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Old 11-29-2004, 06:30   #1 (permalink)
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Question Very weird throttle problem

Today when accelerating after being stopped at the lights, I noticed that the accelerator was really "soft" and easily went down, while the RPM did not go as high as it normally would. I had my foot down flat on full throttle and the engine was only doing about 2000 RPMs and at 60kph. It did not seem like it was laboring (it was low RPMs), but it just did not want to respond to the accelerator. I varied the throttle and about 20 seconds later when my foot was flat down it started to respond and jumped to 3500 RPMs, so I eased off and started driving normally and it was fine for another 15 mins. Engine temp was fine when this happened.

I don’t think it would be a transmission problem because it did not seem to be stuck in a low gear, the engine just did not want to respond.

Anyway after those 15 mins I was stopped at other lights, when I started accelerating, the car felt really "heavy" and it needed about 3000 RPMs to get to 80 kph (normally it is around or just under 2000 RPMs at this speed). Stayed like this until I got home (only 5 mins). The temperature was a bit high when this happened (about the "M" in "NORMAL"). Would this be stuck in a low gear or is it related to the above problem? Also at this time it was idling a bit rough, but before this (when the throttle did not respond) it was idling fine.

The car is a 4 speed auto ED Falcon, car & transmission have recently been serviced. It has been losing a bit of coolant (half a tank per week) for a while and I'm getting that checked sometime this week. Does not appear to be running rich and I don’t see any bubbles in my radiator so I don’t think it's the head gasket. (I hope I'm right!).

What do you think is wrong? Thanks for any information!
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Old 11-29-2004, 07:16   #2 (permalink)
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Re: Very weird throttle problem

The situation you describe at the second set of lights sounds like it was simply stuck in a lower gear. As for what could cause this as well as your first problem, the only thing that comes to mind right now is the Throttle Position Sensor. Might be worth checking it out when you clean your IAC, but see what other people reckon first as I'm uncertain.

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Old 11-29-2004, 07:31   #3 (permalink)
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Re: Very weird throttle problem

Hi Steve,

Would the TPS cause it to be stuck in a low gear but rev like crazy, or is that what you are unsure about?

Quote:
Originally Posted by Steve_T
As for what could cause this as well as your first problem, the only thing that comes to mind right now is the Throttle Position Sensor. Might be worth checking it out when you clean your IAC...
As if I would know how to do that! You know me, want another long thread? LOL

Let's wait and see what else it could be...

Thanks again for ALL your help here and in the IAC thread!
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Old 11-30-2004, 00:05   #4 (permalink)
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Re: Very weird throttle problem

I don't know a hell of alot about the Falcon autos, but I believe they are electronically controlled and a faulty TPS would surely cause shifting problems, so yes, that could possibly be the cause of the low gear/high revs problem. Might also want to follow the entire throttle linkage to make sure it's in good condition. Check the throttle returns spring aswell. Missing vacuum hoses could potentially cause a problem like this, but it seems unlikely that a simple vacuum leak could cause such major hassles.

Things I would check;
TPS
Throttle linkage
MAP sensor
Air and fuel filters (you'd be surprised how much hassle a blocked filter can cause)

Good luck.
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Old 11-30-2004, 02:29   #5 (permalink)
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Re: Very weird throttle problem

Hi Mike,

I guess I'll be checking the TPS then, if it is easy to do...

I don't actually know where it is, but I know where the throttle body is and I know the little "spring throttle thing" which is connected to the accelerator pedal and I can push to rev the engine, I assume that the TPS is near it but I don't know for sure.

Where is the TPS and what does it look like? What would I have to do to "check it", how do I know if it is working or not?

For what it's worth, the car was ok today...

I know for a fact that the air filter is clean. I don't know anything about the fuel filters/MAP sensor/Throttle linkage (what is that?)

Thanks for any help!
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Old 11-30-2004, 06:29   #6 (permalink)
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Re: Very weird throttle problem

AS it was hot today/ yesterday, check throttle cable ????
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Old 11-30-2004, 07:05   #7 (permalink)
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Re: Very weird throttle problem

Ok, I'll just jump in and tell you where the TPS is located since we were talking in the IAC thread and this is very similar. Look back at the last photo you posted where you asked if you had found the throttle body/IAC and I said yes. Well, from the viewpoint of that photo, the TPS is mounted on the left hand side of the T/B. Once you pull you're IAC off, you should be able to see it, access it quite easily, it should just be kinda a little black plastic box/housing which is attached with two screws to the throttle body and has a couple of wires coming out of it going to a connector. As for removing/re-fitting it, I think you have to get 'em lined up at the right angle (they have a range of adjustment). How to get the angle/position right and what values to test for etc. I am unsure. I have an AU2 manual but an ED would not be exactly the same I reckon so best not to confuse matters - someone with an ED might be able to tell you the procedure and specs.

Throttle linkage BTW is on the right hand side of the throttle body in that pic. It is the cam/spring assy. you can see and the black cable attached to it is the throttle cable which comes from the accellerator pedal. Unsure of fuel filter location on ED (it's under the car towards the back on Au's). Unsure of MAP sensor location too, but it's just a little black plastic thing which has a couple of wires connected to it and a vacuum hose coming off it going to the throttle body or inlet manifold somewhere.

Steve.
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Old 11-30-2004, 07:52   #8 (permalink)
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Re: Very weird throttle problem

i'd check your cable if it's fly by wire, check your throttle position sensor,
but it seems like your auto might be flaring, that second set of lights you mentioned it was revving higher for less than it usually did.
could possibly be a fuel pump proplem? maybe it's surging a bit?
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Old 11-30-2004, 08:19   #9 (permalink)
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Re: Very weird throttle problem

Hi Steve,

If I understand you correctly about the throttle linkage (the thing with the red spring?), then it is fine. I have had someone press the accellerator to the max while the engine was off and I saw that it does respond correctly (wide open, I can't "push" it any further).

The TPS sounds easy to get to, hopefully someone can tell me how to test it :)

Does the fuel filter do anything when running on LPG? If not, then it can't be the fual filter because I was using LPG when it happened. I assume the same thing for the fuel pump...

Thanks for all the help!


Bruiser_Matt, "i'd check your cable if it's fly by wire", what cable and how do I know if it is fly by wire? It's an ED Falcon

Thanks everyone!
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Old 12-01-2004, 05:50   #10 (permalink)
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Re: Very weird throttle problem

Yeah, you understood the linkage correctly - when testing it, did it release back to normal position nice and smoothly when the pedal was released?

Nah, fuel filter and pump aren't used on LPG so no probs there.

ED's are not fly-by-wire - BA's are the first Falcon to use that.

Steve.
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