Ford Focus 1.8s idle going up and down when warm
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Virgin
Joined: Jun 2023
Posts: 2
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From: kent
Ford Focus 1.8s idle going up and down when warm
Hi
been working on my car with various bits for about a year now ford focus 1.8s, the last and final issue is when warm the idle goes up and down, running out of ideas
plugs changed
coil packs changed
pcv valve changed
no vacum leaks
starts and drives perfect
tried a different throttle control no difference logic being its unlikely another thottle control would have the same issue, but could still be a option
its odd that when you restart the car every is find for a few minutes
its not overheats all temps and fans are doing whats expected
when on idle revs up and done, link to video https://youtube.com/shorts/i1_LTVOIRoc
some live data https://youtube.com/shorts/GIEfXh59u5Y
some more https://youtube.com/shorts/nViG7nc0JtU
kinda running out of ideas, no error codes, no engine light, drives perfect - anyone had sililar issues and found the solution, im thinking its a fault with the pcm or its been mapped badly as odd everything is fine for a few minutres when you shut off and restart its almost like its on a timer, or could be it is the thorttle control, its defo a low rev issue as when thorttle controls is diconnected and limp mode forced the revs pick up as expected and the problem goes away but thats only because the limp home spring has pushed the throttle open, somthing is telling the etc to closedown to much
been working on my car with various bits for about a year now ford focus 1.8s, the last and final issue is when warm the idle goes up and down, running out of ideas
plugs changed
coil packs changed
pcv valve changed
no vacum leaks
starts and drives perfect
tried a different throttle control no difference logic being its unlikely another thottle control would have the same issue, but could still be a option
its odd that when you restart the car every is find for a few minutes
its not overheats all temps and fans are doing whats expected
when on idle revs up and done, link to video https://youtube.com/shorts/i1_LTVOIRoc
some live data https://youtube.com/shorts/GIEfXh59u5Y
some more https://youtube.com/shorts/nViG7nc0JtU
kinda running out of ideas, no error codes, no engine light, drives perfect - anyone had sililar issues and found the solution, im thinking its a fault with the pcm or its been mapped badly as odd everything is fine for a few minutres when you shut off and restart its almost like its on a timer, or could be it is the thorttle control, its defo a low rev issue as when thorttle controls is diconnected and limp mode forced the revs pick up as expected and the problem goes away but thats only because the limp home spring has pushed the throttle open, somthing is telling the etc to closedown to much
C**t
Joined: Oct 2003
Posts: 7,997
Likes: 269
From: Norn Iron
Give history....sudden problem ? after work ? other ?
It is extremely unlikely a faulty ecu.
Firing the parts cannon is rarely productive.
Air leak is very possible.
View live data and see if idle control is actually active.
It could be a bad map, but why would that happen all of a sudden ? That makes no sense, unless you have recently had it badly mapped ? Again, history matters.
And unplugging the DBW unit isn't limp mode, it's totally disabling the throttle's ability to do anything, except sit at its natural rest position. So proves nothing whatsoever.
It is extremely unlikely a faulty ecu.
Firing the parts cannon is rarely productive.
Air leak is very possible.
View live data and see if idle control is actually active.
It could be a bad map, but why would that happen all of a sudden ? That makes no sense, unless you have recently had it badly mapped ? Again, history matters.
And unplugging the DBW unit isn't limp mode, it's totally disabling the throttle's ability to do anything, except sit at its natural rest position. So proves nothing whatsoever.
Thread Starter
Virgin
Joined: Jun 2023
Posts: 2
Likes: 0
From: kent
Give history....sudden problem ? after work ? other ?
when engine is warm, normally after about 10mins
It is extremely unlikely a faulty ecu.
you would be surprised had all sorts of issues with other makes, but i have no way of testing
Firing the parts cannon is rarely productive.
sofar all the common bits done, coild packs were worn, and plugs new plugs didnt hurt
Air leak is very possible.
Ive checked all the vacumm lines and the inlet manifold has had the seals replaced just to be sure
View live data and see if idle control is actually active.
not sure what you mean here, there is no idle control valve and the requested rpm is low which is why im thinking bad map, car was dead when i got it with a blow head gasket, thats all been done, valves tested, head skimmed
It could be a bad map, but why would that happen all of a sudden ? That makes no sense, unless you have recently had it badly mapped ? Again, history matters.
its always done it as far as im aware
And unplugging the DBW unit isn't limp mode, it's totally disabling the throttle's ability to do anything, except sit at its natural rest position. So proves nothing whatsoever.
when engine is warm, normally after about 10mins
It is extremely unlikely a faulty ecu.
you would be surprised had all sorts of issues with other makes, but i have no way of testing
Firing the parts cannon is rarely productive.
sofar all the common bits done, coild packs were worn, and plugs new plugs didnt hurt
Air leak is very possible.
Ive checked all the vacumm lines and the inlet manifold has had the seals replaced just to be sure
View live data and see if idle control is actually active.
not sure what you mean here, there is no idle control valve and the requested rpm is low which is why im thinking bad map, car was dead when i got it with a blow head gasket, thats all been done, valves tested, head skimmed
It could be a bad map, but why would that happen all of a sudden ? That makes no sense, unless you have recently had it badly mapped ? Again, history matters.
its always done it as far as im aware
And unplugging the DBW unit isn't limp mode, it's totally disabling the throttle's ability to do anything, except sit at its natural rest position. So proves nothing whatsoever.
update the throttle spat out the limp home screw so car broke down completly so will have to get another etc, see how that goes
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