jscherf92

Quick update, ill be back as i work through the troubleshooting today.

Compression Test Results
(Average over 5 tests, warm but cooling down)

Cylinder 1 - 124 psi
Cylinder 2 - 120 psi
Cylinder 3 - 133 psi
Cylinder 4 - 125 psi

I know FSM is looking for 156 with a minimum of 128 and difference between cylinders no greater than 14. Obviously my results are pretty low, but they're consistently low.

I can also add that fuel pressure does increase when it should, so the regulator is doing its job. I've ordered injector filters and o-rings just because so ill be refreshing those when they come in.

Kingtal0n

Great! Good work, good progress.
A note about compression, are all the plugs out when you take a reading? Cranking speed is very important. Your results might increase 10-15psi if you get a second battery connected (jumper cables) and remove all the plugs, and ensure the throttle body is open when you do the test.
Cylinder 3 is asking you to take a closer look. Is something inside it? Is there oil residue hanging around? Are the valve seals good on that cylinder? Why is it slightly higher than the rest? Try adding oil to all cylinder, and see what happens. if they all go up (to meet #3) except number 3, then you have an answer...

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jscherf92

I already notice my errors, I only removed one plug at a time and the TB was most definitely closed. I'll run another test while I still have the tool and report back. I just took some solace in the fact they were all relatively close to one another. I've been checking wire continuity between individual sensors and the ecu and so far they're all checking out so its unlikely that wiring is a problem. I'll keep at it when I can find more time. Very busy week between working retail and upcoming final exams...

KendallH

1. Stop listening to kingtalon, half the things he said are either wrong or dumb.

2. Lean condition is cause by one of two things: too much air post-AFM or too little fuel.

3. Since you would be under positive pressure after the turbo, your intake leak would be between your turbo and AFM, disconnect and plug everything between the AFM and turbo and then check your results.

4. If you still experience a lean condition after that test then your issue is fuel. I would first inspect the tank and in-tank fuel filter. Check to make sure you have 12V at the pump. Wiggle the wiring connectors to see if it changes. Switch back to a stock fuel pressure regulator if you can.

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jscherf92

There's no need to make an attack out of it, we've done some decent brainstorming so far but I appreciate all the help I can get.

I'm looking at the AFM being another name for the MAF so the only thing between that and the turbo is the rubber intake tube. I'll check over it thoroughly, I've got a small vacuum port plugged and the other two are going to the catch can and BOV recirc fitting.

After the air test I'll double check everything in my fuel system and I'll pick up some more fuel line to test the stock FPR just to eliminate another variable. Pump is new and hardwired, tank was removed and thoroughly cleaned, all new z32 filter and lines, I'll be replacing injector o-rings soon and that just leaves the hard lines between the tank and engine bay.

jscherf92

New info, performing the compression test correctly got me 140-145 psi across the board so im no longer concerned about that.

OEM FPR made no difference at all, plugging all holes in the intake tube also yielded no change and i cant find any holes or cracks in the tube itself.

Ill be doing another leak test tonight. So far the only change in AFR under boost is from the increased fuel pressure.

jscherf92

Car ran like shit today. Started right up on the way to work, no real issues to speak of. After work and later in the night it didn't want to start unless I really played with the gas pedal, rpm's kept dropping to ~500 at idle, fluctuating AFR values, engine shaking horribly. Got home and it looked like the fuel pressure was bouncing around a little (maybe 5psi) and it smelled like hot, almost burning rubber. I got a reaction from unplugging each injector individually, nothing was loose, diconnected, melted, or broken that I noticed. I don't have time to dig any deeper tonight but this is incredibly frustrating for it to get worse so suddenly. Hopefully I can take a look at it tomorrow morning and figure out whats wrong...

jbjslambert

was reading back a little bit. this is clearly a non-metered air leak meaning that its sucking in air on your inlet pipe between your MAF and turbo, OR an intake leak. Spray brake cleaner all around the maf area between the maf and turbo an watch for a spike in AFR at idle. may need to rev it up and hold it since it seems to happen more at higher rpms. also spray all around vacuum hoses and intake gasket.

sorry for bad typing...

jscherf92

Will do, thanks for the input. Ive got couplers on the way to replace the old rubber tube with 2.5" hard piping. When that comes in ill swap it in and check for intake and boost leaks. I've been wanting to overhaul the intercooler couplings and clamps for a while so checking them all now is as good an excuse as any...

jbjslambert

intercooler coupler replacement is always a good thing, but i dont think this is the problem you are having...Boost leak will make it run rich. Boost is metered air that has already gone through the MAF. Leak boost out, and now you have less air in the combustion camber than the MAF read. Therefore, rich conditions.

jscherf92

Makes sense. New couplers should be waiting on my doorstep.

On my way to work today I had a situation where I started off from a stop light, made it to second gear and just lost all power. Wideband read full lean, vacuum gauge would still change with throttle but absolutely no response from the engine. I have to assume it was some sort of random fuel cut but my laptop wasn't hooked up at the time so I dont have any log information to tell me what was really happening. I'll add that turning the engine off and starting it back up solved whatever problem it was and i was able to drive away normally.

Hopefully tonight I can limp it home, install my new intake pipe, check everything for leaks and go through more tests tomorrow.

Edit;

It did it again on the way home, full stop at a red light, went to accelerate and got about halfway through the intersection before it started bogging and went full lean. I'm working my way through the intake pipe and hoses that come off of it and haven't found any leaks yet...

More edit;

Still can't figure out timing but i've yet to get a look at the CAS position on the exhaust cam. Went through my intake piping and fixed a couple of very small leaks with 20 psi and soapy water, couldn't see or hear any more. The intake hard pipe idea didn't work out as planned, the couplers were too long and not as flexible as i had hoped but the rubber tube held pressure when tested. Ill have tomorrow night, all day wednesday and some of thursday to keep poking at this, if anyone has any more ideas or suggestions let me know!

jscherf92

Reporting back on the off chance that someone is keeping up with this over the holdiay.

Removed my fuel injectors and 3 of the 4 lower o-rings were knicked/ripped and i can't find anyone selling them locally so that's putting me on hold for a bit.

In the meantime i've reset my tps sensor, backed the throttle stop screw all the way out, got a look at the TB butterfly and adjusted the screw so its just barely holding it, and set the TPS to 0.44v when closed and 4.08v WOT. Nice smooth readings across the range and TPS closed flag at 0.50v.

Hopefully I can get to the dealership early friday morning and get the o-rings to re-install the injectors and move on with further testing. The last time I drove it was slightly more rich than usual, I wouldn't be surprised if the o-rings were leaking and causing some problems. I've gone over every hose, pipe, coupling, and clamp for leaks and found nothing, I also replaced the vacuum line going to the BOV and FPR with a nice thick wall hose.


More developments....
Got the valve cover off, forgot to take pics of the previous setup but I got it to TDC, pulled the CAS and repositioned it. I can say that it was off position but I don't know by how much.

TDC, 2nd mark from left.


Everything I can find shows this as correct, 1.5 links to the left of the intake cam mark, 9 links between dotted links, 3.5 links to the right of the exhaust cam mark. Let me know if this is wrong. Disregard the silver links, the gold link on the crankshaft gear isn't correct.


CAS dot lined up with the left dot on the shaft.


Much better positioning so far.

ultimateirving

Awesome man. Timing will be a major Improvement in engine driveability. I'm crossing my fingers for you. You will have something to be thankful about for tomorrow ;P

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jscherf92

Haha true that, im sure the family will stare with confused faces when i say im thankful for correctly set ignition timing.

jscherf92

Tonight's info, just finished installing new injector lower o-rings and now have a steady fuel pressure reading (38 under vac, 43 atmospheric) on my gauge. Also after removing the valve cover I reinstalled it with all new gaskets and sealant.

Current Warm Idle Readings:
*Idle set to 15 degrees from spark plug wire cylinder 1
CAS set more clockwise but not maxed out.
RPM: ~850
MAF: 1.52 V
TPS: 0.36 V
IACV/AAC: 10%
O2 Sensor: Fluctuating normally
A/F Alpha: 108%
Inj Pulse: 2.4 mSec
Inj Duty: 1.68%
Wideband AFR: 13.5
Vac: 18 inHg

Current Warm Idle Readings:
*Idle set to 15 degrees from coilpack harness loop OR black/yellow wire to coilpack one
CAS Set more counterclockwise but not maxed out.
RPM: ~825 (Much more fluctuation)
MAF: 1.66 V
TPS: 0.36 V
IACV/AAC: 10%
O2 Sensor: Fluctuating normally
A/F Alpha: 113%
Inj Pulse: 3.3 mSec
Inj Duty: 2.10%
Wideband AFR: 14.1
Vac: 16 inHg

Noticeable differences:

Idle/timing hunting when set from coilpack signal wire, fluctuation in MAF signal (hundredths of a volt), more rapid fluctuation in timing, slightly less vacuum and slightly less rich.

When timing is set from coilpack signal wire, the reading from the spark plug wire timing shows to be the first mark on the pulley or 5 degrees ATDC, so a 20 degree difference in ignition timing between reading from the coilpack signal wire or an intermediate spark plug wire. I have tried switching out the coilpacks with no change in this.

Is there any way to completely test a MAF before purchasing a replacement or is it something I should try reguardless? I don't really have a way to test a friends but if I'm gonna buy one its probably going to be a brand new SOHC KA maf.

This is all without actually driving, i'll get to that tomorrow evening. The sweet spot as far as engine behavior seems to be setting timing from the spark plug wire and setting idle speed to about 815. While adjusting the IACV I also backed out the throttle stop screw, this lowered TPS voltage from 0.50 to 0.36 but the throttle closed flag is still set in the ECU and I believe it is closer to how the throttle stop and IACV should be set.

jscherf92

Drove to work today, let the car sit for about a minute idling and it stalled out, possibly need to up the iacv. When driving its still lean at WOT, some cruising afrs sat around 15-16.0, it wouldn't lean out when engine braking, but occasionally would go lean for no reason. I'm gonna do some logging and probably order the new KA maf.

jscherf92

New MAFS arrived today, the wiring specialties harness is expected to arrive Saturday

ultimateirving

How fresh is your o2 sensor also? And I didn't read thru the while thread recently but did you mention it's positioning?

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jscherf92

O2 Sensor is new within the last three months or so. I've got the older one I can throw on for testing but they should both be functional. It's positioned on the 3" turbo elbow/outlet, basically stock position. I've read that the O2 sensor controls the injectors in low throttle situations and the MAF takes over at higher throttle so that points more towards MAF but im sure an O2 issue could wreak all sorts of havoc too.

New info: I got the SOHC MAF wired up and installed, it seemed to smooth out idle a bit and the voltage readings through consult appear to be in a better range than the original. I am still having timing issues, i'm gonna do some reading and see if there is any step i missed during setup, also checking continuity from coilpacks, injectors, and CAS to ECU. My big concern is the coilpack signal being different from the signal wire to the actual spark plug, I cant imagine there should be a 20 degree difference between the two.

Quick drive; Absolutely no change of AFR under boost. Still reading as high as 15.0. Confirmed fuel pressure on the stock fpr is right at 40 psi with vac attached and it does raise with load. I think that just about narrows it down to an ECU issue, aside from the timing problems. I suppose if the timing was off far enough, an added load would only make that worse and its possible that fuel wouldn't be injected in the right interval to make it into the cylinders? I don't know enough about the inner workings of the ECU to do any further testing here but with basically everything being stock its very frustrating.

Alright, I got my hands on an english sr20 manual, ill be checking all of the sensors and components as well as the ecu wiring (some have been shortened/lengthened).

hyd3official

@jscherf inbox me that manual boss.

ultimateirving

If I recall correctly, Wide band o2 sensors normally should be about 12-18 inches from the turbine. So if it's right on the turbo elbow you could be cooking the o2 sensors or getting bad readings.

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jscherf92

Oh no sorry the narrowband ecu o2 sensor is in the elbow, the wideband is on the tail end of the downpipe, about 3" before the flange that bolts to the cat. I'm going through and testing all the voltage, resistance and continuity today. Hopefully something presents itself, I tried logging on my way home but couldn't get it to stall like it has been.

jscherf92

I might have finally made some progress. I resealed the PCV fittings on the intake side, both on the intake manifold and the valve cover, and managed to get the AFR down into the 13's at 7psi. Since it was previous in the 15's this is a huge improvement already. I'm gonna go over all of my fittings and seals and probably put together a venturi smoker or something to test for more leaks.

Max readings under boost from consult:
RPM: 3975
TPS: 3.46V
Injector Pulse: 14.16mS
Duty Cycle: 36%
Air Flow: 3.92V
AFR: 13.0-14.0 (approx)