So exactly what is the additional connector on the S5 water pump housing for anyway? My connector on the harness side broke off because the 14 year old wiring had become a little brittle in that area, but will the car run fine without it?

 

one is for the ECU temp sensor which is required

one is for the AUX fan. and I belive might be for emissions as well. (hooked to ACV) since the S5 doesn't have the rad one.

 

The one sticking straight up??? Like the man said, it's for an aux fan that sits in front of the radiator. A/C type fan.

Or....it's a switch that you can remove, gut the body of the switch.....drill out(the switch body) to the tap size for your aftermarket water temp gauge sensor....tap the gutted body for the thread size of the new water temp switch.......screw the aftermarket gage sensor into what was the old aux switch, then screw the remains into where the old switch was and wallla.....now you have your new aftermarket water temp sensor is installed......and I know, it's after the thermostat, but who cares. You've still got your stock water temp gauge to look after stuck thermostats.

 

ok cool. I still have that ghetto *** clutch fan so I guess I'm good to go.

Now if I could just figure out where that vacuum leak I have to fix is, I'd be all set.

 

Vacuum leak? Buy a can of starter fluid. Spray at the vac hose connections, bac hose connections....ooops. Hybrid car. Hmmmm. Perhaps a vacuum hose going where a *pressure* hose should be??? Too much hybrid for me to figure out. Cap the two sources of vacuun that come from the throttle body and see if you still have a vacuum leak??? Should be one at the front and one at the back....but then again, I don't have a series five throttle body/manifold so who knows.

 

Well I'm thinking it may be something to do with one of my fuel injectors on the secondary rail feeling looser around than the other one. There is a tiny tiny tiny spot where some gas sieped out.

However I used new grommets and o rings, so I dont know. I didnt take out the air bleed sockets and replace the o rings on the secondary fuel rail, so that may have something to do with it, its sure not helping anything.

I replaced the o rings on the primary air bleed sockets though. It could also be from that mismached s4/s5 intake manifold combo, but I put some RTV like you suggested, HAILERS, and it seems to be sealing pretty good.

I'm going to be checking that manifold and those lines like crazy when monday rolls around.

 

I wouldn't worry about the air bleeds. Must be another creature. New grommets, new o'rings should have stopped any air/fuel leaks. It's always possible the body of the injector is leaking. I had one of those. Drove me nuts thinking it was the o'ring.

The air bleeds should be connected to a source of filtered air. Not some vacuum source. It's a different arrangement on series five cars so I can't be specific on how the hose to the air bleeds runs.Later

 

Nope, nothing to do with emissions. It works the same as the S4 one, coming on whenever the A/C is on or if the coolant temp exceeds 207degF.

 

I Ment the switch might be I know on the S4. the thing on the bottom of the rad also controls the ACV. if you unhook it. not only do you lose the cold start. but your ACV will not function right either. I think it was hailers that figured that one out.

so I was just saying it *might* be for emssions as well. since isn't that the same as the rad one in the s4 just moved to the water pump housing?

or does it *only* control the fan?

 

Fan only.

 

what controls weither or not the cold start comes on with an S/5 then?

ecu temp sender?

 

Err, ahhh, duhhhhhh, mmmmmmmmm, I dunno. Probably the ECU looking at the water thermo sensor? Don't own one of those ceeereeees fivvvve. I guess I could look at the relationship chart for a series five ......naaaah. To late tonite.

 

I tore out the cold start anyway.

 

the thermowax (tb mod) cold idle is different then the cold start thing if that's what you are thinking of.


on mine, with the thermowax gone, as well as the AWS. it still revs to 2500-3000 when started in N LOL... o well. I think the BAC and the other vavle facing the firewall must open as well.

 

Yes indeedy. The 3000 startup is a combination of the BAC and the AWS (Air Bypass Solenoid Valve on a series four). If the AWS is disconnected, then you only get about 2200-2400 on startup (broke the wires on my air bypass solenoid is how I found out).

If you look at page F2-38 of the online manual for the series five, you will see a chart?? of what it takes. It shows the things effecting the AWS system. The water thermo sensor, clutch switch, neutral switch, TPS FULL RANGE, and the ignition switch are the items that are a part of the AWS.