some "radical" thinking on the idle control valve

[Jinster]

When I last cleaned my throttle body, I noticed there's a small crack on the plastic casing of my idle control valve. I am unsure if this has been causing any problems, but I have been wanting to replace it for a while.

eBay has Boxster idle control valves around the $300 mark. And I always thought it too expensive for such a simple part.

Then I found this:

WD EXPRESS 134 23002 416 F/I Idle Air Control Valve (Fits: Kia Sportage)

I cannot, tell if there are any differences between this and our idle control valve. On the surface at least, they look exactly the same. Here is a Boxster one for comparison.

http://www.ebay.com/itm/BOSCH-OEM-Fuel-Injection-Idle-Air-Control-Valve-0280140572-/111102734603?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ABoxster&hash=item19de3d310b&vxp=mtr

I wonder if the whole thing is just an exercise in profit.

In terms of what's inside: The valve is normally half open. Apply a voltage one way, it closes. Apply another way, it fully opens. So how can there be that much difference inside the Kia and Porsche idle valves inside to justify the price increase? - my thinking, there isn't any difference.

I am just wondering if anyone has had any experience on any car with "substituting" idle control valves.

[Ahsai]

Um..plausible but the connectors don't match though. They have different "tracks".

Edited October 16, 2013 by Ahsai

[Jinster]

Hmmm... well spotted! Could this, then, be the only difference? And that's how Bosch legitimizes the different part numbers, different price points and prevent part substitution by "enthusiasts"? I mean, the gig would be up quickly if the two were to just fit interchangeably easily....

[Ahsai]

I don't know but do you really want to risk your $$$ DME with a look-alike non-Porsche part? Although I saw the incentive of 1:10 price difference. The crack you in your valve should be easily filled by Q-bond with the supplied powder (btw, great glue and filler for general auto and plastic repair).

If you DO try the Kia part, at least measure the resistance of the coil and make sure it's the same as the stock part. But even then, you still won't know for sure if it works exactly the same way as the stock part (e.g., air flow rate vs voltage supplied/angle of the valve, momentum of the valve, etc.)

[Jinster]

Aha! That's the sort of ideas I was hoping to hear.

Measuring the resistance, a good idea.

I was just going to apply 12V and see what happens to either valve, whether the movements and amount of opening are the same...

[Ahsai]

I was hoping to discourage you but sounds like you're detemined :)

Resistance is only one factor though. The coils inside also have certain inductance. I think the valve is driven by the DME using PWM so its inductance will also impact the actual current going through the coils.

[binger]

Ahsai is correct you should not use this idle control valve without knowing what the ohm values are. If you are not a professional or understand how these systems work I would not play around. If the ohm value is is too low you could blow the driver in the DME or even fry the whole DME. Not worth trying to save a couple of $$ on a idle control valve and spending several thousand on a new DME. Also you may create major drivability issues.

[Ahsai]

Btw, better price here http://www.fcpeuro.com/products/porsche-fuel-injection-idle-air-control-valve-911-boxster-0280140572

[Jinster]

Ahsai, indeed, the price is a bit better there for the genuine article.

But I am so intrigued now, I have just bought the Kia one for $25. :rolleyes: I am going to make this a little project of mine and compare both units in hand and see what I find.

Thanks for the warning Binger. I will make sure I test out the Kia unit with a multimeter and see what resistance values I get. It's hard to imagine that with both units looking almost identical, they would've used a completely different solenoid inside such that they require drastically different currents or PWM to operate. I will try to resist the temptation to just put it in my car without any thorough testing.

As I now understand it, with 3 pin ICVs, the middle pin should be 12V. And each end should be grounded at set a frequency/inverted frequency by PWM. That way, the solenoid is "pushed" and "pulled" at the same time to either shut or open, or being simultaneously "pulled/pushed" in one direction to keep neutral, or somewhere in between by degrees of variations of the PWM...

If only I have some sort of PWM generator to test these valves...

Edited October 17, 2013 by Jinster

[Jinster]

The valve has arrived. Now waiting for my new multimeter that measures inductance.

[Hilux2400]

I am really looking forward to your results and analysis.

It reminds me of parts for my old TR3A in 1962 which were interchangeable with parts from a Ferguson tractor. The agricultural parts were tax free.

I had a similar recent experience with a French campervan. I wanted to replace the bathroom sink which was £350 from the manufacturer and just £32 from another source.

H

[Jinster]

H, and anyone else who might be watching this thread, the inductance multimeter I ordered on eBay from HK is apparently lost in transit. I am being refunded and have placed an order from another seller.

My current multimeter doesn't measure inductance. I figure I should wait until the new meter arrives instead of pulling out the ICV twice, since there is no particular hurry, other than the curiosity that is killing me... :-)

Edited November 26, 2013 by Jinster

[Jinster]

Okay, guys. The results are in.

Kia ICV: inductance 28, 28, 120 (pin1-2, 2-3, 1-3)

Boxster ICV: inductance 42, 42, 172

Doh.......

The physical attributes of the valves, including the valve opening and size, are exactly the same! (other than the pin indexing) What a shame. A small difference in coil gap/length makes a 900% difference in price....

Edited December 12, 2013 by Jinster

[Ahsai]

That's interesting to know.

[flyingpenguin]

Understand inductance is affected by both coil and magnet (the one on the shaft that turns the valve). Have you tried putting original valve in KIA housing?

My guess would be that the DME would cope with the different values. Imagine the effect of temp changes on inductance. Not my car, not my fried DME, but with an "unlearned" (reset by disconnecting the battery) DME, I bet you this will work.

[Hilux2400]

As a control mechanism, have you measured a similar new Porsche ICV to see if it gives the same readings as your Boxster ICV?

It seems to me that what you do not know at this stage is whether a new Porsche ICV is similar to a new KIA ICV. Also whether there is a margin of acceptability between new Porsche parts.

Just a thought.

H

[flyingpenguin]

As a control mechanism, have you measured a similar new Porsche ICV to see if it gives the same readings as your Boxster ICV?

It seems to me that what you do not know at this stage is whether a new Porsche ICV is similar to a new KIA ICV. Also whether there is a margin of acceptability between new Porsche parts.

Just a thought.

H

+1

[Jinster]

Yes. I understand what you guys are saying.

flyingpenguin: I did think about swapping the inside, since it's my housing that's cracked. But I don't see an obvious way to pry apart the housing of the ICV. The whole thing looks sealed. I guess it was just manufactured sealed? On a side note, I epoxied my cracked ICV housing, it made no difference to the (fluctuating) idle when I start the car. Which is not surprising, since the crack was more on the coil part of the ICV, not the valve part.

Hilux2400: I don't have a new Boxster ICV to take a reading from. I know what you guys are thinking. The part may have deteriorated (cracked magnets or whatever) and that resulted in different readings.

I don't know about the DME being able to adapt to this magnitude of differences in inductance. I was fully prepared to accept something like 10% variation either way. But 33% is just too big for comfort. How much of a difference would normal temperature changes have on the inductance? I wouldn't have thought it'd be that much.

Another thing I forgot to do with measure the resistance of the old Boxster ICV. That might have told us something about the integrity of the magnets.... as in, if it returned the same resistance as the Kia ICV... I was in a hurry to put the car back together because it was getting dark. I was trying to diagnose and replace the power steering pump at the same time.

Edited December 14, 2013 by Jinster

[NewArt1]

I'm trying to put together a part equivalents list which could be of benefit to many enthusiasts who don't want to pay the premium prices demanded by "genuine Porsche" parts which are very often manufactured by companies which supply VW, Audi and BMW to name three. Check out the thread at http://986forum.com/forums/performance-technical-chat/49875-porsche-parts-equivalence-list.html and see if there might be something to add.