Jump to content

High engine rpm


fizzwhizz
 Share

Recommended Posts

From fingerz @ www.feoc-uk.com

 

list of checks to help anyone out who has idle problems on a zetec.

 

some of the checks apply to other engines liks HCS....

 

Ok, when you get any idle problems the first thigns you need to check are wiring to ISCV and how dirty the ISCV is. If the ISCV is gummed up then clean it using WD40 type penetrating oil. Reason being it will thin down the gunk and if any of it gets into the motor it wont muck it up. If you use carb cleaner then it can get into the motor and cause problems, but as long as you are careful it chould be ok.

 

Next thing, check the PCV valve which is located next to the exhaust manifold and is below a 90 degree rubber tube/elbow. Remove the rubber elbow, and the little metal thing below it should pull out the rubber gromit it sits in. You can clean these out with solvents, but generally speaking its best to replace them as they are £12 ish from fords. If they are rattling that is normal but could have a weak spring. I cleaned mine out several times but then when i replaced it the engine idled and ran totally different. So its worth replacing anyway to eliminate a possiblity.

 

Once you have cleaned/replaced the PCV valve, and the rubber elbow, run teh car up and if the idle is a little fast, erratic, or lumpy, get a pair of thin nose pliers and whilst the car is idling, pinch the rubber elbow. The engine may change its note or stop running lumpy. If this is the case then the PCV if its not been replaced already, could be faulty causing a slight air leak to the inlet manifold.

 

next check is with the engine not running, follow the route of the breather ppipe from the PCV valve and the rubber elbow, which joins a metal pipe under neath the coil pack (later type zetec E engines) and then antoehr rubber hose joins the metal pipe on the other side of the coil pack and runs down to the bottom of the inlet manifold. This pipe often collapses or leaks in some way. The easiest way to test if this is causing a problem is to have the car raised enough so you can get under it with it running. You will see the hose goes into the bottom of the inlet manifold from the side. With the engine running, get your thin nosed pliers and crimp the pipe an inch or so away from the maifold so you dont damage the take off from the manifold. If the enigine changes note or runs smoother then replace this hose.

 

Other causes of irratic idle where the car progressively judders and then can all of a sudden pick up and run fine at random intervals, but more commonly shortly after a start up, can be a lambda sensor. This happened to Danny Scott's escort GTi and we watched on a diagnostic computer that the short term fuel trim was progressively going into negative numbers as the running got worse until it hit -20 and then corrected itself to 0 and ran ok as possible.

 

One of my escorts used to occasionally pick up randomly and sit at around 1800 revs then drop to idle and be very slightly rough. We tried everythign from lambda sensors to different spark plugs and possible air leaks etc. Turned out to be a head gasket on its way out which would have more than likely shown up by doing a block test. This is a tool which holds a fluid that reacts to combustion/exhaust gases and 'sniffs' to see if they are present in the cooling system.

 

More commonly on mk1 mondeo's fitted with zetec 'E' engines, if the car starts up and runs but cuts out soon afterwards, try disconnecting the power steering pressure sensor which is found in the metal power steering pip along the drivers side of the engine bay. If when disconnected the engine doesnt stall shortly after starting then the pressure sensor is at fault and will need to replaced (i think this is correct - its a while since i had that problem on a Mk1 mondeo). This might cause similar problems on an escort but the pressure sensor is located at the back of the engine and is easier to get to from underneath if my memory serves me right! (could be totally wrong tho!)

 

if your escort idle fluctuates when 'dry steering' then it coudl be a fault with the power steering pressure sensor, but its more than likely a slow reacting idle speed control valve.

 

Also check your throttle body is clean. There is a stick on most throttle bodys that says not to use solvents to clean them as they are covered in teflon or something - ignore that - the cleaner your throttle body the better - they still get bunged up special covering or not!

 

Before you go spending lots of money on your diagnostics at fords or wherever fo r a running problem, make sure you ahve run the engine up and listened for any possible air leaks aroudn the inlet maniold. Its worth checking any vacuum lines that are conencted to the inlt by felling them and moving them around to check their conditiona nd to see if the running of the engine changes atall. Sometimes its worth disconnecting the hard plastic vac pipe from the brake servo and blocking it up at the valve end. If the engine runs better after this, then the servo diaphragm may have a leak! entirely possible, and its happened to me a few times inteh past!. If that changes nothing then carefully refit the pipe to the servo with some WD40 or a bit of spit (lol) to ease the connector back into the rubber gromit so you dont push the gromit into the servo!!! Then try removing the pipe on the inlet manifold end and blocking the hole in the manifold. If that changes the running of the engine and you have already tried taking the pipe out of the servo end with no change then the pipe or the valve on the end of the pipe is at fault.

 

I remember working on a mates car that had a small missfire when first started from cold. It was also losing brake fluid even tho there were no visable leaks anywhere on the brake system. Turned out that it was losing brake fluid out of the back of the master cylinder and filling up the brake servo!!

Link to comment
Share on other sites

Cheers ...

 

But i already knew about that lot :) But nvr heard about a power steering sensor effect idle / running problems :unsure:

 

And theres no air leaks, pcv piping has been replaced, all new gaskets,...

 

Got the car on Diagnostics today, no sensor problem at all. swapped icv, no difference, swapped air flow meter no joy, swapped flywheel sensor no joy ...

 

Im sure it would be alot easier if i cud get the engine to stay running, then avin it keep cutting out...

 

begining to come to a brick wall..

Edited by fizzwhizz
Link to comment
Share on other sites

never mind it works and pur's like a kitten :D :thumb:

 

Job done whoohoo

 

The problem... no idea :unsure: i striped all the wiring out, checked the usal air pipes, vacum hoses, etc put it all back together, fired it up and away she went :D 2 mins at 1300 rpm and then now sits comfy at 800 ish rpm :D

 

took it for a drive and she pulls like a train smooth drive no hesitating no sudden kangerooin no missfires, just runing spot on with a good drink of Shell Optimax.

 

Sweeeeeeeeeeeeeeeeeeeet

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...