Author |
Topic: cosworth stalling bad idle etc etc etc (Read 485 times) |
|
lh120503
Newbie
I love YaBB 1G - SP1!
Posts: 1
|
 |
cosworth stalling bad idle etc etc etc
« on: Feb 10th, 2005, 10:08pm » |
 Quote  Modify
|
I have a 1996 cosworth estate, so many people have tried to fix it, no one has done yet. If I start the car from cold it starts ok but stalls as soon as you take your foot of the throttle, if i hold the revs at 1000 it hunts between 800 and 1100 ish. As it warms up it will continue to run until you put in gear (auto) then it stalls again. If i adjust the throttle screw I can get it to idle at 1000 but when its hot the idle will have increased to 2000 and i have to turn the screw back down again. The hunting idle around 1000 rpm is nearly always there and seems to cause a loss of power when pulling away slowly. I have changed the MAF , the IACV, the leads and plugs, as well as the sensor that looks at the exhaust gasses as they pass through the consrictor pipe to the EGR valve (bolted to bulkhead). If i suck on the egr air pipe i can stall the car so this seems to work. If I disconnect the IACV electrical connector the car continues to run without any difference, i am stuck, ford want £70 an hour to have a look, they may need it for a day, thats £560 and they may not find the problem. At revs above 2000 there are no problems, goes like a rocket. I have sprayed duck oil all round air pipes etc on the top of the engine looking for air leaks, nothing makes a difference. please help me if yo can.
Lee
|
|
 IP Logged |
|
|
|
howiedintheplace
Senior Member
Based near Evesham
Posts: 1194
|
 |
Re: cosworth stalling bad idle etc etc etc
« Reply #1 on: Feb 10th, 2005, 10:58pm » |
Quote Modify
|
I know you have tried to rule this one out already but sounds like a typical air leak/suck problem to me.
I would advise to check again espically around by the fuel rails area towards the back of the engine.
|
|
IP Logged |
Dave
|
|
|
Badboytunes
Guest
|
|
Re: cosworth stalling bad idle etc etc etc
« Reply #2 on: Feb 10th, 2005, 11:05pm » |
Quote Modify
 Remove
|
what colour are the plugs? That is a good indication of the general running of an engine....
|
|
IP Logged |
|
|
|
Eric_R
Administrator
Cosworth Owner 1998 - 2006 & site co-founder
Posts: 1792
|
|
Re: cosworth stalling bad idle etc etc etc
« Reply #3 on: Feb 10th, 2005, 11:14pm » |
Quote Modify
|
Lee,
The sum of our knowledge on poor idle is on http://www.fordscorpio.co.uk/pooridle.htm so you need to work through that.
This has all the symptoms of an unmetered air leak - what happens is that more air is getting in than the PCM knows about, so revs are higher than they should be and out of the range of the IACV to correct - but when you put the car in gear there is not enough fuel to match the air still entering, the combustion fails so the engine stalls at the increased load.
Do you get a hiss of vacuum when you unscrew the fuel filler cap? If yes, the EVAP system is okay, if no then the EVAP system has a leak and will probably be contributing to an unmetered air leak. The EVAP system must be tracked back including the fuel filler pipe and make sure every pipe is airtight.
Next, the 24V has a T peice connector tucked away down the back of the engine. This is often split or broken off and will be another leak.
Check also the vacuum pipe to the brake servo - make sure there is no chafing out of sight.
Check the air bypass pipe from the IACV to the inlet manifold - if this is split or loose this will greatly effect the idle.
Check the large air inlet system joints at the back of the 'silver octopus' - if these have been separated without new O rings they can be a candidate - a drop of oil on these large joints should show them sucked in.
Make sure there are no pipes loose in the vacuum system between the inlet system and the vacuum reservoir down behind the offside headlamp.
If all else fails work slowly round the engine with a peice of tube, one end held to one ear and listen for a hissing sound while moving the other end round the engine.
Meet with an owner equipped with an OBD lead - diagnostics may well offer a clue so have that read too, in standard and Enhanced diagnostics.
You must persevere because there is a leak somewhere.
Have you tried unplugging the MAF sensor? Report back if it is better and we may need to have the MAF checked out in case that is contributing.
HTH
|
|
IP Logged |
After a Cosworth, anything else is just ... ordinary
|
|
|
|
Home
Help
Search
Members
Login
Reply
Send Topic
Print