Ok, after working with my C5 at our local dragstrip this weekend I tried the N20 100hp wet shot again and the same damn thing happened. A couple of weeks ago Speed inc tuned it for me and we tried spraying it on their dyno and it was breaking up or kinda stuttering about 3800 on up so Larry said it was running lean according to the A/F ratio so we bump up the fuel jet 3 sizes and it did the same thing. So he said the stock fuel pump couldn’t keep up and to buy LPE high-flow in tank fuel pump and it’d fix the problem, well I did and the problem still there. What do I do?
Here are my specs for the N20 stuff. I’m running NGK’s BR7EF’s gapped at .032” – it’s the 92mm Nitrous Outlet perimeter wet plate – bottle pressure is 925 psi - high flow fuel rails – FAST 36lb injectors – and I’m taking 6 deg of timing out with my LPE box when the Nitrous outlet single stage N20 controller tells it to activate. The controller seems to be working fine, TPS and window switch and gear lock out seem to work fine.
I guess my initial questions are,
1) The stuttering affect (not-popping) means its running lean still correct? (no I have not checked the plugs, I’m just going off of the same stuttering sound it made on Speed inc’s dyno)

1a) If so that means it’s a fuel delivery problem, how do I find out what needs to be changed/fixed?

2) Would it do the same thing if the timing was not retarding?

I’m just trying to diagnose the N20 problem before wasting another trip back to Speed inc to make a few more dyno pulls. Thanks for the help!

 

If u are going on the sound of stuttering now then are u sure your solenoids are opening. I had a similar problem and the nitrous solenoid wasn't opening everytime. Also verify you have correct fuel pressure

 

my opinion

Could unhook your nitrous and fuel lines to the plate to make 100% sure you got n2o and fuel going through the noids to the plate.
When it starts stuttering on the dyno shut it down and pull some plugs to see whats actually goin on in the cylinders.

Whats your fuel pressure drop to when spraying on the dyno? I'm sure you'll get it figured out

 

Pictures of setup? Are you using a Nitrous filter? Lines not kinked or crimped? Good Ground on noids? Using a FPSS?

My Nitrous was turning on/off (I was able to log the relay status and clearly see the relay was turning off and on), and it turned out to be the relay.

Jim

 

Funny you guys say that, i called Chris at Nitrous outlet and he thinks the samething like maybe the fuel line is clogged or not going through the plate etc. He also mentioned that since i am sharing grounds and positives for both solenoids that maybe the N20 solenoid is drawing all the power away from the fuel solenoid and its clicking on/off...... not to be stupid but how would i change that since there is only 1 12+ wire coming from the controller and a ground is a ground. All my connections are soldered.

I'll check all lines, grounds etc tonight. No FPSS but i do have a gauge on the fuel rail and its 58-60psi at idle, its a bit hard to see at WOT going down the track lol

 

Here's the results: I removed the N20 plate and set it on top of the engine with a towel underneath it, set the activation rpm at 2k and TPS off so it’d activate at low rpms and throttle barely on. Anyway with the bottle off it shot fuel out at a steady stream of all the little holes. So I turn the bottle on and it worked great as well, pretty much showered my garage lol. I even verified that the LPE retard light was working at that rpm as well. Basically everything was working perfect. So i set the window switch higher at 4k and even put the TPS on so i had to be WOT and once again it worked flawless.

So now what cuz everything seemed to be perfect, oh btw my wife verified that the fuel pressure did not change when the system was active. Although this was not WOT and not under a load.

Anyway I’m lost on what to do next.

 

I got my solenoids connected together no problems. Plus if its not going to work I would like for both not to work.

Is your your pick up tube in the bottle pointing down.

I know this might sound stupid but was the traction control turned off. My first time spraying the yesterday I forgot about it.

 

1) i agree, both solenoids clicked on just like they should
2) Yes both bottles have the tubes pointing back and down w/ bottle heaters work
3) Good question but yes the traction control was off, its the 1st thing i do before pulling out of the driveway lol

 

Can you veify the timing is being pulled by the box without applying the nitrous or fuel? IE unhook the dupply relay and still use the window switch and timing box. Or have the timing box remove the timing/be active before the window switch is made. You maybe getting a toggling effect by so much going on at once.

 

You could do that but you will have to check it with a light. That timing box won't report to the PCM.

 

As far as i know all i have to do is put 12 volt positive to the retard wire on the LPE box and it will activate the retard so i'd think it be pretty easy to check? There is one problem, how do i check the timing with a light since there is no timing tag to verify the timing?

Here is a question, how does that box pull the timing anyway considering its all plug and play and nothing taps into the PCM? It all plugs into just before the coils.

 

It takes the signal that fires the coils and delays it. Just like it will (if it's the two step box) cut ignition signals to the coils to hold rpm.

 

RYARBROUGH, i think your onto something.... the 2 step sound is very similar to the sound it makes when spraying it. It's like the 2-step is on but super fast stuttering, like an ignition stutter more than a popping.

One other thing i thought that Larry at SI thought of, what about unplugging the LPE box and just taking timing out at the ECU instead, he said he's heard of that problem happening with those boxes?

Another thing that just came to mind, i do have the coils relocated on this car and the wires do run close to the low voltage wires right by the coils but only for 3" or so. Plus i don't know how to change this if i had too as this is a far away as i can get these wires away from each other. Anyway, could these wires be doing this to make this happen? If so, why wouldn't it do it all the time and not just when i'm spraying it?