Slow 0-60 ucf10
Thread Starter
Lead Lap
Joined: Apr 2017
Posts: 701
Likes: 29
From: Qld
Slow 0-60 ucf10
Hey guys.
my ls400 is taking just a fraction over 10 seconds to get to 60. It used to take around 8. The only major thing that has changed is the timing belt replacement.
any idea where I should look ?? The timing seems to be OK but maybe I should check it again. Engine is smooth. Cats are new. New leads, plugs, rotors, coils etc.
my ls400 is taking just a fraction over 10 seconds to get to 60. It used to take around 8. The only major thing that has changed is the timing belt replacement.
any idea where I should look ?? The timing seems to be OK but maybe I should check it again. Engine is smooth. Cats are new. New leads, plugs, rotors, coils etc.
Advanced
Joined: Jan 2014
Posts: 603
Likes: 135
From: CA
These cars are 15, 20 years old so they're not like they used to be. If you have an OBDII scanner, hook it up & take a look at all the electrical parameters, especially the long-term fuel trims as your may be running rich. You can also change the engine coolant temperature sensor & disconnect the battery to reset the ECU. Be careful w/ the plastic connector as it has been cooked up in the engine compartment & may crack/break on you. Once replaced, that'll help getting some of the performances back.
Fuel pump wearing out? What year and mileage are you at?
On being a tooth off on the timing, I doubt that. I once did that on a timing belt many years ago (Honda V6), was just one tooth off on one of the cam pulleys due to two sets of ambiguous timing marks (the quick check one vs. the real, careful one). That one tooth off made the thing run and barely idle like crap. Nothing as subtle as reduced max power like you're finding.
And my '91 seems as fast as it ever was. If you just did a T-belt job, the only wearing-out thing I can think of would be a valve adjustment, but those usually are only done on these cars when the valves are making noise. Well maintained, they should keep almost all of their power.
On being a tooth off on the timing, I doubt that. I once did that on a timing belt many years ago (Honda V6), was just one tooth off on one of the cam pulleys due to two sets of ambiguous timing marks (the quick check one vs. the real, careful one). That one tooth off made the thing run and barely idle like crap. Nothing as subtle as reduced max power like you're finding.
And my '91 seems as fast as it ever was. If you just did a T-belt job, the only wearing-out thing I can think of would be a valve adjustment, but those usually are only done on these cars when the valves are making noise. Well maintained, they should keep almost all of their power.
Last edited by oldskewel; Jan 30, 2019 at 11:18 AM.
Thread Starter
Lead Lap
Joined: Apr 2017
Posts: 701
Likes: 29
From: Qld
Thanks guys.
it's a 1990 with 70k miles. I changed the coolant temp sensor as soon as I got it. Same with the fuel pump.
it doesn't smell like its running rich at all. I will reset the ecu. Can't hurt.
it does now have a minor exhaust leak on the flange between cats and exhaust manifold
it's a 1990 with 70k miles. I changed the coolant temp sensor as soon as I got it. Same with the fuel pump.
it doesn't smell like its running rich at all. I will reset the ecu. Can't hurt.
it does now have a minor exhaust leak on the flange between cats and exhaust manifold
Wow, that is low mileage. So valve adjustment and fuel pump are probably not concerns, since those are wear-based issues. But the ECU may be time-based, and that may be your problem.
Lexus Test Driver
Joined: Apr 2012
Posts: 6,325
Likes: 515
From: Long Island
These cars are 15, 20 years old so they're not like they used to be. If you have an OBDII scanner, hook it up & take a look at all the electrical parameters, especially the long-term fuel trims as your may be running rich. You can also change the engine coolant temperature sensor & disconnect the battery to reset the ECU. Be careful w/ the plastic connector as it has been cooked up in the engine compartment & may crack/break on you. Once replaced, that'll help getting some of the performances back.
Pole Position
Joined: Dec 2009
Posts: 3,278
Likes: 317
From: ct
If the belt was off by only one tooth you would know. It would have no power and be jumping, hopping, and skipping all over.
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Racer
Joined: Sep 2018
Posts: 1,392
Likes: 66
From: California
After I changed the first T-belt in my 93 it felt the same as yours. It took like 3 weeks to come back to full power. It was running slow for so long I figured that's what I had to live with and then, BAM, pulling out from a stop it just took off like a rocket. The 2nd T-belt I did it only took a few days for the power to come back.
If the belt was off by only one tooth you would know. It would have no power and be jumping, hopping, and skipping all over.
If the belt was off by only one tooth you would know. It would have no power and be jumping, hopping, and skipping all over.
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Racer
Joined: Mar 2018
Posts: 1,908
Likes: 494
From: Nevada
Fan clutch is fine? It's common for them to fail in the fully-on state where it will be constantly spinning and causing parasitic loss. When I got mine fixed there was a significant improvement in MPG and low-end power.
It should not sound like a truck while driving. You should only ever hear it in two cases. For the first 30 seconds after a cold start and sitting in 110f traffic.
It should not sound like a truck while driving. You should only ever hear it in two cases. For the first 30 seconds after a cold start and sitting in 110f traffic.
Racer
Joined: Sep 2018
Posts: 1,392
Likes: 66
From: California
Fan clutch is fine? It's common for them to fail in the fully-on state where it will be constantly spinning and causing parasitic loss. When I got mine fixed there was a significant improvement in MPG and low-end power.
It should not sound like a truck while driving. You should only ever hear it in two cases. For the first 30 seconds after a cold start and sitting in 110f traffic.
It should not sound like a truck while driving. You should only ever hear it in two cases. For the first 30 seconds after a cold start and sitting in 110f traffic.
Thread Starter
Lead Lap
Joined: Apr 2017
Posts: 701
Likes: 29
From: Qld
Fan clutch is fine? It's common for them to fail in the fully-on state where it will be constantly spinning and causing parasitic loss. When I got mine fixed there was a significant improvement in MPG and low-end power.
It should not sound like a truck while driving. You should only ever hear it in two cases. For the first 30 seconds after a cold start and sitting in 110f traffic.
It should not sound like a truck while driving. You should only ever hear it in two cases. For the first 30 seconds after a cold start and sitting in 110f traffic.
I have installed an electric fan in the car so no clutch to worry about. The power loss is definitely down low in the rev range from what I can tell. Tomorrow I will do a compression test and see what I get. I need to get a fuel pressure tester so maybe Ill buy myself that for my Birthday.
I will say that the OEM fuel pump was replaced with a cheap aftermarket, universal option so that could have something to do with it. But the idle and acceleration feels quite smooth.