.....and we are stumped. Basically right now, the car will not start. It's like its flooded. Shows the symptoms that would happen if the intake piping after the maf were to come loose.

So basically here is the scoop. We are re-boosting the car. Install V2 SCer, 2.87 pulley, 370cc 300zx injectors, MEVI, and JWT ECU with S/C and 370CC program. We also removed the Cartech FMU that was in there car. It still has the S-AFC, and T-Rex aux fuel pump. Anyway, at first startup, we seem to have a issue with the S-AFC not functioning properly, it seemed to either loose the RPM reading, or the power would fluctuate and cause the motor to die. We resecured the wiring and it seemed to be fine. Started the car and it ran fine. Had a few issues with oil feed line on the S/C leaking, but that was resolved. So today we started the car again, let it run, check everything for leaks, took the car around the block, made a turn and the car dies. Turns out a clamp on one of the silicone couplers worked it's way loose. Fixed that, start car and it's fine again.

So we take the car out. Seems to be running real nice, idle smoothed out and decided to do some spirited runs. The car ran so much smoother than it ever had. Car pulled strong and hard. 1st gear is totally useless, and we can break the wheels loose in second at 55 mph. So we drive around when suddenly, the idle starts getting rough. We drive some more hoping it would clear out, then the motor dies. First thing we thought was charge piping came loose. Nope, everything was fine. So we though the S-AFC wiring came loose again....we spend a good amount of time playing with it, during this time we could get the motor started, but it would not stay idling for long. Eventually we decided to check the maf, so we pulled it, and notice something was rattling. Luckily Ian had a spare. Got that in, start the car and it runs fine for about few minutes, and then idle goes to hell and the car dies. We tried messing with the S-AFC wiring again, sometimes the car would start, but it won't stay idling for long again and it would sometimes backfire really bad.

We noticed the air temp sensor came loose, but we plugged it back in and it didn't help anything. We've tried swapping out the ECU, redoing the S/C piping, even bypassed the S-AFC all together with no luck. The car happens to be at a Nissan service center coincedentally, and we've borrowed the Consult, but we can't get the car running long enough to take readings. Only able to pull codes from the ECU. Now the car is at a point where it sounds like it's trying to fire, but it won't even run. It seems like the car is running rich, but we pulled a plug and haven't notice any fouling except for maybe a tiny bit of carbon buildup. Right now we are stuck with no freaking clue of what's happening.

Anyone have ideas?

S

 

Those symptoms are the exact same I experienced a few weeks back. But my problems were due to my MAF wiring (had to extend it for the turbo). Once we rewired that, all my problems went away. since you've already swapped MAF's, I have no clue as to what may be causing it. What codes are you getting from the ECU?

 

well, I believe it we got Upstream Oxygen Sensor (0101) Ian checked the CPS harness as it seems that that code is related to the CPS and it appears to be fine, Intake Air Temperature Sensor (0401) which is taken care of because of the loose harness, and EGR Solenoid (1005). I tell you this is wierd. At first I though maybe it had to do with something with the 370cc injectors because I notice some of the guys here had problems with it being to rich during idle and they had to turn down the base pressure, however, Ian is running a JWT ECU programmed for the 370cc injectors, so that issue should be a factor. I dunno, this thing has me so freakin clueless it's hurting my head.....I never get this stumped.....maybe a good night sleep will help.

S

 

What maf (A32 or Z32) is the JWT ecu programmed for?

Have you done a compression test?

 

Tested compression last night - 185 across all cylinders.

Baggs who sold me the ECU and JAY25 who checked it out for me tell me that this ECU previously was on a car with a stock MAF and 370cc Injectors.

Last night we got ahold of a Nissan Consult and were able to test what we could with out limited knowledge of the Consult.

Tested MAF - OK
Tested Injector Cycle - OK

We then used a noid light to verify Injector Cycle - OK.

Used the old spark plug grounded to the manifold trick to check for spark. - It was a small blue spark. Looked good, but not the big spark I expected.

Checked and Re-Checked every part of the SC Piping, manifold conneciton to the engine, sprayed soap and water everywhere.....no air leaks detected.

At this point the car doesn't start whatsoever. I'm pretty sure the MAF was never the problem now. If it was the MAF, then the car would at least start and rev to 2000 before choking....

So I'm at a loss. My car is sitting at a Dealership (auuugh). They won't even look at it because it's modified. Even if they would touch it, they'd just tell me it's because it's modified then charge me $110 for "Diagnosis" (Yes- shops in Seattle charge $110 per hour.)

 

I was playing around with my SAFC once and got it into a mode where the car wouldn't start, and another time when it would start but didn't run very well at all. Have you double checked your SAFC settings to be sure they're all correct? Better yet, remove it altogether and see if that makes a difference.

 

The stock maf is good for a flowrate able to produce up to 350 hp (at the flywheel). With a 2.87" pulley, you are probably going to be over that amount. You should contact JWT to see what they say about your setup.

 

SAFC was removed completely. - it's not even attached to the car anymore.

 

This ECU came from a max with a 2.87 pulley and no FMU. He was running an aux fuel pump thats the only fuel attachment it had.


Ian this car had the MAF on the non charged side, dont know if that makes a difference I do have similar pipes to those for my 5th gen SCer. If you want to swap out piping to install your MAF on the non charged side let me know and we can swap out. I want to install this 5th gen blower on my 95. Whats stopping me is the piping. I just ordered new pipes from stillen last night. Let me know or call me 678 655 6190


Jaime

 

Confused has the 370's and stock MAF, MAF is on the pressurized side...

Ian do you think you may have grounded something in the harness when messing with the AFC?

 

I was thinking that and that's one of the reasons I removed the AFC taps - so I could see the harness better.

Looking at the harness to ECU connector, nothing looks frayed or damaged or pulled out. I'm just not seeing anything wrong there.

There is a possibility however that the CPS is grounding out on the SC bracket. I looked last night and it looked OK, but it was dark. I'm going to go take a look at that in a few minutes hopefully (if I can get away from work).

From reading threads past, I believe the ECU doesn't care whether the MAF is on the charged or non-charged side. It's only a matter of whether or not the HP can blow the MAF. I never boosted past 10PSi however, so i don't think that's an issue.

JAY25 - I'd like to move it to the non-charged side. Is the 5th Gen piping what I need?

That would suck because I just had this piping Chromexed!



IanS

 

I just remembered you did that to them pipes you chromed them. Yes its the 5th gen pipes therefor you can have the same set up like he had.

 

OK - I'll consider it. It all depends on what comes of this. I'm pretty sure the MAF is fine however. I also don't htink I'll be over 350hp....but we'll see.

I'll let you know. Maybe if I charge you for the price of chromexing we can trade then I'll just get the 5th Gen ones Chromexed?

IanS

 

last time my car had an idle problem similar to your i had a bad upper intake manifold gasket. the first one snaped due to age secound one got stretched out from spraying brake cleaner around the gasket to look for vacuum leaks. my car would idle really rough and ofter ended up stalling if i didn't keep the rev up at a light. eventually the gasket being stretched ended up poping out a little on the back side of the manifold under neath the runners. by that time i had a major vacuum leak that i could hear in the car.

hope this helps.

 

Yep - the vacuum gauge the one time we did get it started for 20 seconds or so said 19Hg - pretty good.

Now, the car literally won't start at all. Just cranks and cranks and cranks.

 

That's 350 at the engine- 290 at the front wheels. I think you'll be well over that with a 2.87" pulley on a V2, and a MEVI.

 

I'm thinking crankshaft position sensor. Or maybe the cam timing sensor wires got shorted during the bracket install. Just shooting in the dark, here.

 

Did I miss something?

Or are you not talking about me?

 

I think he meant Brodaiga. Also the car is running again. Looks like one of the CPS wires rubbed on the S/C pulley and grounded itself. Ian will post more details. Also MEVI isn't functioning right now, so I don't think he's pulling 350 at the crank....yet. Got to replace the leaking vacuum hose for the actuator solenoid. Did I mention Ian is the god for Vacuum Leaks?

S

 

Only because I spent a year looking for one vacuum leak....the compressor itself

Sorry Baggs - I had just read a post by you and had Baggs on the brain. I mean Brodaiga.

Car is now running. CPS grounded itslef on the pulley, then while trying to start it we flooded the engine.

Cleaned the plugs and then it finally started. But Cylinder #4 misfired. Turns out we also burned out a coil pack at some point.

Bought a new coil pack, and now she runs great except for being very rich at idle. 40PSI.... I'm considering putting the Cartech back in against JWT's wishes with that ECU.

Anyway - thanks for all the help guys!

I'll be posting pics and dynos of "v2.0" of my car soon.

IanS

 

Ian do you have the pump to always on? that could be the reason for the higher FP... have you tried just a walbro?

 

yeah, but my Walbro flakes out bad when I'm under 1/4 tank....didn't feel safe to not have the Aux plugged in.

After I re-install the Walbro, I'll try that.....

But since my Wedding is coming up - it's going to be awhile before i get to do any major work again.

I'll try unplugging it when I'm above 1/2 tank and let you know.

IanS

 

so Ian, you're not selling the cartech then?

 

Simply not sure yet. I don't know why JWT even says not to use one except that they maybe are scared of someone blaming them for tuning improperly and blowing their engine. Or maybe just that they consider their tuning perfect - which we know it's not quite perfect.

Does anyone know of a logical reason besides liability JWT says not to use a Rising Rate FMU?

IanS

 

Becuase it "in theory" would dump WAY more fuel than you would need.

I would think that while JWT's tuning is not perfect, by any stretch, you would be able to dial it in alot closer with an AFC than the FMU... The FMU is overkill when you already have an ECU and injectors that are ~50% larger than stock.

Besides I would venture to say that JWT's tuning would lean more to the rich "safe" side to begin with, so if anything you would probably want to pull fuel in places.

 

The programming is based on oem fuel pressure. Smaller pulleys require caution on the top end which in the end a 1:1 fpr should take care of that. A regular 1:1 fpr will also adjust the static pressure so you won't be wasting gas at idle and low rpms. It always seems like the inlines crap out more than the walbros but with a 2.87, I would be hesitant not to run one of them.

 

Yeah - I should be able to turn down the Fuel Pressure using a Cartech Adjustable FMU - so why wouldn't I use one to lean it out a little bit up top - on a Dyno with a wideband O2, of course.....not just *****-nilly or anything.....

As for down low, I'd like to be able to run the Walbro AND the Aux pump just for safety, and a FPR should take care of that without being too rich.

Is that what you're saying, in laymans terms, Confused?

(sorry - I just don't necessarilly understand what you typed above and am trying to get the gist of it).....

 

sounds like you got it, set the idle pressure like stock and tune it to the top with the cartech. can you adjust idle pressure with the cartech or do you have an inline fpr with the cartech? The oem fpr won't keep the pressure down.

 

nope, I'm going to have to buy a SARD or something. The Cartech only does anything under boost.

IanS