3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
Sponsored by:

boost gauge gone mad

Thread Tools
 
Search this Thread
 
Old 07-07-10, 03:37 PM
  #1  
Full Member
Thread Starter
 
driftindirt's Avatar
 
Join Date: Apr 2010
Location: calgary
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
boost gauge gone mad

I hookd up my boost gauge to the map sensor sensor on the wall by the intake elbow. This is a 93 rx7 we are talking about with no mods except for a catback exhaust. Boost creeping up to 15 psi and not even under wot. Is mmy gauge reading it in accurately from the map sensor or am i actualy getting a whole bunch of boost creep from maybe a sticky wastegate? Thanx for any suggestions and advice =)
Old 07-08-10, 01:02 AM
  #2  
Rotary Enthusiast

 
Sideo's Avatar
 
Join Date: May 2006
Location: reno nevada
Posts: 763
Received 13 Likes on 11 Posts
If it has the stock ecu it should either hit fuel cut or blow before 15psi. what does the gauge read when car is off? maybe its a gauge that reads absolute pressure, like it would show 1 atm at sea level when the car is off.
Old 07-08-10, 01:30 AM
  #3  
Eats, Sleeps, Dreams Rotary

iTrader: (14)
 
moconnor's Avatar
 
Join Date: Jul 2003
Location: Bay Area, CA
Posts: 4,660
Received 82 Likes on 49 Posts
Your average automotive gauge is extremely unlikely to read absolute pressure. Almost by definition it will read gauge pressure.

If the gauge is an Autometer, it is very likely inaccurate - but most likely not inaccurate enough to indicate 15 psi for a real 10 psi. In other words, stop driving the car until you install a proper boost control unit.
Old 07-08-10, 06:21 PM
  #4  
Full Member
Thread Starter
 
driftindirt's Avatar
 
Join Date: Apr 2010
Location: calgary
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
k but still need to know if hooking up to the map sensor instead of hooking it up near the intake manifold makes any difference? i mounted my gauge where the factory tweeter is so it made sense to use the map sensor. Would hooking up by the intake manifold give me a better or more accurate reading? I was readign through some guides on fd3s.net and not sure exactly where but around the intake manifold was where it was hooked up to.
Old 07-08-10, 06:27 PM
  #5  
Eats, Sleeps, Dreams Rotary

iTrader: (14)
 
moconnor's Avatar
 
Join Date: Jul 2003
Location: Bay Area, CA
Posts: 4,660
Received 82 Likes on 49 Posts
You will get almost the same reading from both.
Old 07-08-10, 07:27 PM
  #6  
Planning my come back

iTrader: (7)
 
MR_Rick's Avatar
 
Join Date: Feb 2003
Location: Austin, Tx
Posts: 3,393
Likes: 0
Received 0 Likes on 0 Posts
Have you tried to hook it up some where else and see if you get a better reading?
Old 07-08-10, 09:28 PM
  #7  
dorito powered

iTrader: (5)
 
KKMpunkrock2011's Avatar
 
Join Date: Mar 2008
Location: Lincoln, NE
Posts: 2,839
Likes: 0
Received 0 Likes on 0 Posts
don't t it into the map sensor line anyways, that line should be used for the map sensor and ONLY the map sensor, not like vacuum hose is expensive.

Any chance you have a PFC and commander?
Old 07-09-10, 12:13 AM
  #8  
Banned. I got OWNED!!!
iTrader: (1)
 
Ratjar's Avatar
 
Join Date: Jan 2009
Location: Orion
Posts: 462
Likes: 0
Received 0 Likes on 0 Posts
so... if you plugged it into your map line/sensor what did you do with your mao sensor? unplugged it? bad idea...

use the nipples on the plenum to get a better reading.
Old 07-09-10, 03:57 AM
  #9  
Put it in the microwave!

iTrader: (22)
 
kensin's Avatar
 
Join Date: Jul 2009
Location: CA
Posts: 1,556
Received 35 Likes on 29 Posts
He T it it in the map sensor. Plug it where the extra nipple is at on the uim.
Old 07-09-10, 06:17 PM
  #10  
TANSTAFL

iTrader: (13)
 
alexdimen's Avatar
 
Join Date: Oct 2003
Location: Richmond, Va.
Posts: 3,770
Received 123 Likes on 82 Posts
Originally Posted by driftindirt
I hookd up my boost gauge to the map sensor sensor on the wall by the intake elbow. This is a 93 rx7 we are talking about with no mods except for a catback exhaust. Boost creeping up to 15 psi and not even under wot. Is mmy gauge reading it in accurately from the map sensor or am i actualy getting a whole bunch of boost creep from maybe a sticky wastegate? Thanx for any suggestions and advice =)
The boost can surpass fuel cut levels in lower gears without fuel cut due to a slow response from the ECU. I would stop driving it first off.

The first thing i would think to check is that the wastegate and precontrol actuator hoses/lines are intact. You also need to check the hoses/lines up to the WG and PC solenoids if you're going that route of troubleshooting. And the solenoids themselves for being stuck open.

the amount and quickness of it's overboosting would make me think the WG and precontrol are not seeing any pressure from the compressor housing at all.

Also remember, the precontrol also controls boost, but only before transition. PC = pre transition. WG = post transition.

If the lines are straight and you have verified all the boost control system is functional then double check the reading with another gauge.
Old 07-10-10, 06:49 PM
  #11  
Full Member
Thread Starter
 
driftindirt's Avatar
 
Join Date: Apr 2010
Location: calgary
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
wow guys great help. havent got around to cheking any of these yet. But will do everything then post a solution if it works out for me jus in case it helps some one
Old 07-11-10, 11:57 AM
  #12  
dorito powered

iTrader: (5)
 
KKMpunkrock2011's Avatar
 
Join Date: Mar 2008
Location: Lincoln, NE
Posts: 2,839
Likes: 0
Received 0 Likes on 0 Posts
if you do have a pfc and commander, make sure your map sensor is plugged in and working properly and then check on the commander screen what it shows you, just another way to verify
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
rgordon1979
3rd Generation Specific (1993-2002)
40
03-15-22 12:04 PM
Jeff20B
1st Generation Specific (1979-1985)
73
09-16-18 07:16 PM
ZaqAtaq
New Member RX-7 Technical
2
09-05-15 08:57 PM
High_Carb_Diet
Power FC Forum
1
09-05-15 09:07 AM
gabescanlon
3rd Generation Specific (1993-2002)
7
09-05-15 12:09 AM



Quick Reply: boost gauge gone mad



All times are GMT -5. The time now is 11:59 AM.