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Discussion Starter #1 (Edited)
Hey all, I've searched on the forums but couldn't get a definately answer on some things:

I just installed the focus central 60mm TB on my SPI and the bracket from my SPI for the throttle cable didn't fit. Are we meant to use one from a zetec or anything special?? I'm looking at getting another SPI bracket and modifying it, as now mine sits rather badly until I sort this out.

2. I also got given a RACTEK intake for free to compliment the 60mm, it had a maf sensor on it but as soon as I installed it threw a CEL. so I have put my MAF from my SPI on there (same same AFAIK) and it's still there. One thing to add is the maf is directly behind the pod filter which I thought was a big no no but that's now it fits?

3. My TB came with a new OEM TPS which I installed the same as the other one but I notice my idle doesn't drop down as much as it used to with the car feeling like it's "running on" when gearing down. I gave it a wiggle and even moved the idle screw with no luck. My incling is that the MAF or the CEL might be behind this a bit (such as my idle being now 1,000rpm) but the running on in gears to me would be the TPS.

4. The idle as mentioned in point 3 is now 200rpm higher.

I have checked and rechecked the TB For leaks, all hoses tight, new gasket etc but to no avail. Any information, suggestions or ideas is welcomed. I have also disconnected the neg, and relearned 3 times with no luck
 

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Used parts, someone may have tweaked the stop screw on the throttle body for a higher idle.
 

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The idle screw on these engines aren't every sensitive. You are going to have to adjust it more that you think lol
 

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Well the CEL we pulled was P1506 Idle Air Contol Overspeed Error which explained the high idle. Suggested he clean the IAC valve with some carb cleaner I think there is debris in the valve openings from a previous manifold cleaning. We also found a leaking hose-this one (just an example from the web).


Replaced it with a piece of leftover I had lying around.
We cleared the code and it took a few minutes of idling but it did resurface. And an unusual thing-idled around 1000 rpm but suddenly dropped to ab. 800 rpm and held there for a few minutes. Blip the throttle and back to high idle.
My money is on a clogged/dirty IAC valve.
 

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Discussion Starter #9
Ok... Still scratching my head a lil.

I changed the IAC with another unit, bit of carbon but nothing major I could see. Started up, seems to have stopped the random 1400 rpm climb down but the idle has gone down to 900rpm (was 1,000rpm before). So I pulled the neg, relearned the car and my CEL light was off (yay!) but idle stayed at 900rpm (originally 800rpm on factory setup. I took my short ram intake off, checked to see if the cable was allowing the TB to close which was fine. Went for a drive and the CEL came back on, idles still a bit high, so I took off the TPS, put my old unit back on to eliminate that, reset the car again, idles 900, no CEL but daylight was fading so I've left it at that.

If the CEL comes back on tomorrow when I drive to work, I might ask my friend Ian to run the OBDII scan tool see if it's still the same code.
 

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Drunkinmonkey
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did you figure this out yet?
 

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Discussion Starter #11
Ok, so, started up this morning, ran perfect. Drove to work, from work then after a beer at the local, started up, idles high (back to 1100rpm) and throws the CEL. BACK TO SQUARE 1. Few times I stopped at lights it will go down to about 900rpm, sometimes 800rpm then sometimes 1100rpm.

Next idea???
 

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Intermittent issues are the worst ones to diagnose.
Try this: bring the car up to operating temperature. While running unplug the IAC. If the idle drops, stumbles and possibly dies then the IAC is functioning correctly. No change to idle means the IAC is faulty.
It could also be a vacuum leak. We fixed one but that curved hose from the valve cover is dry rotted and could be leaking. It usually runs to under the air intake box and is upstream of the MAF. Is is possible routed to the air intake tube after the MAF? That could be a source of unmetered air.
Things that can cause high idle but aren't associated directly with air intake:
Idle is increased if the engine is cold to help warm up.
Idle is increased if the engine is overheating. This increases the speed of the water pump to flow more coolant to the engine and radiator. This speeds up the speed of the radiator fan improving cooling.
Idle is increased if there is a high load on the alternator.
Idle is increased if there is a pressure spike in the power steering.
 
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