sluggish pickup once up to runing temp

[maca]

Hi just wondering if any one has had this problem ? I have a 1uz when it is cold, not stone cold just before it gets up to full running temp, I have very good acceleration. It is very responsive from a standing start, it will spin wheels well in to second gear and does not ping or anything out of the ordinary. BUT once it has gotten up to full running temp it is not as responsive from a standing start. It will not spin the wheels even if I want to. It just seems doughy until it gets to 3500rpm and then it is fine, very good pick up, powers on and goes hard just wondering has any one got any ideas?

 

[och]

Hi just wondering if any one has had this problem ? I have a 1uz when it is cold, not stone cold just before it gets up to full running temp, I have very good acceleration. It is very responsive from a standing start, it will spin wheels well in to second gear and does not ping or anything out of the ordinary. BUT once it has gotten up to full running temp it is not as responsive from a standing start. It will not spin the wheels even if I want to. It just seems doughy until it gets to 3500rpm and then it is fine, very good pick up, powers on and goes hard just wondering has any one got any ideas?

same here, no fix.

 

[madmont]

Is your motor stock? aftermarket exhaust? modified intake?

 

[maca]

reply to Madmont

Yes I do have exstractors system and modified air intake.

 

[maca]

I have bean playing with a couple of things the engine temp sender for the ECU I have found that it ajust,s engine timeing so I tryed a few things. Find the resistance of sender cold and hot cold was 4170 ohm hot was 2600 ohm so I got a 3900 ohm resister and put it in the end of the senser plug once the car was running. Once hot as soon as i pluged it in it ajusted timeing it must have advanced so I went for a drive a big impruvment very good pick up compaired to before when hot. I will let yous know how i go i may be adle to make ajustable timeing for it ?

 

[bdangerous]

i have nearly the same problem,lacks power till about 3000rpm then goes like a scalded cat.It definately feels like timing and not fuel.With the mod to the sensor it means that it is going to fuel up, so your economy(??...)is going to suffer.i have made extratctors for mine, they have a 3" collector then into a 3" single, i will be dropping it back to 2.5" out of the collectors to regain some lost torque.I think it is something that has been missed in the wire up with these conversions,or the O2 sensors aren't getting the right signal for the ecu till gas flow/exh heat gets up, MAYBE, someone like sideshow or the likes could shed a little light on the subject.

 

[madmont]

i have nearly the same problem,lacks power till about 3000rpm then goes like a scalded cat.It definately feels like timing and not fuel.With the mod to the sensor it means that it is going to fuel up, so your economy(??...)is going to suffer.i have made extratctors for mine, they have a 3" collector then into a 3" single, i will be dropping it back to 2.5" out of the collectors to regain some lost torque.I think it is something that has been missed in the wire up with these conversions,or the O2 sensors aren't getting the right signal for the ecu till gas flow/exh heat gets up, MAYBE, someone like sideshow or the likes could shed a little light on the subject.

I would suggest you drop it back to 2" out of the collectors 2.5" is too big

 

[White ls400]

any more info or pics of this resistor

 

[och]

Disconnect your MAF and see if running without MAF you get better torque.

 

[och]

I have bean playing with a couple of things the engine temp sender for the ECU I have found that it ajust,s engine timeing so I tryed a few things. Find the resistance of sender cold and hot cold was 4170 ohm hot was 2600 ohm so I got a 3900 ohm resister and put it in the end of the senser plug once the car was running. Once hot as soon as i pluged it in it ajusted timeing it must have advanced so I went for a drive a big impruvment very good pick up compaired to before when hot. I will let yous know how i go i may be adle to make ajustable timeing for it ?

Ironically, I played with that sensors resistance as well, a couple of months ago. Below I'm attaching a chart with resistance specs.

I've tried various resistors, and with fooling the ECU to think engine coolant temp is lower than it actually is, I was getting a huge improvement in torque from stop, but above 2000rpms the car would ping like crazy.

Now I'm surprised you were able to use 3.9kohm resistor. Did you try it when the car was cold? Because mine wouldn't even start with anything more than 1kohm, but then my engine was already hot. Also, the higher the resistance, the more pinging I was getting, and it was hard pinging, detonation type, not slight knocking thats sometimes caused by lean mixure. I guess the injectors were dumping way too much fuel.

I guess the only fix is a standalone ECU, and proper tune. Maybe a piggyback would work, but I don't know. I've replaced a bunch of stuff trying to get to the bottom of it, but so far no luck. I had my ECU rebuilt, replaced O2s, MAF, full tune up, replaced TPS, coolant sensor, etc... Nothing worked.

 

[och]

Here's more info