Xterra Turbo

[Crystle Rike]

Thiscar will NOT rev past 2K rpm's. Now I know the plugs, wires, cap and rotor are all old along with the gas that is in the car. I'm actually trying to run it out of gas and put some good stuff in it. I'm under the assumption that it is blowing spark out because it just isn't hot enough and yes, it does it even when the supercharger belts aren't on. I have NOT gapped the plugs down yet nor have I stuck a timing light on it after doing a cam swap. I haven't a clue what the cams are; this is my buddies car I'm building for him while he's in Afghanistan. It has a turbo ECU and currently no idle valve is hooked up (questions on that after this). I tried to read and understand the process of checking the codes but the thing flashes at me so much idk what I'm looking at LOL. The book says it flashes a 23, 24 and 31 but if not write down the trouble codes... So it flashes a 23, 24, 44 and 55 where if I remember right one is a crank position sensor (CKP) yet the other is everything is fine?!? I'm lost on that honestly...

As for the idle valve issue, I obviously can't use the stock one so I'm using the Xterra supercharger one. The problem is the 300zx books I have do not tell me which valves are the fast idle and which is the stepper valve. If I were to guess the larger of the two would be the stepper valve. Also, I haven't a clue which one is which on the Xterra setup either so I'm hoping someone can help me with this. Now, it is installed (and the car idles remarkably well even without it hooked up) but I'd like to get it hooked up and done correctly.

I have gotten rid of things such as the AAI valve (I think that's what it was up behind the drivers side headlight and disconnected the solenoid going to it) but I do have the solenoid for the FPR hooked up. Also the little valve on the passenger side of the plenum is no longer hooked up... I believe it was an air bypass valve is what they called it, and along with the EGR valve and solenoid are gone. Could this be causing my lack of RPM's noted in the last post?

P.S. In these videos it is running on the stock injectors. We have a set of turbo injectors but all of them seem to be DOA... I bench tested them and apparently they are all stuck closed. I haven't tried soaking them to get them freed up yet.

Well, I'm not real certain about the supercharger/xterra stuff, but usually if you're not able to rev past 2K then the engine is in Limp mode. Does it seem really rich at >2K rpm? If that's the case, then either your AFM is bad, or not being read correctly. You really need to get the FSM for the Xterra so you can try to figure more about what you're looking at. As for the injectors being too small, that shouldn't be stopping you from revving, it's just going to limit your power at higher RPM. since it's running you might see if you can find a Consult III that could read the actual codes and interpret for you. I assume you're using the stock Xterra harness / ECU etc too right?

We're using all turbo Z stuff, ecu and harness. Nissan didn't change much (i.e. the closed throttle/WOT switch and the 2 wire fast idle/stepper idle valve) so all i'm doing is wiring up the Xterra stuff to the stock Z harness. Someone else told me it sounds like limp mode and yes, it is very rich. I agree with the injectors not allowing it to rev but these are also the big Jim Wolf valves without the spacers installed on top of the valves... My buddy ordered them not knowing the springs and spacers were needed.

Like you said, once I get a service manual I can figure the rest out. I've read a couple different ways to test the codes so I'll do that sometime soon. I am starting to believe it is this limp mode so now I just need to figure out what will cause it, besides the MAF... Would a faulty crank angle sensor do so? I think it threw that code.

I haven't put a timing light on it yet but will be soon... I doubt it's too rich because i'm using the stock NA injectors right now. The turbo ones my friend got are shot... all stuck closed. Might try to clean them. Everyone that knows these cars is saying limp mode. I need to try another MAF.

They are Jim Wolf regrinds and my buddy didn't realize that you needed the spacers and springs. As far as I can tell the cam timing is correct but as I said, there are no spacers installed right now. We should be getting them shortly.

Well I assumed being a MAF setup it can handle the different cams with no major issues. The only thing I would think it would have a problem with is a major displacement jump or raised compression for any additional fuel computations it would have to make.

The timing is out as I have no timing marks on the crank. I basically have the ignition timing set to where it I pulled the most vacuum then backed it off 1in/Hg. I have a wideband on the car so I will be keeping an eye on AFR's. We'll only be running around 5psi so I'm thinking that what ever ECU we end up with will handle it fine. If not he can get something like that, or I can do a full standalone megasquirt or even just an FMU.

The Z31 turbo ECU is more than capable of adjusting for them. You can make anywhere from 170whp to 260whp on the stock Z31 ECU, and it'll still be rich as a pig at high RPMs in boost. But thats the issue, is its rich as **** and can't be relied on for the most power you can get.

No, I haven't replaced the MAF yet mainly because he doesn't have another one laying around, but also because the last month and a half I was fixing his Land Rover so he could drive it while on leave. Once we get another I will put that in, and also the JWT chipped ECU in with the turbo injectors... BTW, are the turbo injectors low/high impedance and the NA ones the opposite? Here is the run down because it is a lot easier to explain it this way.

Therefore I was trying to fire turbo injectors with a NA ECU and they weren't working. I was thinking if the NA ECU fires a low impedance pulse, then it might not be able to trigger the turbo injectors, therefore the injectors may still be good and I just have to swap the ECU's to get them to work.

P.S. If anyone has a working MAF laying around they aren't planning on using and wouldn't mind donating it to the project for a United States Combat Medic please feel free to PM me and I'll get you my address. I'll be sure to tell him who gave it to him.

All 84-87 injectors are low impedance, with 88-89 being High. Low Impedance ECU and trigger high impedance injectors, but if you use high impedance ECU on low impedance injectors you'll fry the Injector Drivers in the ECU.

Is there any way of telling which are low and which are high? The only things I can tell you are the car is an 87 and the turbo injectors we were trying to put in are red, the vacuum connector for the fuel pressure regulator points to the drivers side (we installed injectors and fuel rails) and the plug is different from the stock NA injectors (the little protrusion on the outside of the injector doesn't line up with the one on the stock injector plug). That last one will be the give-away I'm sure...

from what i can tell the parts will bolt up to the vg30 no problem, i would like to know what wich ecu i could use. any chance a xterra ecu would plug into the pathfinder harness? i would also like to know if i can retain my AC with the supercharger, and can the stock fuel pump keep up with with what ever sized injectors came on the xterra/frontier?

Go find a wrecked supercharged Xterra or Frontier. Take the engine, transmission (if yours is auto, if manual leave it), and the entire wiring harness and ECU. Put it all in your Pathfinder, a smaller supercharger pulley, and be happy with it.

Lets just cut to the nitty gritty here. There is no bolt-on and go, supercharger "kit". There have been several attempts by people, even one trying to market it(bad business failed). Because it is custom, its very hard to put a flat price on this mod. I do know that the Xterra/Frontier ECU will not just plug right in. There are some companies that do a computer upgrade that is a plug and play. They will even tune it for you depending upon what modifications you have. Now, Im not sayin it lcant be done(the supercharger), but it may not be as cheap as you are hoping for.

You'll also either need to cut a hole in your hood or install a 2-3" body lift to clear the supercharger. The internals of the engine are strong enough to handle about 400HP conservatively, it's a bad tune and detonation that blows them apart in a hurry.

If you don't have the time then dont do the project. You are looking at a huge investment in time or money. There are no shortcuts or kits. The easiest thing to do is to do the swap from a donor vehicle. You do not have a weekend project you have a get it going in a couple days, tune it in for 6 months project.

Why not a turbo? Cheaper, easier install and more power. STS turbo systems makes a universal kit that places the turbo where the muffler sits. Installed one on a 2000 z28 camaro. Night and day performance difference.

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