darom

I'd also put the multimeter leads directly on the fuel pump and watch the voltage when someone operates the throttle. Voltage drop there won't do any good to a fuel pump operation.

Thanks! I guess if the opening is 6 AN/ 0.34 in, I will need a 3/4 in countersink bit.

My protunerz fuel rail has the same shallow o-ring surface for the CSV line. @HusseinHolland what is the name of the drill bit you used on yours? It looks like a deburring bit (45 degree?). I am heading out to Home Depot, will look for one. Thanks!

I hope so too, I just ordered the same fuel rail from Protunerz. That chamfer for the o-ring will be the first thing I will be checking when I get the part.

Found this link to a pre-made timer relay to get some cheaper build ideas: http://www.okaauto.com/EFITimer.html

Thanks for looking into it! I have the same issue, I am running the MSD-2225 fuel pump, and I think it doesn't have any drain-back valve. I installed one of those Amazon special one-way valves after the fuel filter in the engine bay. After a while, it stopped working. When I took it apart, some corrosion inside created the seal/membrane gaps. What do you think about wiring the fuel pump relay + 5-10 sec timer relay into the ignition switch (ON position)? The fuel pump wires run under the carpet on the passenger side (at least in my 76), providing an easy access.

@Captain Obvious Any updates on your fuel pump-priming project? I use one of those $5 time relay boards to run a 1979 fuel rail fan blower for 10 minutes. It is manually operated. The relay board is attached to a bigger relay to handle the load of the blower motor.

With the correct AAR orientation, at the beginning the idle was at 1100 rpms, within 2.5 minutes I saw the idle speed slowly going down. Once the air regulator valve was completely closed (i could check it by pinching the AAR hose - it didn't affect the idle speed), I set the idle at 850 rpms. It is steady. I will check the car again in the morning to test, but I am positive the issue with high idle/AAR has been resolved. Also I was able to shut the engine down by screwing the idle screw in. I couldn't do it before. I still need to redo my oil pan gasket to get 1-2 in of vacuum : - ) Big thanks to everyone on this forum.

I think I figured out the AAR issue on my car. Yesterday I was bench testing one of my AARs and noticed that blowing air one way allows for more air to pass through vs the other inlet when the curtain is closed. I checked onine pictures of the AAR orientation in the engine bay of other 280z owners and realized that my AAR was/is installed backwards (the electric connector is facing the firewall). I am going to change it tonight after work and see if this improves the idle speed 🙂 If this is the case, I have had the AAR installed wrong way for at least 5 years now. And you know how it feels ...

Zed, I removed and inspected the inside of the AAR after a few test runs. Before the installation, I did the bench testing of it with a 12V and adjusted the curtain to be closed when the coil warms up. Since it can't block air 100 percent, there is still some residual air flow which contributes to 900-950 rpm idle. If I pinch the rubber hose for the AAR, the idle immediately drops to 800 rpm, and it remains steady. In both of my tests so far the idle RPM was the same.

Thanks for the ideas! I might be building a simple on/off solenoid with a cheap time relay board set for 2-3 minutes: https://www.amazon.com/Position-Normally-Pneumatic-U-S-Solid/dp/B06WGRLX58/ref=sr_1_13?crid=5V29CNB41DD4&keywords=12v+solenoid+1%2F4+in&qid=1700523538&sprefix=12v+solenoid+1%2F4+in%2Caps%2C86&sr=8-13

Some ideas for an AAR 🙂 Manually operating heater valve: https://www.amazon.com/Universal-Conditioner-HV-2211C-Control/dp/B003R31YVQ/ref=m_crc_dp_lf_d_t1_sccl_3_3/138-5872620-2836123?pd_rd_w=UzJvp&content-id=amzn1.sym.76a0b561-a7b4-41dc-9467-a85a2fa27c1c&pf_rd_p=76a0b561-a7b4-41dc-9467-a85a2fa27c1c&pf_rd_r=34220AX20P78YFH9FKCE&pd_rd_wg=aMQD8&pd_rd_r=2ead7de1-3b51-42e0-b3bf-74fcaef91ae1&pd_rd_i=B003R31YVQ&psc=1 or this with the timer relay (I use a cheap timer relay for my injector rail blower/fan from a later model): https://www.amazon.com/4inch-Normally-Closed-Electric-Solenoid/dp/B074Z5SDG3/ref=sr_1_31?crid=3G17GRQMH50IC&keywords=solenoid+valve+1%2F2in+12V&qid=1700513498&sprefix=solenoid+valve+1%2F2in+12v%2Caps%2C84&sr=8-31

Hi guys, I ran the smoke tests, found a few areas: 1. valve cover gasket, firewall side - big leak. 2. electric EGR solenoid (leaks inside, not vacuum hose), EGR valve (inside again, not the vacuum line). little leak. 3. oil pan gasket - medium leak here. 4. oil dipstick - little leak. I replaced the valve cover gasket with a cork one, it still leaked. The valve cover/cylinder head appear to be flat. I ordered a silicone one from Milkfab Engineering ($28), the new gasket sealed all the leaks. I made a delete metal plate for the EGR. Replaced all the old spark plugs with new NGKs, replaced the fuel filter. The aux air regulator was replaced with a 300zx unit, which was adjusted to shut. It takes about 6 minutes. The valves were adjusted. The car's ignition timing is set at 15 bdtc, idles at about 900 rpm. The vacuum is at 17. The car has a strong pull, no hesitation while accelerating. Observations: 1. I think once I replace the oil pan gasket, I might get another 1-2 of vacuum. This is a spring project (it is too cold in the garage). 2. The resistance pod is at 2k Ohms. I still can't kill the engine maxing it out at 5k. 3. The 'new' AAR is unpredictable. If I leave it alone, it will close (not completely) after 6 minutes. Two different days while testing - one day the idle is at 900-950 rpms, today it was at 800 rpms after warm-up. I feel the AAR shutter 'curtain' doesn't guarantee the same closure. I would like to replace it with a similar mechanical device (like the 240z choke inside). Does anyone know of a part that might work? This way I will open it up when the engine is cold, and close it when it warms up. Once closed, I can set the ideal 850 rpm at idle. 4. When the engine is cold, within those 5-6 minutes of warm-up period, if at idle once rev'ed up, the engine will pop through intake. 5. I still can't kill the engine with the idle adjustment screw. Hopefully, it is the oil pan gasket leak that causes it.

Thanks Yarb, for looking it up. Just in case I ordered a gasket, Mahle MS16717 (composite) from rockauto. I found a forum chat in the Help Me section where a 280z owner compared it to the OEM from Nissan, they looked identical (with the exception of the price). The plan is to do a valve adjustment as well.

Thanks for the resource! Found the part number, 14035-N3500, gasket manifold, looks like it is available. Will order/replace it once I confirm the leaks in that area.

@Dave WM Thanks! I will run these tests next week. This was a great video. I will check the intake/exhaust bolts torque specs. I replaced the injectors, AAR, AFM, timing chain/front cover gasket along with intake/exhaust one (Fel-pro) 5 years ago. The car passed smog in CA. If this is an intake/exhaust gasket, any preference which brand to get? Rockauto lists some Fel-pro, Beck and other brands. Can I double stack these to get a better seal?

The PCV hose was removed and checked, no cracks. The PCV valve is not stuck. Thanks. I am thinking my stuck open AAR might be the culprit, what bothers me is that pinching it I can completely shut the engine off. Basically, per Fuel Injection bible AAR provides more air when the engine is cold to increase the RPMs (speed up the warm up time). Once it shuts in 8-10 min, its function is over (there is still going to be some air escaping, but the amount is negligible). In my case, it is still open adding more air thus creating lean condition. I have a used AAR from a 300zx (?) with a removable cover. I can install it to test the theory.

I did some testing tonight, and @Zed Head you might be onto something. I couldn't kill the engine with the idle speed screw. I could lower the engine's RPM's to 700s until the screw's end of travel, but it would still stay running. Another test with the potentiometer. Mine is a 5K unit, I couldn't use it to kill the engine either. The most noticeable difference is when it is at 0 Ohm (runs bad at idle when it is cold, when revved up, there is popping) and 2K Ohm - the RPMs will pick up, the engine vacuum will go up to 14. Putting it at 5K shows no difference. I can however kill the engine by pinching the Air Regulator's rubber hose. I bought a unit brand new years ago from a Nissan dealership. Per atlanticz.ca's site, it appears the valve never completely closes. I have another spare which I confirmed works by closing its plate completely after 7-8 minutes. I removed the AFM, the door is not stuck, opens/closes smoothly with slight pressure. No cuts/holes in the rubber AFM/intake hose. I ordered a small smoke machine from Amazon, it will be here next week. Hopefully I will be able to pin point the source of a vacuum leak (unless it is the AAR's which is feeding too much air?). Thanks, Den

I ran the engine with the potentiometer on max (I might have a 5K unit), the engine ran on fast idle at 1500 RPMs. I couldn't kill it. Tomorrow I'd lower my idle speed to check for any vacuum leaks. Thanks, this is a good idea. Just for laughs I swapped my ECU with 1 spare unit I had. Same part number as my stock unit, A11-600 000, it has less pins than the one that was in my car. The can ran rich (I could tell by the exhaust smell), I turned off the potentiometer completely since it didn't make any changes. The fuel pressure at idle was 32 psi (vs 30 psi before), the vacuum was 12 (vs 14 before). No more popping through the exhaust when I was revving the engine. (in the picture: the bottom is my stock unit). It is good to know that if a problem doesn't go away with a potentiometer, an AFM adjustment won't help much. I'd hate opening it up and messing it up even worse. I put my old ECU back to look for vacuum leaks tomorrow. Appreciate your help.

Even with 1200 Ohms added to the water temp sensor circuit, the car still runs lean, bogs down until is fully warmed up. When it is warmed up, I still can hear lean popping noises through exhaust. I don't have to smog it any more, maybe bump the BTDC to 15-16 degrees?

Hi guys, I am looking for your advice before I open my AFM unit and start messing with it. Symptoms: when the car is cold, it runs very lean, bogs down, popping noises, lack of power. When it warms up, more manageable to drive, although it occasionally makes the same popping noises. it also smells lean from the exhaust. What has been done: 1. Remanufactured AFM, sealed up. Adjustments to the air bypass screw don't help richen up the mixture. 2. I went through all the FI Book tests, the air temp sensor in the AFM/water temp sensor in the t-housing, all pass. Cold and warmed up. 3. Throttle positive switch - adjusted, at idle, middle position and at wide open per FSM. 4. The fuel pressure gauge shows 30 psi and idle, 36 psi at acceleration. New fuel MSD-2225 fuel pump with a pre-filter, clear gas, no rust in the tank. 5. Vacuum gauge shows 14-15. I am guessing this is a low reading. 6. Idle - 850/900 rpm, 11 BDTC 7. Some time ago I installed an inline pod resistor for the t-stat water temp sensor. If it is at 0 Ohm, the car runs lean, revving up from idle produces lean popping. If I set it at 1000-1200 Ohm, the car can be revved up. 8. This is a CA car, came with a functioning EGR valve, while testing I disconnected it. 9. New intake/exhaust gasket, valve cover gasket, no air leaks around the oil pickup/oil filler. Removing the oil filler cap, reduces the RPMs, engine wants to stall. 10. Air regulator was tested, it closes up after 10 minutes. Pinching the hose produces engine stumbling. 11. The injectors were replaced with brand new units a while back. 12. The timing chain was replaced a while back. I haven't done any valve adjustments. I am wondering if there is anything else I missed before I open up the remanufactured sealed AFM and start messing with its CCW movement to richen up my mixture. I also have another used ECU unit I can swap. What bothers me is why the AFM's bypass screw doesn't make any changes? The car spent all its life in CA and was a joy to drive. Once we moved to WI with colder climate and mornings, I found myself adjusting the in-line pod resistor to add 1000-1200 Ohm. This week-end we had temps in the 40s, I went to fill it up and noticed this leaning mess. Thanks! Den

I ended up installing my new spare MSD-2225 fuel pump. If (or better, when) this one fails, I will go Dephi route with its lifetime warranty. Thanks to all for your insight.

@SteveJThanks for the link to the curved fuel hose. I wish I found it before I made a U-shaped 3/8" line out of the brake line. @Zed Head My bad, I have had 2 Ultra-Power fuel pumps. They look identical to the previous owner's Airtex, even share the same 8312 part number. Delphi shows the maximum pressure of 107 psi, I can't find the minimum one. The OEM part it referenced is E8312 (Amazon link: https://www.amazon.com/Delphi-FD0035-Electric-Motor-Solenoid/dp/B000CGFV2Y) The Delphi's warranty PDF mentions that "This Limited Lifetime warranty lasts as long you own the vehicle in which the Delphi Electric Fuel Pump or Fuel Pump Assembly is installed. This warranty is not transferrable and applies only to the original purchaserof the product." I guess I can give it a shot, although swapping fuel pumps even when they are offered for free, is still a messy time consuming job. Thanks for the pump refernce.

Hello guys, My car has been sitting for 3 weeks. My E8312 fuel pump didn't work today. Cold winters apparently have nothing to do with my issues :-( There is a 12V directly at the pump's terminals. The clear plastic pre-filter was full of fuel since the tank is full and previously I lowered the pump/filter. Rockauto is going to give me a refund (minus FedEx s&h fee to send the faulty unit back to them), since this is the 2nd unit that failed on me within a year. I have put about 40 miles on the car since the installation. I am going to improvise and put the MSD 2225 unit there. I also have an old E8312 laying around, I found a youtube video of a guy who takes it apart and cleans it. Not sure if I want to go this route since the aluminum pump's canister edges need to be pried apart. Any ideas why I am facing such bad luck with fuel pumps? Here in WI they sell high octane gas without ethanol. Should I put that instead of the regular 10% ethanol one? Thanks!

Installed a u-shaped 3/8" brake line to take care of 90 degree kinks with the replacement 8312 fuel pump. Will keep my fingers crossed that it will last.