Wiring Help

[NeoMaggots]

I think I may have wired my Boost cut sensor in wrong. when doing a rb25det NEO swap into my s13. A few connectors were missing on my motorset. There were 3 wires Black and white inside a shieded cable. and a red one. I'm not sure if I mucked something up, but I spliced in the boost cut sensor to these. The red w/silver stripe, Black, and white matching colors the ones stated earlier. The car seemed like it liked the change. idle was very stable no hiccups. Power was burning up the tires in the 1st 2nd chirping 3rd on .7bar with the factory controller. but when I partially released the gas pedal my face ended up in the steering wheel. and when I engine brake and attempt to reengage the gas pedal it does nothing until halfway and boom power is back on. Other than those two conditions the car drives perfectly normal. so I unplugged the sensor and heres where I am concerned the idle jumped up to 2k. I cannot bring it down even adjusting the AAC set screw. Only unplugging the TPS sensor or Unplugging the AAC valve will drop idle to normal but then it hiccups. Also if I plug the Boost cut Map sensor back in it idles happy as can be. I was driving the car for 2 months with no boost cut sensor and it idled fine. Did I somehow splice the 3 wires for the traction control motor? I am missing that connector also since my s13 doesnt have traction control. I am very worried thank you all.

Edited September 11, 2013 by NeoMaggots

[Guilt-Toy]

what a riddle.

[NeoMaggots]

yeah, I think Ive burned up a circuit in the ECU somewhere. : /

[Ben C34]

Something weird is happening, as you can normally disconnect the boost sensor and it doesn't have a noticeable effect on running at all.

[NeoMaggots]

The Voltmeter is pointing @ some large wiring errors or a short hidden somewhere. my AAC valve was not getting the full 12v. I spliced it in directly to Batt for a test and the idle will now drop down to stock values 600-800 rpm area. I can also unplug the boost cut sensor and the idle will remain in that area. Going to test each sensor here tonight and run some new 12v ignition wires to the injectors, coils, aac, o2 and Camshaft position sensor. Does the VVL solenoid need its own 12v source also? I think I had too many sensor running off one power wire and they werent getting the proper voltages to function properly

[NeoMaggots]

shrug well I don't know. I can't adjust the TPS to the correct voltage under load. Only under load am I having issues. My AAC valve is also stuck closed now >< I give up, plans now are to run it until it explodes no fluid changes nothing. going to turn the boost up to 14psi and hope I can do some major engine damage. Then I am going to make a awesome RB coffee table and build a new LSX. This rb motor is a nightmare.

[NeoMaggots]

Does the ECU control the AAC valve opening and closing? I know the coolant temp adjusts one portion of it. I pulled it apart last night and applied power and ground and the valve would pop open. Is that for cold starts? But how does it close? mine just stays open until I disconnect 12v ignition source. : ?

[scotty nm35]

The cold start valve is under the manifold, the AAC is a secondary valve. But what do you care if you plan to ditch the engine?

I could think of much better engines to drop in, but none as simple to build or tune as the LS.

[NeoMaggots]

Where under the manifold would I find this Cold start valve? On my Neo the aac valve only has 2 wires going to it. There are no other plugs wires or solenoids. From the looks of things the high idle should be based off the coolant Temp? Inside the AAC there is a place where coolant pressure would cause a valve to open or close. And yes the RB is going to be future replaced with a LSX but it needs to make a 1,500K road trip next week in order for me to rip this nightmare out. And my issue was, The pigtail I was using was not the correct one. so I had the signal wire to the ECU crossed with the other 2 wires that connect to the little brown Ground box by the ECU. Pulled the harness back out stripped it down to bare wire went over every CM. The only thing I could find wrong was that signal wire mix up to the boost cut sensor. The car is idling much better now. Though if I plug the Boost cut sensor into the crossover pipe when I'm at full throttle full boost it will cut. which is weird because I am running stock wastegate pressure. But yeah this thread is probably useless. I would just delete this if I could.

Edited September 13, 2013 by NeoMaggots

[Hanaldo]

Do you have an accurate boost gauge? You could be getting boost spike that is causing the cut. Otherwise it doesn't sound like there is much wrong with the engine. Typical engine swap teething problems. If you're ready to pack it in after just those little issues then you never had much chance.

[GTSBoy]

The Neo doesn't have the same IAC and AAC setup that the earlier RBs have. The idle valve at the back of the plenum is plumbed into the coolant circuit aso that when it heats up it closes the cold start bypass bath in it. The rest of it is pretty much a normal stepper motor idle valve.

The boost sensor should not cut anything at even fairly high pressures in lower gears. I (accidentally) ran 1.2 bar in my car whilst setting up my boost controller and there was no boost cut. There is quite a nasty boost cut at somewhat less boost than that in higher gears though. So it does seem to be gear dependent (or maybe load dependent).

[NeoMaggots]

Hmm so if I take the vacuum line off the boost cut sensor the car runs 90% to me. Everything is perfect power etc, only issue is my high idle stopped functioning but that doesn't sound like its controlled electronically so maybe I just need to rebleed those hard lines to the aac

[GTSBoy]

The coolant path in there could well be completely blocked up. When I put my Neo into my R32, I had to dig in there with a pick to clear out the corrosion plug that was stopping the bleeder from working. Unscrew the bleeder and see if there's any flow.

[NeoMaggots]

well I popped the bleeder valve, got a little trickle but the water temp was only around 60 degrees centigrade. its 1:13AM but I'm bored so heading out to go pull the AAC off again and clean everything to brand new status. I'll get some pics so all the S1 and S2 rb25 owners can understand this valve better.

EDIT!!! So before I waste my time pulling off the AAC, could the reason be that I have one of the coolant lines mixed up going to that? I would assume not since pressure should build up equally in the system. hmm guess ill pull it

Edited September 14, 2013 by NeoMaggots

[NeoMaggots]

Roger its Locked closed.

[NeoMaggots]

a little bit of carbon build up, and the valve controlled by coolant. well i don't think thats how closed it should be =p And this is what a RB25det NEO AAC valve looks like, there are no other valves to control idle on this engine for reference.

[NeoMaggots]

Well, That brought my idle up a little bit more, The coolant valve was definitely siezed a tiny bit. But my attention was diverted. Its 4:07 am probably about as cool as it gets in Texas 27 degrees centigrade and I am getting a cold start knock. Sounds like mains, is that too chilly for 2050w? this is the second time I have heard it. It literally only knocks for 2-3 seconds about 2-3 knocks then its fine. Monday its being driven 24hrs straight on the highway, should be interesting.

[GTSBoy]

I don't think I'd use a 20W50 over here in an RB engine...it gets a lot colder than your 27°C here. But 27 isn't really a low temp for 20W50. Still, 'twere I you, I would be using a 15W50 or 10W50 anyway.

Your problem may be more to do with poor maintenance on that engine in its past life. Might have had infrequent changes and so had more wear in the bearings and/or pump. Means it takes an extra rev or two to build enough oil pressure. I have certainly heard all of my RBs do similar things at different times. Sometimes you'll get an engine that will do it infrequently.

[NeoMaggots]

going back to my beloved Rotella 15/40w the stores just opened. it gets 38 centigrade during the afternoon, No cold start knocks then =p I have one oil sample bottle, label/package left. I'll post the results of it in a week or so as soon I get my email. I'm thinking theres some wear from low oil pressure at some point. I do know last time I pulled the rockers to reseal a small leak, there was definite signs of alot of oil under there all pooled up exhaust side cyl 3 enough to be to the top of the rocker cover. I deleted my catch can when I noticed this and hooked up the crankcase ventilation to factory specs. so I may have had some head pooling and caused starvation, though since I have owned this motor I have never ever seen less than 20psi of oil pressure reading on my Stack gauge. There were also a few journeys to 107-108 degrees centigrade registering on my water temp gauge back when I ran a bumper. Now I have the temps stable @ 79 degrees moving and 82 degrees @ idle. Sound right?

Edited September 14, 2013 by NeoMaggots

[scotty nm35]

10W40 should be fine for those temps, 15W40 is getting a little thick at startup for my liking...

If the oil filter non-return valve is leaking it can cause the startup knock issue too. Perhaps try a different brand?