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AEM V1 1100series JZ

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hey everyone,

I need some help with this one! overview of the vehicle. Big BorgWarner Single turbo, 2jz non-vvti, stock intake manifold. stock throttle body, aeromotive

FPR set to 45psi with vacuum line dissconnected. Rc PL-4 1000cc injectors. fuel is E85 only.

Ill post the MAP FILE on here for you to view all my settings and tell me if you see something that would be causing this vehicle to be excessively lean at the

RPM range of 1800-1900RPM only. As youll see in the FUEL MAP that giant spike in fuel and then come back down. As im building the fuel table the engine is

asking for that ridiculous amount of fuel, so I do what its asking for and the engine drives great, fuel is just fine when all around. I just cant stand looking at

this fuel map with that massive fuel increase only at that rev range. If any of you have come across this please help me. This isnt making any sense to me. Ive

checked for vacuum leaks using a smoke machine. Ive dissconnected and even plugged up the IACV on the engine to see if the engine still

asks for that fuel increase there. Sure enough still does it. Which is why im sharing this FILE so that maybe someone can spot my mistake on my tune. by the

way its a street tune. PLEASE HELP Im all out of ideas. By the way Ive tried contacting AEM since they are local, but they no longer provide technical support

for V1 models.

Attached Files

I still have not figured this problem out. But brain storming, I can only come up with it being a signal problem possibly in the wiring(unless someone can spot something in the .CAL and share with me) It's just so strange how it's so rpm specific and it's every single time. I'm just not sure how and where to even begin if it's a wiring issue. Just knowing the fuel map has such a big spike for fuel in that range, but the car drives smooth I know it's just a band aid fix and it's a indicator that something is not right. Unless I'm wrong? Idk.

Thoughts? Anyone?

Usually strange peaks (or dips) in efficiency have to do with wave the frequency in the intake or exhaust. I would think that with your turbo application it may have something to do with the turbo sizing, location, exhaust pipe diameter, etc.

One idea -- can you adjust fuel timing on that ECU? Can you change the fuel timing around that RPM to see if that changes things?

When you say fuel timing are you referring to injector phasing? I have not changed those numbers. Left them the way aem set it up on the base map.

I've corresponded with someone who has chased this situation for years tuning various ECUs. Most of the cars he works on are 2JZ engines, but I think some others encountered it also. Injector phasing (fuel injection angle / fuel injection firing angle) was usually my first suggestion, but he never got satisfactory results from adjusting injector phasing on the cars that did this. He very recently told me they solved it on a car by adding a fuel pulsation dampener. Assuming it is caused by a fuel pressure pulsation, you might get lucky if you try adding a restrictor or changing the length of the vacuum line feeding the fuel pressure regulator.

thank you Scott, Will see if the dampener has been removed or not. and Ill try seeing if i can shorten the vacuum line to the FPR. Thank you and that tuner for the response. Will post update when possible.

I just want to update this problem and say it has been solved. So for anyone with this similar experience, we added the factory fuel pulsation dampener and it works. It has cleared up the lean spike of fuel at the specific rpm and the fuel map now looks as it should. Thank you to everyone who replied. I know many people dont deal with factory fuel line vehicles, but when you do...

Sad thing is alot of people just removes the damper to get more flow or whatever and dont understand what it really is there for.

Just for reference. Radium have aftermarket dampers that doesnt put a restriction in the feed line.

BTW if you search up Paul Yaw on youtube he has a seminar that in a part of it he speaks about this particular problem. Its well worth watching.

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