen it at 800rpm to make it stay steady.
08-16-11, 08:45 AM
#7
The 20B AFM flows the most, if you can in fact source one. It outflows the other AFM's according Mazda's specs--max is 44.2 lb/min of airflow. See https://www.rx7club.com/2nd-generation-specific-1986-1992-17/specs-cosmo-afm-961741/ I am unsure how this would work with idle and injector presets. It might be worth a shot.
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08-16-11, 10:29 PM
#8
I can adjust my idle afr fine on the S5 rtek 2.1.
I can lean it or richen it at 800rpm to make it stay steady.
I can lean it or richen it at 800rpm to make it stay steady.
You aren't talking about the variable resistor are you? Because that only makes very minor adjustments, not the kind you would need to make to run a significantly larger afm. Then again the difference between the n370 and n390 is smaller than the difference between the n318 (s4 t2 **** box) and the n390 so it may work after all....
08-17-11, 12:44 PM
#9
Another possible culprit is the Walbro 255hp drops flow badly at high fuel pressures.
With the stock lines and fuel filter you can get some really high pressures at the pump outlet under boost when the FPR starts raising the pressure.
I had a similar problem with 720/1600cc and walbro 255hp on my BNR stage 4 and Bryan pointed me in the direction of upgrading the fuel pump.
I went with Bosch '044 and a low restriction filter and it solved my issues.
First, put a fresh fuel filter in if you haven't already and make sure your Walbro is a 255hp (high pressure) and not regular 255- I went through this as well.
Though this may not be your issue at a mere 10psi boost....
With the stock lines and fuel filter you can get some really high pressures at the pump outlet under boost when the FPR starts raising the pressure.
I had a similar problem with 720/1600cc and walbro 255hp on my BNR stage 4 and Bryan pointed me in the direction of upgrading the fuel pump.
I went with Bosch '044 and a low restriction filter and it solved my issues.
First, put a fresh fuel filter in if you haven't already and make sure your Walbro is a 255hp (high pressure) and not regular 255- I went through this as well.
Though this may not be your issue at a mere 10psi boost....
08-17-11, 03:46 PM
#11
You aren't talking about the variable resistor are you? Because that only makes very minor adjustments, not the kind you would need to make to run a significantly larger afm. Then again the difference between the n370 and n390 is smaller than the difference between the n318 (s4 t2 **** box) and the n390 so it may work after all....
08-24-11, 10:23 AM
#14
im going to try and change my wideband sensor, just incase it is faulty. Though I dont think it is reading wrong.
According to my log, injector duty cycle is at 84% at 6.5krpm at 9psi.....unless I might really need way much more fuel then I realize
According to my log, injector duty cycle is at 84% at 6.5krpm at 9psi.....unless I might really need way much more fuel then I realize
08-25-11, 12:14 PM
#20
Another possible culprit is the Walbro 255hp drops flow badly at high fuel pressures.
With the stock lines and fuel filter you can get some really high pressures at the pump outlet under boost when the FPR starts raising the pressure.
I had a similar problem with 720/1600cc and walbro 255hp on my BNR stage 4 and Bryan pointed me in the direction of upgrading the fuel pump.
I went with Bosch '044 and a low restriction filter and it solved my issues.
First, put a fresh fuel filter in if you haven't already and make sure your Walbro is a 255hp (high pressure) and not regular 255- I went through this as well.
Though this may not be your issue at a mere 10psi boost....
With the stock lines and fuel filter you can get some really high pressures at the pump outlet under boost when the FPR starts raising the pressure.
I had a similar problem with 720/1600cc and walbro 255hp on my BNR stage 4 and Bryan pointed me in the direction of upgrading the fuel pump.
I went with Bosch '044 and a low restriction filter and it solved my issues.
First, put a fresh fuel filter in if you haven't already and make sure your Walbro is a 255hp (high pressure) and not regular 255- I went through this as well.
Though this may not be your issue at a mere 10psi boost....
this is my suggestion.
i can't count how many cars i have seen built using the stock relays and wiring which inflate the issue with serious drops in voltage at higher RPMs and loads.
rewire the pump to at least ensure it is doing it's job as best possible and/or monitor the voltage to be sure the relay isn't sucking up all the pump's juice.
08-25-11, 04:38 PM
#21
I will test out the fuel pressure and check the fuel punp to see exactly what kind it is. The pump has a constant 12v-14v, rewiring it was the first thing that came up.
I bought a fuel pressure tester and was about to work in the car, but it was raining too hard outside. I will have to try again tomorrow, if its not raining lol
I bought a fuel pressure tester and was about to work in the car, but it was raining too hard outside. I will have to try again tomorrow, if its not raining lol
08-26-11, 11:00 AM
#22
How can I tell if I have a walbro pump or not, the one I have has no marking. Previous owner said he did install a walbro, though now, im not sure lol
From a quick test, at idle pressure is 38, with fpr unplugged it went to 41
From a quick test, at idle pressure is 38, with fpr unplugged it went to 41
