Need help with an A/F issue on new build
03-05-2019, 12:22 PM
#11
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Thread Starter
Passenger bank is lean. Using an Autronic ECU.
Injectors are wired correctly for firing order, firing sequential. Cam is decent in size with very little overlap. Just enough to keep the exhaust valve cool. If overlap was an issue both 02s would show it??
Injectors are wired correctly for firing order, firing sequential. Cam is decent in size with very little overlap. Just enough to keep the exhaust valve cool. If overlap was an issue both 02s would show it??
03-05-2019, 02:33 PM
#12
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After the turbos were mentioned by Hogie - I thought that would be worth a try because of tolerance differences possible internally between the 2 ??.
And in one of my posts mentioning about --- O 2 placement AND DEPTH of the install . So I really think your buddy is possible spot on as to what I mentioned. It would have to be that or the turbos to narrow the issue down.
Or the other thought in the mix injector ports for the lean side not sealing well. But will add the 4 things that can be common with the injectors not sealing is --- fuel leaks possible (but I have seen that without as well on the Intake manifold side ) - 2. stumble idle - 3. and off rpms - 4. and I have seen AFR difference with it as well. Just saying
And in one of my posts mentioning about --- O 2 placement AND DEPTH of the install . So I really think your buddy is possible spot on as to what I mentioned. It would have to be that or the turbos to narrow the issue down.
Or the other thought in the mix injector ports for the lean side not sealing well. But will add the 4 things that can be common with the injectors not sealing is --- fuel leaks possible (but I have seen that without as well on the Intake manifold side ) - 2. stumble idle - 3. and off rpms - 4. and I have seen AFR difference with it as well. Just saying
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03-05-2019, 05:00 PM
#14
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Same as above but what did the plugs look like on both sides and what rpm is cruise? It would have been nice to check the new plugs you installed at cruising speed after a mile or so and compare. After reading post 10 is it possible you may have to stagger injector sizes kinda like we do with jetting carbs to help balance banks.
03-05-2019, 05:07 PM
#15
Same as above but what did the plugs look like on both sides and what rpm is cruise? It would have been nice to check the new plugs you installed at cruising speed after a mile or so and compare. After reading post 10 is it possible you may have to stagger injector sizes kinda like we do with jetting carbs to help balance banks.
03-05-2019, 06:33 PM
#16
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iTrader: (7)
I was taking a stab at it without much experience EFI other than daily drivers vehicles I rarely open the hood on anymore. Good point with the idle and cruise. Not sure what cruise rpm is but likely very little load on engine like idle. Wonder what numbers show in neutral at various rpm's with no load.
Last edited by getrdunn; 03-05-2019 at 06:35 PM.
03-05-2019, 06:44 PM
#17
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Thread Starter
Just wanted to say thanks to all for trying to help. I really appreciate it.
02 sensor location/placement is good.
Injector seal is good. Swapped injectors from bank to bank with more lube on o rings. Also used propane to look for vacuum leak around outside of intake, vac lines and injectors. None found. Engine runs smooth. If it wasn't for the different readings I would say everything is normal.
Running full exhaust to the rear bumper with electric cutouts by rear of door. Should be no reversion and false reading on 02 sensors.
Plugs all look the same. Very clean because of the e85. No sign of oil(from internal vacuum leak on the intake sucking from valley).
Cruise rpm was 2000ish-55/60mph on first drive.
injectors are Injector Dynamic 2000's which are 220lb injectors. IMO they are one of the best injectors on the market. Very linear across the range. Just sent back to them to test and flow them. They came back with a detailed flow chart for each injector at different pulse widths. They were all plus/ minus about 1% across the pw range. My ECU has individual cylinder correction for fuel and spark for all loads and rpms. I inputed all flow data in so technically all the injectors should have identical flow at the intake port at any given time. Balanced intake ports are another concern.
Going to swap turbos now and next install pressure gauges on headers.
If I determine it is because of different pressures in the headers I can change fueling on one bank to even out the a/f everywhere.
02 sensor location/placement is good.
Injector seal is good. Swapped injectors from bank to bank with more lube on o rings. Also used propane to look for vacuum leak around outside of intake, vac lines and injectors. None found. Engine runs smooth. If it wasn't for the different readings I would say everything is normal.
Running full exhaust to the rear bumper with electric cutouts by rear of door. Should be no reversion and false reading on 02 sensors.
Plugs all look the same. Very clean because of the e85. No sign of oil(from internal vacuum leak on the intake sucking from valley).
Cruise rpm was 2000ish-55/60mph on first drive.
injectors are Injector Dynamic 2000's which are 220lb injectors. IMO they are one of the best injectors on the market. Very linear across the range. Just sent back to them to test and flow them. They came back with a detailed flow chart for each injector at different pulse widths. They were all plus/ minus about 1% across the pw range. My ECU has individual cylinder correction for fuel and spark for all loads and rpms. I inputed all flow data in so technically all the injectors should have identical flow at the intake port at any given time. Balanced intake ports are another concern.
Going to swap turbos now and next install pressure gauges on headers.
If I determine it is because of different pressures in the headers I can change fueling on one bank to even out the a/f everywhere.
03-05-2019, 06:46 PM
#18
Registered
Thread Starter
I was taking a stab at it without much experience EFI other than daily drivers vehicles I rarely open the hood on anymore. Good point with the idle and cruise. Not sure what cruise rpm is but likely very little load on engine like idle. Wonder what numbers show in neutral at various rpm's with no load.
