Tanman

Wow, it seems only recently that the infamous hobb switch and the fuel problem has been brought to my attention. Strange that I only noticed the lag problem once the BOV was installed. Anyways, I searched everywhere and the fix is provided, but nowhere does anyone have a picture of the actual part. I think jgadlage has it on his homepage, but cardomain sites are down right now. I even search the internet and found one tiny picture of a hobbs switch. So is this the part?



If so, I guess you remove the vacuum hose connected to the white object in the center of the picture. That same object has a black part behind it, and it also has three wires connected to it, one of which is cut. Also, can someone explain why this wire is cut?

Thanks,

BlackCat

iTrader: (6)

Yep that's the Hobb switch alright. There's a hose running into it from the side. You just detach that hose and plug it. I use a golf tee as a plug.

Here's a shot of the Hobbs switch

http://images.cardomain.com/installs...57_16_full.jpg

Note where I stash my yellow golf tee when I just can't stand that aux pump noise any more.

Golf tee in use

http://images.cardomain.com/installs...57_17_full.jpg

Tanman

Hehe cool that you're using a golf tee instead of a hose cap .

Alright, so I disconnected the vacuum hose to the hobbs switch and switched the car to the accessory position. I heard a short screecing sound, then the car is quiet. Is that all it's supposed to do to let me know the aux fuel pump is on?

Chunger

iTrader: (1)

Yes, the Factory FP relay (which triggers your Aux pump) will shut off if the car isn't started and running after turning to the ACC position.

Tanman

Cool, I'm going to get some hose caps and plug them and hopefully my fuel issues will be fixed. I can't afford the $300 fuel pressure gauge kit right now .

BlackCat

iTrader: (6)

When you turn the key to the first notch, accessory, you'll hear the aux fuel pump power up. Then you'll know that its all set up right.

When I first started to disconnect the hose I found that the aux fuel pump would get very noisy during a real long drive. That's why I stuck the golf tee on the side rubber whenever I don't think I'll be boosting.

Jer

iTrader: (2)

Hey guys,

While we're on the subject of FP relays.. I need help finding mine in my 5th gen When we did the install we spent so much time trying to find the relay without success, that we ended up tapping into the ignition... it wasn't where the stillen manual said it would be!

Tanman

So do you plug both sides or just the vacuum tee side? The car already feels better after I plugged just the vacuum tee.

Chunger

iTrader: (1)

You just need to make sure to 'plug' the vacuum SOURCE (the hobb switch doesn't need it)

Tanman

Ok thanks. The car feels a lot smoother now. Might need a fuel pressure gauge and AFC still, but this helps. Thanks all.

Engloid

This can be the result of noth having the bov adjusted properly. In other words, you get pressure built up in the intake pipe...the bov then vents it ALL out when you shift. Then when you hit the next gear it has to build boost back up.

I'm not sure what you're trying to do with the hobbs switch though...fill me in on this. May be something to be learned...

Tanman

The BOV is tightened down pretty far to prevent air leak during idle, and with only 4 psi boost (Greddy gauge reading), I don't think the SC is making enough boost to make the BOV open correctly.

The hobbs switch is a part of the Stillen SC kit and it turns the auxillary fuel pump on and off in conjunction with boost. This on\off feature causes fuel pressure to rise and drop, causing the uneven feel of the car, thus the "lag" issues. When you start to boost, the hobbs switch turns on the aux fuel pump, but it takes a second for it to supply the extra fuel, and that second feels like lag. By disconnecting the vacuum line to the hobbs switch, you're turning off the switch, so the aux fuel pump is always on. Downside is the aux fuel pump is noisy and might not be able to withstand constant operation, even though it's rated for 100% duty cycle.

This is a summary of what I've found out from other org members, so credit goes to them .