Got NOS? Check your fuel pressure! - Nitrous Oxide Forum

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Got NOS? Check your fuel pressure!
Monday, March 08, 2004 6:42 AM
(Yes, I know it's "nitrous" and "NOS" is a company...the title was just to get your attention )

I read a "blew my motor" thread recently by red96sunfire. First I'd like to say I'm sorry to hear about that and good luck on your rebuild. Second, I'd like to point out something that I don't think has gotten adequate coverage here, and just might save someone a melted piston.

Zex is often referred to as "smart nitrous" or "newbies nitrous" because it's got the vacuum connection to use the stock fuel regulator to increase fuel flow while spraying. That makes the installation very easy and quite a bit safer than a standard dry kit. The assumption that's being made there is that your fuel pressure is high enough to support spraying in the first place. red96sunfire installed nitrous on his car at 144K miles and the damage to his motor doesn't sound like any kind of age-related mechanical failure. It sounds more like he leaned out on #3 and melted his spark plug (and probably more). I'd bet that lean-out was because of low fuel pressure.

I'll offer my car as an example. It's a 97 Saturn SC2 which should have 44lbs of static fuel pressure (vacuum line disconnected from the regulator). Disconnecting the hose allows the maximum rated pressure through the regulator and that's how it should be tested. At around 50K miles, I was noticing some performance degradation so I tested the system's pressure. It was only 34 psi!! This would cause operating problems with the motor under normal conditions, and would definitely not be able to support spraying even a small shot of nitrous. My car, fortunately, has an adjustable regulator stock so I was able to adjust things back in line. J's don't have that luxury.

What makes the pressure get low like that? The most common thing is just simple wear. The regulators used on these cars are a spring loaded diaphragm and, over time, that spring can lose it's tension. It could be from a loss of efficiency in the fuel pump so that even if the regulator is working normally the pump can't keep up. It could be a severlely clogged fuel filter preventing the pump from getting enough fuel to the rail.

Whatever it is, if you don't have enough fuel and you spray your engine will end up like red96sunfire's.

The moral of the story is IF YOU ARE GOING TO SPRAY, CHECK YOUR FUEL PRESSURE FIRST!! I don't have a J service manual handy, but you can find out in there what the pressure should be. Then buy or borrow a pressure gauge and check it out on your car. If it's lower than it should be DON'T SPRAY. Fix the problem first and make sure everything is ok before you put your engine through that kind of stress.

Any questions, let me know.

<br>




09:f9:11:02:9d:74:e3:5b:d8:41:56:c5:63


Re: Got NOS? Check your fuel pressure!
Monday, March 08, 2004 7:03 AM
thank you for that info...should be helpful to some of these newbs out here wating to spray <br>

<img src="http://ourworld.cs.com/FireNv3/eco1.jpg">

Re: Got NOS? Check your fuel pressure!
Monday, March 08, 2004 10:56 AM
Quote:

Zex is often referred to as "smart nitrous" or "newbies nitrous" because it's got the vacuum connection to use the stock fuel regulator to increase fuel flow while spraying. That makes the installation very easy and quite a bit safer than a standard dry kit. The assumption that's being made there is that your fuel pressure is high enough to support spraying in the first place. red96sunfire installed nitrous on his car at 144K miles and the damage to his motor doesn't sound like any kind of age-related mechanical failure. It sounds more like he leaned out on #3 and melted his spark plug (and probably more). I'd bet that lean-out was because of low fuel pressure.



Well, thats EXACLTY what happened. And I actually thought I would have enough fuel cuz everyone talks about ZEX like its GOD!! Well, obviously not. Plugs melted from the extreme lean conditions...ends of em burnt off. It popped through the intake and well, thats it. Motor just stopped. Now, i pulled the plug and wire off #3 and it DOES run so hopefully the block isnt hurt. The build is coming!! <br>


Re: Got NOS? Check your fuel pressure!
Monday, March 08, 2004 1:16 PM
wut psi should the 2.4 motor be wheni check it anybody?
Re: Got NOS? Check your fuel pressure!
Monday, March 08, 2004 3:56 PM
Yeah, and how about the ECOTEC? whats its stock PSI?
Re: Got NOS? Check your fuel pressure!
Monday, March 08, 2004 7:43 PM
2.4= idle PSI is at like 40-43 and W.O.T is up around 48-50.


<br>



Re: Got NOS? Check your fuel pressure!
Tuesday, March 09, 2004 12:13 PM
GI Joe, sorry I missed your call, ill call you as soon as i get the chance. <br>

<BR>
<A HREF="http://www.j-body.org/members/brandoson/cars/1/"><IMG SRC="http://66.36.165.169/J-Body/Molded_Sig.jpg" BORDER="0"></A>
It's cheaper to blow them up than build them up
Re: Got NOS? Check your fuel pressure!
Tuesday, March 09, 2004 9:24 PM
So Zex is the only one that raises the fuel pressure? I thought all dry kits did it that way. <br>

O noes!
Re: Got NOS? Check your fuel pressure!
Wednesday, March 10, 2004 1:58 AM
Zex should advertise itself as the easiest install, it is most definitely NOT the safest.

And all dry kits do increase fuel pressure, to utilize stock injectors to add fuel. Zex is the 'smart' nitrous system, because they put all thier crap in one box, to make it easier to mount. They also use a voltage sensing switch to trigger the spray at WOT, whereas the traditional kit uses a microswitch somewhere on the throttle linkage.

In the respect its the easiest to install, and in some respects least complicated, its also the least serviceable, and most common to cause massive failure. Ususally because of the users own disattention. <br>

<b><i><FONT face="century gothic" size=3 align="top">Cody</i>, <font face="century gothic" size=2>1994 Civic Si___________________</b><img src="http://hometown.aol.com/codiferus17/images/hatchy.jpg" border="0" width=157>
<A HREF="http://www.jaydm.com/" TARGET="_blank"><img src="http://www.jaydm.com/pictures/jaydmbanner2.jpg" width="468" height="60" border=0 alt="JDM Honda & JDM Acura Import Tuning !"></A>
Re: Got NOS? Check your fuel pressure!
Friday, March 12, 2004 5:51 AM
could someone post a pic on where to do this on an eco there is no haynes or chiltons for it <br>


1989 Turbo Trans Am #82, 2007 Cobalt SS G85





Re: Got NOS? Check your fuel pressure!
Saturday, March 13, 2004 2:10 AM
theres a valve on your fuel return line, right on top of your fuel rail. It has a black cap. Unscrew the cap, screw in a pressure tester and turn the car to run to make sure its sealed. Then start it up, and check the pressure.

The pull the vacuum line of the regulator to get full static pressure.

i dont know stock pressure, but thats how to check it. <br>

<b><i><FONT face="century gothic" size=3 align="top">Cody</i>, <font face="century gothic" size=2>1994 Civic Si___________________</b><img src="http://hometown.aol.com/codiferus17/images/hatchy.jpg" border="0" width=157>
<A HREF="http://www.jaydm.com/" TARGET="_blank"><img src="http://www.jaydm.com/pictures/jaydmbanner2.jpg" width="468" height="60" border=0 alt="JDM Honda & JDM Acura Import Tuning !"></A>

Re: Got NOS? Check your fuel pressure!
Thursday, March 18, 2004 9:24 AM
Does anyone happen to know the idle/WOT fuel pressure stats on a (2000) 2.2 OHV? <br>





Re: Got NOS? Check your fuel pressure!
Thursday, March 18, 2004 10:39 PM
come on guys none of you knew about fuel pressure and nitrous? I mean this is a very good thread, but damn. There is not a "smart nitrous" system. You need to check all of this even before you buy the kit.

I guess we all need to start somewhere though. But we do not need to start by blowing our engines to pieces.


Ryan
Re: Got NOS? Check your fuel pressure!
Wednesday, March 24, 2004 9:57 AM
Why would anyone run Nitrous and not check fuel pressure? Why would anyone run Nitrous and not check injectors to confirm even flow? Why would anyone run Nitrous on a tired engine? Why would anyone run DRY Nitrous and not go to larger injectors? Why would anyone run Nitrous on a tired engine?

Why would anyone run more than a 50 shot of Nitrous?

When Nitrous was invented no one thought about putting it on a Cavalier.

After one blown engine and a recent fire. I have completed everything I ever wanted to do to a LD-9 auto and Nitrous. . <br>

RD King
Re: Got NOS? Check your fuel pressure!
Wednesday, March 24, 2004 5:53 PM
Ooooooooooooookay... <br>





Re: Got NOS? Check your fuel pressure!
Saturday, April 03, 2004 3:39 PM
I work at a Pontiac dealer and had our drivability tech find out stock fuel pressure for the Ecotec. 50-60 psi with engine not running. He told me that when the engine is idling you loose about 10 psi of fuel pressure, so if I was going to buy the RK Sport fuel pressure regulator I should tune it in with the car running. Just trying to be helpful!
Re: Got NOS? Check your fuel pressure!
Friday, April 09, 2004 9:03 AM
juiced wrote:

Why would anyone run Nitrous and not check fuel pressure? Why would anyone run Nitrous and not check injectors to confirm even flow? Why would anyone run Nitrous on a tired engine? Why would anyone run DRY Nitrous and not go to larger injectors? Why would anyone run Nitrous on a tired engine?

Why would anyone run more than a 50 shot of Nitrous?

When Nitrous was invented no one thought about putting it on a Cavalier.

After one blown engine and a recent fire. I have completed everything I ever wanted to do to a LD-9 auto and Nitrous. .


This, Gentlemen, is what happens when you huff the sulfur impregnated nitrous....

"this is your brain and this is your brain on non med-grade nitrous" <br>

<img src=http://members.aol.com/codiferus17/Avatar.jpg border=2>
<b><i><FONT face="century gothic" size=3 align="top">Cody</i>, <font face="century gothic" size=2>1994 Civic Si</b>
Re: Got NOS? Check your fuel pressure!
Friday, April 09, 2004 8:51 PM
lol @ cody <br>


Re: Got NOS? Check your fuel pressure!
Saturday, April 17, 2004 10:59 PM
I checked the pressure on my 2.3L quad 4 and it is reading 40 PSI at idle. Not sure if this is where it should be but I just changed the fuel filter and ran my car of a can of injector cleaner so it should be about right if the info helps anybody. <br>


Cardomain|Myspace

Re: Got NOS? Check your fuel pressure!
Thursday, April 22, 2004 12:29 AM
Unless you disconnected the vacuum to the stock regulator to check the static pressure (in which case 40PSI is NOT your idle pressure) that sounds kinda high.

40 PSI sounds more like a proper static(WOT) pressure. <br>

<img src=http://members.aol.com/codiferus17/Avatar.jpg border=2><img src=http://members.aol.com/codiferus17/Spacer.jpg><img src=http://members.aol.com/codiferus17/Avatar2.jpg>
<b><i><FONT face="century gothic" size=3 align="top">02EcoPower</i>, <font face="century gothic" size=2>1994 Civic Si</b>
Re: Got NOS? Check your fuel pressure!
Wednesday, May 12, 2004 5:50 PM
the book for my 3.1 says "ignition on, engine off, fuel pressure 41-47"

Re: Got NOS? Check your fuel pressure!
Sunday, July 18, 2004 1:46 AM
i'm spraying a 55 shot on my civic. here's what i got before i hooked up the zex kit

msd full ignition kit
1 step colder spark plugs
bigger fuel pump
adj fpr
aem fuel rail
retard ignition timing 4 degrees
set fpr at 46psi at idle

you can spray safely if you know what your doing. the zex kit is made for stock cars running stock everything. i just did the upgrades to be on the safer side.
Re: Got NOS? Check your fuel pressure!
Friday, August 06, 2004 9:09 AM
Hey everyone!

New here to j.body but not to performance 4-cylinders and nitrous/turbo apps.

All this is great info. Everyone here should count themselves lucky the help available on this forum thats for sure.

I was wondering if any here install fuel pressure safety switches for the efi nitrous applications. Losing and/or monitoring the fuel pressure is certainly a great idea when spraying or otherwise but not having safety buffers like that switch to turn off the nitrous solenoids in case of pressure drop is another.

I look forward to talking with you all!

-John
Re: Got NOS? Check your fuel pressure!
Wednesday, August 11, 2004 10:14 PM
My WOT is almost 60psi and idle is at 50-55 <br>

<img src="http://registry.gmenthusiast.com/images/sinistercav/siggymay.gif">
Re: Got NOS? Check your fuel pressure!
Friday, November 05, 2004 6:25 PM
what psi should the ecotec be at?
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