Rats Nest Removal
05-09-2003, 06:19 AM
#11
Senior Member
Join Date: Aug 2002
Location: Eastern PA
Posts: 1,801
Originally Posted by pengaru' date='Feb 17 2003, 05:55 PM
i'll take pics of it later, the thing is, if you have a shop manual or have downloaded a vacuum diagram for your car, it's straightforward. You're removing the rats nest because you've eliminated the emissions junk, which renders the rats nest pretty pointless (theres so much vacuum line it makes sense to have it all in steel tubes routed nicely so you can figure out whats going on when you connect the emissions junk). So when you remove it, you just take it out, cut off the brackets (you still need the integral brackets which support the intake) and throw it away.
Now you look at what you have left, likely fuel pressure regulator, boost sensor, and thats probably it unless you have a turboii, which I have not done so I'm not sure what else is on that car through the rats nest, probably a bit.
You cap everything but the **** you have kept, use the vacuum diagram to find out where those things got their vacuum source before, and just run a vacuum line directly to that source. On NA there is a line going from the LIM between the primary injectors, up to the dynamic chamber, you keep this as it is supposed to improve fuel atomization at low rpms. You run your FPR straight to the back of the dynamic chamber, by the BACV and AWS solenoid theres a nipple. Then you take the boost sensor and run it directly to the UIM, near the junction between the UIM and LIM... it's right in the center on the side facing the passenger side of the engine bay. Cap the rest. It's that simple.
Don't forget your two fuel lines, the feed and return, just get fuel injection hose from the store and run the lines directly to the fuel rails over the block.
Realise you are eliminating some things that are supposed to improve 'driveability', some of these things don't always see vacuum.. the solenoids are used to control that. Your mileage may vary, I'm happy with my removal so far though.
I'll try take some pics later.
Now you look at what you have left, likely fuel pressure regulator, boost sensor, and thats probably it unless you have a turboii, which I have not done so I'm not sure what else is on that car through the rats nest, probably a bit.
You cap everything but the **** you have kept, use the vacuum diagram to find out where those things got their vacuum source before, and just run a vacuum line directly to that source. On NA there is a line going from the LIM between the primary injectors, up to the dynamic chamber, you keep this as it is supposed to improve fuel atomization at low rpms. You run your FPR straight to the back of the dynamic chamber, by the BACV and AWS solenoid theres a nipple. Then you take the boost sensor and run it directly to the UIM, near the junction between the UIM and LIM... it's right in the center on the side facing the passenger side of the engine bay. Cap the rest. It's that simple.
Don't forget your two fuel lines, the feed and return, just get fuel injection hose from the store and run the lines directly to the fuel rails over the block.
Realise you are eliminating some things that are supposed to improve 'driveability', some of these things don't always see vacuum.. the solenoids are used to control that. Your mileage may vary, I'm happy with my removal so far though.
I'll try take some pics later.
05-09-2003, 04:21 PM
#12
Senior Member
Join Date: Apr 2002
Location: IL
Posts: 2,930
Glad to hear it, my car ran fine too for the couple days I had that setup in place.... now with the TWM everythings different.
The only room for error is placement for the remaining vacuum lines, if you don't put them back to the nipples they originally connected to (via the rats nest before) you might goof up and end up on a nipple that sources before the throttle body (no/little vacuum with throttle closed), which would be bad.
The other thing to be careful about is, if you replace the vacuum lines, there is an orifice in the boost sensor line, you want to keep the orifice. Some people have alot of problems without it present. Like I said before, your mileage may vary.
The only room for error is placement for the remaining vacuum lines, if you don't put them back to the nipples they originally connected to (via the rats nest before) you might goof up and end up on a nipple that sources before the throttle body (no/little vacuum with throttle closed), which would be bad.
The other thing to be careful about is, if you replace the vacuum lines, there is an orifice in the boost sensor line, you want to keep the orifice. Some people have alot of problems without it present. Like I said before, your mileage may vary.
05-09-2003, 06:35 PM
#13
Senior Member
Join Date: Aug 2002
Location: Eastern PA
Posts: 1,801
hmmm, I didn't notice an orifice in that original line and I did replace the 3 lines with silicone tubing... like I said it is running fine though.
What symptoms should I notice with the orifice gone (which it is)?
What symptoms should I notice with the orifice gone (which it is)?
05-09-2003, 08:12 PM
#14
Senior Member
Join Date: Apr 2002
Location: IL
Posts: 2,930
from what I remember it's often linked to hesitations.
the boost sensor is in a kindof bad place to get pressure, being right on one of the primary intake runner, pretty close to the engine port, it gets alot of pulsations. The orifice is there to restrict this so the signal can be a bit smoother for the ecu... you can think of it as a damper.
As far as I know the exact function of the boost sensor is not documented though there are some people trying to reverse engineer the stock ECU to better understand how it works, from what I've gathered it's main use is advancing the timing, so with the pulsations it the timing advance might be a bit wacky.
However, some people have left the orifice out and claim no problems *shrug* it seems pretty car specific, one thing I do know is mazda engineers probably put it there for a reason, and it isnt a significant weight penalty, doesnt make things significantly more complicated, nor does it clutter the engine bay or make the car more difficult to work on.... and as far as I can tell it does not hurt the performance.
So I don't see any reason to remove the orifice
the boost sensor is in a kindof bad place to get pressure, being right on one of the primary intake runner, pretty close to the engine port, it gets alot of pulsations. The orifice is there to restrict this so the signal can be a bit smoother for the ecu... you can think of it as a damper.
As far as I know the exact function of the boost sensor is not documented though there are some people trying to reverse engineer the stock ECU to better understand how it works, from what I've gathered it's main use is advancing the timing, so with the pulsations it the timing advance might be a bit wacky.
However, some people have left the orifice out and claim no problems *shrug* it seems pretty car specific, one thing I do know is mazda engineers probably put it there for a reason, and it isnt a significant weight penalty, doesnt make things significantly more complicated, nor does it clutter the engine bay or make the car more difficult to work on.... and as far as I can tell it does not hurt the performance.
So I don't see any reason to remove the orifice
06-02-2003, 12:12 PM
#16
Senior Member
Join Date: Aug 2002
Location: Eastern PA
Posts: 1,801
I took it all out on mine and it just cleans everything up, simplifies, and makes it easier to work on the engine... If you're saying help in terms of power increase.. probably not. Another good thing though is that I checked the wiring harness and wrapped it up good with electric tape which it needed, cleaned up all the grounds in there, and ran new fuel lines... these things are good for a car so old.
04-19-2005, 03:55 PM
#20
Member
Join Date: Nov 2002
Location: Easton, PA (15 mins. from KDR)
Posts: 60
when you remove the rats nest what do you do to support the TB since the rats nest holds it up in place? also the 3 vac lines in the front of the TB have to do with the oil system right, do those connect to the rats nest or can those just be left alone?