76 280z microsquirt project

[madkaw]

Better use some RTV or buy the expensive gasket they recommend . The flange is warped probably like mine . I used a machinist straight edge and there was .020 drop off on the end . I bought the 75$ gasket but some red RTV would probably l

work also . 
my car makes all kinds of whistles and gear noises . 

[darom]

yes, same problem it seems with these intakes. I used a thin layer of Permatex Ultra Copper, the leak is stopped, i checked with my smoke leak detector.

 

I fixed my timing table (more conservative numbers), re-calculated my Bosch 0280155968 injectors flow at 36 psi (without vacuum it is at 43 psi), and re-generated my VE table using the built-in TS calculator.

 

43.5 PSI (3 BAR) 430 cc / min = 41 lb / h

Calculation:
old/original fuel pressure = 43.5
New Fuel Pressure = 36
Size of Fuel Injector in lb/hr = 41

New flow/Size of Fuel Injector = 37.298 lb/hr or 392.01 cc/min

 

The IAC is disabled, the valve opening is plugged. I can't re-check the idle startup with engine cold at the moment, but when warmed-up, I can't get the RPMs lower than 1.5-2k. The only air leak is at the throttle body with the blade which is barely open (if I close it more, the car dies). The engine's vacuum is at 15-16 at the 1500 rpm. My valve cover vents the gases via a small filter. The PCV valve is connected and operational.

 

If someone has time to review my tune with a datalog and tune for any issues, I'd appreciate it.

 

Should I proceed with turning my IAC on at this point? Or I need to test the cold startup before going with the IAC enabled?

 

Thanks.

 

PS With the throttle blade barely open, the car is making a loud annoying whistling noise. With IAC installed, the blade will be completely closed and this nonsense should stop, I hope.

CurrentTune.msq 2024-10-27-no-IAC-VE-inj-changed-calculated-flow-7.mlg

[darom]

I found out that the IAC plug in my throttle body is actually leaking air, possibly causing this RPM increase. I sent an email to Pro Tunerz asking if this is intentional or if their plug should be sealing the opening 100 percent.

[darom]

Protunerz got back to me and suggested dremeling the edges off in the throttle body.

 

First I tested it while pointing my air compressor's nozzle at it and it made the annoying noise. Removed the throttle body and took sharp edges of openings with a dremel tool:

 

It passed the air compressor test. After installing it, the noise is gone 80 percent, there is still some noise when the throttle blade opens up.

[darom]

Hi guys,

 

What should be my idle fuel pressure? I have been running a FPR set at 43 psi without vacuum attached, which translates to 35-36 psi at idle (440cc fuel injectors).

Is this an ok FP for operating these injectors?

I finally got my idle sorted out with the Open Loop mode. The IAC is a sob, makes annoying noises, and I don't trust it that it stays in the set position 100 percent (I set mine in Always On). The idle would occasionally dip accompanied with the IAC noise. I'd try getting another unit to test.

 

Thanks!

 

2024-11-12-good-idle.msq

[darom]

Yesterday I drove the car with the autotune running. I started a thread on msextra about my sync loss issues at: idle/IAC question if someone has time to review my tune/datalog. Thanks

 

 

 

Edited Monday at 02:35 AM by darom

[madkaw]

Looked at your tune briefly . Might try increasing step size for better reliability . Mine only stays stable if power is always on like yours . 
Not sure I see anything that would cause a sync issue 

[darom]

Thanks, Steve! I will put 4-5 min steps instead. I noticed that every day (here in WI, we were at 45-50F for the past 3 days), my engine startup/warmup bevaves differently. I had to fiddle with the VE table/timing to get a stable idle. It might explain this if my IAC is not predictable and can't keep its position.

 

I have been doing some reading and it seems that 5v vref switch to a 12v feed for the HALL sensor most of time doesn't resolve a sync issue. I have an osilloscope and would try logging the HALL sensor's output.

 

Would you recommend switching over to the closed loop idle mode or stay with the open loop? I have no a/c, the radiator fan is not electric.

[Bernard]

Just bought an n42 intake manifold that came with the micro squirt module, injectors, wiring, throttle body, fuel rail w/regulator, etc.

 

I’m only using the manifold and do t need anything else. Would anyone be interested in buying all the other stuff for cheap - $100 for all?

 

I have photos if needed.

 

Thanks,

‘71 240zxt

 

 

[madkaw]

5 hours ago, Bernard said:

Just bought an n42 intake manifold that came with the micro squirt module, injectors, wiring, throttle body, fuel rail w/regulator, etc.

 

I’m only using the manifold and do t need anything else. Would anyone be interested in buying all the other stuff for cheap - $100 for all?

 

I have photos if needed.

 

Thanks,

‘71 240zxt

 

 

Yeah - I would 

sfinnerty1018@gmail.com

[madkaw]

On 11/17/2024 at 9:42 PM, darom said:

Thanks, Steve! I will put 4-5 min steps instead. I noticed that every day (here in WI, we were at 45-50F for the past 3 days), my engine startup/warmup bevaves differently. I had to fiddle with the VE table/timing to get a stable idle. It might explain this if my IAC is not predictable and can't keep its position.

 

I have been doing some reading and it seems that 5v vref switch to a 12v feed for the HALL sensor most of time doesn't resolve a sync issue. I have an osilloscope and would try logging the HALL sensor's output.

 

Would you recommend switching over to the closed loop idle mode or stay with the open loop? I have no a/c, the radiator fan is not electric.

Maybe a pull up resistor at the CAS might help . My truck gave me fits and I ended up putting a pull up resistor at the CAS - even though the board had one - it fixed my issue . 
my buddy even put an oscilloscope to it and said the signal was fuzzy . The pull up resistor was a Hail Mary