View Single Post
16Volt 16Volt is offline
Registered User
16Volt's Avatar
Join Date: Oct 2013
Location: Seattle, WA
Posts: 1,050
I have pretty much the same issue with my car. My FID (Face In Dash) usually only happens when the car is up to operating temp but the first full boost pull of the day in 2nd and sometime 3rd. If the car is hot or its hot outside the issue is very hard to replicate. For instance it did not occur while on the dyno and that was a full 3rd gear pull.

My thinking is that when the intercooler is cold the air is just dense enough that it creates enough boost to hit the cutoff switch. I am running a bigger B&B intercooler, headers, muffler and TiAL WG which supposedly has a 1 bar spring in it.

The overboost switch in my car looked new when I bought it but I replaced it anyway, same issue (though less frequent).

I replaced both my fuel pumps with 044s and upgraded the wiring, no change in FID.

I have a lug that I can ground the overboost circuit to and test but.....I am seriously to chick***** to test it.

1. The overboost switch is supposed to kick in at 1.2bar correct?
2. For those folks running 1bar springs or even more boost, are you just grounding the switch and running bareback with no protection?
3. There are two lines to the WG, one is a signal line from the intercooler and the other is a vent line. The vent line is just open to atmosphere in my car, the thinking being it just needs to be open to allow the underside of the diaphragm to move down correct?
4. I have a small regulated air supply, in theory I should be able to dial in 14psi to the WG signal line off the intercooler and should feel air exit the WG exhaust pipe correct?

If I feel air escaping the vent line we know that the diaphragm is torn thus the WG is not opening creating an overboost condition correct?
- 86 Porsche 930 - Mr.Hyde
- 86 BMW 635CSi - Dr.Jeykell
- 2006 Infiniti M45 Sport
Old 10-16-2014, 04:00 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #28 (permalink)