Idle air valve

[JonA]

My idle air valve has been dead for a while and I have been putting up with the rough/low idle on cold start while trying to justify $300.00 plus for a new valve. Bosch's number for the correct valve is 0 280 140 501. I have another valve that works that came out of a Volvo. It is Bosch #0 280 140 542 and is very similar with the same 3 pin connector.
Anyone know what the difference is and if I can substitute this Volvo valve into my 924S?

Thanks,
Jon

[thomasryan]

cross reference list

[mytrplseven]

Porsche no longer sells the replacement IAC. O'Reily's Auto Parts does sell one, however, that is manufactured by Borg Warner, a long time leader in auto part manufacturing in the US.
Good prices as well. You can check them out on line.

[alfadoc]

Likely the only difference is the composition of the bi-metallic spring on the inside, or the size of the drilled passages. This means it could close at a different rate than the original as the engine warms, or it might flow a slightly different amount of air. Really, the only thing to do is to try it.

[JonA]

I'm not sure there is a metallic spring in there. This is the three wire valve. My understanding is that the ECU pulses the motor to open and close the valve. Wonder if there is any risk of harm to the ECU if I try this new one. The ECU was rebuilt last year and I'd hate to screw it up....

Jon

[88Silver924S]

See: Idle Valve

Some people have carefully taken these apart and found a broken wire connection, gummed up valve (cleaned with brake cleaner?), or a bad o-ring or other broken seal that can be fixed. Maybe you are lucky and yours just needs a cleaning? Good luck.

[djnolan]

Place a WTB ad on the used part forum

[DannoXYZ]

Try some of these 3-wire idle-valves:

Airtex 2H1099
BMW 13631707378
Carquest 73-4320
Citroen 616960
Fiat 60574613
Renault 7401317057
Sidat 87063
Standard Motor Prod. AC42 or 14767
Volvo 3411388
Volvo 1317957
Wells AC125

Used on these other cars:

Eagle Medallion 88-89 L4-2.2L
Eagle Premier 88-90 V6-3.0L
Peugeot 505 87-88 V6-2.8L
Volvo 242 83-84 L4-2.3L
Volvo 244 83-87 L4-2.3L
Volvo 245 83-87 L4-2.3L
Volvo 740 85-87 L4-2.3L
Volvo 745 1985 L4-2.3L
Volvo 760 84-87 L4-2.3L
Volvo 760 85-87 V6-2.8L

[DannoXYZ]

Yeah, no bi-metal spring. Those were standalone coolant-temp based cold-start injector and air-valves. On our cars, it's a DME controlled PWM valve.

Rock Auto has the Volvo Airtex valve for $135.
Amazon has an AIP Electronics valve for $89. Warning, this is Chrysler replacement.

[JonA]

Well I had a minute this afternoon so I pulled the idle control valve out and pulled it apart. Easy enough to do. Unfortunately it is toast. the contacts/brushes are burned away beyond help and the commutator is badly scored. Those parts on the Volvo valve do not match so making one good one is not possible. And according to the literature the volvo valve cannot substitute into the Porsche so I am shopping for a new valve. May try Standard, certainly a lot cheaper.
Until I get a new valve I plugged the ends of both hoses and put everything back together. Can't imagine it will run any worse than it was.

Jon

[John_AZ]

ebay?

http://www.ebay.com/itm/Porsche-951-944-Turbo-Idle-Stabilizer-Valve-ISV-valve/261918325510?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%2 6asc%3D31196%26meid%3D6e6b2ff520dc48bb9223b7539619 388a%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D2617 42273167&rt=nc

J_AZ

[DannoXYZ]

Originally Posted by JonA

And according to the literature the volvo valve cannot substitute into the Porsche so I am shopping for a new valve. May try Standard, certainly a lot cheaper.

Why wouldn't it work? Physically and electronically they are the same. There are apparently some differences:

1. impedance of the windings should be 10-14ohms for Volvo, 20-25ohms for Porsche.

2. Another difference I found on some Megasquirt boards is that the Porsche valve is controlled with 100-147hz PWM signal while the Volvo is about 500hz. But that's only differences in the ECU. I wonder why the valves themselves would care.

[JonA]

Danno, I don't know why they don't cross. One side has a larger hose connection but that would be an easy fix. My slight electrical background tells me that the Volvo valve with less resistance thru the windings is going to draw more current from the ECU and I wonder if the ECU is robust enough to handle that.

John, From my autopsy it doesn't appear that these valves last long. I am hesitant to try this valve from e-bay because it is probably at the end of it's life. If I can find an aftermarket one for reasonable money I will probably go that way. It's a roll of the dice eithor way!!

Thanks to all for the input. It's very helpful to benefit from everyone's experience. And I'm able to still drive this puppy while things sort out so it's all good.

Jon

[John_AZ]

I did an edit on my post when I saw that Larts had one listed. I have bought from Larts and was very satisfied with the product.

J_AZ

[JonA]

So I ordered a idle air valve from Amazon, made by AIP Electronics, for $89.00. Figured this was a better gamble than a used unit even though the AIP unit has gotten some bad press. I would have preferred the the AirTex valve but it was out of stock everywhere. Part arrived and looked good and was installed last weekend. It works and idle is now where it should be. Wondering how long it will last!
Next I'm going to pressurize the intake and do the bubble test for air leaks. See if I can't get the idle to smooth out just a little more.

Jon

[John_AZ]

Sounds like a plan.

I rebuilt my TB-throttle body on the '87 a few years ago with the Arnnworx kit.

My TB "O" rings on the shaft seal were completely rotted and falling apart.

Instructions/details (search for your part):

Porsche 944 Turbo Throttle Body Reseal Kit Porsche Throttle Body Reseal Kit for 944 Turbo [951TBK] - $20.00 : ArnnWorx Specialty Tools

Results after rebuild felt minimal but I felt it was a combination of repairs that made a difference. I use nonperforated screw clamps on all vacuum hoses but I may switch back to the OEM Oetiker clamps.

John

[mytrplseven]

Originally Posted by John_AZ

Sounds like a plan.

I rebuilt my TB-throttle body on the '87 a few years ago with the Arnnworx kit.

My TB "O" rings on the shaft seal were completely rotted and falling apart.

Instructions/details (search for your part):

Porsche 944 Turbo Throttle Body Reseal Kit Porsche Throttle Body Reseal Kit for 944 Turbo [951TBK] - $20.00 : ArnnWorx Specialty Tools

Results after rebuild felt minimal but I felt it was a combination of repairs that made a difference. I use nonperforated screw clamps on all vacuum hoses but I may switch back to the OEM Oetiker clamps.

John

Hey, John
I'm going to be in Phoenix until Saturday and thought I'd look you up. If you're open to a visitor from Florida for a bit, PM me with address and convenient time if you're available.

[John_AZ]

I got your PM.

Have a great 4th of July in AZ!

John

[sausagehacker]

Dang, I wish I saw this earlier. I have a variety of bosch idle valves (3 pin) you could have tried/bought for cheap.