240z wont go

[disepyon]

So the problem i am having is kind of hard to explain. I wanted to take my z out for a drive tonight but it seems i cant. This is a stock 72 240z. The motor idles fine and revs great like it should, but the problem is when i try and drive the car. When i step on the gas pedal to get going, the car wont go. I have to lightly press on the pedal to get the car up to speed. I dont hear any unwanted noise from anywhere. The clutch and flywheel are in ok shape because i just recently put the engine back together not to long ago. spark plugs are only about 3 weeks old.

 

could my distributor be the problem?

 

Any idea?

 

Thanks,

Brent

Edited January 29, 2012 by disepyon

[Six_Shooter]

So when you put a load on the engine it won't rev?

 

The engine revs, but there is no power transfer through the tranny to the wheels?

 

You're going to have to describe it much better.

[disepyon]

So when you put a load on the engine it won't rev?

 

The engine revs, but there is no power transfer through the tranny to the wheels?

 

You're going to have to describe it much better.

It idles and revs fine. For instance when i shift in first gear from a dead stop and try and drive it like normal, as i step on the gas pedal to get going the car will have trouble moving up to speed. I can press the pedal all the way down to the floor and the car will still be moving along slowly.

 

I really dont know how to explain it better.

[seattlejester]

If your're sure the clutch is fine, maybe check the clutch fluid resevoir? Sounds like maybe it's poor engagement.

[disepyon]

THanks ill check that, i did remember the fluid looking a bit old and nasty.

 

I just took the spark plugs out and looked inside the piston chambers to see if maybe i flooded them. Results are that the first two pistons are wet and the rest are dry. I checked spark before this and they all sparked. could this wetness cause this issue?

[disepyon]

inspected the clutch fluid and cylinders. Turns out the slave cylinder is leaking. Now can this cause my problem and why would it?

 

[Jasonmreiss]

No, fix it, but that's not your problem

[Jasonmreiss]

No, fix it, but that's not your problem

[disepyon]

I also noticed that the first two pistons are covered in black stuff but the rest are all clean. Not sure what that is an indicator of, anyone?

Edited January 29, 2012 by disepyon

[19762802+2]

Have you checked the oil in your carbs? Is the car warmed up when you try to drive it? Does it stumble when you put it in gear and try to go?

[disepyon]

Have you checked the oil in your carbs? Is the car warmed up when you try to drive it? Does it stumble when you put it in gear and try to go?

no i havent checked the oil in the carbs. I do warm the car up enough to drive. It does stumble a little bit after i put it in gear and gas it.

[19762802+2]

Well it sounds like your running really rich on the first carb. Have you tuned it recently? I would check the carb oil as well, not having enough oil will cause the piston to rise too fast causing it to go rich.

[disepyon]

Well it sounds like your running really rich on the first carb. Have you tuned it recently? I would check the carb oil as well, not having enough oil will cause the piston to rise too fast causing it to go rich.

 

Thanks for you info, really helping me out.

 

I am going to retune the carbs tomorrow and see it that will help. I did notice my idle last week raise up a bit from before.

 

I just went out and pressed with my finger on the piston lifters, the front carb piston falls really fast compared to the second carb piston, it falls slower.

 

Is it easy to replace the oil? as in drain the old and fill with new? Ive never had to worked on carbs, i just know how to tune it. the manual says use either 10w-30 or sae20.

[19762802+2]

Thanks for you info, really helping me out.

 

I am going to retune the carbs tomorrow and see it that will help. I did notice my idle last week raise up a bit from before.

 

I just went out and pressed with my finger on the piston lifters, the front carb piston falls really fast compared to the second carb piston, it falls slower.

 

Is it easy to replace the oil? as in drain the old and fill with new? Ive never had to worked on carbs, i just know how to tune it. the manual says use either 10w-30 or sae20.

 

All you have to do is take of the bell's, depending on your year it should be 4 or 3 screws holding the bell's on, then carefully pull the piston out, You don't want to bend or damage the needle, poor the oil out of the middle shaft, put the piston back in very carefully so you don't screw up the needle, put the bell back on and fill with oil, I use Auto trans fluid which should be about SAE20 and it works fine for me. You don't necessarily have to take it all apart and drain the old oil, you could just top it off, but if you want to change the viscosity or just have new oil in the pistons then I would do it like I explained.

 

Is there a difference in resistance when you push the piston up? if it's low on fluid it will be easier to push up and vice versa.

Edited January 29, 2012 by 19762802+2

[disepyon]

All you have to do is take of the bell's, depending on your year it should be 4 or 3 screws holding the bell's on, then carefully pull the piston out, You don't want to bend or damage the needle, poor the oil out of the middle shaft, put the piston back in very carefully so you don't screw up the needle, put the bell back on and fill with oil, I use Auto trans fluid which should be about SAE20 and it works fine for me. You don't necessarily have to take it all apart and drain the old oil, you could just top it off, but if you want to change the viscosity or just have new oil in the pistons then I would do it like I explained.

 

Is there a difference in resistance when you push the piston up? if it's low on fluid it will be easier to push up and vice versa.

yeah, but the first carb is harder to push up than the second carb. Takes more effort, but the first carb piston falls down faster than the second. kind of strange.

 

Mine is the 4 screw type according to the manual, but looking at mine, the suction chamber only has 3 screws.

[seattlejester]

If you give the car more than a little bit of gas does it stay stationary? As in the engine revs, but the car really isn't moving (very diagnostic if you can do this facing uphill)? Does the car stall when it's in gear?

 

If the clutch assembly isn't working properly or the slave is supplying partial pressure, or the clutch assembly was installed incorrectly it can be causing pre-emptive slip. So even when you are completely off the pedal the motor isn't fully engaged to the transmission.

 

I know anecdotes aren't the best, but we had a friend that just replaced his clutch and had the same problem. Car would start and rev perfectly fine, but wouldn't move unless it was fed gas at a very slow rate, could barely go up hills as the clutch continued to slip. At the time we thought it was either air in the clutch line, or a problem with the clutch pedal return spring or something of the sort as he swore up and down he installed everything correctly. Turned out he didn't torque his pressure plate down 100% and either the bolts rattled loose or he sheered them so the clutch was backing off of the motor when it supplied too much torque, so it would only move when engine speeds were very very low and was only engaging from the pressure the throwout bearing was putting on the pressure plate/clutch.

Edited January 29, 2012 by seattlejester

[Two80z4me]

If you give the car more than a little bit of gas does it stay stationary? As in the engine revs, but the car really isn't moving (very diagnostic if you can do this facing uphill)? Does the car stall when it's in gear?

 

If the clutch assembly isn't working properly or the slave is supplying partial pressure, or the clutch assembly was installed incorrectly it can be causing pre-emptive slip. So even when you are completely off the pedal the motor isn't fully engaged to the transmission.

 

I know anecdotes aren't the best, but we had a friend that just replaced his clutch and had the same problem. Car would start and rev perfectly fine, but wouldn't move unless it was fed gas at a very slow rate, could barely go up hills as the clutch continued to slip. At the time we thought it was either air in the clutch line, or a problem with the clutch pedal return spring or something of the sort as he swore up and down he installed everything correctly. Turned out he didn't torque his pressure plate down 100% and either the bolts rattled loose or he sheered them so the clutch was backing off of the motor when it supplied too much torque, so it would only move when engine speeds were very very low and was only engaging from the pressure the throwout bearing was putting on the pressure plate/clutch.

 

 

+1, had this happen before. Beginners mistake, happens to the best of us.

[disepyon]

I torqued the pressure plate and flywheel down, so that cant be the issue, however im thinking that the clutch fork assembly might be messing up as i didnt pay to much attention to it when installing. Ill look into that and replace the slave cylinder and see what happens.

 

The car did have trouble going up my drive way, i had to really rev the engine to keep it from bogging out or stalling you can say.

 

thanks for all your input.

[disepyon]

CASE SOLVED!!

 

Car feels fantastic and performs superb.

 

Turns out the clutch slave cylinder just needed to be readjusted. I guess it wasnt allowing something to disengage.

 

I went ahead and took out the suction chamber and piston, cleaned it and filled with new fluid. Both were pretty nasty. After that i retuned the carbs and everything works great.

 

Thanks for all your help experts!!