Loss of power!! Need rb20 GURU

[Wongger]

I have an rb20 in my 240. One problem that has been bothering me for awhile. Sometime when I hit boost (sometimes even before) the car will just lose all power. I could floor the car and it wouldnt move one bit. It usually continues to stay like this until I switch gears (sometimes will continue) or let off the gas and wait 2-10 seconds.

Been told that this is a vacuum leak. Wondering if it could be anything else before I start changing all my hoses lol.

Also been told it could be a faulty FPR? not really sure though

Thanks in advance!!

Thoughts?

[rb25det250sx]

does the car jerk and sputter like there is a miss fire? that could have something to do with your injectors or ignition.

Also this happened to me somewhat when i first bought my 25. the turbo was s*** and fins were eaten, and the timing was off one or two teeth, lucky for me my pistons never seen valves. check that out. dont continue to drive it. could serously damage somthing.

[Wongger]

When I mean loss of power the car basically acts as if its turned off..... This happens for 1-10secs. The car wont rev (I could floor it and it do a thing). The turbo is in good condition, no fin damage. Timing doesnt seem to be off considering it was running completely fine 2 months ago when I installed it.

Not sure what a Missfire feels like...

[Carl H]

is mechanical timing sound?
may have jumped a tooth and skipped time.
recheck the ignition timing.

[Wongger]

I really dont think its timing. This only happens once and awhile. If it was timing wouldn't it happen always?

[R32ONP]

yea it would happen all the time...have u set tps corectly sounds like ur getting a major "flat spot"...could be air leak so look for a vac hose that coulda poped off or is torn etc....could also be a leaky bov???

[Cjmartz2k]

Kinda sounds like a wiring problem to me. I would expect more of that than normal since most of the RB's on here are swapped into a different chassis with a custom harness.

[R32ONP]

on another thought it could be the ecu pulling the timing...like knock sensor related...is the car giving any fault codes u need to start by checking for codes

[Wongger]

I wanted to check for codes except I didnt think anything would come up considering its only happening once and awhile (getting alot worse now).

How can I check the TPS, or set the TPS?

I was told by a guy on GTRCANADA that it was my knock sensors. Nobody has been able to help me find part numbers/a part that will work. Any suggestions?

I have been slowly replacing the vac lines. I dont have a boost gauge lol, so I cant tell if its losing boost.

[Vkoslak]

My rb20 used to do that. I tried damn near everything. Different mafs, different injectors, adjustable fuel pressure regulator. I eventually discovered corrosion in the mafs wires themselves. I could get the car to stall by pushing on the wiring harness. As soon as I replaced a large section of mafs wire, the car ran fine. I would check the mafs wiring first, then move on to the mafs itself.

[Wongger]

Last night I cleaned the maf and check the coilpacks. The maf was pretty dirty, idled alot better in the morning, not sure if the problem is still there though.

The coilpacks where all fire. Well, at idle. They could be losing amps at higher rpm?

I think its something to do with my knock sensors. Ill have to find some replacements

[julio]

I have never had a car lose all sense of power from bad knock sensors. It depends on the car/ecu, but the car should still have some power even if they are telling the ecu all sorts of bad things are happening.

Below is a dyno graph of my old turbo maxima (VE30DE, T04E 60 trim) running 8.5 psi. My knock sensor was straight up gone and the ECU pulled timing until it started to ignore it at a certain RPM. I'm sure you can tell what RPM that was. Anyways, it made spool awful until 3,500rpms, only putting down 125 wtq where it should be putting down 175wtq-ish if not more.

[R32ONP]

check the fault codes bro.....

[Wongger]

Found the problem. It was the maf. It was the wiring. I guess it had corroded. I just replaced most of it. Runs awesome . Thanks for all the help guys!