Wierd acceleration problem
 

Looks like I am joining the rest of you guys in suffering problems....


it happened once before but now was happening all evening. Accelerating away at normal rate, the accelerator gets harder to push down....pressure builds up (like a spring was underneath it) but the revs are not rising, then BAM the revs go through the roof and the car tears off down the road...this is happening at various speeds but.....in 'N' the accelarator travel is perfect....very easy to modulate the rpm....whilst driving though, it surges and is very disconcerting.

Sorry about the describtion but the best that I can do

:confused:

Thanks

James

Re: Wierd acceleration problem
 

[QUOTE]Originally posted by Jamsvx
[B]Looks like I am joining the rest of you guys in suffering problems....


it happened once before but now was happening all evening. Accelerating away at normal rate, the accelerator gets harder to push down....pressure builds up (like a spring was underneath it) but the revs are not rising, then BAM the revs go through the roof and the car tears off down the road...this is happening at various speeds but.....in 'N' the accelerator travel is perfect....very easy to modulate the rpm....whilst driving though, it surges and is very disconcerting.

Sorry about the description but the best that I can do

:confused:

Thanks

Giday James, That description would involve everything from a old coffee cup under the pedal to a seizing engine.

If the pedal has a definite resistance to movement, then it would seem to be in the throttle cable, the cruse cable, the throttle butterfly, or the calf muscle below the knee.

When it, as you say, " then BAM the revs go through the roof and the car tears off down the road". Do the revs go up first then, the car 'tears off down the road". Or do the revs and the car accelerate together?

If the revs go up first, then it accelerates, it is a transmission problem. If they both go up together then it's a problem with the engine hesitating.

Check the throttle and cruse cables for kinks. The fact that it is ok in N, doesn't mean as much as what is it like with the motor turned off. Is it smooth then or not.

Harvey.
P.s. More substanitating evidence needed.;)

Re: Re: Wierd acceleration problem
 

Thanks for the reply Harvey:

Giday James, That description would involve everything from a old coffee cup under the pedal to a seizing engine.

If the pedal has a definite resistance to movement, then it would seem to be in the throttle cable, the cruse cable, the throttle butterfly, or the calf muscle below the knee.

That was the first thing I thought of so I pulled over and, with engine running, put it in 'N' and played around with the accelerator - the revs rose and fell at the same rate of throttle application....ie, gentle press and the rpm increased gently...more aggressive application saw it rise faster....taking foot off throttle saw them fall immediately....this is something I forgot to mention, when the 'sticking' happens, if I back off, it still feels like power is being applied for about 1.5 to 2 secs, then it drops off.....also, the power light remain illuminated (when a full throttle application to activate that mode) for about 1.5-2 secs after my foot is taken off the accelerator.


When it, as you say, " then BAM the revs go through the roof and the car tears off down the road". Do the revs go up first then, the car 'tears off down the road". Or do the revs and the car accelerate together?

I wil check again tonight but from memory, it is simultaneous...a sequence is like this

60kph...about 2000rpm
More throttle applied, resistance felt though pedal, like its being pushed against a spring - rpm and speed do not change
Increase throttle application about 50% now
Revs climb to about 4500rpm, engine opens up, very prominent 'shunt' throughout the car - like it was dropped back 2 gears - James flung back in seat, pedestrians shake fists in air

If the revs go up first, then it accelerates, it is a transmission problem. If they both go up together then it's a problem with the engine hesitating.

Its not like a 'flaring' where rpm increases without corresponding increase in speed....its like I can't get the rpm to increase (imagine that the acceletaror arm was 'bending' in the middle - closed analogy that I can draw)

Check the throttle and cruse cables for kinks. The fact that it is ok in N, doesn't mean as much as what is it like with the motor turned off. Is it smooth then or not.

Motor turned off??? What should be smooth with engine off???


Thanks

James

PS: had a transmission cooler fitted about 300km but this has happened once before before the cooler was fitted

Hi James,

Havey is asking if the mechanlcal operation of the pedal and linkage feels smooth and normal throughout the travel from shut to full throttle and this can be checked without the engine running.

Hi Trevor

I was thinking about it after work and thought that was what he may have meant.

Blake told me to take off the H6 cover (boxer for you??? JDM car!) and to apply lubricant to the throttle cables....I gather that the inner cable is the accelerator but what is the outer cable??? Cruise control??? When I moved that, on the half moon shape mounting, it did not retract inside the 'pipe/tube' unlike the accelerator cable.

Car seemed to drive ok last night - was on and off the rpm/accelerator and could not replicate the problem....the upside was that a side effect was that glorious howl of the engine!!!

I might try some of that anti-carbon build up stuff - seems that Australian Liberty's and WRX's are afflicted by it (bad fuel + horizontal engine I'm told) so the SVX may be in the same boat - I saw one about 3 years ago with the engine in bits for that reason

:eek:

*crossing fingers*

James

Sticky cable
 

Hi James

Sorry to hear of your problem. With your initial description, I would strongly suspect a cable problem.

Harvey is correct, check it with the engine off. What can happen, the inner [the actual cable, outer part is a sleeve] can fray and start to come undone, usually from a sharp bend or kink.

If it sticks on fully open throttle, it could burst your engine:eek:

Without making you panicky, replace the cable straight away if it is the problem. It is not an expensive piece, way cheaper than an engine or an accident.

Joe:)