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Any help? Lean A/F @ high RPM

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Old Sep 15, 2008, 09:35 AM
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After testing the FPR, went back to inspecting the pumps again and found one of the lines on the pump had come lose from the housing. It is hard to get a screwdriver down in the base of the assembly if using clamps of this nature. Used different barb fittings that were longer in length at the base so you could clamp them down easier to secure them better.

After this we put it on the dyno and the AFR's were in the low 11's again for the pump gas map. Cleaned up that tune and made over 350whp on 20psi which we kept conservative as our goal was the E85 tune.

Drained the tanks and put in 10 gallons of E85. Final numbers were 484whp and 390wtq @ 32.5psi peak. Mid 11's with IDC's at around 88% @ 7400rpm.

The Greddy Profec B Spec II wouldn't give me the boost I wanted, plus when I got anywhere near 100% duty cycle on the unit it would act up. Put a jumper harness together to have the Greddy solenoid controlled by the stock ECU and it worked out great and I was able to get more boost this way and it was much more consistent.
Old Sep 15, 2008, 09:37 AM
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Originally Posted by Aby@MIL.SPEC
Your right....sorry about that.

I thought i clicked paged 1 & I scrolled up.....I saw your post on top of page 2, thinking it was page 1....yeah, maybe i ought to try this new thing called READING

sorry bro btw, i havent had / made the time to try your suggestion....thanks

No big deal.

Hope you get the Gauge to EMS issue figured out, let me know if I could be of more assistance when you when you work on it again.
Old Sep 15, 2008, 10:34 AM
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Originally Posted by kcevo
...
Drained the tanks and put in 10 gallons of E85. Final numbers were 484whp and 390wtq @ 32.5psi peak. Mid 11's with IDC's at around 88% @ 7400rpm.

...
Did you try going to 12:1-12.2:1? E85 likes to be lean. I get "rich" knock at anything below about 11.8:1.
Old Sep 15, 2008, 10:39 AM
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Originally Posted by mrfred
Did you try going to 12:1-12.2:1? E85 likes to be lean. I get "rich" knock at anything below about 11.8:1.
Nah left it at Mid 11's, didn't have any knock at all when tuning it on E85. All the E85 cars I tune I leave them in the mid 11's as I haven't seen any drastic power/torque increases with going to leaner a/f's like 12's.

This car also had an external wastegate dump from the 38mm w/g which didn't trigger anything at all thru the stock ecu as far as knock activity.
Old Sep 16, 2008, 07:57 PM
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I am sorry I am not quite sure what I read (long day), the pump was bypassing or the power came loose to the second pump?
Old Sep 17, 2008, 09:35 AM
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Originally Posted by JohnBradley
I am sorry I am not quite sure what I read (long day), the pump was bypassing or the power came loose to the second pump?
No loss of power or bypassing (well it would have been in this case). The fuel supply line from one of the pumps to the fuel assembly came loose thus not providing fuel to the sending unit and to the rail. Thus the one pump that was working was supplying fuel to the sending unit/rail, but fuel was dumping back in the tank due to the supply line being off. So in turn it would have been bypassing fuel in this case.z
Old Sep 17, 2008, 12:48 PM
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I had a similar issue when I switched to E85. No matter what I did with the fuel table it would start going way lean past 5500. I found it went away after I more closely adjusted the injector latencies.

Is it possible that because of the dramatic increase of fuel you're supplying with E85 that latencies become more important?

I should mention that I was already running E85 on stock injectors when I switched to FIC 950s, so I was starting from scratch with adjusting my latencies.
Old Dec 10, 2008, 08:49 PM
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very educational... i just have a single drop in Walbro intank pump and it goes from 11.2 and jumps too 12.1 afrs right exactly at 5500rpm using a wideband on a dyno. I mean immediately jump that high. Richening it up the fuel maps doesnt do anything. Sometimes its sporatic (good clean run in the mid 11 afrs, but majority it does this weird lean hop to 12.1 @ 5500rpm) After reading the above, i'm going to check my fuel pump and make sure its fitting in there tight. But can someone tell me WHY its always 5500rpm like you guys experienced? Does the factory fuel setup demand more fuel right at this rpm range or something?
Old Dec 11, 2008, 12:00 PM
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Its just how it is I think. Its very close to peak power and the highest boost level before tapering on a stock turbo. On gasoline for instance a stock pump will do the same thing and lean out right there, throw in a 255 and that right where it will then start to go rich.
Old Dec 27, 2008, 02:36 AM
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John,
is it possible that the Fuel Pressure Solenoid could fail (w/out triggering a code) causing the FPR to not get correct pressure signal from the intake manifold causing a lean condition after 5500rpm? I just thought of this while i was researching the Evo fuel system....
Old Dec 27, 2008, 01:40 PM
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I am not sure how that Fuel Pressure Solenoid works to be honest. I know you can take it off and flash away the code and not look back. I havent ever seen one not throw a code though, but I'll admit its always been for idle overrun not low pressure. If you have a pump and still have issues the likely canidate is something in the install F'd up. No O-ring or collar on the pump and its bypassing and losing pressure.
Old Dec 27, 2008, 01:52 PM
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do you have an aftermarket fuel rail?
Old Dec 28, 2008, 05:16 PM
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Originally Posted by JohnBradley
I am not sure how that Fuel Pressure Solenoid works to be honest. I know you can take it off and flash away the code and not look back. I havent ever seen one not throw a code though, but I'll admit its always been for idle overrun not low pressure. If you have a pump and still have issues the likely canidate is something in the install F'd up. No O-ring or collar on the pump and its bypassing and losing pressure.
gotcha... thx !
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