trans problems again...

[UZZ30-Québec]

ok, new crappy thing found today since it was pretty hot.

When the A/C is activated, and i'm on a red light or a stop, the car really wants to move when the RPM is higher. I know this is normal due to ISC adjusing the engine to supply power to the compressor. But when the ISC let drop the IDLE at a red light, the car wants to accelerate and today it even stalled. I really start to think i have a problem with my transmission. Also yet again, i realised that the car pulls a lot more in 2nd gear than 1st. whatever IS the RPM. I was on "power" mode. gave 1/2 throttle, car accelerates, shifts at about 5000RPM and it was pulling quite more but i wasn't giving more throttle. i know the T/C stall speed can answer slow take-out but passed 3500RPM i don,t think it can cause an acceleration loss ???.

Also, with A/C on, on neutral, if i rev the engine to about 1300RPM, it revs a few seconds, than it starts to shake, it,s not a 4.3 GM V6 but it shakes a little, this might be normal since the A/C compressor sucks power but would it be hard enough to drive to make the engine shake?

i really think something's wrong somewhere and i can't figure it out. the car should pulls more in 1st gear passed 4000RPM than the 2nd gear. it,s like if something is holding the throttle but the trac control was de-activated.

also, below 2500RPM the engine has very low power in 1st gear. when it reaches 2500RPM it,s like if it has a VTEC and torque shows up. But this i beleive would be caused by the T/C.

passed 80km/h i do beleive it has 250HP and it pulls like 250HP, but on take-off it's not faster than my poor 7M cressida.

What are your opinions about this? Would the traction control holds the gas in 1st gear even if it's deactivated to gives the car a smooter acceleration? this week i,ll try to remove the Throttle cable for the traction control to see if it'll change something.

1995 canadian SC 400

 

[UZZ30-Québec]

well, looks like i'll have to find the answer the hard way!

today it wasn't doing that stalling stuff, dunno why.

If i get a lot of spare time, i'll try that A-340E T/C swap to see if it helps.

 

[UZZ30-Québec]

Did some search on the forum and now i'm all ****** up

so the US SC400 has the A340E ???? but not the LS ??? for all years?

then why is the engine revving slower on highway if both the SC and the MX has a 3.9 rear end?

what about that famous torque converter stall speed if i don,t have this problem with my MX and it's the same transmission with 70 less horsepowers ???? (and only 200 pounds lighter)

ohh man i think i'll start to cry... too much contradicted infos. I shouldn't have sold my damn R-154 and throw it on the car, it would have solved all the problems.

 

[flyboi001]

my 96 sc does the same thing its a dog in the first 2000 rpm of first gear!

 

[WDoherty]

an r-154 would have been nice, you can still find them on ebay around $300. My sc is a dog at low rpm as well and i beleive it runs proper so that's just the way it is. I did some spirited driving tonight and i do think you get a better pull feel from second gear in these cars because of their top-end nature and the power it takes in first to get the heavy beasts moving from a stop.

 

[stevechumo]

I used to have similar symptoms but it turned out it's the ECU. This was my symptom. If I had the A/C on while driving and stopping at red light, the engine run fine, and the gear was in D normally. But if I turned off the A/C while stopping at red light with the gear in D, the engine stalled. I asked a mechanic to fix this and paid him $200 for 10 hours of work and tuning.

I'm not sure exactly what he did but he told me he changed out to stiffer springs near the sensors, I don't know what sensors. The result is when I had the A/C on, the RPM is raised up to about 700 RPM, and when the A/C is off, the RPM is dropped down to about 400 RPM, which is still good for the engine not to stall. Before he fixed it and with the A/C on, it was only about 500 RPM, so when the A/C is off, it went all the way down and killed the engine. And if I didn't turn on the A/C, there's no problem at that time. You may check this first before running into your tranny.

 

[Nick M]

but on take-off it's not faster than my poor 7M cressida. What are your opinions about this?

In my experience, the 7M Cressida is just as quick from a stop as the LS. Especially with an older A341E, which has a much taller 1st gear.

If your car stalls at a light with A/C, you will have stored DTC's. Pull them. If somebody puts up the wiring diagram to his car, I will give you a more thorough answer.