CA not making power/revving correctly/hiccupping

[240Clarke]

S13
CA18DET
GT28RS (13psi wastegate), 370cc, 255 pump, Z32 fuel filter

Okay, so my car has no power. (insert CA18 joke here) Im talking 30 seconds to 60mph no power. Cant get to redline in pretty much any gear kind of loss in power.

There is not a miss, though it feels like it is stumbling on its face when above 3k rpm, but it does keep rising, albeit slowly, so the MAF is at least somewhat functional. By disconnecting one coil at a time, there is a change in idle every time, so each cylinder is firing.

Plugs are gapped at .034 and are only 2 days old.

Im running rich (11.2-11.8) at idle, though it was also like this when it was running well.

Wasnt idling for s***, so I adjusted the TB screw and reset my TPS afterwards to .47v at idle which is within spec (improved very slightly).

Timing is at 9btdc. 10btdc is what is in the FSM, so that wouldnt be causing it.

Compression was good a couple weeks ago when tested, within 7psi between all cylinders.

I have one large ground going to the engine, I ran 2 other small grounds, one from the intake manifold, and another for the coils.

The MAF wiring is haggard AF. Its cut up, and spliced together. But... it worked fine up until late when my MAF stopped working. I ran an external ground to the core support off of the existing ground and it worked again.

My problem didnt start until a couple weeks ago. Trying to solve the issue of it running rich, I went and had a boost leak test done. The flange for the BOV was leaking. Fixed it. Still running rich, went back and had a smoke test done on the vacuum system performed. The IACV was leaking bad. Mind you, the car was still running well with good power. I brought it home, pulled the IACV, resealed it with copper sealant, and reinstalled it. Went to start it the next morning, and the MAF didnt work, though I hadnt touched it the night before. Didnt idle, didnt rev above 2k, nothing. Ran the new ground, and it worked fine again. Driving a couple days later, there was smoke coming from my exhaust. Found out the seals on my turbo had given way, and oil was leaking out of the compressor side intake.

I took it as a sign I needed to upgrade, got a Disco Potato and equal length mani, and 2 weeks later, when everything came in, installed them. Thats where I am now. I have no power, the car wont rev correctly (as mentioned above, feels like I have no power to rev through the range) and stumbles when accelerating. And I am not building more than 5psi of boost, though I have a 13psi actuator.

I have tried trouble shooting, but have not figured it out. I really want to be able to bring my car to Hyperfest, so I need some advice!

I have tried to be as detailed as possible, but if any other info is needed, ask away.

Thanks for the suggestions beforehand.

[bradsopex]

Replace your coolant temp sensor first. It's a cheap part, and can save some headaches. The ECU references your engine temp to determine the proper enrichment. Mine behaved similarly sometimes, and we determined that the CTS was out. Replaced it and the engine ran much better.

[boost_boy]

The coolant temperature sensor is not the problem here. It won't hurt to change it, but disappointment in the fact that your engine will still perform the same will slap you in the face quickly. What method are you using to set the timing? And for reference, 15* BTDC is your target timing. If you want to argue with me about it, save it and leave it at 10* BTDC and enjoy the misery. Lastly, back-up off some of that boost because the only thing you're doing is raising your egt and your intake temperatures. Please take the time and correct the AFM wiring. Mickey mouse work will yield you EPCOT CENTER-like performance "BORING". Give it a swing and let us know how it goes.

[240Clarke]

Thanks for the reply guys. And I am not arguing with you boost_boy, I will give it a shot as soon as I can. The car stopped holding fuel pressure yesterday evening, though it held it fine yesterday. Not sure if this is saying my filter or pump is going bad, but I will inspect both elements as well. And I will have to go buy a soldering gun for the afm wiring. Its wired correctly, just connections are a bit shotty. I appreciate the help guys."

Also, I can not turn the boost down. Running off the wastegate.

[bentvalves]

you mean when you shut the car off the fuel pressure gauge drops to 0 right away not holding pressure?

bad fuel pressure regulator if so.

[boost_boy]

Yeah, clarify that dropping fuel pressure thing. As you can see, some of us really want you guys to enjoy your cars/engines. I wish I can come to everyone that's having issues and correct them, but that's just not going to happen. But when you guys are presenting your dilemmas to the powers that be, please be as overly-detailed as possible. We're going to get you squared away my friend, just you be patient and help us help you.

[240Clarke]

Ill be more detailed. While the pump primes, fuel pressure is where it needs to be. As soon as the pump stops priming, fuel pressure drops IMMEDIATELY back to between 10-20psi and then continues to fall, just slower. This began 2 days ago, at the same time, my car stopped being able to run or drive all together. Engine barely runs for more than a second or two before dying. With my foot to the floor, I can sometimes coax it to run for around 5 seconds, not well.

Before this, when the car actually drove, just not well, it was holding fuel pressure for at least a couple min after turning off the engine. Just fall very slowly back to 0.

*I have a Nismo Type A FPR, with not even 75 miles on it yet. Bought it maybe 5 weeks ago. Isis 255lph pump, about 2 months old. Z32 fuel filter, bought in February.*

[boost_boy]

More bad new: Your fuel pressure regulator has a failing diaphram, so it needs to be replaced. These fail as I've had two of them fail on my watch. Some are good and some are a joke. I believe that's where most of your problems lie, now that you've added more details.

[s13drifter88]

Werent the Isis 255 pumps having some failure issues?

[Clarke240]

I hate when people start threads about having issues then never post the resolve, and I did just that.

A year later, here you go.

Less than 10 miles later my motor developed a miss. Compression check yielded 12psi on cyl 3, and 40psi on cyl 4. Pulled the motor and disassembled, and had cracked ringlands on both pistons, and the rings were so broken they were overlapped 3 times in some spots. The fuel pressure regulator was also going bad, as the posts above indicate. Replaced it with another Nismo unit (which is already starting to go bad on the new build.

The motor is built now, using all new components, 84mm Wiseco pistons, K1 rods, ARP everything. Even with only the SR T25 Im using currently, she is twice as quick as it ever was with the GT2860rs.

Also replaced the harness on the new build with a WSP harness, Ill never not take that route again. Thanks for the help guys!

[float_6969]

It sound like the failing FPR caused you to run lean and toast some pistons. That sucks. I'm glad you rebuilt it and I'm REALLY glad you let us know what happened!