Recently had a nice size cam installed on my car and I hadn't run the car on nitrous until last night. It feels like it sputters up top, sort of like someone is hitting an on and off switch.

I don't have a FPSS. Could it be the nitrous in the bottle? I put the heater on for about 25 minutes because it is pretty cold out, but it still does it. It sort of lugs forward. Tuning?

Any help?

 

Well I don't know how you have your activation switch set up but when I first installed my nitrous the wide open throttle switch was not in the best location. You may just want to start with that, making sure that the switch is being depressed during the entire run. What was happening to mine was that during the shifts the motor would flex and the switch was not being pressed at all times causing the car to feel like the nitrous was coming on and off (sputtering). Just something to check. Hopefully it's nothing major. Good luck and let us know what you find.

 

I have the TPS WOT/Window switch. So I doubt it's anything related to that.

Thanks for the quick response.

 

Get a FPSS or a Lean Shut Down Switch......... If your fuel pump can't keep up your motor will be short lived..........$50.00 Ins. for the FPSS............

 

I have the Walbro 255

Theoretically, I should be fine...right?

 

that word is disaster waiting to happen.

What's your AFR, and fuel pressure while spraying? What was the bottle pressure?

 

Good question... I have no idea.

When I took it to get tuned, my bottle was empty and I was too far away from home to get it.

I want to take it back though to get it checked out.

 

I highly recommend a wideband 02 to keep tabs on things. Dynotune now makes a AFR shutdown switch that you can use with a wideband (or even a narrowband, but not as accurate). But at least you should have a FPSS.

 

sounds like bottle pressure

 

X2...

You dont have a pressure guage?

 

I don't think it's bottle pressure either. Barely had the bottle filled up when I sprayed.

Could it be my plugs? They have about 7K miles on them...but not a lot of spray.

 

you said it was cold...a full bottle can still have low pressure

# things are critical to the proper operation of your kit

Bottle pressure
Fuel Pressure
Air/Fuel Ratio

without knowing those 3 things we would all be guessing on what is going on.

 

I had the same problem I hooked the lm1 .my a/f was steady 11.5 to 1 when the spuddering was happening my a/f would drop to a 10.1 to 1