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        General >> Problems >> Over revving again!
        
(Message started by: cossieguy on Nov 28^th, 2006, 11:16am)

Title: Over revving again!
Post by cossieguy on Nov 28^th, 2006, 11:16am

Right my strange revving problem has resurfaced. Car starts fine and sits steady at 750-800 rpm. After a period of driving the revs feel above what they should be, if you take feet off pedals the car will pull itself along ie like having the cruise control on, it wont slow down due to drag etc but keep steady at the the speed your going. When stopped in neutral it will idle at 1000rpm. I must stress it is intermittent and during the same run it will rev normally then change to high revving and back again. The car has a new IACV on and the MAF is clean. It went in for FDS scan last week and the only thing found was a split pipe in the egr system no fault codes. Any ideas?

Title: Re: Over revving again!
Post by Simmo on Nov 28^th, 2006, 11:22am

Could you have answered you own question..... is the cruise control cable somehow sticking or being 'fouled'?.

Title: Re: Over revving again!
Post by cossieguy on Nov 28^th, 2006, 11:44am

on 11/28/06 at 11:22:51, Simmo wrote:

Could you have answered you own question..... is the cruise control cable somehow sticking or being 'fouled'?.

Possible, but i don't think so, it only appears when engine has warmed up and doesn't explain the intermittent nature of fault, the car only stays at the same speed because the revs are slightly higher than they should be. Just to be sure though where abouts is the CC cable located?
Guy.

Title: Re: Over revving again!
Post by Simmo on Nov 28^th, 2006, 11:55am

The motor for the Cruise control is just behind the FOS head lamp. A cable from that runs back to the throttle linkage and is side by side with the accelerator cable which of course comes from the bulkhead direction.This (http://www.fordscorpio.co.uk/manual/speedcontrl/ccactuator.pdf) should help you. As you are reading the Cruise control details the 'throttle cable' shown is of course the CC 'throttle' cable. You can see the main one alongside.

Title: Re: Over revving again!
Post by cossieguy on Nov 29^th, 2006, 7:17pm

Further hints/symptoms. If I reset the car(Battery off) then the problem goes away until I kick down and give it some. Then the idle goes wonky again. Is this something to do with the throttle positon sensor?

Title: Re: Over revving again!
Post by harry.m1byt on Nov 29^th, 2006, 8:34pm

Do the symptoms also begin after you have reset it by battery diconnection and then floor the throttle with ignition off?

I'm thinking along the lines of a sticking throttle linkage perhaps.

Title: Re: Over revving again!
Post by cossieguy on Nov 29^th, 2006, 9:20pm

on 11/29/06 at 20:34:35, harry.m1byt wrote:

Do the symptoms also begin after you have reset it by battery diconnection and then floor the throttle with ignition off?

I'm thinking along the lines of a sticking throttle linkage perhaps.

Funny you should say that, I was thinking about it while washing up and started looking at it along those lines, would explain the symptoms. Will try it tomorrow and see. Don't know if its got anything to do with it but, a while back I had another problem and it was suggested to start the car with accelerator to floor(Apparently it shouldn't start) mine started no problems!?
Guy.

Title: Re: Over revving again!
Post by hellblue on Nov 29^th, 2006, 9:46pm

Did you clean out the throttle body too?Seen it somewhere if battery is removed you need to start engine leave at idle for 3/4 min? then fast idle 1/2 min? to let ecu relearn its values (someone may conferm this)so does this mean that some thing is being learnt by using the kick down?Loom prob.? any extra load on the engine will cause the rpm to pick up a bit,ie if it thought it had a power steering loading the ecu wouldnt see that as odd so may not see a code? just some thoughts

Title: Re: Over revving again!
Post by Simmo on Nov 29^th, 2006, 10:13pm

If the battery is removed then certainly the ecu has to re-adjust and learn the 'values' of the sensors again and the usual advice is to take the car for a varied run ie:urban,fast main road etc, in order to achieve that.

Title: Re: Over revving again!
Post by Dave on Nov 29^th, 2006, 10:48pm

I had this for quite a while, a really good clean of the throttle body, butterfly valves and return springs cured it. Had to do it more than once but *touch wood* its been fine for a while.

Like yours it was intermittent but got worse over time.

Title: Re: Over revving again!
Post by cossieguy on Nov 30^th, 2006, 7:50am

Cheers for that Dave, have we got a write up for cleaning out the throttle body and associated bits anywhere?
Guy.

Title: Re: Over revving again!
Post by scorpio_man on Nov 30^th, 2006, 8:13am

hi there

this guide (http://www.btinternet.com/~madmole/HowDoI/Howdoi.html) is not too bad. it's for a 16 valve mondeo, but gives you a good idea.

cleaning the idle valve (http://www.granada-and-scorpio-online.com/forums/showthread.php?s=&threadid=12204)
hth