|
|
|
|
| Author |
|
|
Automotive Monomaniac
|
Question re "Overboost Switch"
My engine has been cutting out on hard right turns... and then it runs normally when I straighten the car out again.
 I think I may have found the problem. After poking around with a flashlight last night, I noticed the "overboost switch" wire had vibrated loose. The wire has a rubber housing, so it was kept in loose contact with the switch. I assume right turns pulled on the wire and it broke contact... and when I went straight contact was again made. My questions: Will the engine die if the overboost switch is disconnected? What does the overboost switch kill (fuel or ignition)?
__________________
2018 - Porsche 911 Carrera 7MT / 2018 - Porsche Macan 7DCT / 1993 - Cadillac Allante / 2023 - RAM TRX (on order) |
||
03-19-2008, 08:33 AM
|
|
|
Registered
Join Date: Nov 2007
Location: Calgary AB
Posts: 258
|
I might stand to be corrected but I was having similar troubles which affected the fuel not the ignition, I had the switch replaced but the mechanic mentioned that you could just ground it to disable the switch however leaving your engine vunerable.
__________________
Q 1991 RRC 1995 993 C2 2002 996TT 1984 930 Turbo (gone and missed) |
||
|
03-19-2008, 09:15 AM
|
|
|
Automotive Monomaniac
|
Quote:
 You are saying the switch must be connected or grounded. If so, then I have found my engine cut-out problem. If the switch can be left completely disconnected and the engine still runs, I have to continue searching. You don't want to disable the switch.
__________________
2018 - Porsche 911 Carrera 7MT / 2018 - Porsche Macan 7DCT / 1993 - Cadillac Allante / 2023 - RAM TRX (on order) |
||
|
03-19-2008, 09:21 AM
|
|
|
Registered
Join Date: Nov 2007
Location: Calgary AB
Posts: 258
|
The Germans are efficient (being one of them) if you didnt need it, it wouldnt be there, my opinion. The last thing that I want or could afford is grenading my engine and having to replace it.
Off topic but how do you like your fabspeed? I just bolted up the single outlet with air intakes and a 1 bar spring...it should be on the street tonite
__________________
Q 1991 RRC 1995 993 C2 2002 996TT 1984 930 Turbo (gone and missed) |
||
|
03-19-2008, 09:51 AM
|
|
|
resident samsquamch
Join Date: Oct 2005
Location: Cooterville, Cackalacky
Posts: 6,815
|
Quote:
__________________
-jeff back in the saddle: '95 993 - just another black C2 *SOLD*: '87 930 GP White - heroin would have been a cheaper addiction... "Ladies and Gentlemen, from Boston Massachusetts, we are Morphine, at your service..." - Mark Sandman (RIP  )
|
||
|
03-19-2008, 10:14 AM
|
|
|
Registered
Join Date: Nov 2007
Location: Calgary AB
Posts: 258
|
Sandman,
Disconnect and disabled are two different thngs. Am I correct that if it is disabled the car will still be operational but vunerable to damage?
__________________
Q 1991 RRC 1995 993 C2 2002 996TT 1984 930 Turbo (gone and missed) |
||
|
03-19-2008, 10:19 AM
|
|
|
|
resident samsquamch
Join Date: Oct 2005
Location: Cooterville, Cackalacky
Posts: 6,815
|
The car is not operational, UNLESS you have grounded the wire that once connected the switch. The fuel pumps won't run. I know this because whenever I remove my 965 intercooler, which has the overboost switch on the actual intercooler, I can't run my fuel pumps (to check fuel pressures for example) unless I ground that wire.
__________________
-jeff back in the saddle: '95 993 - just another black C2 *SOLD*: '87 930 GP White - heroin would have been a cheaper addiction... "Ladies and Gentlemen, from Boston Massachusetts, we are Morphine, at your service..." - Mark Sandman (RIP )
|
||
|
03-19-2008, 10:23 AM
|
|
|
Registered
Join Date: Nov 2007
Location: Calgary AB
Posts: 258
|
Gotcha, so i was correct...As Emission said I answered his questions but in a round about way.
Have patience I am new and trying to learn these cars!! Thanks
__________________
Q 1991 RRC 1995 993 C2 2002 996TT 1984 930 Turbo (gone and missed) |
||
|
03-19-2008, 10:26 AM
|
|
|
resident samsquamch
Join Date: Oct 2005
Location: Cooterville, Cackalacky
Posts: 6,815
|
As for actually disabling the switch, I think it's set to cut the fuel pumps at 1.2 bar (from what I recall...might be wrong about this number), and I've seen a few threads where people have tripped it. So I guess it can be thought of as a good safe gaurd. However, if it really is 1.2 bar, I'm not sure if the damage is already done???!!!
__________________
-jeff back in the saddle: '95 993 - just another black C2 *SOLD*: '87 930 GP White - heroin would have been a cheaper addiction... "Ladies and Gentlemen, from Boston Massachusetts, we are Morphine, at your service..." - Mark Sandman (RIP )
|
||
|
03-19-2008, 10:29 AM
|
|
|
Registered
Join Date: Nov 2007
Location: Calgary AB
Posts: 258
|
running naked through a mine field...dont want to take the chance or find out.
I just had a 1bar spring installed. Pros and Cons??
__________________
Q 1991 RRC 1995 993 C2 2002 996TT 1984 930 Turbo (gone and missed) |
||
|
03-19-2008, 10:33 AM
|
|
|
Automotive Monomaniac
|
Quote:
__________________
2018 - Porsche 911 Carrera 7MT / 2018 - Porsche Macan 7DCT / 1993 - Cadillac Allante / 2023 - RAM TRX (on order) |
||
|
03-19-2008, 10:37 AM
|
|
|
Automotive Monomaniac
|
Quote:
- Mike
__________________
2018 - Porsche 911 Carrera 7MT / 2018 - Porsche Macan 7DCT / 1993 - Cadillac Allante / 2023 - RAM TRX (on order) |
||
|
03-19-2008, 10:38 AM
|
|
|
Wayah Road Warrior
Join Date: Jun 2002
Location: Greenville, SC
Posts: 1,536
|
There is another thread from a couple of days ago (Name this part ....)
http://forums.pelicanparts.com/showthread.php?t=398655 that was talking about the overboost relay. Is that the same as the switch? If not, do you have pics of the switch?
__________________
02 996tt White 87 930 GP White (Sold) 87 911 Targa Guards Red(Sold) |
||
|
03-19-2008, 11:24 AM
|
|
|
Registered
|
When I got my car the switch was disabled, grounded to the same connection on the intercoler as the intercooler ground. My wastegate had 1.1 bar worth of springs in it, so I am guessing that the previsous owner got tired of the fuel pumps shutting down.
I went down to .8 bar in the wastegate, and continued to have problems with the overboost. I even installed a new switch. I hate the location that it is in with regards to the 965 intercooler. I agree with teh folks that have moved their switch closer to the intake. Since I have had off and on issues with mine, I may do this as well. Bill |
||
|
03-19-2008, 01:33 PM
|
|
|
resident samsquamch
Join Date: Oct 2005
Location: Cooterville, Cackalacky
Posts: 6,815
|
I have a .80 bar spring in my Tial, and I have the mods to rock a 1.0 bar spring, but...
__________________
-jeff back in the saddle: '95 993 - just another black C2 *SOLD*: '87 930 GP White - heroin would have been a cheaper addiction... "Ladies and Gentlemen, from Boston Massachusetts, we are Morphine, at your service..." - Mark Sandman (RIP )
|
||
|
03-19-2008, 02:32 PM
|
|
|
Registered
|
I am with you 100% sand_man. Not to mention when I had all the springs in the Tial, the car was REALLY fast, and I am sure I would have lost my drivers lic.
Bill |
||
|
03-19-2008, 02:34 PM
|
|
|
Automotive Monomaniac
|
I took out my 1.0 bar spring and put the .8 bar spring back in...
__________________
2018 - Porsche 911 Carrera 7MT / 2018 - Porsche Macan 7DCT / 1993 - Cadillac Allante / 2023 - RAM TRX (on order) |
||
|
03-19-2008, 03:21 PM
|
|
|
A fellow Pelacanite
|
Quote:
__________________
1981 UK 930. G50/01 shortened, 964 3.8RS Fibreglass Body Kit, 18" Alloys 8.5" F & 10" R, 225's F & 285's R, Special Colour Metallic Blue Paint, FIA Sparco Evo's, A/C and Air Pump removed, Electronic Boost Controller, GHL Headers, Tial46 WG. Fitting - New service kit. Needs Fitting - Innovate XD-16 Kit, Kokeln IC. Stephen's K27 HFS, EVO Intake Assy & his Modded USA Fuel Head. 1983 UK 911 3.2 Carrera Sport Coupe. Black, Black Leather with Red Piping, Black Alloy Gear Knob, K&N Air Filter Element, Turbo Tie rods. Needs Fitting - K&N CO Sensor, Round A/F Dial Gauge, Factory Short Shift Kit. http://www.danasoft.com/sig/Iamnotanumber.jpg |
||
|
03-19-2008, 03:49 PM
|
|
|
Registered
Join Date: Nov 2007
Location: Calgary AB
Posts: 258
|
Nathan,
I am running a stock IC and turbo and min 95 octane.
__________________
Q 1991 RRC 1995 993 C2 2002 996TT 1984 930 Turbo (gone and missed) |
||
|
03-19-2008, 08:29 PM
|
|
|
Automotive Monomaniac
|
I should add that I dropped down to a stock spring only because California's gas sucks (only 91 octane), and I was getting predetonation.
 With stock boost, I don't have the issue. If you can get better gas, and your mixture is rich enough, I wouldn't worry about 1 bar.
__________________
2018 - Porsche 911 Carrera 7MT / 2018 - Porsche Macan 7DCT / 1993 - Cadillac Allante / 2023 - RAM TRX (on order) |
||
|
03-19-2008, 09:49 PM
|
|
