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Running lean up top

10K views 54 replies 12 participants last post by  Rboughne1 
#1 ·
History:

60lb injectors, TimmyC lower pulley, TimmyC intake

Went to a local shop and got a dyno tune. They said I was running lean up top and I peaked at ~434rwhp.

I asked a 3rd party and they said, "Find a shop that knows what they're doing. There is no way you're maxing out with 60lb injectors."

Jeremy Formato tuned my car and said, "You're pretty lean up top." We came to the conclusion that the inline regulator/filter had 100k+ miles on it and was clogged. We pulled it, cleaned it and got the same results.

I just recently had the inline regulator/filter replaced and took it back to the original shop with the same results. "You are running lean up top."


Concern

With the recent recall notice about the overheating terminal that melts the gas tank, which causes fuel to leak. Is it within reason to suspect this defect to cause a voltage instability/dip that would impact fuel delivery? I've considered installing a Boost-a-Pump but, with the recent recall, I'm hesitant because I don't want to aggravate an already partially malfunctioning component.

Am I sitting on a fireball?

Where is the terminal located and how do I access it? I'm an electronics guy; not so familiar with engine compartments.
 
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#2 ·
If there are no restrictions in the fuel system, and it seems like you've eliminated the biggest possibility, then the fuel pump is not flowing what it should. If that lack of flow is caused by resistance in the terminal that is the subject of the recall, then increasing voltage with a Boost a Pump would only exacerbate the problem.

Accessing the fuel pump electrical connections isnot easy. It's on top of the fuel tank. You have to drop the rear suspension cradle to access the straps that hold the tank up. Taking it to the dealer would not be a bad idea iif you don't have a lift.
 
#4 ·
So Jeremy tuned yours with a lower pulley and injectors, and you have NO PROBLEM with IATs?! He won't even INSTALL my lower pulley and injectors bc the IATS he says will be too high. SO WTF!?!? What other mods do you have that he can tune the lower pulley and injectors, but not mine? I've got intake, headers, and exhaust. Your IATs aren't high? PM me PLEASE operator!

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So Jeremy tuned yours with a lower pulley and injectors, and you have NO PROBLEM with IATs?! He won't even INSTALL my lower pulley and injectors bc the IATS he says will be too high. SO WTF!?!? What other mods do you have that he can tune the lower pulley and injectors, but not mine? I've got intake, headers, and exhaust. Your IATs aren't high? PM me PLEASE operator!
Sent you a PM. If he can map mine off yours, it should be ok...

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So Jeremy tuned yours with a lower pulley and injectors, and you have NO PROBLEM with IATs?! He won't even INSTALL my lower pulley and injectors bc the IATS he says will be too high. SO WTF!?!? What other mods do you have that he can tune the lower pulley and injectors, but not mine? I've got intake, headers, and exhaust. Your IATs aren't high? PM me PLEASE operator!

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Sent you a PM. If he can map mine off yours, it should be ok...
That's why I need your input....
 
#6 ·
Exchanger is on the way. Even with that he is saying, based upon the heat here in the summer, that I'd need to direct the brake cooling duct into the air filter cavity and thin the coolant from 50/50 to 70/30 to make it survive the IATs. Bc I'm in PA, I am unable to thin coolant. So I'm screwed...
 
#8 ·
The difference between 50/50 mix and 70/30 is going to be a few degrees, tops. Certainly not enough to be a factor in a decision.

Furthermore, saying that the lower pulley is ok in Florida because you can run more water percentage while ignoring the much higher ambient temperature is short sighted at best.
 
#18 ·
There are two spots you can measure boost. One is before the intercooler and one is after. The intercooler is a restriction and there is always going to be more boost before it than after. That is the reason that some people are seeing more boost than what I report. The proper place to measure boost is from the nipple near the IAT2 sensor. That's where the stock MAP sensor reads and that's the line I always tee into on the dyno.
 
#20 ·
I'm going to try n work my way into a rental for the winter. I've read that they cannot send an unsafe car back on the road and gm is suppose to pay for the rental till the parts r here. Who knows if it will work but I'd rather drive a dealer car than any of mine in the winters of Wisconsin haha
 
#21 ·
i am running a 2.4 upper, heat xer, intake, gutted cats, 3in exhaust, 60s, intercooler pump. tuner said mine was running lean up top and i couldnt believe it. so after further investigation i noticed it was running lean PASSED 6500 rpm. above 6500 i am at 122% duty cycle on injectors WHEN shifting manually. when i put it in manual and back in auto such as your racing, it was at 68%. just something to look into.

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oh and today just dynoed 445-419

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forgot ported blower. sorry
 
#25 ·
hey boomys10 weird you mention the lean on manual mode b/c i noticed mine will mess up usually when doing a roll race where im downshifted into second and usually will mess up immediatly when shift into third like trans problem or somthing car feels werid but if i downshift into second take off then put over into drive it wont do it once it shifts itself into 3rd. idk kinda werid but werid u mentioned going lean when manually shifting it maybe thats my problem was pulling timing at top of second then took a second once went into 3rd to readjust idk lol.
 
#26 ·
that could be a few things. i am NOT A TUNER!! mine used to stumble between shifts, then slowly start evening out again. it ended up being the fuel filter, which is also the regulator on the car. found on rock auto for 120 instead of the 190 from dealer. with the torque management left in the car on the shifts, you will notice it pull timing on the shift so its not shifting under power to help the tranny last longer, so that could be it. you might be running out of fuel on the top, (could be the filter as well) i was suggested to avoid a boost a pump if a new pump is needed. exploring a few intank options now, but also have a bosch 044 sitting on my kitchen table as well. also, and this is something i could imagine alot over looking, what are your plugs gapped to. i had mine gapped to 35, running 13lbs of boost on a 50 degree night and it was stumbling on the top and shooting fire. regapped EXACT plugs next day to 32 and hit the dyno, made 445/419 with no stumbling and a completely smooth graph.
 
#29 ·
Be careful bc since I made my post on ur thread I ran my Lean and blew it up haha melted a hole through piston 3 at the top edge through rings and all had to replace the engine wasn't fun I got Tim c's lower pulley spectre 1 and 2 intakes tims throttle body his heat exchanger injectors mufflers and tuned my tuning guy to me I need a booster pump and I didn't listen to him so I paid the price so it hasn't gotten run hard until I get that pump lol
 
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