Well this year I started doing performance mods to my car. The first thing I bought was my Zex Dry Nitrous kit - w/ 75shot jet. I wanted to be on the safe side so I did some researching on here to see what was required to run this kit. I ended up with a list of
1: Zex Kit
2: Walbro Fuel Pump
3: FPR
4: Air Fuel Gauge
5: Fuel Pressure Gauge
6: SAFC(optional)
7: Upgraded Injectors(optional)

I went and bought all of this except the injectors. I read that I could get by without them.
Well I installed everything and found that my Air/Fuel Gauge wouldn't work, after doing some checking I found my O2 sensors were bad and assumed this was the problem. I got new sensors in, and replaced them. But the gauge is still jumping all over and not giving a true reading.(problem number 1)

I am borrowing a friend of mine's A/F gauge to see if maybe there is something wrong with mine, but in the mean time, figured I would get everything else ready. Well I tried to increase my fuel pressure and started having more problems. I understood it that if I want to run a 75shot dry, I need approx 68-70PSI at WOT. Stock fuel pressure is supposed to be 36PSI and 40PSI at WOT or something close to that. so I started by setting my fuel pressure at that. Well now my car seems to be flooding when I first start it. I have to let it warm up before I drive anywhere or it will quit on me. Well all of a sudden at the first of this week, the problem went away and the car was running great. I had no problems with it flooding at all. I thought maybe the ECU needed time correcting something? seemed far fetched, but I hoped that was all it was.

So later on that week I upped my fuel pressure again, hoping to finally get to shoot off the nitrous. Well after setting the fuel pressure at 55PSI and just giving it a shot of gas, I noticed that the car was spark knocking.(problem 2) I dropped the fuel pressure back down and my car started flooding when I started it again.

The next day I had off, I decided to change the knock sensor. I had already ordered a new one because mine was throwing ghost codes, so I figured I better change it ASAP. I changed the sensor, and ran the car for a couple days with the same pressure, no problems except the flooding.

Well today I put the fuel pressure back up, and the car is knocking again. I put the pressure back down, but the knock is still there.(still problem 2) On top of that, I now hear a noise that sounds like a click/spray noise. it sounds like a tick then psssstt.(problem 3) It almost sounds like it should be the injector.

Can I run less fuel pressure and just tell my SAFC that I have more air coming in? wont that increase the injector pulse and let more fuel in?

I am about to give up on my car before I blow it up and its not worth anything.
Does anyone know what might be causing some of these problems? Any suggestions at all?

I'm starting to think that maybe I should have just left my car running the way it was and just make it look nicer.

Thanks guys,

M

 

Well I changed my fuel filter...that was the only thing I didn't change and that fixed the flooding/lean problem. plus that let my fuel pressure drop now that it had more flow.
So now all those problems are fixed except the spark knock. I still can't figure out why its doing that. I'm running higher octane gas and ran a bottle of fuel injector cleaner through it, but still getting the problem.
I'm going to pull the plugs tonight to make sure all cylinders are firing properly.

I was talking to a fellow max owner and he suggestion it was a coilpack. Is there any chance it could be a coilpack going bad, causing no fire in a cyl making it knock.
I would figure it would just miss if it was.

 

Probably irrelivent to your problem but what spark plugs are in there right now?

 

You have pretty much everything you need and yes I wouldn't upsize the injectors either for nitrous.

I would recommend you go down to the lowest shot you have jets for and see if you still have the problem.

Second I wouldn't try and tune with an A/F meter from the stock o2 sensors, they are only accurate for N/A a/f ranges ie 13-15 not for where you want to be with nitrous in the 11-12 range. Use a wideband and forget the A/F using the stock o2's.

Also I am not sure I understand when you say "I upped the fuel pressure" are you referring to wot setting N/A or when spraying? If you are referring to increasing it while spraying then the pressure increase has to come from the fuel jet not the fpr. The fpr only regulates N/A fuel pressure only.

You could run less pressure and increase using S-AFC but that is not going to change anything if you still run the same A/F ratio.

You really shouldn't need an S-AFC to run nitrous. I use it because of the high shot I use (ie 150) to keep it even across the band but this is the first I have even used it because I didn't have a wideband.

PS As Nismo asked, what plugs are you running. I you are running platinums that can cause your problem. Run copper plugs gapped at .035.

 

Why are you bumping up your fuel pressure? Your ZEX kit has the fuel pressure line in and line out on it. You need to follow the directions sent to you by ZEX when you hooked it up. The vac line going to your FPR goes to the box and back out goes back to the fpr (basically so the box is between the vac and fpr)

The Zex nitrous kit increases the fuel pressure when your spraying nitrous. You DO NOT increase it manually on your car. You should never change your base fuel pressure anymore than 3-5psi to compensate for NA mods. Nitrous kits operate totally on their own and do not require any adjustments to the stock fuel pressure level. Leave it alone.

If you do not have the vacume hooked up through the ZEX nitrous control unit as I described above (as the manual says that you received with the kit) then you have not hooked the kit up properly.


It sounds like your spraying with no added fuel (turning up your base fuel pressure is not the correct way to do this!!!!) The nitrous kit does it automatically, or SHOULD.

Dear god no. Don't mess with stuff like this. This is how motors get blown up and people blame it on nitrous when it is the installers fault. Please please please go and read your ZEX manual.

If you do not undersatnd the whole vaccum line setup through the Zex nitrous control unit like I said you need to call zex and read the manual because it's not setup properly. If you do have it setup like that then the kit will operate just fine on it's own, it will bump fuel pressure accordingly. If your hearing knock and it's setup properly then you have other problems it's not the nitrous kit. You can try adding in some fuel at the RPM level your having a problem at. Go in 3-5% increments on your SAFC only at that RPM level until your satisified.

How do you know your getting knock?

 

Sorry haven't been quite busy lately to reply. Sorry for being such a noob, but I was trying to do things the "correct" way and I guess just didn't even come close.

I'm running NGK Coppers for Spark Plugs gapped at .40
so I should gap these to .35 instead?

The smallest jet I have is a 75 shot, I tried ordering smaller ones from Zex, but had an extremely hard time doing so and still couldn't even get them ordered because they wouldn't deal with me because I'm canadian with a canadian credit card.

I can hear the knock with my ears its so loud. I've had a few mechanics listen to it and they tell me its a spark knock. I'm getting the knock without even running the zex kit. I wanted to make sure I could get the mods running right before I even bothered using the kit.

I hooked the vac lines up like this. I had my fuel pressure set to 38psi and 45 at WOT and when I turned the kit on(with the bottle off) and hit my WOT switch, my fuel pressure didn't go up at all. so I assumed I had to increase my base fuel pressure instead.
So I assume either its a bad control box, or a have a pinched vaccuum line somewhere?

my kit didn't come with a manual and I haven't been able to get on zex's website in months, not sure if its just the firewall we have at work. I called Zex and they just tell ya to go look on the website.

I'm going to go re-gap my spark plugs and drop my fuel pressure back to stock pressure and check for any pinched vaccuum lines.

Thanks guys,

 

.35 would be the minimum you would want to run. Even try .30 for kicks. Going smaller will not hurt you ever, going larger will. Are you running a colder plug? (higher number like 7 or 8?)

75hp is nothing for your motor, don't worry about that.

If you have knock loud enough you can hear it, it's likely no knock but something else.

Thats because with the bottle off hitting the WOT switch does a whole lot lot of nada. THe system uses nitrous pressure through the vac line to the FPR to create the extra pressure on the diaphram to keep it closed in order to bump up the pressure. With the bottle off nothing happens just as you noticed. If the kit did that all the time then you woudl end up with 60-70psi of fuel pressure at WOT when your not spraying.

Yes re-gap start at .35 go to .30 even and try it (and in between) Spray it then shut the motor off and cost to a stop and read the plugs. Should look liek chocolate milk to black even. No biggie either way. White or gray is problems. Put your fuel pressure back to stock as well. Make sure your using a spark plug one range colder than stock for a 75hp shot. SOmebody else on here can tell you what it is. (BKR7ES probablly...)

 

I'm running 1 step colder plugs BKR6EIX-11 I believe is the number
I'm going to fix my pressure and regap today and try to spray. I'll post the results. Thanks very much DSMJim

 

OK, I tried the kit last night. the fuel pressure went up to about 70-72 and gauge showed 2 bars into rich. Not sure how accurate the gauge was reading though.
I stopped spraying and shut off the car, coasted to a stop and checked the plugs and they were as black as they were before I started spraying. I tried it a few times and checked it each time with the same results.

I'm impressed at how it worked even though I only have 600lbs in the bottle. I can't wait until I get a bottle heater and boost that up to 1100lbs

Thanks for all your help guys, expecially DSMJim!

It now feels great to be in the spraying world, even if I'm just starting off.

 

which Zex dry kit are you using? I was lookin in their catalog and they dont seem to make a dry kit for the max...

 

I just have a universal dry kit. It came off an integra, but seems to work fine for the max.

 

So, did you by the kit from ZEX, or some guy with an Integra?
As far as black plugs go, get your bottle preasure up and it should lean the A/F out a bit.
As far as your credit card goes it doesn't matter where it was issued, they're international.
If you want smaller jets, find a local speed shop and go get some. Doesn't matter what the brand name is, they will interchange.