Wacky RB issue

[stevespeed]

I have an RB25DET Series 1 swapped into my S13

Swap has done to it
Greddy intake manifold
Q45 Throttle Body
Front Mount Intercooler
Stock Ecu (no upgrade or retune at all, no SAFC 100% stock)
GreddY RS BOV
Running 8Psi currently sometimes I step it up to 13 but recently put it back to 8
stock intake pipe with the stock MAF
Walbro 225LPH fuel pump
Stock fuel pressure regulator
all stock sensors, no wideband.
pulling 15-16 inchs of vacuum at 800RPM idle
Timing was set at 20 degrees btdc at 650+-50RPMS with a mac digital timing light and the CAS has not moved at all since, timing belt and head are both new.


So whats been happening is that I was driving down the highway one day and the car felt like it lost alot of power, so I took it home and started fiddling with it, after a plug change BCPR7E-8 (i think..), and boost leak tested it to see if that was the problem.

The Boost leak test returned nothing wrong so I started just redoing vacuum lines to make sure that was not the issue either, and took it out for another spin.

First time out the car just felt extremely down on power and sluggish getting to redline. Next drive first felt insanely down on power like the engine was just struggling to breath, and then in 2nd during a WOT pull the car felt like it hit a brick wall and basically just stopped accelerating.

I currently am thinking its either an Ignitor chip or a MAF.

thoughts/ questions about the setup. this has been haunting me for weeks

[robbie2883]

what do your afr's look like?

[stevespeed]

i dont not have a wideband.... I can try to look at the narrowband readouts with a multimeter

[Bluefire]

Is the ecu throwing any codes? Possibly knock sensor issue? Also timing should be 15degrees for Rb25

[robbie2883]

Is the ecu throwing any codes? Possibly knock sensor issue? Also timing should be 15degrees for Rb25

eh...i've seen people set it at 20 and 15....eitehr way at 20 he should have more pep not less.

i would highly recommend getting a wideband. you won't be able to tell anything from ur narroband..your dmm would have to have a pretty fast sample rate to read it too.

[stevespeed]

I tried doing the KA way of pulling codes from the ECU but i guess this doesnt work that way? I feel like a complete noob trying to doing this blind.


I am going to try a new MAF later

[robbie2883]

you might as well just throw your wrenches and wallet at it while you're at it. and replace the tires....

not trying to be an a** but the whole "let's throw parts at the problem" philosophy kind of gets to me. why not troubleshoot it properly? test the coils with a meter, ohm them out, check fuel pressure, ohm out the injectors, check the signals with a noid light. and figure out what you're afr's and your active timing are doing.

[stevespeed]

I have checked teh fuel pressure, and i am going to do a huge battery of tests on it tomorrow, the reason why I am putting on a new maf is cause my friend has an RB like 5 miles away and I just thought it would be advantageous to try another MAF and ignitor since they were 0 cost and just sitting on my friend's shelf.

Realistically the reason why I am at that point is because I am running out of tests.

I can assure you thats it not just a single coil or a single injector that is failing, it would have to be both. The problem started while I was driving down the road one day and went away and came back which lead to me believe it was either a leak or a sensor.

After doing a boost leak test and testing for leaking vacuum I have come to the conclusion that is neither of those.

I do not like "Just throwing parts at it" approach either but I assure I am to the point that I just have no idea whats going on after I am not even joking around 48 hours of labor straight in trying to diagnose this problem.

[eh?]

Check that it didn't jump timing. 20* base and 15" of vac is troubling. Correct rb25 timing is 15* and should be about 18-20"

[stevespeed]

Found the issues, the MAF sensor seem to have eaten itself alive due to.. something? and it looks like the poor vacuum is because of a really really really REALLY bad coupler that I have in the system.

Ill check the timing again once my friend with his baller a** Matco Digital timing light gets back in town.

[SullivanRacing06]

the maf ate its self or it melted due to heat...