Help!! lean spike on throttle tip in - Ford Mustang Forum
 
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post #1 of 5 (permalink) Old 06-13-2012 Thread Starter
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Help!! lean spike on throttle tip in

I'm running a 2.8 pulley&10% od bal and 47# injectors, and the new JLT 4” cai. Got the car tuned and drove home few Fridays ago now, I played around and ran the car pretty hard that Friday night. Parked it and didn’t fire her up till later Saturday afternoon. The car hesitated and any throttle it wanted to die. Well it was going lean on instant throttle. I reinstalled the tune and she seemed to be able to run at that point, but now I have a lean spike on tip in of the throttle and in between shifts. We have installed different intakes, multiple sized injectors 39#,60# and 72# injectors and the issue is still there. The car is drivable, but instant hard throttle the car bogs out “goes lean” for a few seconds, then it is good and drives normal. I did have a loose ground wire on one of my fuel pump controlled, fixed that and still seeing the issue. Fuel pressure is good, voltages are good.



any ideas? I'm am at a loss here...


Broken B302 right now...
D1SC build in process ~20lbs with e85 at 10.5 compression,id1000 injectors,aeromotive eliminator return style fuel system,frpp intake,gt500 tb
With the saleen she made 517/504 SAE at 15lbs boost 2.8 pulley & 10% od balancer.
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post #2 of 5 (permalink) Old 06-14-2012
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I see all your mods in your sig and I'm guessing you didn't do this all at once. Assuming at some point the car was running fine, what changed between then and now?

You mentioned "new" JLT 4" cai. Was that the change? Is this a larger MAF housing than you had before? If so, were the MAF transfer functions adjusted for it? Also bigger is not always better in the case of a MAF system. While it may be great for WOT, having too large of a MAF housing can cause issues on transitions and off-idle/tip-in.

-HD

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post #3 of 5 (permalink) Old 06-15-2012 Thread Starter
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the 302 was pretty much the only change other than heat exchanger, fuel pumps and what not. been through diff intakes, diff size pulleys, diff brand and sized injectors. None of this has worked.

Broken B302 right now...
D1SC build in process ~20lbs with e85 at 10.5 compression,id1000 injectors,aeromotive eliminator return style fuel system,frpp intake,gt500 tb
With the saleen she made 517/504 SAE at 15lbs boost 2.8 pulley & 10% od balancer.
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post #4 of 5 (permalink) Old 07-24-2012 Thread Starter
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wrong post, delete me

Broken B302 right now...
D1SC build in process ~20lbs with e85 at 10.5 compression,id1000 injectors,aeromotive eliminator return style fuel system,frpp intake,gt500 tb
With the saleen she made 517/504 SAE at 15lbs boost 2.8 pulley & 10% od balancer.
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post #5 of 5 (permalink) Old 07-26-2012
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It's a tuning issue, and a hard one to figure out at that. I've been trying to figure this problem out ever since I installed my supercharger and it's been getting better, but it's still there. This issue pops up a lot on the SCT forums but I haven't found a conclusive answer on how to fix it yet.

Does it get better as the car warms up? Once my engine is up to operating temp the issue almost completely goes away, still a little lean on tip in but not too much. The PITA about this problem is that there isn't an obvious way to adjust transient fueling based on temperatures, only MAP pressure and RPM. There has to be some way of doing it but I haven't found it yet

Power in Numbers: None of us are as dumb as all of us
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