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Rb26Det Into Gts4

MJTru

By MJTru,
in Engines & Forced Induction

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MJTru Mentor

MJTru

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Hi, i just finish my Rb26 swap into my gts-4. the car runs and idle great, but it wont rev past 5500 rpm's. The car is running stock injectors for now with the D-jetro power FC. All my PIM values are OK, and the fuel pressure seems to be fine at 37psi. I would rev the car and it revs good to like 5500 rpms then looking at the Wide band gauge i notice that the car leans out at that rpm.

The motor came out of a car from japan that i got, but the gtr body was to rotten, so i just took it out and installed it into my gts 4. I noticed that the car has got HKS 272 cams, and adjustable cam sprockets, but i have them set at zero both on intake and exhaust. i don't feel as if this would stop it from reving out. Looking at the power FC hand commander i see that one O2 sensor isn't reading, but will this cause it not to rev out pass 5500 rpm's????

What else can cause the car to not rev past that rev limit (5500 rpm and lean out) everything seems to look normal. the only think i can think of is the fuel pump control circuit is wrong seems to go lean and hit rev limit when those lights come on. F/P1 and F/P2.

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GTSBoy Grand Master

GTSBoy

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Don't f**k about with it. If you suspect it's leaning because of low fuel pressure, put a fuel pressure gauge on it.

/rocket surgery.

Also, 272 cams will breathe quite differently to stockers. So if the PF isn't tuned for those cams, expecially seeing as it is a D-Jetro and you therefore don't have a nice reliable load signal from AFMs, then it could quite possibly go lean just from that.

Check the fuel pressure, then, if that's OK, start adding fuel into the map at the point where it's leaning.

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MJTru Mentor

MJTru

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So these bigger cams is what is causing my load cell to be in the L5 point at idle. ??? Hmmm.

I was thinking to add more fuel as well. So I used th inj correction in the power fc to add fuel across the whole grid and it was the same. Didnt rev past 5500 rpm's.

I do have a fuel pressure regulator with a gauge and at idle its been at around 40 psi. So I know its at the right pressure or around it at least.

What I was meaning is as I rev the car and look at the wide band gauge I noticed that it leans out. One question I have is if these cams are causing a lean condition. I still should be able to get them to rev out and not lean out with stock injectors right. ??

I have a set of 1200cc injectors. I pretty sure these had reved out when they were in. Hmmm. I dont seem to remember. Thanks for all your help mate.

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Ben C34 Grand Master

Ben C34

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GTSBoy means put a fuel pressure gauge on it and check what it is doing under load. It might be leaning out due to lack of fuel, but likely to be the dodgy tune you are trying to run. There is no point adding fuel to the map just to find out the pump is screwed.

Edited by superben
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MJTru Mentor

MJTru

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This is the same gtr fuel pump and tank that came out the gtr from japan that I put into my gts4.

Prior to this rb26 is was running a rom tune on the rb20 with 550cc injectors and a holset hx35 turbo. All seemed to be fine with that.

I understand and will log fuel pressure under light loads in the event the pump is going. The car only sat for like 2 months.

Thanks for all your help GTSBoy I really do need to get this sorted out though.

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MJTru Mentor

MJTru

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This is the same gtr fuel pump and tank that came out the gtr from japan that I put into my gts4.

Prior to this rb26 is was running a rom tune on the rb20 with 550cc injectors and a holset hx35 turbo. All seemed to be fine with that.

I understand and will log fuel pressure under light loads in the event the pump is going. The car only sat for like 2 months.

Thanks for all your help GTSBoy I really do need to get this sorted out though.

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MJTru Mentor

MJTru

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Ok I just took the car for its first drive. Drives good till about 4500 rpms then it fuel cuts it just dies. Looking at the wide band as I drive its not leaning out until it dies. The the wide band goes of the charts lean.

Im sure iys fuel cutting.

I used the whole gtr wiring harness from the Gtr. Im just stumped to what can cause it to just fuel cut like this. The power fc is a DJetro unit for a rb26. The rb20 that came in the car never had a power fc rb20_180sx.

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MJTru Mentor

MJTru

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Ok on the power fc in sensor/sw check I notice that when ever the fp2 comes on the car cuts the fuel or ignition, it just dies. Eveytime this is whats happening. F/P is on when the car is running. As I start to move the F/P 1 comes on. Then as the rpms start to rise the F/P 2 comes on then it fuel cuts. Something is wrong here.

I realy never did get my head around the fuel pump circuit. But im thinking that when ever the ecu sends this output its killing the pump or just putting itself in fuel cut mode. I might be wrong as well.

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MJTru Mentor

MJTru

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GTSBoy. The gtst body harness was never changed over so its still the stock one. The gtr has a different way of staging the fuel, well thats how im thinking. Now the gtst I believe dont even stage the fuel. I just need to find that wire on the gtr ecu pinout and just remove it to trouble shoot the issue. To be exact the fp2 out put.

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MJTru Mentor

MJTru

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GTSBoy. The gtst body harness was never changed over so its still the stock one. The gtr has a different way of staging the fuel, well thats how im thinking. Now the gtst I believe dont even stage the fuel. I just need to find that wire on the gtr ecu pinout and just remove it to trouble shoot the issue. To be exact the fp2 out put.

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GTSBoy Grand Master

GTSBoy

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GTSt does not stage the fuel. Well, it does.....the voltage is dropped pretty much at idle. It sounds like you need the complete R32 GTR manual (you can download it) which has wiring diagrams for both RB20 and RB26 in the back. Could be helpful for you trying to work out what the differences in the FPCM might be.

Most people change the fuel pump wiring to direct power the pump via a relay anyway.

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MJTru Mentor

MJTru

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Well I figured it out. I feel very bad saying this. But the car just needed gas. Damn. The smallest thing beat me up for 6 hours. Well I have even worst news. Thr motors oil pump failed and its now dead. Sad.

Im planning on rebuilding it. From what I know the head is still in great shape. But it only had hks 272 cams on stock springs, with hks cam sprockets, MLS head gasket. And fully stock bottom end.

I will make a new topic for engine build.

Thanks to all.

I'm happy that I got the D-jetro power FC figured out. After the tune it lasted for like half an hour and man at 14psi it hauled ass.

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MJTru Mentor

MJTru

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It looks to be a n1 unit. If I can remember the n1 has 11 teeth or gears and the oem stock ones are 12.

The one on there was 11 teeth one. Nismo n1.

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