Ignore info below... not getting enough sleep causes problems.

Yes, fuel exists at the right bank on a 4th gens. His pictures are correct.

Maybe you guys are getting confused with the front bank rear bank terms. The bank near the front of the car is actually the REAR bank... I think you know this already, right? So that makes the bank near the cabin the FRONT bank. Confusing, eh?

 

ic.....so should I lower my fuel pressure to stay away from 100% duty cycle? will that richen out my car?

I had a less than 10:1 AFR from last dyno.....what could've gone wrong in these 6 months? I only add the pressure bleeder valve and cat-back.


it would be best to tap it into the front exhaust manifold, but there will be a lot of work.

 

I didnt know that! why? I thought the bank close to the cabin is the rear bank and the one near the front of the car is the front bank.

 

Ya I knew that but like you said that would be too much work. I guess I'll just put it where you did, would you reccomend that?

 

sure.

It is still not too far away from the exhaust manifold. but since it is on the ypipe, I would wrap the ypipe to avoid getting some false readings.

Other than that, if your EGT gauge has warning feature, set it at 780 celcius. If not, let go off the pedal at 780celcius. because the reading is not directly taken at the exhaust manifold and it might read lower.


have fun~

 

That's NOT what his pictures are showing. His pictures show the FPR on the bank "closest to the cabin", which means RETURN line not feed.


I think *YOU* are confused. RIGHT bank = FRONT bank = side closest to the cabin, which is the *SAME* as our 5th gens. according to this picture from a 2K1 FSM:

http://forums.maxima.org/attachment....tachmentid=868

 

Interesting... maybe it's different for a 99.


What was I typing?.... I think I'm on crack.....

 

since the fpr is downstream of the injectors wouldn't injector 6 be getting the highest pressure since that's where the pressure will build up first?

is this the correct diagram?
2-4-6-fpr
1-3-5
front of car

if so, 6 should have the highest pressure since that's where the pressure starts to build then it would build pressure down the rail and number 5 would have the lowest pressure, if i'm thinking this correctly. correct me if i'm wrong.

 

front, right, left, rear...

 

No, its the same fuel setup that my 97 (and EVERY other 4th gen I've seen) has.

To make sure everyone has this clear...on a 4th gen fuel ENTERS the LEFT bank, and EXITS at the RIGHT bank.

 

Well, I'm chiming in a little late, but I just want to confirm what Eric has been saying, on a 4th gen the fuel enters the left bank rail (which is at the front of the car), and exits from the fpr on the right bank rail. Now, why the left bank would be called the rear bank when it is in the front of the car is a mystery to me.

Second, cylinder numbering is

firewall
1 3 5 - fpr
2 4 6 - fuel in
front of car

 

I must be smoking the SAME crack as Kev.

246
135
Front of car

According to the FSM I saw. I'll have to look again.

 

This thread is starting to make my head hurt.

I'm pretty sure Steve had it right...even numbers on the left bank (at the front of the car).

 

my vg is the same as what the 4th gen guys are saying.

firewall
1-3-5-fpr
2-4-6-fuel coming in
front of engine

the 5th gens must just be weird.

 

Or its just 5th gen owners.

 

I'll be verifying the 5th gen. cylinder order tonight.

 

Oops...forgot to reply to this.

ejj<~~~was correct.

 

I had forgotten all about this "discussion".

 

Just searching for something on [maxidose] lean issue and I found it. I hate it when I say I'm going to do something and I forget or don't do it.

Anyways, I traced out the injector wire colors to verify the cylinder order and it matched YOUR order.

 

I can't take all the credit...Nissan had a little something to do with it.

 

Swear my brain has turned into swiss cheese in the past couple years.

Must be all the beer killing brain cells.

 

still looking into my lean issue?

anyways, this is something interesting : I am now NA and I still see pretty high EGT. I can take her up to 780C from 2nd - 3rd - 4th @110mph. I guess I am still running lean.


oh~ having 4 gauges with no boost makes my car

 

Yeah, I'm convinced your stock pump is weak or your bypass valve is opening.

According to my latest Turbo&HighTech Performance mag, an inline pump can only pump what the in-tank pump can feed it. They then went on to show how even though your psi increases, the actual flow(gal/hr) can drop dramatically.

I know damn well *THIS* is the REAL reason you're dumping your SC UNLESS you're going turbo later.

 

hmmmm...but I am able to hit 110+ psi of fuel. if the fuel pump is weak, I dont think I am about to go that high.

my car is running lean from mid rpm. I always thought it is something wrong with MAF reading or MAF cant communicate with the injectors. I monitored the MAF during WOT and it was reading fine.

plus I switch to a higher flow inline pump....still the same. that pump is a powerful one, 60 gallon / hr.



one of my several reasons but true...I cant have the car running lean like this forever....something gotta be done and I choose the easier route. if Deac got the injectors to fit....hmmmm.....

going turbo? looks like I am following someone's footstep.

 

Even though you get 100+psi, that does NOT mean you're getting the *VOLUME* you need to support the airflow your SC is making.

For example, the stock GSR pump at 13.5V:
PSI,LBS/HR
-------------
35, 224
40, 211
45, 198
50, 185
55, 172
60, 159
65, 147
70, 133
75, 89
80, 22<~~~

Again, an inline pump can ONLY push what the in-tank pump can feed it. Pressure is RELATED to volume, but not directly related. The higher the pressure the LESS volume once you pass the pumps maximum supportable flow, which is when the bypass valve opens as a safety measure. You can keep ramping up the pressure, but more and more of the fuel is dumping out the bypass.

Go buy the T&HTP April 2004 issue.

 

A fuel pump problem would manifest itself as a lower than expected fuel pressure at WOT. If the injectors are asking for more fuel than the pump can deliver at a particular fuel pressure, then the pressure will go down until the flowrate is achieved. Think of a garden hose with an adjustable nozzle. As long as the nozzle is partially closed, pressure in the hose is going to be high and the flowrate low. Open up the nozzle and flowrate increases and pressure goes down

Maxi said he was getting 110 psi. The big question is, was that at low flowrate (such as during a static test of the pump), or was that at WOT? If he saw 110 psi at WOT, then the fuel pump is delivering all the fuel the injectors are asking for and the leanness problem lies elsewhere. Dirty or weak injectors?

 

By the way, I went back to the beginning of the thread to see what the symptoms are. I'm not sure that 810C at 110 mph is abnormal or an indication of leanness. Sustained high speed running is going to result in a lot of fuel being burned, resulting in higher EGTs than you might be used to seeing.

I ran my car at about 120 mph once and the EGT climbed past 815C and was still climbing when I backed off. That was at partial throttle, so no boost pressure to increase fuel pressure. The ecu was controlling fuel delivery, so it should have been okay (assuming the Nissan engineers knew what they were doing when mapping fuel curves), but we get used to limiting EGTs based on boosted runs, and 815C is kind of high for boost.

 

I believe the flow drops because the fuel pressure is high and creates enough resistance towards the pump and thus the flow rate decreases because it couldnt pack any more fuel. But this doesnt mean that volume of the fuel is low because you are still seeing 110+ psi of fuel. There is still a lot of fuel inside my rail and for some reason, it just wont go into the engine.

 

It was later noted on dyno. I thought the EGT reading was ok too. I wanted to see my gain from a 2.5" cat-back and turned out this lean problem showed up.

here is the linky to my 10:1 dyno vs 14:1 dyno. They are 8 months apart.

http://home.earthlink.net/~doctorkiw...o-14vs10-1.jpg