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Discussion Starter #1
Hi all. I have searched thrue all threads including supra forums about this and haven't found an answer.

Car: 02 Lexus is300 2jzgte aristo
Single turbo 6262.

I recently got a apexi neo and also
Bigger injectors to help with the fueling.
Has an in tank walbro 255

When I installed 650cc sidefeed drop in injectors the very first time it fired right up and actually idled decently.

When I went to try to start it again it won't catch. Just cranks with no luck of turning over. I pulled the plugs sure enough they were flooded. Cleaned it got it started barely after a million tries with my pick up truck connected for more crank power.

Also I installed ngk one step colder plugs.

Is there a way I can fix this issue with out going standalone? I mean I know the problem is it basically floods when cold thinking I still have my stock 440cc in there. Did anyone ever have this kind of an issue? I know the NEO isn't the best for tuning but I don't have the funds for a standalone. Any help? thanks.
 

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Go back to the stock injectors and save some money for a link setup. 650cc is the absolute limit with the NEO and really it’s not going to help much when you’ve gone up nearly 35% in injector size. That’s just too much fuel to try and ask the NEO to reduce based on it’s MAF manipulation alone.
 

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Discussion Starter #4
What are you using for fuel pressure regulation?
I'm on stock fpr
Go back to the stock injectors and save some money for a link setup. 650cc is the absolute limit with the NEO and really it’s not going to help much when you’ve gone up nearly 35% in injector size. That’s just too much fuel to try and ask the NEO to reduce based on it’s MAF manipulation alone.
So you mean it's basically impossible to run 650cc with neo?
 

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Well I didn’t say impossible, but you are already hinting on what the edge of possible would be with your OP. Save some money up and try and get a stand alone to properly tune the car. Piggyback systems can only offer so much. Besides the factory ECU has been known to learn that it’s being manipulated and starts to take back over.
 

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Question. Where you running lean on the stock injectors? If not, why bigger? The only way to make the Neo come close would be to use a custom mapped MAF sensor. But this may not resolve some issues that may come up.
 

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Discussion Starter #7
Well I didn’t say impossible, but you are already hinting on what the edge of possible would be with your OP. Save some money up and try and get a stand alone to properly tune the car. Piggyback systems can only offer so much. Besides the factory ECU has been known to learn that it’s being manipulated and starts to take back over.
Okay yeah, I just tried tuning the car on a highway, it definitely isn't easy and it's doing weird things like when you think you got it good. Then it starts to act up again. Like others stated fighting with it.

Whats a good standalone that won't break the bank? I heard good things from map ECU but isn't that's still kinda a piggy back .
 

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Question. Where you running lean on the stock injectors? If not, why bigger? The only way to make the Neo come close would be to use a custom mapped MAF sensor. But this may not resolve some issues that may come up.
I wasn't running lean at all. But I was told if I wanted to push more boost I would need bigger injectors so the 440cc aren't pushed to 100 percent duty cycle. It made 434whp at 15.7 psi. I'm happy with them numbers but was told its dangerous
 

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I wasn't running lean at all. But I was told if I wanted to push more boost I would need bigger injectors so the 440cc aren't pushed to 100 percent duty cycle. It made 434whp at 15.7 psi. I'm happy with them numbers but was told its dangerous
Now the reason I got a piggy back is because my afr was leaning out in wot. It would start to dip around 4k when the turbo was at full boost.
So like 14.5 then down after 4k rpm.
Not good
 

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I wasn't running lean at all. But I was told if I wanted to push more boost I would need bigger injectors so the 440cc aren't pushed to 100 percent duty cycle. It made 434whp at 15.7 psi. I'm happy with them numbers but was told its dangerous
You might be okay with a custom MAF sensor. But the stand alone would be better. You will probably want more after a while.
 

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Discussion Starter #11
I never heard of a custom maf sensor. Is there one I can buy? I'm also running a hks fcd set to 7
 

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Wow 14.7 is definitely a problem. I think you may Have better success switching to 550cc with what you are currently using to tune rather than the 650cc. However that means selling the 650cc and buying new injectors. With what you have now, I would probably go with the HKS F-con V.

you really shouldn’t push the car that hard with those afrs. That is just asking for trouble. Those injectors are probably already running very near 100% already or on the ragged edge trying to keep the A/F lower.
 

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I never heard of a custom maf sensor. Is there one I can buy? I'm also running a hks fcd set to 7
It is not cheap. Also requires changing the wiring connector on he MAF. You will need to know the size of the injectors and the size of the intake tube. So for example 650cc and 2.75 dia for stock. I can gen them scaled for any pipe up to 3.5 inch. Also need to know if it is boosted and doing blow through or standard. It would be scaled with a 40 point map vs 9 point stock. They run roughly around $300.00. They are reprogram able for a small free to do so.
 

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Discussion Starter #14
Wow 14.7 is definitely a problem. I think you may Have better success switching to 550cc with what you are currently using to tune rather than the 650cc. However that means selling the 650cc and buying new injectors. With what you have now, I would probably go with the HKS F-con V.

you really shouldn’t push the car that hard with those afrs. That is just asking for trouble. Those injectors are probably already running very near 100% already or on the ragged edge trying to keep the A/F lower.
Thanks, it's not running at 14.7 at wot anymore. It did that when I didn't have any tune on stock ecu with stock injectors. Its actually running pig rich now with the neo. I managed to have it down in 11afr at wot.
My real problem was or is still that it's a pain in the ass to start it from cold. And also it seams like it dont like the neo, it just messes with afr and boost and I constantly have to adjust it. I did hear on supra forums guys had no problems or no real problems using neo even with bigger injectors. I'm not sure if it's because mine is a vvti jdm or not.
 

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It’s just a piggyback trying to accomplish what a stand alone can do completely on its own. The NEO can only manipulate the signal. The problem is the signal is still getting sent to the stock ECU. A stand alone can take COMPLETE control over cold start enrichment.
 

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It’s just a piggyback trying to accomplish what a stand alone can do completely on its own. The NEO can only manipulate the signal. The problem is the signal is still getting sent to the stock ECU. A stand alone can take COMPLETE control over cold start enrichment.
Thanks, I totally get what you're saying. My other question would be tuning the neo . Would you have input as to when your afr should drop in wot. Right at 2k rpm say if you pin the throttle down. My afr drops to 11 when it passes 4k. Around 2500-3500 its like 13ish.
 

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Thanks, I totally get what you're saying. My other question would be tuning the neo . Would you have input as to when your afr should drop in wot. Right at 2k rpm say if you pin the throttle down. My afr drops to 11 when it passes 4k. Around 2500-3500 its like 13ish.
That’s the thing, 11 afr isn’t bad but it’s probably a little richer than it needs to be. And 13 is too lean for a WOT pull. That’s where it seems like the NEO is trying to manipulate the signal while the factory ECU is still trying to ALSO take control.
 

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Discussion Starter #18
I hate this freaking neo now. I'd like to get a standalone but I need to sell the neo. If I add fuel to 3 to 4k rpm it also adds fuel at 5 and 6k with out me adding fuel. So for it to work properly I add fuel from 2 to 4k then I have to take out fuel from 4-6k that doesn't sound right and I haven't seen anyone tune a neo like that.
 

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I have not personally used a NEO but I’m aware of how they try to work. It seems to me that you should sell that NEO and go with a stand alone tbh. It’s honestly the best option to try and get ahold of correct fueling and timing. Especially since you have just “tapped” into the MAF signal and that signal is still being sent to the factory ECU. What I would gather is that if you add fuel percentage around 2-4K, and you don’t change 4K+ it would seem that the factory ECU is still trying to add fuel above 4K all on it’s own because it normally would do so on the factory motor.

So you probably have your Own fuel settings on the NEO above 4K rpm PLUS what the factory ECU is trying to provide to the engine so you get an extremely rich AFR of 11.
 

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I have not personally used a NEO but I’m aware of how they try to work. It seems to me that you should sell that NEO and go with a stand alone tbh. It’s honestly the best option to try and get ahold of correct fueling and timing. Especially since you have just “tapped” into the MAF signal and that signal is still being sent to the factory ECU. What I would gather is that if you add fuel percentage around 2-4K, and you don’t change 4K+ it would seem that the factory ECU is still trying to add fuel above 4K all on it’s own because it normally would do so on the factory motor.

So you probably have your Own fuel settings on the NEO above 4K rpm PLUS what the factory ECU is trying to provide to the engine so you get an extremely rich AFR of 11.
You are 100 percent correct on that!
Its doing just that, the ecu is adding fuel on its own when I add fuel on lower Rpm's then it floods after 4k. I've seen it going into mid 10s afr now.

What's a good standalone would you recommend? I would like a plug and play so I can install it myself then have it tuned by someone. Driftmotion sell infinity 6 plug and play for jdm 2jzgte vvti. But it is pricey.

Just seeing what other options are
I'm out in PA close to Philly there isn't too many shops around that know much about these engines.
 
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