sorry if it's long but i want to give you all the info.

here's the problem:
I recently had a nos wet kit installed on my 91 350 and i'm not feeling any gains.

here's what i've done to help solve the problem:

1st i checked to make sure the system was working properly after it was professionally installed, ie. bottle pres is in the 900 range, cylinoids work, etc. everything seems normal but there are no gains when it's activated.

2nd i install a fuel guage to make sure that the pressure is at the right amount and isn't droping to low. it starts around 38 and then blips down to 20 returning back to 38........ so i decide to replace the pump to make sure everything is ok(it was old anyway). after pump replacement
the same thing happens only now it's around 40 jumping down to 30 and back up, mind you it's a quick surge but it's still dropping.

granted the car itself is old, but all the ignition and fuel system is new. i was told i could run a 100 shot with no problems but i haven't seen any gains from it.

I can't trust any shops in my area to look at it and everyone i know who does run nos has been lucky with their direct bolt and go.

is there anyone who can suggest what i should look at or what i can do to fix this problem; it seems simple but something must be missing.

 

How is your WOT switch wired? If it's on the linkage in the engine, are you sure it's being activated?

Close your bottle, make sure there is NO nitrous in the lines. Start your car, and raise the RPM's a little. While holding the RPM's up a little (1000-1500 rpms or so)activate your WOT switch, and only fuel should shoot in. Your car will bog a little from being rich. If this happens, at least you know the fuel is correct.

This following suggestion is not recommended, but I have held the fuel and nitrous line over the side of the car, aiming it away from everything, and activated the WOT, to make sure both fuel and nitrous were coming out. Since we are talking about 1000PSI, this is at your own risk. I can be lazy at times, but if you simply get a good grip on the lines, you have no probs.

You running any platinum plugs? Some people suggest that as much as 2 runs fouls them up.

What jetting are you using? Is this a 5151 kit?

------------------
1989 IROC-Z 5.7L
NOS 5151 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

 

by jetting do u mean nos if so it's 100.

i've checked the system and nos and fuel does come out. i'm at a pure loss.

the plugs should be fine the car runs good otherwise

I ran the car at around 3,000 when parked and bliped the micro switch on the throttle body at it jumped a little but there isn't any acceleration difference on the road. (not the best idea i know, but i'm out of ideas)

someone please help!

 

This is just a stab in the dark. I am very experienced w/ NOS, but this just stumps me. First, maybee your NOS supplier filled your bottle w/ air and not juice. If the bottle filler is low or empty on NOS...that means you are "spraying" air....not nitrous. Second, make sure your solenoids are in the right direction....meaning "in" and "out"
hope this helps

 

This is just a stab in the dark. I am very experienced w/ NOS, but this just stumps me. First, maybee your NOS supplier filled your bottle w/ air and not juice. If the bottle filler is low or empty on NOS...that means you are "spraying" air....not nitrous. Second, make sure your solenoids are in the right direction....meaning "in" and "out"
hope this helps

 

bottle has been filled three times now by different people........ the purge works or at least looks like it does and when you unhook the lines of the plate on the tb it sprays nos........

the car doesn't hesitate when it's activated nor does it move; much anyway, you can here it kick in a tiny bit but were talking maybe 1-500 rpm's if that.

i'm at a loss; is there anyone who has a suggestion?

 

granted you have your wiring correct for the solenoids, do this: first, unhook the bottle from the line, and open the bottle for a fraction of a second to verify you do have nos and not just compressed air. it will be very cloudy and you will see it disappear very very rapidly. next hook the line back up but remove it from the nitrous solenoid, and have someone stand at the front of the car while you momentarilly open the bottle to make sure nitrous is reaching your solenoid. if no nos sprays out of the end of the line then you have a kinked or bent main line. if it does spray, take the line and hook it back up to the solenoid. take the nos plate that goes between the throttle body out and open nitrous bottle (make sure its connected to the solenoid good). nothing should be happening. now with the nos injector nozzle removed from the car, activate your arming switch then activate your WOT switch manually and verify that nos is shooting out of your jets. if nothing happens you either have your wiring to your solenoids wrong, your solenoid is bad, or your jets are clogged. btw, do you have a nitrous filter on your system?

[This message has been edited by u r sofa king we tah did (edited September 15, 2001).]

 

Some good pointers by these guys. I just ran into this problem, you gun it and pressure just drops, even with 2 pumps, but back to your first post, its your adj. fuel pressure reg. that is bad, you really want to replace that, unplug the vaccum hose and see if it drops in psi, it should.

2nd MAKE SURE YOUR ABLE TO PUSH THE GAS PEDEL DOWN ALL THE WAY, SO THAT IT DOES HIT THE MICRO SWITCH, DO IT WITH THE CAR OFF AND HAVE SOMEONE WATCH THE SWITCH AND LISTEN FOR THE "CLICK"
3rd check with your company if its NOS, that you have the right jettings, you could be too rich, or lean were you wont even notice it, if it was too rich, which I doubt. As long as you have a "FOG" (hence a fogger nozzle kit) coming out when you hit the microswitch, you should be fine.
Do this after you have made sure the switch is gettin hit. Go outside to a lonely road, at idle, which you can spray at, youll be fine, pretend your at the track (dont have the nitrous on yet) and leave see how it feels, and how bad the tires go up in smoke. Now turn your nitrous on do the same thing, and see if you feel the differnce, you should!!!!!
Please keep us updated.

 

my jetting was so rich from nos it was ridiculous. My car wouldn't go any faster with nos. It took me a year to figure that out after replacing everything else.

------------------
1991 Firebird
350 L98 (was a 305 TBI),T-5,Edelbrock TES and cat back,Accel manifold
NOS,subframes,jegster torque arm,MSD Digital 6
AFPR,Lakewood lcas
Hurst linelock,SLP cam (206 212 .480 .486),relocated battery,cold air,Hypertech chip,centerforce df,clutch
poly bushings and mounts
AFR 190s
Harland sharp 1.5 rockers
autopower rollbar

12.33 @ 114.83 juiced uncorrected

13.510 @ 102 non juiced uncorrected

 

I also had big problems with plugged filters. I kept getting crap n2o. I purchased a huge filter from nos to elimate the problem.

 

*Did you have a fuel pressure saftey shut off switch installed?
*Your fuel pressure is way to low to be running NOS... The saftey switch shuts off the NOS when your fuel pressure drops below 40psi....so this way you don't lean out the motor... that is why you feel it periodicly until it drops in pressure.... as noted earlier, replace your fuel regulator with a new adj. regulator... and i would run the fuel pressure around 43psi when squeezing a stock motor...
*If your bottle was filled with air, you car will pop and fall on its face (to much fuel not buring)so that can't be it
*If your jetting was wrong it would fall on its face and blow smoke or pull like a raped ape... so that can't be it

 

well, i bought a nos filter; an adj fuel reg; and a booster fuel pump.......

we'll see what happens this weekend, the safety switch is plummed in line, but isn't wired up so that couldn't be it.

if anyone else has any suggestions please post; otherwise i should let you know over the weekend if any of this stuff helped. if it doesn't i'm getting rid of it.

 

For a NOS wet kit for our cars, the fuel pressure may drop to the 25PSI range. Mine drops to about 26PSI, and the instructions say that anything under 25PSI should be addressed. So if are now reading into the 30PSI range with your nitrous activated, your fuel pressure is not a problem.

Also, what size are the jets on the nitrous and on the fuel? Make sure they are not switched around. For a NOS wet kit, it should be 55N and 42F, even though NOS does jet their kits a little too rich.

------------------
1989 IROC-Z 5.7L
NOS 5151 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

[This message has been edited by Omar (edited September 20, 2001).]

 

First: Keep in mind that you have about 1.5-2 feet of fuel line from the soleniod to the TB that has to be filled with fuel when the soleniod opens. That is where you are seeing the initial fuel pressure drop. If the press. stays low then you have problems.

Second: With the engine OFF, arm the nitrous system. Then open the throttle blades and hit the micro switch for 3-5 seconds. If you see a quick burst then the they start to fade away then you have a restriction somewhere along the line. If you see a constant flow, your problem is beyond me. After you done with this check remember to disconnect the coil wire from the coil or the distributor and crank the engine for a good 10 seconds. This will evacuate and nitrous that made it into the cylinders and prevent catastrophic failure! Hope this helps.

 

thanks guys i appreciate the input; i working busily this weekend trying to solve the problem and want to thank all of you greatly for your opinions and suggestions. please keep them coming........

i'll keep you further updated as to whether what you guys have suggested actually works sometime tomorrow or monday! again thankyou everyone.