Need TPS help / nitrous not hitting

[redfirepearlgt]

I understand. I got burnt on a intake elbow and throttle body I bought off of ebay for my 2002 one time. The elbow was okay but the TB was junk. I bought a BBK 75mm and the car was fine and retuned fine.

That controller if working correctly will output 12vdc on the stage one output (red wire) when WOT is detected and greater 3000 RPM is seen based on your settings. So if its doing that with the red wire disconnected from the relay its working fine.

 

[darrens07gt]

Ok so I did some troubleshooting today. First I took off the fuel solenoid and aimed it into a bucket (nitrous bottle was closed and there was no N20 in the line). I touched the power wire to the battery and woosh gas sprayed into the bucket. Fuel solenoid working good. Next I filled the line with nitrous and got the pressure up. I removed the N20 solenoid and aimed it at the bucket. I had my better half touch the wire to the battery so I could have a firm grip and woosh. The N20 sprayed out like a pressure washer. N20 solenoid good.

Then I unhooked the NOS window switch and had my N20 hooked straight up to the arming switch. This is dangerous since there is no fail safe so I only sprayed 2nd gear and shut it down before a shift needed to happen. The N20 definitely hit. So now I knew the problem was still in the NOS WOT/window switch. So with the bottle off I hooked the NOS unit back up and watched the display as I drove. Everything looked fine. The rpm and voltage displayed matched what I expected it to be. Then I went WOT. The TPS voltage display only went as high as 4.5 on the display. At the engine it went as high as 4.9 so I set the switch to engage at 4.6. This was the problem.

I reset the switch to 4.2 and opened the nitrous valve. The N20 kicked on and the car drove like a bat out of hell on the 100 shot. Happy that the problem was fixed I shut the bottle off, refilled it at the speed shop and am now waiting for my dyno appointment on Monday morning.

I can't wait! Thanks for all the responses in this thread.

 

[slow06stang]

I'm glad it worked out for you. At least you had a good reason for settings being wrong. My problem was my own mistake.

 

[redfirepearlgt]

Ok so I did some troubleshooting today. First I took off the fuel solenoid and aimed it into a bucket (nitrous bottle was closed and there was no N20 in the line). I touched the power wire to the battery and woosh gas sprayed into the bucket. Fuel solenoid working good. Next I filled the line with nitrous and got the pressure up. I removed the N20 solenoid and aimed it at the bucket. I had my better half touch the wire to the battery so I could have a firm grip and woosh. The N20 sprayed out like a pressure washer. N20 solenoid good.

Then I unhooked the NOS window switch and had my N20 hooked straight up to the arming switch. This is dangerous since there is no fail safe so I only sprayed 2nd gear and shut it down before a shift needed to happen. The N20 definitely hit. So now I knew the problem was still in the NOS WOT/window switch. So with the bottle off I hooked the NOS unit back up and watched the display as I drove. Everything looked fine. The rpm and voltage displayed matched what I expected it to be. Then I went WOT. The TPS voltage display only went as high as 4.5 on the display. At the engine it went as high as 4.9 so I set the switch to engage at 4.6. This was the problem.

I reset the switch to 4.2 and opened the nitrous valve. The N20 kicked on and the car drove like a bat out of hell on the 100 shot. Happy that the problem was fixed I shut the bottle off, refilled it at the speed shop and am now waiting for my dyno appointment on Monday morning.

I can't wait! Thanks for all the responses in this thread.

You may wish to set that at 4.7 as the procedure says to set it 0.2vdc less. Glad you got it resolved. Now go see Brent and the boys.

 

[darrens07gt]

You may wish to set that at 4.7 as the procedure says to set it 0.2vdc less. Glad you got it resolved. Now go see Brent and the boys.

If I set it at 4.7 the nitrous would never kick on. The TPS wire in the engine bay may reed 4.9 V but the NOS window switch never gets higher then 4.5 but 90% of the time it holds steady at 4.4 V when I'm WOT.

Think of it like a cop using a radar gun on your car. The cops radar says 65 but your speedometer said 62. The only number the judge is going to care about is the cops radar of 65. My TPS is the speedometer, the NOS window switch is the cops radar and the nitrous is the judge. The nitrous only cares about what the NOS window switch says because that's what's activating it.

So for my situation 4.2 is the best I can set the TPS rise number to. I've confirmed my appointment for Monday morning so I'll post back with the numbers Monday night.

I'm hoping for 340 RWHP NA and 430 RWHP on spray. But we'll see.

 

[RocketcarX]

Think of it like a cop using a radar gun on your car. The cops radar says 65 but your speedometer said 62. The only number the judge is going to care about is the cops radar of 65. My TPS is the speedometer, the NOS window switch is the cops radar and the nitrous is the judge. The nitrous only cares about what the NOS window switch says because that's what's activating it.

Smooth Criminal

 

[redfirepearlgt]

If I set it at 4.7 the nitrous would never kick on. The TPS wire in the engine bay may reed 4.9 V but the NOS window switch never gets higher then 4.5 but 90% of the time it holds steady at 4.4 V when I'm WOT.

Think of it like a cop using a radar gun on your car. The cops radar says 65 but your speedometer said 62. The only number the judge is going to care about is the cops radar of 65. My TPS is the speedometer, the NOS window switch is the cops radar and the nitrous is the judge. The nitrous only cares about what the NOS window switch says because that's what's activating it.

So for my situation 4.2 is the best I can set the TPS rise number to. I've confirmed my appointment for Monday morning so I'll post back with the numbers Monday night.

I'm hoping for 340 RWHP NA and 430 RWHP on spray. But we'll see.

gotcha. So I wonder if that must be what the note in the TPS setting procedure was referring to then -

NOTE: Output voltage with the key on engine off of a drive by wire vehicle may be lower as these systems use the
throttle plate to control idle air instead of an IAC.

So did you initially read a higher voltage at the TPS source at WOT with your voltmeter than what the box was displaying at WOT? I understand what you had to do to make it work and that makes perfectly proper sense. Just trying to understand how 4.9vdc was originally read though only 4.5vdc is seen on the WOT/RPM display unit. Sounds like in the end its better to hook the unit up and go straight to key on engine off WOT and see the value on the display and set the WOT SP .2 below that (on a rise signal). Makes it easier as well. Less probing.

 

[darrens07gt]

gotcha. So I wonder if that must be what the note in the TPS setting procedure was referring to then -

NOTE: Output voltage with the key on engine off of a drive by wire vehicle may be lower as these systems use the
throttle plate to control idle air instead of an IAC.

So did you initially read a higher voltage at the TPS source at WOT with your voltmeter than what the box was displaying at WOT? I understand what you had to do to make it work and that makes perfectly proper sense. Just trying to understand how 4.9vdc was originally read though only 4.5vdc is seen on the WOT/RPM display unit. Sounds like in the end its better to hook the unit up and go straight to key on engine off WOT and see the value on the display and set the WOT SP .2 below that (on a rise signal). Makes it easier as well. Less probing.

All I know is I hooked up a voltmeter to the TPS wire in the engine bay and turned the key on (engine was off). In theory if someone pushed the gas pedal to the floor then the voltmeter should have gotten a signal. But in reality the voltmeter didn't react at all as long as the engine was not running. So I had a friend start the car and floor the gas in neutral. Obviously it would hit the rev limiter quickly but I was able to see the voltmeter had gone to 4.8 V by the time that had happened.

That's why I initially set my WOT switch to activate at 4.6 V. At the time I thought that was the accurate number to use. But then the system still didn't kick on. I had the window switch mounted on the passenger side under the glove box so I couldn't see it while I was driving. I re-located it to the dash just below the dip in the double brow (between the two vents). Now I can see it when I'm driving. So I disconnected the power wire to the solenoids so they would not kick on and went on a test drive with my nitrous activation switch on.

It's really kind of cool. The display on the window switch will actively show you what your current engine RPM is and what your current TPS voltage reading is. So at idle it was showing 800 rpm and 1.0 V. As I drove both numbers went up of course. When I went WOT several times on back roads I noticed the display would correctly show my RPM but only showed 4.4 V with an occasional 4.5 V for the TPS. I don't know why this is the case unless my voltmeter is off. Either way I was at least able to identify the problem. Once I reset the TPS setting to 4.2 V I had no more issues with the Nitrous not kicking on.

 

[redfirepearlgt]

To quote Gus Grissom...."F*CKIN A BUBBA!" Look forward to seeing some ET's once you get the tune dialed in.