simple nitrous questions

[1jimmy__d]

well i have it installed and it looks like the hobbs switch is broken after only being used like 10 times! i bypassed the switch by screwing both wires to one terminal i tried it after and it worked! i think nos should send me a new one for free. i bought this last summer and it worked barely at all! how much are they if they wont give me one for free? seems to pick up pretty good, NOT as good as my other mustang though. i think becaseu this car has a lot more power than my other one did, but this gives a little push towards the bacl of the seat

AS far as that poopping before, it is stil there only when the car is cold and accelerating harder than a smooth increase. when the car gets up to operating temp, the popping stops! ANY ideas?

PS I kept the timing at 12 for now, it seems to work with no problem. take care!

jim

How do you know the Hobbs switch is broken? Do not use your nitrous system without that switch properly hooked up! Seriously, you could ruin your motor. When I was had the stock 5.0 under my hood...& I was young and dumb...I was having trouble getting my nitrous system to work properly. It would work for a second then shut off, or sputter. So I stupidly unhooked the Hobbs safety switch. I went to the track a few weeks later and began melting spark plug tips! I mis shifted once with the nitrous on and blew a 6ft. flame out of one of my tailpipes! Fast & the Furious style...no joke! You can get a new switch at your local speed shop. Who installed this system for you? Or did you? If you had it installed by someone that knew anything about dry nitrous systems on fuel injected cars they should have known how important the Hobbs switch is and that it must be connected and working properly to assure the safety of your motor. Did you say there is a larger than stock fuel pump in that car? That's strange though because even the stock fuel pump flows enough volume & pressure so that the system should work fine. That's the key to a safe nitrous system...making sure that your fuel system flows enough volume to hold the boosted fuel pressure up to around 80+psi. for an entire 1/4 mile run. When I had a 100hp shot of nitrous my 155lph intank pump was sufficient. But when I stepped up to the 150hp shot...that's when the Hobbs switch began cutting off the nitrous flow because I didn't have enough fuel volume. So now I run a MSD inline pump that flows about 200gph (I think??...it's been a while). I still don't understand why your new Mustang with all the mods it has on it doesn't feel as fast as your old stang?! Or did you mean just when using the nitrous on the 2 cars? Did you even use the nitrous system on the other one? Sorry for all the questions. Just trying to get a feel for what exactly is going on here. Give me some more details and we'll figure this bug out. About the popping...did you ever change your fuel filter?

[1jimmy__d]

i went to a shop who installed it. i am thinking it is the switch because it tested fine when he unhooked the line to the TB and the car was off. when i bypassed the switch that is the only time it worked. is there a way to test to see if this thing is working any other way. i have a 155lph fuel pump and a gague hooked up under the car. the gague never drops to 0 though, should it? (i mean after the car is off?) it says it idles at 38 psi and when i give it gas, it goes to 35. i think the gauge may be broken. do these numbers sound right?

i actually just rehooked the lines to the hobbs switch and tested it again. i may be going crazy but i think it worked in 2nd gear but couldnt tell when i shifted it into 3rd. in 2nd i punched it waited to go above 3 grand , then triggered the arming switch. it seemed to pep up a little then. i tried the sam ein third and couldnt feel a jump when i hit it, (which i think i should). i think i am just going crazy.

can i test the hobbs switch by starting the car and unhooking the line to the TB. then giving it full gas to see if it sprays?
about the 2 mustangs, this car is a LOT faster , i was talking about when hitting nitrous only! MAN, I should just go to the track and try it without a couple runs, then with it.

oh yeah i never changed the filter, the guy before me changed it about 7 thousand miles ago.

[1jimmy__d]

oh boy i come home tonight after being gone for about 5 hours and hear a hissing noise coming from under the hood. i pop the hood and notice that nitrous is leaking from the line that comes from the bottle to the solenoid!!! the whole solenoid is covered with ice and probably lost all my f-n nitrous. i tried to tighten it up to see if it would help, but it didnt. it must be coming from the connection that is directly touching the solenoid. maybe it needs to be tightened some or it needs some more sealent crap on there. what a pain in the ***. i am going to bring it back to the guy again tomorrow and see what this *&%$ has to say

Do you have the manual that came with the nitrous kit? If so, that should explain how to properly test the system. However...you could do it the way you said with the nitrous line removed from the throttle body. But then you'll have a big hole in your incoming air tube that would cause a big vacuum leak. Not sure if that would matter or not really? It could possibly affect the way the computer adjusts the timing & fuel...but don't quote me on that. A new Hobbs switch is cheap though. And you should be able to buy one from your local speed shop, or from the place that installed the system. Your 155lph pump should be sufficient for your 75 shot. Are you sure you have the 75hp shot nitrous jetting in there, and not possibly bigger jetting? Just a thought. But even with the 75hp shot you really should know if & when it is working. I mean...it's frickin nitrous! If your system is working properly...then you should definitely know when it kicks in. And you really shouldn't be using the nitrous under 2500rpms...3000 is even better. Your timing at 12 sounds fine. although it wouldn't hurt to put it at 10 just to be safe. You can always pull your plugs right after a nitrous run and try to get a feel for how the nitrous & fuel is burning in them there cylinders. I would seriously recommend changing your fuel filter. All it takes is one dirty tank of gas to clog that thing up. Even if the guy did change it just 7,000 miles ago...you should change it again. Just another thing to eliminate as the problem, you know.
As for the nitrous leaking out now, I'd seriously think about taking it somewhere else to have your system checked out. But being that you already paid this other shop I'm sure...you'll probably want to go back there first and demand that they get this thing running correctly. A nitrous system is fairly easy to install. I can't belive yours is leaking. I hope this mechanic knows that he should be using liquid teflon on all the nitrous connections and not teflon tape. That crap can clog your solenoids and then you'll have to get them rebuilt. Is this system new? If not, then maybe you do need to have your solenoids checked for dirt and gunk and get them rebuilt. It's not that expensive. Sorry this is so long. Try to answer my questions about the manual and whether or not this system is new. don't worry...we'll get this thing figured out.

[1jimmy__d]

hey simi! I do have the manual for the kit and the kit was in my other car, which worked only a few times. i changed the fuel filter yesterday but havent tried it out yet. i am not sure how much nitrous is left after it leaking out that other night. i ended up just tightening up the actual bolt that is on the solenoid. the kit was pretty much already assembled from being in my other car. he did use the appropriate teflon as well. i hope with me tightening it up that things may work. i am not sure if my fuel pressure gauge under the hood is working or not. it is at 37 when at idle and when given more gas, it drops down a little then goes back to 37. after shutting the car off it goes down to 15 after a long while, but never 0, (should it?) I am going to go tonight to a guy who has a fuel pressure gauge i can hook up to the schrader vavle and see what the pressure is for sure. I tried adjusting the fuel pressure through the FPR by BBK, but that didnt work ou to well. When i went to loosen the nut to adjust the allen wrench screw, it would turn both at the same time! PLus it didnt seem to adjust the fuel pressure at all according to the gauge. so now i may have really screwed up the pressure which is why i will take it tonight hopefully to see what it is idling at for sure. What should the pressure be, 40 at idle? and 80 with nitrous? If I have enough pressure and it isnt working still, i would say it is the hobbs switch. everything wlse seems to be working fine. now i may have to fill up the bottle again to be sure there is enough in there!!! Thanks simi, take care,

jim

oh yeah, if the solenoids are gunked up, would it spray only a little nitrous in there, or none at all?

Your fuel pressure should be at around 38psi. with the vacuum tube attached the the FPR. With the vac. tube disconnected I believe it's more like 42 or 43psi. So it sounded like yours "was" set correctly before you messed with it. Yes, it's normal for the fuel pressure to drop down a few psi. when you give the motor some throttle. As for setting the adjustable FPR...you have to use both a wrench (or socket) and an allen wrench. The nut locks the allen bolt in place. So you crack the nut loose with a rachet & socket, or wrench...then use an allen wrench to adjust the fuel psi. Then lock it down by tightening the nut, but keep an eye on the guage to make sure the proper setting stays where it should be. It's really pretty easy. But since you messed around with it now, it's probably a good idea that you are using your buddy's fuel pressure guage to properly set it. Did you say that yours is under you car?? If so, that is a strange place to have it. Mine is hooked up to my Schrader valve, like I mentioned before (I think?) with a T connector and the Hobbs switch on the other side of the T.
As far as the solenoids still functioning if they are gunked up...that's a tough call really, because you don't really know how bad they are...if they are even dirty at all. But when mine were jammed up with teflon tape, the system still worked some of the time. But the power seemed to be down and the system didn't work consistently. Good luck Jim. Keep me posted.

Shad-

[1jimmy__d]

Man, I must have just missed this post before i left. thats why i posted that other one. damn- Well after going to my mechanic (not the guy who installed it this time; a guy who does work for me on the side) I believe we figured out what the problem was. I arrived at his house at 9:30 and left at 1:00 in the morning. It turns ou that one of the solenoids wasnt working and the fpr needed adjusting. He disassembled the one bad solenoid and he thought it may have been caught up or something, then reassembled it. It worked fine after that. He also saw that there wasnt continuity with the hobbs switch. He adjusted the thing to where we saw continuity and then that worked. (this may not make any sense as it really didnt to me either last night ). anyways, we set the fuel pressure at 44 to make sure there was enough fuel, if i need to i can back it off to your recommended 38. I drove it home last night and it seemed to work I gave my mechanic 40 bucks which i think is cheap for the aggrevation that I went through (plus he said he only wanted 20 bucks). So i think I will keep the fuel pressure at 44 for the time being UNLESS you think i should drop it to 38 for sure

the gauge IS located on the schrader valve as well. I must have meant under the hood, not car.

Thanks for all your help SImi, I really appreciate it hopefully this will be the last post from me about this topic. If you could answer my LASt question (haha) about that fuel poressure, that would be great. Take care,
***** I actually just went and changed the pressure so it runs at 39-40 psi. I figured you would say to lower it anyways*******

Thanks again,

Jim

[Rick 91GT]

With N2O too much fuel is as bad as not enough fuel....both can damge pistons. I would suggest going back to the reccomended pressure and see how the plugs read, and go from there.

Glad you pinpointed the problem Jim. Sounds like that was it. As for the fuel pressure, definitely leave it at stock...even with a motor that sucks in more air & fuel then a stock 5.0...you still don't need to raise the fuel pressure above the stock setting. Your computer already does that for you when necessary. And the nitrous kit you are using is set up to work off of the stock fuel pressure setting...which, as you already know...it then boosts it up to around 80psi. to compensate for the nitrous. Glad to have helped you out. Let us know how the nitrous is working for you now...or some new track times when you get around to going. Take care.

Shad-