xripstickx

The fuel pressure gauge should be here tomorrow. In the meantime I tested the TPS and I have .41 volts closed with the hard idle switch ON, then only 3.8 volts wide open & hard idle switch off. Hard idle switch seems to be working fine but shouldn't the TPS be reading 5V when fully open?

code 55 means "All OK" I have not tested the TPS, Ill start looking in to that. I was thinking the same thing about the gauge so I am ordering a fuel pressure gauge to do some more testing. I will keep updating this as a go because this problem WILL get solved. And then after I plan on making a good write up on all the steps to test everything related.

I have both an APEXI PowerFC and the stock ECU, same issue no matter what one im using. I deleted the air regulator valve and it did not correct the issue. (my thinking was that if it was not closing once up to temp it would be alowwing too much air.) I also tried unplugging the AAC while it was running and there was no change at all. That leads me to believe that even though its now clean I dont think its operating properly. Unlpugging this should cause some sort of change if it was doing anything at all. I did put 12V to the solenoid on the AAC and it did actuate but im not sure if once it gets hot it stops functioning. (thats exactly the case with the relay for my driver power window. When left out in the sun the window wont go up or down but when cool it works fine) My MAFS are bran new from nissan and unplugging either one of them causes a huge change in the way the engine runs. I think im good with the AFMS.

UPDATE gasket came in. re-installed the AAC (the one pictured). no luck. still cant find anything worth a damn for the fuel pump mod.

Its blowing my mind that everyone is saying that the fuel pump earth mod is common but yet I cant find a single write up with working pictures anywhere. DAFUQ?

waiting on new gasket to arrive. In the meantime i have seen some talk of a fuel pump ground mod but noone seems to explain ecactly what wire it is that need to go to chassis. Heres a pic. Anyone know what wire need to be grounded to bypass the resistor? I ohmed out the white and the black/yellowstriped wire and get about 30k to ground on both. I am lost. What one is the one you run directly to gound?

So I got to the AAC and it was nasty. I am reading conflicting things online. Some people say the AAC controls the idle and the IAC just does electrical load balance and others are saying the opposite. Also I found a million write ups on removing the AAC and cleaning it but nobody seems to ever clean their IACV (or at least they dont post about it). Anyone know for sure? I still dont really see how im going to get the IACV off without removing the plenum. Hopefully I dont have to. If the IACV (the one i havent taken off yet) just assists the cold start idle I am not opposed to blocking it off completely as I dont need it to be perfect on cold start. This is not a daily street car by any means.

Anyone know a good write up on removing/cleaning the IACV?

That makes perfect sense as to why it doesn't seem to have this problem when the engine is cold since the second valve is wide open allowing the engine to breath through that while the IACV is slacking. It might be a pain in the ass but so is me trying to figure this out for the past year with no help. I feel pretty optimistic about it and cant wait to get to working on it tomorrow. Thank for the help!

seems like if IACV was sticking and not responding to the quick release of throttle fast enough then you could expect it to act like its starving for air momentairly until it catches up! Going to go forward with that. Ill remove it and clean it and let ya know how it goes. Anyone remove this without removing the plenum?

i found this description on another forum. "gtr.co.uk" IACV (Idle control valve) I'm not overly knowledgeable about this component as I don't actually have this on my car. A lot of people remove this and/or block the piping and rely on tuning to do its job. It is located very much under the air plenum above the oil filter. Basically, this component will allow more air into the system depending upon how cold the water temperature is. As the water temperature rises, the valve will gradually shut until this device is no longer used. if this description is correct wouldn't it not matter if i blocked it off completely? edit: after more research it seems this is not actually how it operates at all. can anyone confirm?

Do you think I could just block the air supply to the IACV and the AACV, then adjust idle with throttlestop and see how it responds? Looks like ill need to take the intake manifold off to get at the IACV and i dont have an extra manifold gasket at the moment. My thinking is if someone did adjust the stop for a sticky IACV I can just block it completely and adjust the throttlestop to a position that will keep it stable and not have to factor for the extra air coming from the sticking IACV. If this works that would point to a dirty/sticky valve. Im all about trying to eliminate possibilities as easily as possible so I can identify the problem before i spend more time fixing stuff thats not broken. I am thinking this is a good troubleshooting step but im sure most people on here know more about rb26 than I do.

Update, I got the ecu throwing 55 now but the problem has not changed. Also the problem seems to be much worse once the engine hits operating temperature. While its cold it seems fine. Now im looking up exactly how to test the things sinista32 listed.

so just a 500k ohm resistor from the knock sensor 1 pin on ecu harness to ground? At least to see if this is whats causing my problems? Can i just put a jumper off of the pin that has the working knock ? or will this throw off the resistance for both?

I have the stock recirc valves too. I tried that. Still the same issue. the idle speed is good the problem is only after acceleration when returning to idle it stalls. I am looking into this knock sensor issue and I am noticing that i get a .5 Mohm on the ecu harness knock sensor 2 and unlimited on sensor 1. I am not sure what one is 1 and 2 on the block though. Also not sure if this is related to the issue but i have read that a disconnected knock could put engine in a limp mode.