Rb26 loss of power

[Grettar1]

I have an 89 gtr, when cruising at hwy speeds 60mph or 100 kph, at a steady throttle position it loses throttle response and I see a/f go lean, up to 19 or so, if I try to rev it with the clutch in it acts like it's loaded up and then it will come out of it and run fine at consistant 13.8-14.6 a/f. It is very intermittant. The rb26 is built with forged bottom end, ported head, arp studs, 06U00 turbos, upgraded radiator, stock injectors, stock ecu, adjustable aeromotive regulator, new copper plugs, divided twin turbo pipe, apexi filters, stock dumps with 4 inch exhaust, no cat. The mafs are stock but have been resoldered. The stock front turbo spit a wheel and put a small dent in that o2 sensor, but if it was damaged internally I would think it wouldn't be an intermittant issue. I still have stock fuel pump but it doesn't seem to be losing fuel pressure as it comes out of it so quickly, but I may be wrong. I have a new fuel pump but it was broken in the package when I opened it, and I gave not returned it yet. Any insight you guys could give would be great.

[Black BNR32]

Bad maf solder
Turbo shuffle
Throttle sensor

[Grettar1]

Throttle sensor new, can't see any dead spots when checking. Not shuffle for sure. I dîdnt solder mafs, so I'll check it. When I blew the front turbo it soaked the maf and filter with oil. I cleaned everything with and cleaner, then after new turbos installed pcv hose collapsed and started filling rear turbo inlet with oil from valve cover and sprayed on rear turbo maf and filter. I cleaned all again with maf cleaner and installed catch can with blocked pcv and intake pipe. No more oil issues, but maybe I need to clean better? I used almost a full can and dryed with light air pressure, but maybe still oil contaminated or maf solder. I'll have to check that. Thanks for help

[Skym]

Is the stock ECU retuned?? If not, then engine would be running lean if turbo's are upgraded (I assume they are). Stock ECU most likely will be detecting knock via knock sensors on intake side of engine and pulling ignition timing (creates a flat spot / V shape on dyno graph in the mid range), running engine slightly richer (switching to knock maps or also known as low octane maps). Engine running too lean = loss of response.

[Grettar1]

It is stock and has not been tuned. It did this before the new turbos also. It sounds possible, but why is my wideband running a consistant 14.1 to 14.8 at cruise when it occurs, hard accel into boost never an issue and wideband readings are 11.3 to 12.5 under hard accell boost condition. It's just odd to me that it loses it so intermittantly. My boost is set at 12.5psi until I get my nistune installed and my 660 injectors in. I did bump my fuel pressure 2-3 psi over stock. I wonder if there is a broken solder joint in on of the mafs, as they were 'fixed' before I purchased the car. The connectors were all broken and half assed wire repaired and were held in place by mechanics wire. Needless to say I have new connectors on them soldered in correctly. There was a lot of oil on them since my turbo failure, I suppose some of it could have got inside to the board.

[Skym]

Retune the ECU.

Anything above 12 is too lean on boost. Ideally you want around 11.4:1 to be safe when on boost. Some tuners use 11.6:1.

From what I understand, fuel pressure matches boost level. If fuel pressure is too low the boost / pressure helps to stop the fuel exiting injectors. You can temporarily bump the fuel pressure up, hard wire the fuel pump for 13.5+ volts (more lph from fuel pump).

Stock ECU can switch in and out of knock maps when it detects knock, then it doesn't.

With turbo failures (oil seal failure on intake side) the idle valves get coated, so does the inside of intercooler that needs to be cleaned out.

[Black BNR32]

I thought soldering automotive wiring was a no no, as it's susceptible to vibration. I thought crimping was the proper way to do it.

[Black BNR32]

It definitely sounds like a poor contact somewhere. I suppose injector wiring and 02 sensor wiring could also cause those symptoms.

[Grettar1]

Soldering is ok if done correctly, crimps need the proper tool to do it right. The connectors I bought had pigtails on them so I didn't need to disturb the crimped pins. I put the catch can on after I installed the new turbos and the pcv hose collapsed and these nice new turbos started to suck oil out of the valve cover. I'm thinking this may be the oil in the intercooler and bov pipe work getting injested in through the intake and cutting the octane of the fuel. Causing detonation. I lost a half quart of oil, it's amazing how that small amount of oil can lay in those pipes and cause hella smoke. I started cleaning all the pipe work out tonight. Hopefully my "new" used turbos didn't lose the compressor side seals. But from the amount of oil laying in the bov piping, I think it was sucking it in on boost coating all the pipes and causing my smoke. I guess I'll find out after it's cleaned out. I ran it without the intake pipes and the rubber hose from the twin turbo pipe to intercooler off and I see no oil pooling at the inlets or spraying through the twin turbo pipe when reving it. You would think if the compressor seals had failed I would see some spray? But I see nothing.

[Skym]

Usually pools on the bottom of the intake piping (when had a stock turbo failure on compressor side).

Injector loom is known to playup, same with the coilpack loom.