When I hit the button to activate the nitrous, I immediately hear the sound of spark knock. I ran datamaster on the few times I sprayed it and it showed my "Long Term Fuel Trim Value" to be lean. Normally they stay right at 128, but when I was spraying, they went to 137. Also, the knock count immediately rose up and the computer pulled 5 degrees timing for a split second, then the timing returned to 36 degrees. Is 36 degrees too much timing for such a small shot of nitrous?

I also found out I was using AC Delco 41-906 platinum plugs. I was told that platinum plugs were a big no-no with nitrous, but never knew why. I replaced them with TR6's, but I haven't sprayed it yet. What problems would platinum plugs cause when combined with nitrous?

and for my last question, if I'm running lean with the 50 shot jets, could I put in the fuel jet meant for the 75 shot to make the mixture a little more rich, or is that a dumb idea?

 

Get to a dyno or someone with a wideband.

Use the next bigger fuel jet and see what happens. Going one step richer isn't going to hurt anything other than power if its too rich. From the sounds of it you need more fuel anyways.

36 total timing? Or is 36 what is programmed in? Just asking cause if you set it to 36 somehow an extra 4 or so degrees will show up.

On my 95 I am running around 36 NA, but plan on pulling about 3 just to be on the safe side. I pray you have some forged stuff, cause if you are pinging on n20 on hyper pistons.... uh oh

Richer jet for sure, I wouldn't spray it until you can see a wideband.

 

What problems would platinum plugs cause when combined with nitrous?

and for my last question, if I'm running lean with the 50 shot jets, could I put in the fuel jet meant for the 75 shot to make the mixture a little more rich, or is that a dumb idea?[/QUOTE]
.... Platinum plugs run WAY too hot for nitrous use and the platinum tips have been known to come loose in the combustion chamber causing major problems....even if you had perfect jetting, you'd most likely detonate with them.........and yea, Like Jsetzer mentioned for now, go up one, or even 2 jet sizes on your fuel side for your next spray....if everything ends up ok, then return to the leaner recomended fuel jetting....Ofcourse the wideband is the way to go(and that's also my strong recomendation), but if you choose not to, at least make sure to read ALL your plugs after your first sprays till you know for sure what it's doing.... also, even for your small shot, I'd spend the cash and get a MSD digital 6 so you can choose your exact timing retard while spraying.....and also have the benifit of a spark cutting revlimiter (VS a fuel cutting factory one)

 

Thanks for the help 36 degrees is what was programmed in for my initial tune, not sure if it's too much for nitrous though. I do plan to hit the dyno and have it properly tuned in the next few weeks. I just wanted to experiment with the 50 shot since a few weeks would be too long of a wait to spray it Also, the MSD 6 does sound nice, but its way too much for me at the moment, but it definatly sounds worth saving up for.

I'll go ahead and jet it down and try it again with the right spark plugs. If I hear pinging again I'll just stop and wait for it to get properly tuned if my motor stays together

Thanks again

 

If I set 36 degrees on my lt1 it will actually end up being 40-41 degrees. I don't have a quick answer as to why, but it has been talked about before. You may just have too much timing.

 

I just went out to yank the fuel jet out and noticed it was clogged I recently replaced the fuel rail and blew it out with compressed air before installing it, but evidently I missed something.

I'm lucky as hell it's just a 50 shot or I would be crying about a blown motor....It appears that my problem was I was spraying all nitrous with no fuel at all.

thanks again for the help

 

Yea , lucky it was only a 50 shot ......post how it works out for ya

 

I cleaned the jet and tried again and it still spark knocked I let off the button immediately though. I also noticed the computer isn't going into closed loop during WOT and the carbon canister purge is coming on.

The car also surges a bit so I think I got a vacuum leak somewhere. I'm gonna replace both TB gaskets around the plate and replace the cracked vacuum elbow and see if that fixes my lean condition.

I did put in a bigger fuel jet, but I'm gonna fix these problems before spraying again

 

Did you get rid of the platinum plugs?

 

yea, i put in NGK TR6