Just a question.

[March]

Hey guys,

been a while since i have posted on here. I have my car put together, took about a week with the help of my friend to get the engine installed, and wired up. had some small things come up, wich was expected, but over all it wasent too bad.... exept for the guages... that was a pain in the ***. well anywasys. i have a question for yuou guys and i hope you can answer. the car is running fine, for normal driveing, but when i get on it, it seems to bog down at high RPM, almost like it isnt getting enuf fuel..."just guessing". the other thing is, when i get on it the speedo will stop reading at a certain point and drop to zero... this happens only when i get on it, not normal driveing. my thoughts where maybe, when i acceleratre that quicky the trans twists and is perhaps pinching a wire cending signal to the speedo. i relly dont know and thats why im asking. but if you guys culd give me your input on these problems it wuld help me out alot. thank you very much.

thank you in advance.

-March

[Darius]

Did you solder your connections? It seems like the VSS signal is being interrupted under acceleration. Just retrace your wiring and make sure it isn't being pulled taught or shorting out along the way.

[March]

ok thanks, ill try and retrace that this weekend... im planning on dropping the transmission and seeing if everything is ok in that area as well.

im still searching for an answer on why my car seems to... not nesisarily die out, but bog down when it reaches around 6,000 rpm. it does that in each gear, and im not sure what the problem is.

thanks again

-March

Forgot to add... was told that it may be my ECU? if you culd please give me more info on that it wuld help me alot.

[Darius]

What octane are you running? If it is not high enough, you could be getting some knocking and the ECU pulling timing or dumping fuel causing it to feel like the power plateaus.

Did you set your timing to base according to the FSM when you installed the motor?

[alysesparents]

i had the same problem with my car bogging/sputtering at high rpm's it was my spark plugs they werent gapped properly make shure they are gapped at 30hope this helps

[March]

hey,

thank you for the input and yes i did do the timeing acording to the FSM. we have checked the sparkplugs and they are all gapped properly and look fine.... although i will be replaceing them soon.

i cant tell you what octane im runing becuse im relly not sure... i use premuim gas. i think it is 93... but dont hold me on that one.

o yea... fuel pump... i put the skyline fuel pump in the car.. is that sufficent enuf?

thanks again guys.

let me kbnow if you thijnk of anything else it culd be or find soemthing on this problem.

-March

[Darius]

How noticeable is it? Is it faily subtle? Mine runs rich as hell because I don't have it tuned, so it feels the same way at about 5500 rpm. I am running lower compression, so that might be it too.

93 should be good as well as the GTS-T fuel pump.

How do you have your valve covers ventilated? Breather or do you run the vapor back into the intake of the turbo?

[March]

hey sorry that it took so long for me to reply, i have it running back into the turbo... or im pretty sure i do. and yes it is very nitceable, the car is running funny. my buddy helped me tune it, fixed the timeing and idle, its idleing at about 8-9000 rpm, wich from what ive read is right. the only problem with that is, after driveing for a while the rpm's drop relly low when i slow down to stop, almost dieing out. i think that it may be due to electical issues, but im not 100% sure on that. im going to look into getting better grounds for everything, if you know where i can find a kit for that please tell me.

as i said before, my buddy thinks alot of the problems may be due to the fuel map, and electrical. im not sure on the compression, ill have to get back to you on that.

thanks in advance,

-March

[l0nestar]

March,

Hey man, long time no hear! Glad to hear you are still around. Sorry, nothing great to contribute But for the grounding issue, You can go to any car-audio shop (or Best-Buy, Circuit City, H. H. Greg, etc.) and just buy like 10ft of #2 or #4 battery cable and some ends and cut them to length, then solder them. Use good quality battery cable for wiring amplifiers (many fine strands / conductors, flexible) It is 100x better than using standard automotive battery cable (less conductors, less flexible). You can use the crimp-on ends, but I would suggest soldering + heat-shrink, but that is just me. HTH!

PS, call me some time!

[March]

ok so my buddy looked at my car and took it out for a drive and told me, pretty much the fuel air ratio is messed up. so... he told me to either get an aftermarket ecu, or redo the one i have. he also told me that i culd start out by getting an external regulator or something to that nature? i cant remember what he said exactly, but he told me that it wuld probly fix my problem. you guys know what i am talking about? and if you do can you please tell me where to find a good one?

thanks

-March

[mello88]

Do you have the stock fuel pressure regulator still? You can pick up a fuel pressure gauge and tee adapter from Jegs for under $30 to monitor your fuel pressure at idle with the vac reference unhooked from the stock FPR. You should be right at 3bar/43.5psi. If not buy a Nismo FPR and reset your fuel pressure per the FSM.

If you pick up a wideband o2 sensor and gauge, you can then rechip your ECU and have it rom tuned, or if you have the funds pick up a standalone EMS. Failing that you could take the cheap/half-assed route and go with an SAFC to "fix" your AFR... Might wanna read up on why SAFC/piggyback solutions are not ideal.

[March]

yea, the stock FPR is still on there, but the one the guy was tellin me to get was an adjustable one... if you guys know anything about that? apperently my car is dumping too much fuel into the engine and not enuf air causing it to backfire, and sometimes die out when comeing to stops, also i have a huge powerloss in my engine becuse of that. what he was sayiong makes sence i just wanted to know more about it. and what wuld be a good company to go thrugh for that.

if you can please explain the wideband o2 sensor and gauge. and when you say rechip.... is that just buying something for it, or does it mean sending it somewhere?

thanks in advance

-March

[Darius]

Sounds like you could have metered air escaping before combustion and it becomes especially apparent at high RPM. I'm betting you have a boost leak somewhere. That would cause a rich condition and backfiring etc.

Do you have an aftermarket fuel pump? If not, you should. It is also a good idea to verify your baseline fuel pressure like mello88 said. You may not need an adjustable FPR if your stock FPR is maintaining the proper pressure with zero vacuum. If you need an FPR, just get a Nismo and be done with it.

[March]

i have the stock skyline pump in there. and to moniter that i wuld need the wideband o2 sensor and gauge? im thinking my FPR is fine, the guy was just tellin me to get an adjustable one so that i culd controll, and i guess even it out to fix the problem, but what you are saying makes sence so i guess the first step is to get the sensor and gauge. whats an inexspencive, but reliable one?

[Darius]

Wideband O2 and inexpensive are not used in the same sentence. You can get a decent one with hand held readout for about $300-350 if you search around. I personally have an Innovate brand O2 sensor but have not installed the O2 bung in my downpipe yet.

I doubt that if you have a stock skyline pump with a stock skyline motor with stock skyline ecu that a wideband O2 is going to tell you anything you don't already know. You can already tell it is running rich. Borrow a pressure gauge that you can hook in-line with your fuel feed line and turn the ignition to ON, but don't start the car. It should pressurize the system to 43 psi. Then, pull the vacuum line off of the FPR and start the car. It should idle at 43 psi as well. Shouldn't be any difference really. If it is not 43 psi, THEN replace it with an adjustable FPR so you can dial it in to the stock setting. If the stock FPR is functioning properly, start searching for a boost leak in your intercooler piping.

[March]

ok cool, thank you very much. ill do that and let you guys know what i find out.

thanks again

-March