Hey All,

I have a slight problem with my car and will try to explain to the best of my ability the situation.
Im not a complete car nutter like some so please excuse some terms I may use.

A few days ago my car (which is an auto) began to idle very roughly and low, the rpm gauge was intermittently jumping between 200, 500, and 800 rpm, the car would shake at the lights because it would almost stall!
It just so happened that my car was due for a service so i took it to my mechanic to get the service done and also sort out this idle problem. Apparently he hooked up a device to diagnose the problem but the diagnostic machine didnt give him any codes, so he started the process of elimination. He changed the map sensor and TPS. (I dont know what these are, sorry).
The car now idles perfectly without moving at all when the car is stopped, however, the morning after these items were changed I started the car and as soon as it started the revs dropped to zero and the car stalled right away. I tried to start it again and it did the same thing. In order to keep the car running I had to press the accelerator slightly to keep the revs at around 900rpm. After about 30 seconds of this the car was able to idle but at a low constant idle, around 500rpm. Once the car was warm the idle rev's went to around 800 rpm.
I took it back to my mechanic the following day and he plugged an existing cable into a small roundish part that sits on the throttle body (held in by two 10mm screws), after he plugged it in I started the car and it idled at 3000 rpm's!!!!
(sorry I dont know the name of that part) I went to a wrecker to get another upon his recommendation, i changed it over tonight but the same thing happens, it idles at 3 grand. Can it be possible that the part i got from the wrecker and the one already on my car are both stuffed?

I will call my mechanic tomorrow but thought maybe someone here can point me in the right direction of a solution? As long as ive known this mechanic he has been very good.

Any help is greatly appreciated.

cheers,

Did the mechanic clean out the throttle body and Idle Speed Control (ISC) motor which bolts onto the throttle body? Classic thing to play up causing it to idle like s**t.

Thanks for the quick replies and help guys. You were all right, the Idle valve/speed control was the problem. The replacement one I got from the wreckers was also seized in the same "high RPM" spot as my original one. I went back to the same wreckers to see if he had another one, he did, I changed it over and the second replacement one works ok, the only thing is that when the car is in park it idles at around 1100, when its in drive it idles at around 850. So even the second one I picked up isnt spot on. I will get a new one soon. Apparently they cost around $110. Now that this idle problem is solved another issue has popped up which I will post as another topic.

As always, thanks heaps, really appreciate it.

Your idle screw has been turned up too high too compensate a faulty Idle Speed Controller.

reset your base idle as per the instructions and you will find you will need to back off the idle screw a bit.

If that is a bit much then start the car when at operating temp in park or neutral, unplug the Idle speed controller plug, the revs should drop a bit. Now put a flat head screw driver on the idle screw and turn it anti-clockwise until the revs sit on about 500-600rpm.

Turn motor off, plug the isc plug back in and it should idle fine..

Once the idle is back too normal, reset the computer by removing the negative lead of the battery for about 30mins.

Hey guys,

After fitting a new idle valve control the problem of the car revving to 2000rpm upon start up (when warm) was still happening.

I called on old friend who used to work at city ford years ago in the spares department to see if he had any ideas. Luckily for me he lives around the corner and I went there asap, he used to be a mechanic years ago.

He removed the air intake hose that goes to the throttle body and said the butterfly was a little loose. Upon fixing the butterfly we kicked it over and it still revved to 2000rpm, he then backed off a little grub screw on the side of the throttle body and that bought the idle down to 900 rpm. He said that screw was in too far, so "el_fairmont" you were right about that.

There is one thing im not clear on, I called my mechanic as i wanted to let him know how I went with this problem, he also asked to be kept informed. I told him exactly what I have said here especially about the grub screw. He told me that he thought that screw was merely a "stop" of some kind and that it had no bearing on the cars idle whatsoever, and that the cars idle is completely controlled by electronics only. I dont know who's right!? I dont want to think that my mate did some sort of quick fix for me. I wanna make sure I nail this problem so i can sleep!

My only other issue is now my transmission is changing gears at funny rev's so i have taken your advice and disconnected the negative terminal from my battery, I am just about to hook it back up so I hope everything goes well. I also hope that when the car is cold tomorrow morning that it kicks over and idles ok. Will let ya know how I go, thanks again guys, really, reallllllllllllllllly, appreciate the help.

cheers,

Hey all,

I hooked the battery back up (after being disconnected for an hour). The car is still changing gears at very high revs, it will only go from 1st to 2nd when it gets to 3000-3500 rpm.

Could I have a problem with the tps? Im not sure what controls the auto's gear changes in my car.

idle is still fine now.

thanks,

Have you got economy on? if not, it will change gears at higher rpm

The base idle can be adjusted using the idle screw which moves the butterfly inside the throttle bore. Generally it shouldn't need adjusting as set in factory when car built, but due to other symptoms (wear and tear etc) it sometimes requires adjustment.

Did your auto box change at high revs before you took it too the mechanic, if it did then I would check the auto fluid level. Your car should have a Dipstick being an early ef. Operating temp leave in park while running and check the level.

TPS should be 0.7v at idle and about 4.5V at wide open throttle, back probe the middle wire on the plug with positive lead of multimeter and put black lead negative on the lower wire. Just turn the ign on but don't start the car.

hey,

The auto was changing fine before taking it to get this idle problem fixed. I forgot to mention earlier that the cars computer was changed also during the process of elimination as the car didnt give him any codes when hooked up to the diagnostic device. So, the map sensor, tps, ivc and computer were all changed at once. Also, the auto has enough fluid, I topped it up a few weeks ago, before this idle issue. El_fairmont, you are correct, I have a dipstick ont he auto as my car is a 94 ef.

So from what I can understand, the tps controls or tells the auto when to change? So this is where I should focus my attention for the moment to fix this problem?

jpinckney5209, dont think the economy button is the problem cause before i took it to the mechanic the car would change gears fine with economy off or on. Plus its changing up gears a hell of a lot higher than if the button was off.

thanks,

Hey guys,

I forgot to mention before, this is off topic but thought id ask as its a simple thing (I think!).

I noticed my power steering pump is leaking and dripping on the alternator so I wanna fix this asap before it destroys my alternator. Why couldnt they just design a simple half moon cover that sits over the alternator to protect it a bit from falling fluid. Seems logical.

Anyway, Does the power steering unit need to be fitted with any "o" rings, etc, or does that tapered main fitting just get screwed into the back of the pump as is? Metal to metal?

cheers,

Yeah it should have an o-ring.

hey "Lee lee..."

I had a gut feeling it is supposed to have an o ring. Is there anywhere I can get an exploded view of the power steering pumps connections. Wanna make sure i get all the parts, etc I need.

thanks heaps,

There is 2 o-rings you need to replace. The first one is in the adaptor fitting that the high pressure hose nut screws into. The second is in the outlet fitting that screws into the back of the pump. Will need a 1in open end spanner to undo it. Generally the one in the back of the pump causes the most problem.............

Cheers

Hey guys,

I picked up a new power steering pump today but received only one very very small o ring with it. I will have to get the other o ring tomorrow.

Also, I put my original tps back on and the auto changes gears fine now. I dont get it, the brand new tps makes the auto flip out and do crazy s**t. I did notice that the new one doesnt have the ford logo on it so maybe its a s**t after market new one. I dont know. My mechanic sourced it.

So, in summary:
-car begins to idle like s**t.
-take car to mechanic
-Diagnostic tool doesnt give any codes (process of elimination begins).
-Mechanic changes map sensor (2nd hand), tps (new), idle valve control (2nd hand) and main computer (2nd hand).
Result?
-when car is warm it idles fine.
-when cold, car would stall upon start up, had to press accelerator to keep car running until it warmed up, once warm, car idled fine.
-Auto begins to change gears at very high rpms.
Solution
-replaced idle valve control with new one
-fixed up loose butterfly in throttle body
-adjusted idle screw
Idle problem completely solved, car idles fine warm or cold, no problems upon start up.
-still left with auto misbehaving.
-fitted the cars original tps back on and auto behaves the way it should.

I will keep an eye on the car over the next few days and keep you posted.

As usual everyone here has been awesome and saved the day! Big thanks from me!

speak soon,

Hey if the problem persists I will suggest that the inhibitor switch on the transmission could be at fault.
One side of the switch prevents your engine starting in gear, but the other part of the assembly houses a potentiometer which tells the ECU to increase the engine idle speed in the event of a load placed on the engine such as selecting drive or reverse and it compensates by raising the rpm the moment the transmission is shifted into gear. The rpm should be noted to actually raise a little when shifting.

Get under the vehicle and locate the inhibitor switch. Remove both wiring connectors and inspect for dirty contacts, common. Spray with penetrating lubricant ensuring all dirt is removed and reconnect.

also the others are completely correct and your mechanic is a dic! just remember when adjusting the idle you must have the ISC disconnected don't do it while running.

I recommend you download the EF/EL workshop manual here : http://www.megaupload.com/?d=8X2ABHET