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| Au1 |
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(this was originally mentioned here but was off-topic so I've started a new topic.)
Just trying to fix unsteady idle on my AU series 1 Fairmont (built October 1998). muzza wrote: Just be careful with the idle. I have not recently surfed through this forum on the issue so the info may be here somewhere.. I know part of the AU idle info is here... but I'll cover it of quickly anyway.... In the XF-EL the ECU expects the engine to idle of its own accord (i.e. the throttle body plate is adjusted for base idle with the idle controller disconnected). The Idle controller is used only to raise idle when the engine is cold, when the aircon is used (in I6 only) and in some instances when the engine is running. In the AU, the idle is fully controlled by the idle controller. The throttle body plate is adjusted just a smidgen off closed just to prevent binding. The ECU must be "trained" to control idle correctly. One of the guys here did outline the procedure so have a search. Not sure of the history of you car, but it may be worthwhile performing the training procedure first. Hopefully, no one has twiddled the throttle plate screw. I did have an idle issue with my AU V8 and I did need to replace the idle controller. One needs to run through the idle retraining procedure when the controller is replaced. It was a few years ago, but I bought a genuine Motorcraft controller out of the US for around $90 incl postage ($500 from Ford Aust and $350 from Bursons). I also replaced the PCV valve as those do not last forever and also affect idle. Hope that helps.... Thanks muzza. I last looked at this problem in December. In short:
Below are a couple of graphs from FORScan showing the problem. This is over a 3 minute period (RPM is light green) (click on image for full size):  And over a 1 minute period with some other sensors (RPM is blue) (click on image for full size):
 At present, there are 2 known faults. Alternator is dying, but still works more often than not - I've got a replacement ready for when it goes dead. And (apparently) carbon canister valve is stuffed and may have damaged the ECU. So, had to disconnect that valve. Any thoughts? Last edited by Au1 on Sun Feb 14, 2016 12:18 pm, edited 1 time in total. |
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| muzza |
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Sorry, have not looked at any traces so cannot assist as have no experience with that.
But, when you say "had to disconnect that valve", do you mean the IAC ? If you have the IAC disconnected and have adjusted the throttle body plate to achieve idle then that would be an issue. The AU idles only via the IAC. With it not there the whole idle system is in disarray. |
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| Au1 |
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Hi muzz, sorry I've just corrected the layout of my previous post so all the text is visible now.
The valve for the carbon canister is currently disconnected (as I'm told it is faulty). IAC valve is new and seems to be OK. |
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| rod hansen |
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The au1 has a throttle cable and an iac valve, six cyl.
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| muzza |
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Yes, all AUs have a throttle cable and IAC valve.
The XF to EL have a throttle cable and IAC valve. The XF-EL will idle without the IAC... the IAC only increases idle. The issue is that idle in the AU (AU1, AU2 and AU3) is totally controlled by the ECU via the IAC, timing and fuel and from inputs from the O2, MAP and temp sensors. In the XF-EL the ECU expects the engine to idle by itself (via the Throttle Body plate adjustment) and is then only increased via IAC, timing and fuel and from inputs from the O2, MAP and temp sensors. Without the IAC there and with the throttle body plate correctly adjusted (as per factory setting) the AU will not idle. So if the IAC, in an AU, is removed and the throttle plate is adjusted to achieve idle than that totally confuses the ECU and the engine will never idle correctly. Amongst other things it will also upset the shift points in the auto as the TPF will be in the wrong place. That is why the TPF on an AU is not adjustable - the throttle plate setting should never be moved from its factory adjustment in an AU. If you have adjusted the throttle plate on an AU then idle will never be able to be correct. |
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| Au1 |
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muzza wrote: If you have adjusted the throttle plate on an AU then idle will never be able to be correct. Nope, we're good - I haven't moved this plate. Something I noticed earlier is that (on the second graph), I was unable to find a correlation between the amount that the IAC was open and the actual engine revs. I was expecting to see these two items pretty much agree with each other (with a slight delay), but no such luck. Might be time to replace that ECU? 
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| rod hansen |
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Why are you blaming the ecu, if the only problem you have is an unstable idle check your inputs and outputs, it could be running too rich or too lean, if your engine is stock it should be easy to find. What sought of equipment do yo have, eg a scope, gmm, scan tool.
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| rod hansen |
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muzza wrote: Yes, all AUs have a throttle cable and IAC valve.
The XF to EL have a throttle cable and IAC valve. The XF-EL will idle without the IAC... the IAC only increases idle. The issue is that idle in the AU (AU1, AU2 and AU3) is totally controlled by the ECU via the IAC, timing and fuel and from inputs from the O2, MAP and temp sensors. In the XF-EL the ECU expects the engine to idle by itself (via the Throttle Body plate adjustment) and is then only increased via IAC, timing and fuel and from inputs from the O2, MAP and temp sensors. Without the IAC there and with the throttle body plate correctly adjusted (as per factory setting) the AU will not idle. So if the IAC, in an AU, is removed and the throttle plate is adjusted to achieve idle than that totally confuses the ECU and the engine will never idle correctly. Amongst other things it will also upset the shift points in the auto as the TPF will be in the wrong place. That is why the TPF on an AU is not adjustable - the throttle plate setting should never be moved from its factory adjustment in an AU. XF used bosch motronic and you actually screwed the air bypass in till you seen the ecu just applying an earth on the idle speed motor with a scope. From ea to au ford used allen EEC 1V fuel injection and ignition systems and the idle speed control motor controls the idle speed. If you have adjusted the throttle plate on an AU then idle will never be able to be correct. |
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| muzza |
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Yes, the ECUs in the AU are pretty bullet proof, but you never know.
The 104 pin ECUs in the EF were a nightmare with high failure rates (is why Ford went back to the 60 pin EECIV for the EL) but the 104 pin ECUs in AU have been very good. I would not discount the ECU, but, as Rod suggests would exhaust the other things first. The IAC is only used during idle, the engine being in closed loop mode. Once the pedal is depressed then the you are in ''off-idle" mode the IAC is not used. I does come into play, I believe, in deceleration mode - slowing the rate of revs reduction when the foot comes off the throttle. Am nearly the limit of my knowledge..... |
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| Au1 |
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muzza wrote: Yes, the ECUs in the AU are pretty bullet proof, but you never know. Ah, well I only mentioned ECU replacement as it needs to be replaced anyway to fix the carbon canister valve issue. An auto-elec checked it out some time ago and advised that the stuck EVAP valve has damaged the ECU. To fix this, both the ECU and valve have to be replaced, and the new ECU paired to the BEM. muzza wrote: The IAC is only used during idle, the engine being in closed loop mode. Once the pedal is depressed then the you are in ''off-idle" mode the IAC is not used. The idle issue I've seen occurs whenever the car is idling - cold or hot. The graphs shown above were taken when the engine was still warming up but had not been driven and had not had the throttle touched. I does come into play, I believe, in deceleration mode - slowing the rate of revs reduction when the foot comes off the throttle. But even after being driven all day, I can stop the vehicle, shift into neutral, and the engine will resume it's unsteady idle speed. Any thoughts as to other things to check for? Thanks muzza. |
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| muzza |
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Rod,
XE used Bosch L-Jetronic. XF uses EECIV. Only EECIV is shown in the Ford factory manuals and spares catalogues for the XF. Have personally replaced the Bosch system with EECIV out of XFs in three XEs. The XF EECIV works far, far better. Don't get confused with the fact that both the XE and XF used the Bosch airflow sensor box. Those look the same but are electrically totally different (including different connectors back to the loom). "From ea to au ford used allen EEC 1V fuel injection and ignition systems and the idle speed control motor controls the idle speed." Disagree with that :- XF to ED used EECIV 60 pin ECU. EF used EECV which is a 104 pin ECU. EL used EECIV (60 pin ECU) even though Ford left the EECV logos on stuff in the engine bay. If you look at the labelling on an EL ECU it actually has "EECIV" on it. Have played with these a lot - have the Ford factory manuals as well as internal dealer service info. XF - EL :- Base idle is always set with the IAC disconnected (and engine at running temperature) and by adjusting the throttle plate screw and then the TPF accordingly. AU :- ECU needs to be trained to idle - throttle plate screw and TPF are at fixed settings. TPF is not adjustable. |
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| muzza |
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AU1, PM me your email address.
I'll send you some pages out of the AU workshop manual. |
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| Au1 |
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muzza wrote: AU1, PM me your email address. I'll send you some pages out of the AU workshop manual. Done! 
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| Au1 |
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an update:
checked out some workshop manual information (thanks muzza!) and did some more research. I decided to replace the induction manifold gasket - even though it looked fine. Here's the one I took out. Who can tell me what's wrong with this picture? (click on image for full size):  (click on image for full size):  The new one is in now, and engine is running a lot better. More power - but idle seems about the same as before. I ran through the process to setup values in the ECU KAM again. Only this time, did the extra steps required for TPS. I'll include them below for reference (edited for clarity by me) and mostly quoted from here. Quote: To set the correct idle speed of the engine:
Then perform the following to set the TPS values:
After all this, the idle hasn't changed much. Still jumps around a bit, but there now appears to be a slight link between IAC and RPM: (click on image for full size):  Engine seems to be 'missing' at idle so next thing will be spark plugs. 
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| rod hansen |
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Mate how can you say it still idles the same as before, you would of had a dead cylinder miss at idle with that gasket, as long as you did not break it when removing it.
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