supra NA loss in power

[gazzi123]

Over past month or so it seems my supra is loosing power.

 

For instance i tested it by after pulling off from the lights and put my foot to the floor and there was no pull until it hit 5/6000rpm ...when it used to kick in at 3/4000rpm?

 

also on idle there is a high pitch humming sound which i dont have a clue where its coming from.

 

is there anyway of flushing the engine etc?

or what can be done to improve the pull?

 

To be honest my gearbox has main shaft ware and my clutch wil need replacing soon would this have anything major to do with the power it puts out?

 

Cheers peeps

[Homer]

First thoughts are to check that there are no splits in the vacuum lines. The one that could cause the symptoms you describe (and I had this myself), was the vacuum feed to the intake butterfly valve was disconnected. It made the whole mid range feel very flat and no real power until around 5.5k rpm.

 

The line is VERY difficult to see, it goes to an actuator underneath the intake manifold, just after where it splits from one into two branches, the actuator is just under the front branch. It's a bit difficult to describe!

[gazzi123]

cheers homer mate ill try and have a look

[Homer]

Post up if you have problems finding it, I could grab some pics from the service manual if needed

 

One other thought - have you changed the rotor arm or dizzy cap recently? Another issue I had was the timing was a bit out, but it caused quite a lot of lost power across the entire range (about 15lb/ft)

[gazzi123]

i think the dizzy cap was replaced or something to do with the cap was replaced.

 

whats the best way to check timing?

 

cheers homer for your help if i have any problems ill drop you a PM if thats ok.

[Homer]

Timing can be checking with a timing light and measuring the timing off the crank pulley. Timing meters are cheap, but any garage will be able to do this in a few minutes, it's very simple.

 

Probably best to post in here rather than PM as I'm a bit infrequent on the forum

[Dnk]

clutch slip ?

[Homer]

clutch slip ?

 

Yup, fair suggestion. I missed the last line about the clutch needing replacement. Unfortunately had this very problem happen today

 

EDIT: Also take a look here (between the p*ss taking there are some good ideas here ): http://www.mkivsupra.net/vbb/showthread.php?230114

[gazzi123]

yea possibly clutch slip...cheers homer ill drop into my local mechanic

[Nic]

my clutch wil need replacing soon would this have anything major to do with the power it puts out?

 

clutch slip ?

 

If your clutch is slipping then it will definitely feel different when accelerating. If you are not sure if the clutch is slipping, put it in say 3rd or 4th gear at 30mph and accelerate, if it is slipping you will see the rpms rise a lot faster than the car is accelerating. If this is the case then don't drive the car before getting the clutch renewed.

 

If it's not the clutch then as Darryl/Homer says it could be the manifold butterfly not opening.

 

Also have a read through the 2JZ-GE Service Manual HERE

 

ps. You need a thick skin on here some times, you may get some negative NA comments but it is just good humoured banter, just be proud that you own a Supra.

[gazzi123]

If your clutch is slipping then it will definitely feel different when accelerating. If you are not sure if the clutch is slipping, put it in say 3rd or 4th gear at 30mph and accelerate, if it is slipping you will see the rpms rise a lot faster than the car is accelerating. If this is the case then don't drive the car before getting the clutch renewed.

 

If it's not the clutch then as Darryl/Homer says it could be the manifold butterfly not opening.

 

Also have a read through the 2JZ-GE Service Manual HERE

 

ps. You need a thick skin on here some times, you may get some negative NA comments but it is just good humoured banter, just be proud that you own a Supra.

 

cheers ill have a look at that mate,

 

yep but theres only so much pointless banter that is acceptable. which is funny sometimes but just goes over the top like kids lol

 

cheers nic ill have a read of the manual

[Purity14]

You should know if it is the clutch slipping surely?

[gazzi123]

yea i would deffo know....but it may be the start of it, as power is not as when i bought it so trying to get as much advice as possible and cancel everything out and try everything you guys can come up with

[Purity14]

You are saying that you would 'deffo' know;

 

 

Try answering this question - Is the clutch slipping or is the clutch not slipping?

[Nic]

yea i would deffo know....but it may be the start of it, as power is not as when i bought it so trying to get as much advice as possible and cancel everything out and try everything you guys can come up with

 

First rule in/out the clutch slipping, as I suggested high gear low speed accelerate, this puts the clutch under the most load and if it is slipping you'll know.

 

If it's not the clutch then let us know and we'll go from there.

[dangerous brain]

Loss of power suggests that the engine itself is not performing as it should. Consistent clutch slipping would stink of burning clutch or the car would just not take off from a standstill. Go back to basics. Open the bonnet and look at the engine. Are there any pipes that are disconnected or perished? Are your air supply pipes all intact. Look at all your electrical plugs are they all intact? Maybe your MAF sensor could do with a clean? When was your air filter last replaced? For that matter when was the car last oil serviced? Look at the basics first, engines work on Air, Fuel, Ignition, and Cooling. On top of that you can get performance problems from exhaust baffling coming adrift and blocking the exhaust. I'm not sure why your gearbox would tire out at this point in its life its certainly not usual.

[gazzi123]

Loss of power suggests that the engine itself is not performing as it should. Consistent clutch slipping would stink of burning clutch or the car would just not take off from a standstill. Go back to basics. Open the bonnet and look at the engine. Are there any pipes that are disconnected or perished? Are your air supply pipes all intact. Look at all your electrical plugs are they all intact? Maybe your MAF sensor could do with a clean? When was your air filter last replaced? For that matter when was the car last oil serviced? Look at the basics first, engines work on Air, Fuel, Ignition, and Cooling. On top of that you can get performance problems from exhaust baffling coming adrift and blocking the exhaust. I'm not sure why your gearbox would tire out at this point in its life its certainly not usual.

 

i honestly dont know the gearbox is like it , all can think of is it was abused before i had it or being forced into gears.

Getting gear into 1st is very stiff and also reverse.

 

ill have a look at all things suggested and give it ago and see what happens.

 

cheers peeps for your help really appreciate it

[The Raven]

As homer said, it sounds like a vac pipe.

 

The noise you hear did that start around the time the problem started? If so can you not find where its coming from? I had a problem with my TT that was a little bit like this turned out the be a faulty TPS. No dash lights up when the fault is happening?

 

The red handbrake sign and engine light working?