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Sluggish off the line - Normal?

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Old 11-02-08, 03:09 PM
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daudi81
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Originally Posted by Och
Daudi, does it ping sightly around 2500-3500? The "ping" sound may not be as pronounced as on other cars, but I bet its there.
I'm not sure, next time I drive it I'll listen closely. What would that signify?
Old 11-02-08, 03:11 PM
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Wrong air to fuel ratio.
Old 11-02-08, 03:16 PM
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I rarely push mine up to 3K rpm, but I generally keep it between 1500-2500, and even when i try to speed up a little, it feels like the car is struggling.....

Very weak off the bat....very weak....
Old 11-02-08, 03:28 PM
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daudi81
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Originally Posted by Och
Wrong air to fuel ratio.
How do I fix that? Tuneup?
Old 11-02-08, 03:56 PM
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Originally Posted by daudi81
How do I fix that? Tuneup?
I don't know... I spent two years battling this problem in my LS400, with no success at all. Replaced whatever could be replaced, tuned up whatever could be tuned up, with no success at all.

I recently bought a SAFC piggy back computer, but havent had a chance to install it and tune it. Hopefully that will help.
Old 11-02-08, 04:30 PM
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kyoso23
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My SC400 digs out from a stop pretty nicely. It will spin the 275's in the rear every time if I want it to, and if I put the stockers on it is a smokeshow. It's no drag car or anything but it's not a dog. Maybe your injectors are dirty or you have a semi clogged fuel filter?
Old 11-02-08, 04:40 PM
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Yours is a 97 with updated ECU and hot wire MAF.

This sluggish condition that a lot of us are experiencing applies mostly to early 1UZ's with Karman AFM's.
Old 11-02-08, 04:45 PM
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Daudi, you may notice that when the car is completely cold, like in the morning, it has a decent pick up until it warms up. Thats because the ECU is using base fuel maps and ignoring the signal from O2 sensors. But once it starts reading the O2 sensors, it leans out your engine and it feel gutless like a mid 90ies Civic, yet guzzles us fuel heavily because you end up having to push it hard to accelerate.
Old 11-02-08, 04:51 PM
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daudi81
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Originally Posted by Och
Daudi, you may notice that when the car is completely cold, like in the morning, it has a decent pick up until it warms up. Thats because the ECU is using base fuel maps and ignoring the signal from O2 sensors. But once it starts reading the O2 sensors, it leans out your engine and it feel gutless like a mid 90ies Civic, yet guzzles us fuel heavily because you end up having to push it hard to accelerate.
So...sell it and get a newer SC400?

I really like my SC400, but getting economy car performance with 18-20mpg is kinda stupid IMO.

What year is your LS400 Och? And what year did Lexus upgrade the ECU?
Old 11-02-08, 05:02 PM
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Mine is a 94, with LS they changed the setup from 1995 on. With SC's, I'm not sure, I believe in 1996. Also with LS400 they added VVT-i onto the 1UZ engine, to make it a total beast. I'm not sure if SC400 ever shipped with VVT-i 1UZ, I heard it did in 2000.
Old 11-02-08, 05:03 PM
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Originally Posted by daudi81
So...sell it and get a newer SC400?
If I knew what kind of hell I would be going through with my LS400, I would've bought a 95 instead of the 94, defenately.
Old 11-02-08, 05:11 PM
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Originally Posted by Och
Mine is a 94, with LS they changed the setup from 1995 on. With SC's, I'm not sure, I believe in 1996. Also with LS400 they added VVT-i onto the 1UZ engine, to make it a total beast. I'm not sure if SC400 ever shipped with VVT-i 1UZ, I heard it did in 2000.

I'm pretty sure the 98+ SC400's have VVT-i. But I didn't know that when I bought my SC400. Sounds like I'll keep this SC400 till I graduate (2yrs), then get a 98+ when I can afford it. However, with the amount of gas I'll be putting into this SC400 it could be awhile!!
Old 11-02-08, 05:17 PM
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Well Im in a process of installing a piggy back computer onto my LS to adjust for these fuel maps. I'll update how well it works once I finish, so it might be an easy $300 fix.
Old 11-02-08, 05:26 PM
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Originally Posted by Och
Well Im in a process of installing a piggy back computer onto my LS to adjust for these fuel maps. I'll update how well it works once I finish, so it might be an easy $300 fix.
I'm very interested. Let me know how it goes!
Old 11-02-08, 07:28 PM
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OK, just took it out for a spin to 0-60 time it and listen for the "ping" around 2500-3500.

Anyway, I listened very carefully and there is definitely no ping at any rpm on the car. Also, I had 0 problems chirping or spinning the tires off the line (I've babied it since I got it, so this is the first time I actually tried to spin the tires). 0-60 time was slightly less than 7 seconds, even on a slight incline, but I just timed it with a friend and a stopwatch - so who knows how accurate that is.

I don't know, maybe my expectations are really high. I am just used to driving my '04 Honda Odyssey, which is about 1000 more lbs and slightly less hp/tq numbers. Granted the Van is only 4 years old, vs 16 yr old car, they have about the same mileage. The Van just seems so much more zippy and "light" in straight line acceleration compared to my SC. I'm guessing the van just has higher power numbers in lower rpm settings.


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