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Hey guys, so my 08 si has, i/h/e and hondata flashpro. I've done a datalog and noticed it ran really lean, so I flashed it back to completely stock, still ran really lean, afr running between the normal 13 or 14 to 16,17,18. So since it still ran lean with the stock tune, would my mods do that? Or could it be somthing as simple as needing to clean my maf? I know I need to get it professionally tuned, but cant for a few months, I need it drivable till then. And I dont have any stock parts to put on if my mods are causing this, thanks

 
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question.. Do you have a comparison of AFR vs throttle position? I'd imagine partial throttle sitting around the 14.7ish mark. WOT likely be around 11-12.5 or so. Completely off throttle, it may peg high, or at least sit high in the AFR range (like the 18+range). If that's the case, completely normal.

 
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No, it gets real lean as I'm 75% plus throttle about 4,500 rpm to redline mostly. But it also leans out up to 15,16 while partial throttle and when I get into the gas right after I shift. I also have a lean bank 1 code as well, btw

 
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Well, that's a horse of a different color.

i/h/e wouldn't shouldn't cause a lean condition. The only thing I can think of, and only bc I've read about this issue with 10th gens.. If the MAF housing/sensor are reading erroneously, it can cause an issue. All this info is gonna be from a 10thgen and theoretical speculation, so bear with me.

MAF housing too large, MAF is gonna read a smaller amount of air that's being fed into the engine (e.g. lower than actual). Assuming the K20 fuel delivery in your Si is MAF dependent, it's gonna feed fuel as it's indicating, and if it's indicating less air than actual, it'll cause a lean condition. I can't imagine it causing a lean condition that high tho.


More google searching says flash to a map for an Injen SRI.

 
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Alright man, I'll give that a shot, but just in case I'm gonna pick up some maf cleaner and do that. But yea, my Ktuned intake is 3.5in. So much more air coming in then stock, that's for sure

 
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Yeah, there were problems with 10thgens where the MAF housing (particularly in Injen intakes) weren't sized properly and causing fuel issues. Also, aftermarket companies (like PRL motorsports) has a race MAF option on their intakes that are 1) bigger than stock and 2) explicitly mention you need a tune for. That extra big-*** MAF housing might be the root of the issue.

 
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Well I put that injen intake basemap on and it seems to be a lil less lean, but just in case today I'm gonna clean the maf, and ran a bottle of Lucas injector cleaner in my gas tank as well. Eliminate the cheap variables first, haha. But I am gonna have it dyno tuned in a few months. I cant wait for the feel of the extra power, especially if I'm running lean, obviously power will be down. Thanks for ur help man

 
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np my dude, that's what we're here for. No lie, I had a completely different response typed up, then I decided to look up if the 8thgen had a MAF (7thgens didn't), then recalled the issues I've heard of 10thgen intakes and their MAF problems on some intakes (spoiler alert, the Injen sri/cai is garbage for the 10thgen). Hopefully at least your car is running safer rn, enough to the point where it's usable as a daily without fear of FUBARing the engine due to overly lean conditions. What are your AFRs looking at now that you changed the tune?

 
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Still running between 14 and 16 but doesnt spike higher then that unless i get on it in the higher rpm. Just needs to be able to get thru a few months till I can afford my tune session. I'll let u know if it changes after I clean the maf

 
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A lot safer than hanging out in the 16+ range. Yeah, please keep us updated

 
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Lil off topic, but do u know what this is, its leaking coolant, and what part number would it be?

 
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Probably a temp sensor

 
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You would thing, but I went to three autopart stores and the coolant temp sensor they give me looks nothing like what I need, this sensor is underneath the radiator hose, next to the shifter bushings

 
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can you take a picture a bit further out? trying to see the position of it on the engine so I can compare part numbers and pics

 
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That is the back-up light switch, it has nothing to do with coolant. It has to be leaking from somewhere else and ending up on that sensor.

 
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Weird, haha but ok, thanks, I'll try to figure it out
"edit"
just checked with car running, it most definitely is leaking coolant out of whatever sensor that is, for sure. Saw it myself leak out, everywhere else is dry

 
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Oh ****, that's on the tranny itself. Initial pics, I thought the sensor was sitting horizontally.

*scampers off to avoid work and research this*

 
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There is no coolant in the transmission. I understand it looks like it is coming from that sensor but it has to be coming from somewhere else. The main water passage is directly above that, possibly coolant is leaking into/onto the harness and running down into/onto the sensor? That sensor could cause a transmission fluid leak but it wouldn't look anything like coolant.

 
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Yea, that's whats confusing literally everything else is dry
and I'd have to look again, but I dont actually think it's in the trans, it's part of the block just after the trans case

 
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Technically it's in the clutch case, still part of the transmission. Number 5 in the below pic.

 
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What is that part?

 
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Switch Assy., Back Light
Part Number: 28700-PHR-003

It is a switch that turns on the reverse lights when the transmission is shifted into reverse.

 
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Mods can close out this thread if they want.

 
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But what if we don't wanna?

 
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So funny, I fixed that leak..made me feel like a huge idiot tho just had to remove my radiator hose, clean it a bit, and tighten her back up. Ah well, no more coolant puddles on my tranny, haha

 
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At least it was a free and simple fix