Need TPS help / nitrous not hitting

[darrens07gt]

I have an appointment for a dynotune at Brenspeed in less then two weeks so I need to have this problem diagnosed and fixed before then. I installed a nitrous outlet plate kit on my 2007 mustang gt. It is jetted for a 100 shot and has a bottle heater, purge and NOS window switch. The bottle heater worked great and built up good pressure. The purge worked good as well. But when I went WOT the nitrous just didn't seem to hit.

I'm thinking the problem is likely my NOS window switch. I bought it because it acts as both a window switch and WOT switch so there would be no need for a microswitch behind the gas pedal. I wired it all up per the diagram found in the owners manual found here:

http://documents.holley.com/199r10482rev4.pdf

I set the on RPM to 3000 and the off RPM to 6400. But when it comes to the TPS settings I had no idea what to program it at. I'm lost with the whole rising throttle and falling throttle stuff. Now I bought the window switch used from a member here so he had the TPS mode set up for whatever car he was running. I just left his values in it hoping he had a 4.6 like mine and that his settings would work for me. Perhaps they don't.

Does anyone have experience setting with the NOS TPS setup on a 4.6 3V engine? I bought a voltmeter but I'm not sure exactly where the TPS is to do the test. Any help would be greatly appreciated.

 

[Marble]

On mine (zex) there was a procedure to calibrate it. It involved arming the system and going WOT for a determined amont of time. No part throttle spraying for me.

 

[redfirepearlgt]

Brenspeed is doing custom tuning? Or Benspeed is loading one of their library tunes and then providing a dyno pull?

Sorry had to ask. Caught me off guard.

 

[darrens07gt]

Brenspeed is doing custom tuning? Or Benspeed is loading one of their library tunes and then providing a dyno pull?

Sorry had to ask. Caught me off guard.

Both. They pre-load a tune ahead of time and load it onto my car. Then they take a pull and see how it looks. They will tweak the tune and pull again to see if they made more power. Rinse and repeat until they are happy they got the max power the car is capable of while keeping a safe A/F ration.

At least this is my understanding.

 

[RocketcarX]

I would have a qualified shop or tech finish the install, just way too much at stake to fck it up.

 

[redfirepearlgt]

I set the on RPM to 3000 and the off RPM to 6400. But when it comes to the TPS settings I had no idea what to program it at. I'm lost with the whole rising throttle and falling throttle stuff. Now I bought the window switch used from a member here so he had the TPS mode set up for whatever car he was running. I just left his values in it hoping he had a 4.6 like mine and that his settings would work for me. Perhaps they don't.

Does anyone have experience setting with the NOS TPS setup on a 4.6 3V engine? I bought a voltmeter but I'm not sure exactly where the TPS is to do the test. Any help would be greatly appreciated.

This again is not rocket science but it will require a voltmeter and two people to set up and verify, as well as the ability to use and read a volt ohm meter.

Make sure the device is set up for a rising TPS value.

Simplest process to obtain your TPS WOT VDC value -

Get a straight pin and push in into the back side of the TPS connector so you have something to place your lead on. (DO NOT ALLOW THE STRAIGHT PIN TO TOUCH ANYTHING METAL!) This is referred to as "back probing". Have someone press the throttle to the floor with the key on / engine off (do not start the car). The throttle will go to WOT. Take the voltage reading and record it. (make sure the voltmeter is set to VDC.

BTW - if you notice the example photos in the procedure use a 4.6L 3V.

Now you have a value. Say its 4.7vdc. The procedure says to subtract 0.2vdc from the WOT value. 4.7 - 0.2 = 4.5vdc. Program this value into your device where the procedure tells you to. Now your WOT reference set point has been established.

So what has been created is a truth statement. You have a WOT setpoint value of 4.5. You have a rising RPM on value of 3000.

TRUTH STATEMENT -
IF TPS equals 4.5+ and RPM equals 3000+ THEN NOS RELAY ON. ELSE OFF.

This means that in order for the device to turn on your NOS relay which fires the solenoids The throttle position must be equal to or higher than 4.5VDC and the RPM must be equal to or higher than 3000 RPM.


Follow the procedure in the section that walks you through checking the final operation. You will do that without attaching the plumbing to the TB.

It really should be that simple. BRENSPEED if they are smart will still verify the settings before loading the tune and doing a live hit. I would expect them to double check your work and settings before any tune has been added, then again after the tune is installed. It would not be wise customer service not to take anything like this as a given when so much is at stake. So if they check your work don't take it personal. Some would. It's just protecting one's back side.

The NOS procedure is very well written. Take the time to review it. Follow the guidelines and you will be fine. My assumption I that your TPS setting is not correct or the connection is poor. Otherwise if all is working and you are getting 12 vdc on the red wire to the relay, the relay or solenoid is faulty.

Hope this helps. Whatever you do, DON'T do a live test hit without that car having the proper tune in it no matter how tempted you may be.

Good luck. I foresee many trips to the speed shop in your future.

 

[RocketcarX]

Brenspeed will not check his work as it makes them liable if it blows up, I can almost gaurentee that.
He would need to pay them to finalize the install in order for them to assume that level of liability.

 

[redfirepearlgt]

Brenspeed will not check his work as it makes them liable if it blows up, I can almost gaurentee that.
He would need to pay them to finalize the install in order for them to assume that level of liability.

Good point. I dealt with them years ago. I should have known better than to think that. LOL!

 

[darrens07gt]

This again is not rocket science but it will require a voltmeter and two people to set up and verify, as well as the ability to use and read a volt ohm meter.

Make sure the device is set up for a rising TPS value.

Simplest process to obtain your TPS WOT VDC value -

Get a straight pin and push in into the back side of the TPS connector so you have something to place your lead on. (DO NOT ALLOW THE STRAIGHT PIN TO TOUCH ANYTHING METAL!) This is referred to as "back probing". Have someone press the throttle to the floor with the key on / engine off (do not start the car). The throttle will go to WOT. Take the voltage reading and record it. (make sure the voltmeter is set to VDC.

BTW - if you notice the example photos in the procedure use a 4.6L 3V.

Now you have a value. Say its 4.7vdc. The procedure says to subtract 0.2vdc from the WOT value. 4.7 - 0.2 = 4.5vdc. Program this value into your device where the procedure tells you to. Now your WOT reference set point has been established.

So what has been created is a truth statement. You have a WOT setpoint value of 4.5. You have a rising RPM on value of 3000.

TRUTH STATEMENT -
IF TPS equals 4.5+ and RPM equals 3000+ THEN NOS RELAY ON. ELSE OFF.

This means that in order for the device to turn on your NOS relay which fires the solenoids The throttle position must be equal to or higher than 4.5VDC and the RPM must be equal to or higher than 3000 RPM.


Follow the procedure in the section that walks you through checking the final operation. You will do that without attaching the plumbing to the TB.

It really should be that simple. BRENSPEED if they are smart will still verify the settings before loading the tune and doing a live hit. I would expect them to double check your work and settings before any tune has been added, then again after the tune is installed. It would not be wise customer service not to take anything like this as a given when so much is at stake. So if they check your work don't take it personal. Some would. It's just protecting one's back side.

The NOS procedure is very well written. Take the time to review it. Follow the guidelines and you will be fine. My assumption I that your TPS setting is not correct or the connection is poor. Otherwise if all is working and you are getting 12 vdc on the red wire to the relay, the relay or solenoid is faulty.

Hope this helps. Whatever you do, DON'T do a live test hit without that car having the proper tune in it no matter how tempted you may be.

Good luck. I foresee many trips to the speed shop in your future.

I tried this at autozone and it did not work with the car off. But when I started the car and went wot the reading was 4.8 which is what I was told to expect.

So I checked the NOS window switch and it is set to 3000 on, 6400 off, rising tps 4.6V and 8 cyl. In theory it should be working. But all I can do is heat up the bottle and purge the line. The system does not hit. So now I need to check all the wiring and solenoids. This is what I get for buying a used kit.

I'm thinking of disconnecting the NOS window switch and wiring up straight to the arming switch just for a quick test. I'll get up to 30 mph in 2nd gear and gun it/arm it to see if the nitrous hits and then shut it down before I wound need to shift into 3rd. If the nitrous hits then I will know the problem is related to the window/wot switch. If it doesn't then I'll know the problem lies elsewhere like a bad solenoid or something.

 

[RocketcarX]

Test it with no nitrous in the lines and just see if the controller clicks the solenoids. Let go as soon as you feel them click so they don't overheat.

 

[46addict]

Brenspeed will not check his work as it makes them liable if it blows up, I can almost gaurentee that.
He would need to pay them to finalize the install in order for them to assume that level of liability.

Isn't that standard practice at all shops, not just Brenspeed?

Going back on topic, I would check the basics first. Double check to see if the relay (if you're using one) is wired up and grounded properly and make sure the switch/ground/power wires are connected to the correct pins.

 

[RocketcarX]

Isn't that standard practice at all shops, not just Brenspeed?

That is the perspective I am coming from

 

[redfirepearlgt]

Did you check to see if the tan wire is correctly landed on the COP trigger wire? If the NOS unit does not see the RPM value it will never function either.

At this point I would apply 12vdc to the stage one wire that feeds the coil on the relay. make sure the red wire is disconnected from WOT/RPM module so you don;t back feed 12vdc into the unit just to be safe. This will test the function of the relay and the solenoid which is what you were thinking about doing to begin with. If all of that is working it may be time to see if NOS will give you a hand. Often times good companies will lend a hand to a second hand buyer knowing eventually they will gain something from it. Post back when you find out more.

 

[redfirepearlgt]

Good luck btw

 

[slow06stang]

Not sure on nitrous setup if it has similar types of settings as a wot box. At one point I changed some settings on my wot box and had weird issues. I don't remember if I inverted the clutch or changed a voltage threshold. Nothing bad came of it but it definitely had me baffled as to the symptoms. Good luck.

 

[darrens07gt]

So here is where I am at:

I replaced the relay just for the heck of it with a brand new one. Before I hooked the 12V power source cable for the solenoids to 87 of the relay I touched it to the positive terminal of the battery to see if I could hear the solenoids click. I definitely heard the N20 solenoid click. Not sure about the fuel one

Next I re-checked all my settings on the NOS window switch. This is when I indeed found a problem. The TPS was fine but the ignition signal was off. The display of the window switch should be showing the cars current RPM whenever the car is running. So at idle it should be showing me between 750 and 1100. It was showing 135. I double checked the wiring and they seemed to be fine. Then I called NOS technical support and they found an issue with my setup. The previous owner of the window switch set the ignition input signal to "08" for 8 cyl. This seemed logical except that only applies to cars with aftermarket MSD ignition systems. Mine being stock should be set at "00".

After I re-set the value to double zeros I noticed that my display was now showing the correct rpm while the car was running. That was it!!!!

Or so I thought.

I went for a test run with the bottle heated up and I still felt nothing. I don't have any way to officially test it so I picked two landmarks on the road and did an NA WOT run from 20 mph in 1st and noticed I hit the 2nd landmark at 100 mph while shifting into 4th gear. I went back and did the same run and once again with the N20 engaged and again I was shifting at 100 mph into 4th gear at the second landmark.

One step forward and two steps back.

 

[redfirepearlgt]

So here is where I am at:

I replaced the relay just for the heck of it with a brand new one. Before I hooked the 12V power source cable for the solenoids to 87 of the relay I touched it to the positive terminal of the battery to see if I could hear the solenoids click. I definitely heard the N20 solenoid click. Not sure about the fuel one

Next I re-checked all my settings on the NOS window switch. This is when I indeed found a problem. The TPS was fine but the ignition signal was off. The display of the window switch should be showing the cars current RPM whenever the car is running. So at idle it should be showing me between 750 and 1100. It was showing 135. I double checked the wiring and they seemed to be fine. Then I called NOS technical support and they found an issue with my setup. The previous owner of the window switch set the ignition input signal to "08" for 8 cyl. This seemed logical except that only applies to cars with aftermarket MSD ignition systems. Mine being stock should be set at "00".

After I re-set the value to double zeros I noticed that my display was now showing the correct rpm while the car was running. That was it!!!!

Or so I thought.

I went for a test run with the bottle heated up and I still felt nothing. I don't have any way to officially test it so I picked two landmarks on the road and did an NA WOT run from 20 mph in 1st and noticed I hit the 2nd landmark at 100 mph while shifting into 4th gear. I went back and did the same run and once again with the N20 engaged and again I was shifting at 100 mph into 4th gear at the second landmark.

One step forward and two steps back.

Great. All troubleshooting seemed to be pointing back to the settings on the unit OR the tan wire not getting proper signal from the COP trigger wire you attached it to. I would have been pulling my hair out as well with the 08 setting. Glad you got it all working. Now its off to Brent and the boys.

So do you run at Route 66? Just curious. I have some old acquaintances in the Aurora area that run there.

 

[darrens07gt]

Great. All troubleshooting seemed to be pointing back to the settings on the unit OR the tan wire not getting proper signal from the COP trigger wire you attached it to. I would have been pulling my hair out as well with the 08 setting. Glad you got it all working. Now its off to Brent and the boys.

So do you run at Route 66? Just curious. I have some old acquaintances in the Aurora area that run there.

I think you missed the part where the nitrous is still not hitting. I found and fixed one problem but apparently there is still another issue yet to be identified.

I have run at Rt. 66 but not with this car. Last time I ran there was with my 99 LS1 Trans Am. That car was setup for drag racing as it had an automatic, huge torque converter and mickey Thompson drag radials. I was running mid 11's with 1.5 - 1.6 60's.

I hope to run this car there soon but I have no illusions of this car doing as well as my Trans Am did. This car's a stick, it has 20's all the way around and the 3V is no where near as good a performer as the LS1. 5.0 is a different story but I don't have a coyote so I'll just have to do the best I can with what I have.

 

[redfirepearlgt]

I think you missed the part where the nitrous is still not hitting. I found and fixed one problem but apparently there is still another issue yet to be identified.

I have run at Rt. 66 but not with this car. Last time I ran there was with my 99 LS1 Trans Am. That car was setup for drag racing as it had an automatic, huge torque converter and mickey Thompson drag radials. I was running mid 11's with 1.5 - 1.6 60's.

I hope to run this car there soon but I have no illusions of this car doing as well as my Trans Am did. This car's a stick, it has 20's all the way around and the 3V is no where near as good a performer as the LS1. 5.0 is a different story but I don't have a coyote so I'll just have to do the best I can with what I have.

YIP I missed that. Was a long weekend at NMRA Bowling green Saturday. Just curious if you have verified you have pressure through the line and out the jet when the solenoid is commanded on or over ridden as you did to test it dry? Just because a solenoid fires electrically doesn't mean its opening mechanically. I've had electrically actuated solenoids at work stick closed even though they are firing electrically. May wish to check into that. Brake Line lock systems have been known to have similar problems over time with the solenoid energizing and not firing.

At least its getting closer. If i were closer I'd come give you a hand with it.

 

[darrens07gt]

YIP I missed that. Was a long weekend at NMRA Bowling green Saturday. Just curious if you have verified you have pressure through the line and out the jet when the solenoid is commanded on or over ridden as you did to test it dry? Just because a solenoid fires electrically doesn't mean its opening mechanically. I've had electrically actuated solenoids at work stick closed even though they are firing electrically. May wish to check into that. Brake Line lock systems have been known to have similar problems over time with the solenoid energizing and not firing.

At least its getting closer. If i were closer I'd come give you a hand with it.

Well my plan right now is to check the solenoids first. This time I'm going to go further then just listening for the click. I'm going to remove the solenoids from the plate and aim them into a 5 gallon home depot bucket. Then I'll have someone touch the positive battery terminal with the solenoid wire. I'll hear the click but this time the gas and N20 should spray into the bucket. If one or both does not then I'll know I have a bad solenoid(s). If they do both work then I'll check the plate to make sure it's not clogged somehow. After that I have to start looking at the window switch again.

It was a used kit and that was my biggest mistake. This is not the type of mod you should buy used. I'm learning that the hard way.