Nitrous popping on 100hp shot

speedball1969 · 08-08-2003

1989 5.0, auto, 4.56 gear, headers, 2.5 exh w/ flowmasters,B-303 cam, TF upper & lower, 75mm M.A. & T.B., adj fuel pressure reg set atset @ 37 p.s.i.'s @ idle. The problem is when the nitrous is activated by the Full Throttle switch is starts to pop. Not an actual backfire, but like cutting in and out. Running #49 jets on nitrous & #51 on gas. Have retarted timing about 3 degress's from where it was set and it was extremely worse. Actually was backfiring, so it was turned back to where it was. Its a new N.O.S. dry kit, and it worked fine before the headers were put on.

Just wondering if any of you know of something that Im missing. I ran multiple time because I do not have a purge system and wanted to make sure that there was no air in the lines. Running 93 octane once, then used 104+ octane booster with the gas, and no difference.

Thanks

jeff's01 · 08-08-2003

Did you get rid of the platinum plugs and run a step colder. I didnt see that in your list.

blownlightning · 08-11-2003

Check spark plug gap .030 is good if you have a stock ignition,also change the fuel filter if it hasn't been done in the last year or 10k.
Check all your vacuum lines,fuel pressure regulator and all the nitrous lines especially the T-fitting w/ the jet

Fast1 · 08-12-2003

Mine also did this...The WOT switch wires are loose from their connectors...Or else ur cap and rotor are shot

billy brown · 11-15-2003

i ran 150 shot on a 02 lx with a cobra intake and 24# injectors ,e cam 373 gears and bbk headers . i ran autolite 23 plugs -gap at 052 and never had probs unless it was really cold out . mine was a wet kit and it goes just infront of th tb on a dry kit i goes in front of the mass air where do you have your nozzle ?

billy brown · 11-15-2003

sorry i ment a 92 lx

EricD · 11-28-2003

Is your fuel pressure at 37 because its a wet kit? Stock pressure is 40 i beleave.

Mana4Real · 11-29-2003

The first thing I thought of was ignition... Someone already mentioned this, but I thought I should repeat that you must close the gap. .030"-.035" should be good.

Also what pressure is your fuel pressure at for the N2O system? The jet combo you have, you should be running at 7 psi. If your running off the fuel rail pressure (you said 37 psi) then you are running WAY to rich. If you need F/I jet combinations let me know. I can get em for you. I have em at work.

SickStang · 12-09-2003

I run my press at 42-44 or so and my gaps are a .055. Is that to high. I have trw forged pistons and I don't know my compression ratio but I think it's prob 10:1. I alos have my timing at like 10 or so becuase I can't even advance it, I detonate. Right now she runs great, should I changee anything and what about if I spray it.

Mana4Real · 12-09-2003

I might close the gap on your plugs a bit... Also get a digital 6 box from MSD that way you can advance your timing, then when you spray, it activates the timing retard and you don't have to worry about it. So your car will run strong N/A and safe on the juice. Anymore questions, just PM me, I'm not in this forum very often.