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Need help finding cause for lean condition at Idle Whipple 3.0 Gen 5

919.s550

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Recent Whipple install has been one headache after another between initial package delivery being delayed, to FexEx completely trashing the 1st blower unit and needing to get another blower shipped out, to missing parts and having to delay install to now having a potential ‘intake leak’ I cannot seem to find. Here’s a little about the car
2019 Mustang GT PP1 w/ Gen 5 3.0 Whipple on a 3.875 pulley
NGK 6510 .028” gap
Stock fuel pump with Lethal Performance BAP
DW95 injectors
93 Octane fuel
132mm Throttle body on stock Whipple closed air box
IAT2 brass temp sensor
Full Corsa exhaust with 1.875” headers

So still trying to get past the base tune. Car seems to idle perfectly to say the least, drives good however at idle after car is warmed up Short term fuel trims climb high have gotten up to 30-45%+ (seem to climb higher and higher the longer the car idles, have only seen it get to 45ish%) indicating a lean condition, was advised by the tuner it’s a intake leak. Aside from looking at the trims you would not know the car is running rough aside from the excessive fuel smell coming from the exhaust. According to car’s vacuum gauge (unsure of accuracy of the thing) it idles at 21inHg.
Now to what I’ve done:
I have smoke tested the system only found 1 leak around the IAT treads which has been fixed but made no change in the fuel trims
Have plugged off intake side of the PCV system and venting the valve cover side.
Have plugged Purge valve line
Have plugged off brake booster line
Have removed SC lid and verified O-ring around the perimeter was good and while in there also checked bypass O-ring. All is good.
Smoked tested a few more times both while engine was cold and hot (was thinking maybe something was expanding and allowing air in?) no smoke exiting was found.
Have also tried the gas Trick around potential leak areas with no change to fuel trims either. I’ve tried looking at other posts, haven’t found one with my issues. I can provide the 2 logs I’ve gotten so far, they’re .csv files but I’m unsure how to post them on here. any help is greatly appreciated
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AceS550

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Have you checked for exhaust leaks upstream from the oxygen sensors and/or ruled out biased oxygen sensors?
 

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45% correction is MASSIVE. Like so large I can't believe it runs.

Make sure your fuel pressure is correct,
Make sure the part numbers for your injectors are correct,
Make sure o-rings around the injectors aren't leaking at the intake,
Make sure all PCV/Breathers are correct,

Logs will help everyone, including your tuner (make sure to sent them to them first)
 

larr12

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Double check the throttle body gasket.
 

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919.s550

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Have you checked for exhaust leaks upstream from the oxygen sensors and/or ruled out biased oxygen sensors?
I have not yet, however AFRs 14 and also it’s correcting both side banks. I was thinking about the headers/02s I remember I had a leak around a year ago and it was the header itself (Corsa warrantied it) also replaced the gasket and made sure there wasn’t a leak then, but again that was a year ago I’ll probably go back and double check.
 
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919.s550

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45% correction is MASSIVE. Like so large I can't believe it runs.

Make sure your fuel pressure is correct,
Make sure the part numbers for your injectors are correct,
Make sure o-rings around the injectors aren't leaking at the intake,
Make sure all PCV/Breathers are correct,

Logs will help everyone, including your tuner (make sure to sent them to them first)
I know when I saw it it didn’t make sense to me seeing the car idle as good as it is.
Fuel Pressure is good (~70ish psi)
I’ve eliminated the PCV reroutes into the intake and have plugs for now just till I find what’s causing this. Valve covers are vented into the atmosphere for now.
Verified Part #s for the injectors, however spoke to my tuner, I have a set of ID1050x we’re going to try, will update this post once those are on. Planning on removing the injectors and rails/play around with them seeing if anything changes maybe the o-rings are not sealing correctly.
 
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919.s550

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Is your maf sensor pointed in the right direction?
Yes, Also I work at a dealer & we got another 5.0 on the lot we tried swapping MAFs to rule out of it was failing. Same readings
 
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919.s550

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Double check the throttle body gasket.
Gasket seems to be good & not leaking for now. Have read the gasket whipple provides isn’t very good and people will replace it with something else. Will probably look into that.
 

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Did you put the o rings on the lower intake bolts inside the manifold? The ones that hold the lower manifold to cylinder head.
 

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I had a very similar issue. Shop installed the blower kit and upon first start fuel trims showed a significant lean condition. Car did idle and drive down the road. Verified that whipple sent the correct injectors with the kit and provided the correct stage 2 tune (I was running the whipple tune at the time). All that checked out.

Shop did a smoke test, but could not find anything. The only thing they could think of was possibly one of the o-rings rolled out of it’s groove installing the blower, so they decided to pull the blower back off.

They told me the o-rings looked fine, but what they noticed was these two tabs (pic below) on the bottom of the blower were kissing the cylinder heads and possibly not allowing the back of the blower to fully seal. They trimmed some material off these tabs, reinstalled the blower and everything was perfect after that. I’m not aware of anyone else having this tab issue.

I emailed whipple, they said it was not possible for those tabs to make contract with the heads as they should have been at least 3 inches away. Not sure…but the issue was resolved after that.

Strange yours get worse as the car comes up to temp. Either way, I bet you’ll have to pull the blower off and take a look if nothing else obvious is wrong.

Here are those tabs I as talking about:

65447707-DA93-4FB5-90A4-669745BC22D3.jpeg
 
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919.s550

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I had a very similar issue. Shop installed the blower kit and upon first start fuel trims showed a significant lean condition. Car did idle and drive down the road. Verified that whipple sent the correct injectors with the kit and provided the correct stage 2 tune (I was running the whipple tune at the time). All that checked out.

Shop did a smoke test, but could not find anything. The only thing they could think of was possibly one of the o-rings rolled out of it’s groove installing the blower, so they decided to pull the blower back off.

They told me the o-rings looked fine, but what they noticed was these two tabs (pic below) on the bottom of the blower were kissing the cylinder heads and possibly not allowing the back of the blower to fully seal. They trimmed some material off these tabs, reinstalled the blower and everything was perfect after that. I’m not aware of anyone else having this tab issue.

I emailed whipple, they said it was not possible for those tabs to make contract with the heads as they should have been at least 3 inches away. Not sure…but the issue was resolved after that.

Strange yours get worse as the car comes up to temp. Either way, I bet you’ll have to pull the blower off and take a look if nothing else obvious is wrong.

Here are those tabs I as talking about:

65447707-DA93-4FB5-90A4-669745BC22D3.jpeg
I believe I came up on your post elsewhere on the forum, I was trying to find it again see if you by chance knew your trims after it warmed up and idled for a bit. I think you’re the only one I’ve seen post about this issue so I’d say it’s pretty rare. I’ll see if I can get a borescope down there see if I can take a peak at those tabs but you may be right and I may have to pull the blower either way. I’ll try some of the other options some of the others mentioned first and leave that as a last resort lol I really don’t want to pull the blower back off 😬
 

J17GT

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I believe I came up on your post elsewhere on the forum, I was trying to find it again see if you by chance knew your trims after it warmed up and idled for a bit. I think you’re the only one I’ve seen post about this issue so I’d say it’s pretty rare. I’ll see if I can get a borescope down there see if I can take a peak at those tabs but you may be right and I may have to pull the blower either way. I’ll try some of the other options some of the others mentioned first and leave that as a last resort lol I really don’t want to pull the blower back off 😬
Unfortunately, I don’t know what the trims were. I even dug out my old whipple SD card, no logs saved on it. Hope you get yours figured out!
 

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If your kit Is a 5 bolt pulley kit (new casting design), do you recall any issues with the blower to head bolts? The 80 mm bolts (inside with o-rings) and the 55 mm (outside) bolts were not the correct size for my kit. The bolts would bottom out and weren't threaded the whole way.. I had to drop down to 75 mm and 50 mm bolts to make it work. I could see this causing all sorts of issues if someone didn't notice during install.
 
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919.s550

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If your kit Is a 5 bolt pulley kit (new casting design), do you recall any issues with the blower to head bolts? The 80 mm bolts (inside with o-rings) and the 55 mm (outside) bolts were not the correct size for my kit. The bolts would bottom out and weren't threaded the whole way.. I had to drop down to 75 mm and 50 mm bolts to make it work. I could see this causing all sorts of issues if someone didn't notice during install.
Went back this AM and messing with the injectors I noticed what you were saying. The 4 outside bolts WERE bottomed out. I took out the Injectors rails cause i was messing with something else and found that. When I put everything back in this afternoon I’ll update if that was causing the issue. Thanks
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