linderpat

I have that same regulator on my crossbar (MY86.5) and it is part of the smog system. Before my intake R&R, my vac hose came off. It connects to the 7 way splitter under the intake in the Vee. I think it will affect performance if not working properly or if there is a vac leak from its being disconnected

Rich9928p

Hot start problems can be caused by a faulty Temp II sensor or corrosion at the connections. All that it takes is an ohm meter and a guesstimate of the engine coolant temperature. Measure the resistance values at the Temp II sensor and at the LH/EZF connector.

Note the orientation of the protruding alignment notch on the outside of the sensor. Prong 1 is the sensor for the Electronic Ignition and prong 2 is the sensor for the LH fuel injection. Clip one of the ohm meter leads to prong 2 (LH) and clip the other lead to a ground point [Do NOT connect the ohm meter leads between the two prongs of the sensor]. Repeat the resistance measurements for prong 1 (Electronic Ignition). The proper Temp Sensor II resistance measurements are:

0 C / 32 F: 4.4 - 6.0k Ω (Ohm)
15 – 30 C / 59 - 86 F: 1.4 to 3.6k Ω
40 C / 104 F: 0.9 – 1.3k Ω
60 C / 140 F: 480 – 720 Ω
80 C / 176 F: 250 – 390 mΩ

If the resistance readings are not correct range, the temperature sensor must be replaced.

If the resistance readings are in the correct range at the sensor, there could be a problem with wiring to the LH controller or the connector itself could be corroded. Measure the resistance from the Temp II sensor connector to the LH and spark controller connectors to confirm the circuit is good.

6mil928

jim will this cause any negetive effects just blocking it off and pulling it?

Jim bailey - 928 International

Jason your car does not have that BUT you have a similar looking "idle valve" solenoid which opens when the A/C compressor is turned on. If removed b;ocked and you turn on the A/C the car may stall idle slow.

PorKen

On '85 and early '86 up to some point, that valve is located near the passenger shock tower.

dprantl

Oh yeah, now I know what you're talking about. It was always in the way when installing the passenger intake tube...

Dan
'91 928GT S/C

TAREK

I want to thank everyone who responded and provided insight/help. My problem turned out to be caused by bad injectors. One specifically had a broken tip sleeve. I'm off and running again. Thanks again

Tarek

TAREK

Spoke too soon. Problem is back

mervynp

Apologies for bumping this thread, but I am in the middle of a vacuum refresh and this part on my 86.5 does not hold vacuum when I test it with the Mitivac. I took it off and noticed that it will hold vacuum if I block off the two larger connectors at the bottom, would I be correct in thinking this is not how it was designed to work?

If it is indeed knackered, is it the same part as 944 110 429 00 as I can't find the 928 110 429 07 in PET or on the usual suspects websites? And is it really $700!!?

Mrmerlin

Mervy please post a picture of the part your talking about

mervynp

This is the little swine. The position is as shown in Fabios picture and it looks like the hoses connect to the engine just below the oil filler cap and then on towards the carbon canister respectively, which makes me think this is part of the vapour control system, but I have been wrong before.....

Thanks,

Steve

Mrmerlin

it should hold vacuum,
and when vacuum is applied the 2 bigger lines should be open to pass fuel vapors.

mervynp

Mr Merlin,

many thanks for all your help, I got a replacement that does indeed hold vacuum and it is all plumbed up.

Now for the next problem, the black plastic valve that the above one is connected two, which I think is for the carbon canister, also does not hold vacuum, so I removed it by spending an hour or so cursing and swearing at it before removing the wheel well lining and pushing the hose through from the other side.

I can now test this, if I pump the small control pipe with the mitivac it opens the valve, it seems to stick a bit and doesn't always close but that aside is this normal, my guess is yes.

I am a little concerned that this is a VW/Audi part, not that there is anything wrong with that.

I am also a little concerned that this is then blocked with a bit of black electrical tape at the top of the Y connector. Badly. I think I should take this blockage out, but people don't block pipes for no good reason and am scared of what this is hiding. Any thoughts?

Cheers,

Steve

syoo8

Sorry to dredge up an old thread…


I have the same problem that mervynp has encountered. My 928.110.429.07 "Control valve" will not hold vacuum.



After scouring Rennlist about this part, this is what I have learned thus far:

This control valve is part of the fuel vapor charcoal container system and under certain conditions it pulls air through the container to purge the accumulated fumes. It will affect performance if not working properly, or if there is a vacuum leak from being disconnected.

It should hold vacuum, and when vacuum is applied the 2 bigger lines should be open to pass fuel vapors.

Since I don't really want to spend $700 for a replacement part…

What happens if this part does not hold vacuum? What does "it will affect performance" mean, exactly- does anyone know?

Eplebnista

If the part does not hold vacuum, you will have a vacuum leak when the system attempts to pull fuel vapors out of the canister. Given when evap systems normally attempt to do this, you will not likely notice any difference in vehicle performance but vacuum leaks are not desirable.. The evap system, however, will not be working at all. Whether that has any impact on your abilitiy to pass emissions where the car lives is well beyond me.