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Greetings everyone, I am new to Club Lexus and I joined to reach out to fellow members about some problems I'm having. Now before you all start roasting me, please understand that I am new to all of this. Thank you.
Now to the good stuff...
I have a 1999 GS300 that I completed the NA-T conversion on. I'm running a single turbo, 3 inch IC piping, MAF in the IC piping, at 6 PSI. I have upgraded the spark plugs to NGK 4644 at .033 with new coils and wires. Currently on stock injectors and no tune (nobody in NJ can tune my Lexus sadly). Also I have a full straight pipe from the turbo back, with the 2 primary o2 sensors in place.
Well, she runs. Sort of. It's idling pretty rough, and reeks of fuel. It's not throwing and CEL codes for misfires, but bank 1 is extremely rich. Like 19/0 rich.
Now driving, it sucks. It really does. I'll hit the gas to start accelerating and it sputters and misses but makes its way up thru the RPMs slowly. Then all the sudden it's like the RPMs fly up out of nowhere, the boost kicks in (steady at 6) and I go flying.
Im really confused as to why this is happening so any help would be great. Thank you so much.
something i seem to preach alot about is the size of the mass air flow sensor housing. you said your running 3 inch intercooler piping. does that mean the mass air flow sensor is in three inch piping? from what i recall, the gs300 has a stock inner diameter of 2.6 maybe. do yourself a favor and precisely measure the inner diameter of your mass air flow sensor housing. and include some pics. im assuming your fuel trims are in the high positive 20's? rich would be -20's.
Greetings everyone, I am new to Club Lexus and I joined to reach out to fellow members about some problems I'm having. Now before you all start roasting me, please understand that I am new to all of this. Thank you.
Now to the good stuff...
I have a 1999 GS300 that I completed the NA-T conversion on. I'm running a single turbo, 3 inch IC piping, MAF in the IC piping, at 6 PSI. I have upgraded the spark plugs to NGK 4644 at .033 with new coils and wires. Currently on stock injectors and no tune (nobody in NJ can tune my Lexus sadly). Also I have a full straight pipe from the turbo back, with the 2 primary o2 sensors in place.
Well, she runs. Sort of. It's idling pretty rough, and reeks of fuel. It's not throwing and CEL codes for misfires, but bank 1 is extremely rich. Like 19/0 rich.
Now driving, it sucks. It really does. I'll hit the gas to start accelerating and it sputters and misses but makes its way up thru the RPMs slowly. Then all the sudden it's like the RPMs fly up out of nowhere, the boost kicks in (steady at 6) and I go flying.
Im really confused as to why this is happening so any help would be great. Thank you so much.
Nick
Turbo Tommy can tune it
InstaGram @Tutomoracing. Newark NJ
he specializes with haltech, but also finesses. Aem ems , v2 etc
At 6 psi you have no real need for a tune, definitely no need for a stand-alone. The whole point of the GTE ECU mod is to utilize the millions in R&D and tuning Toyota did years ago and just run the turbo ECU. Anyway, I agree with "badblackgs", start with a proper sized MAF housing and go from there. You may also have a boost leak, tried a leak test?
Do you have a catalytic converter though? If not, you need to trick your O2 sensors. I used 90 degree de-foulers made for O2 sensors off of ebay. I didnt have a check engine light for 2 months. No cat + no way of tricking ecu + turbo = very rich and borderline flooding engine.
Also, once you get things running and not rich, I would pick up some light blue injectors from 1995-1997 GS300 with the non-vvti 2JZGE non-turbo. They are 310cc compared to your oem 250cc, and will ensure you never lean out or damage the engine after mutliple wide open throttles.
Thank you for your reply! I have not yet checked for boost leaks although I was informed that it won't create my problem unless leaking after the MAF. I have no boost leaks or vacuum leaks after the MAF.
Do you have a catalytic converter though? If not, you need to trick your O2 sensors. I used 90 degree de-foulers made for O2 sensors off of ebay. I didnt have a check engine light for 2 months. No cat + no way of tricking ecu + turbo = very rich and borderline flooding engine.
Also, once you get things running and not rich, I would pick up some light blue injectors from 1995-1997 GS300 with the non-vvti 2JZGE non-turbo. They are 310cc compared to your oem 250cc, and will ensure you never lean out or damage the engine after mutliple wide open throttles.
I have no catalytic converters. Both downstream o2 sensors are unplugged.
Thank you all for your kind posts and taking time to help me!
What I have tried today is disconnecting the turbo from the throttle body. I installed intake piping as if it were an N/A engine. Just pipe, MAF, and an air filter. But the problem is still persistent. This leads me to believe that my turbo isn't the problem here, and that it is probably because I have no downstream o2 sensors. I will be ordering more bungs and the "trick" adapters tonight.
No problem! okay so you don't have cats as I suspected. Yes, the O2 sensors feed CRITICAL information to your ECU to adjust timing, and fuel during closed loop operation in cold starts, any idle, partial throttle cruising or anything below full throttle to keep that perfect 14.7:1 AFR.
Even on an N/A car, deleting cats without tricking the sensors will be a problem. The ECU has no way of knowing what is going on other than the MAF and Crank/Cam sensors which are pre-ignition sensors as far as fuel being burnt. Basically what happens is your ECU sees that maybe .8x or more air is moving through your exhaust. Combining this with a turbo, it probably jumps to 1.2x or more, thus dumping fuel in to match. Although in reality, there is probably only .5x or so more, so you need to trick the O2 sensors to believe everything is good like with the stock cats. Then it will measure the correct amount of air.
Hopefully your o2s are still good and not ruined.
At full throttle however, the ECU ignores the O2 sensors and just relies on the MAF sensor. It doesn't car about emissions or AFRs. We care from a tuning perspective to make safe reliable power with a good tune but the engine isn't programmed to care per-say. That is why when you floor it, it takes a while, but then takes off real nice. The O2 sensors aren't playing a role here.
Even though my car is highly modified I attribute not ever seeing a check engine light by making sure everything thing works perfectly in OEM/stock form and then slowly modding one by one to rule out factors. I'm glad you are ordering the bungs! Make sure you buy ones that have one small hole at the end. These work perfect. Also, I bought stainless steel ones because I'm crazy, but also had to get 90 degree angle ones because straight ones wouldnt fit although ymmv.
Also, those 1995-1997 310cc injectors I recommended, you can get them cheap. They drop in 100% plug in play. Same connectors, height, o-rings and everything. I've verified this myself on a 2JZGE VVTi.
If you want to do WOT alot on a stock ECU, I would highly recommend those for the different seasons alone/elevations and air density differences to be safe at all times. You don't want a small 250cc injector at 90-100% duty cycle injector at WOT. You want a larger cc injector around 60-80% not working as hard at WOT so it won't get stuck open, stuck closed, burnt out, and cause (a) possible cylinder(s) failure(s)
This information is all so helpful! Gosh I love this website. Ok so I just ordered myself (4) o2 sensor spacers because some people on other forums said they have better luck with longer ones so I'll just double up if it doesn't work. I also ordered 2 more bungs for the downstream sensors and a brand new downstream o2 sensor because like the idiot I am, broke it. I found a nice set of refurbished injectors but I was wondering if you could be so kind to make sure they are the right ones for me. The link is below. Apparently they are 308cc so I should be okay.
And just to clarify real quick, both upstream o2 sensors are connected to the downpipes and plugged in. Just the downstream o2 sensors are disconnected.
I love the site too! I especially like helping to return what I've gotten from here and to those who are willing to learn.
Yes those are the ones. Although, there are so many fake injectors out there they are hard to spot. Even if they say OEM Denso in the description, they can be really convincing but poorly made Chinese copies. Chinese copies can get stuck open, closed, etc. and cause engine failures. Like on the RX8 injectors, the only differences is this small two bubble mold casting that are probably 2-3mm that you could easily miss between real and chinese ones. I would buy ones known from someones car and buy a new O-ring kit. But this is just IMHO. I've never had bad luck with used injectors.
Those might be real densos in your link, but I can't be for sure.
Ebay item number for injectors: 292182270084
Ebay item number for o ring kit: 281742475946
Here is a pic of one I took next to a 1UZ vvti injector (2JZGE is the same shape/casing and cc at 250 just the 2JZ is blue instead of pink)
I love the site too! I especially like helping to return what I've gotten from here and to those who are willing to learn.
Yes those are the ones. Although, there are so many fake injectors out there they are hard to spot. Even if they say OEM Denso in the description, they can be really convincing but poorly made Chinese copies. Chinese copies can get stuck open, closed, etc. and cause engine failures. Like on the RX8 injectors, the only differences is this small two bubble mold casting that are probably 2-3mm that you could easily miss between real and chinese ones. I would buy ones known from someones car and buy a new O-ring kit. But this is just IMHO. I've never had bad luck with used injectors.
Those might be real densos in your link, but I can't be for sure.
Here is a pic of one I took next to a 1UZ vvti injector (2JZGE is the same shape/casing and cc at 250 just the 2JZ is blue instead of pink)
Ok I will keep my eyes open for a good pair of used injectors. I don't mean to bring this topic back to yesterday, but the more I read up the more I don't think o2 sensors are my problem. I have both upstream o2 sensors plugged in and in place. Just my downstreams are unplugged. This can really cause terrible idle, terrible gas mileage, and.a rich condition??
Yes it can and will. Why wouldnt you think not having two sensors plugged in that control AIr to fuel ratios in idle and under full throttle wouldnt affect things on a car let alone modified? Rhetorical question
My post above even explained why it idles and cruises horribly but at wot it goes good
Yes it can and will. Why wouldnt you think not having two sensors plugged in that control AIr to fuel ratios in idle and under full throttle wouldnt affect things on a car let alone modified? Rhetorical question
My post above even explained why it idles and cruises horribly but at wot it goes good
Alrighty I get what you're saying. After everything comes in I will install it. Then I'll get back to u with an update on how it's running. Thanks.
08-01-17, 09:08 PM
GS300 NA-T Running Terrible
