Sorry to be Redundent - Help

[siteunseen]

I un tapped mine for you to see. It goes in between the original Datsun connectors, one wire or side only though. If you do it like mine you'd turn it to the right or clockwise to add fuel.

[FastWoman]

Yes, mine is wired entirely under the dash. Doing it like siteunseen, it does not matter which wire you plug the pot into.

BUT... If you're suddenly having to limp home, the pot isn't going to help much at all. It's still a fuel delivery issue. Furthermore, if you have inadequate fuel delivery/pressure, you're not going to get a stable tuning with the pot. You have to fix the pump first, if that's indeed an issue. Strap a fuel pressure gauge to the windshield wiper, and go for another 0.1 mi drive!

[bhermes]

Thanks.

Siteunseen this is exactly what I am planning on doing. FastWoman, I have the pressure gauge on the windshield wiper ready for a ride.

One additional item. I let the car idle for about 20 minutes and it seemed a little inconsistent. I then rev'd the engine some and got a nice (or not so nice) backfire and the car started idling much better. Any thoughts?

[FastWoman]

Backfire making an engine run better? That might be a myth born in Hollywood -- Chitty Chitty Bang Bang sort of stuff. Or maybe a good backfire might have unclogged a carb jet back in the day. However, with a modern(ish), fuel injected engine, backfire is never good and never helps the engine run better. A good, hard rev, on the other hand, can blow the crap out of your cylinders and un-foul your plugs, so that's a good thing. But not the backfire.

BTW, backfires will traumatize your AFM, sometimes bending the vane! Fortunately the '76 has the backfire valve in the vane, but that still doesn't make it bulletproof.

A backfire (meaning through the intake, not out the exhaust) means your engine is running extremely lean. Your test drive should tell a lot about the fuel delivery. And the pot will probably tell a lot about your mixture.

BTW, it goes without saying that you need to eliminate any intake leaks as a first step towards getting the mixture right. You also need valves in proper adjustment and your timing set right. You've already ticked proper fuel pressure (at least idling in the driveway) off the list, so you know your FPR is working correctly. Then after you've done all this, that's the time to tweak the mixture with the pot.

[siteunseen]

Also, needing to find a z expert in the area just until I get a little more knowledgeable.

When I needed mine 20 years later, from back in the late 80's, I called my local Nissan Dealership and talked to the Parts Manager. He knew exactly who I was looking for and gave me the name of the garage he was currently at. Said he comes to buy parts all the time for our L motors. Or you could call an import auto parts store and ask who they would recommend. I hope we can help you figure this out on your own but you may need a valve adjustment and the timing set proper, not that hard but if you don't mind somebody else working on it then that'd be the easiest thing to do.

[bhermes]

Finally got a day with roads clear and above 30 degrees. I went to go for a ride and I have a decent fuel leak around the fuel pump. I had some issues a few months back and had all of the fuel lines replaced and put on a new filler hose. Seems that something was not reconnected properly. Need to get this fixed and hopefully the drive will happen later today.

Weather is going to be nice soon and I need to get this thing running good.

I will be back with a post soon on what I find from the drive and the fuel readings.

[bhermes]

Only got about 20 miles of driving on the car over the weekend. Nothing really to report. Car ran fine with no issues.

Fuel pressure was good.

Is there any chance that when the tank gets low the car would run bad? Pump not able to pull from bottom of tank? I have about 8 gallons in the tank now plus or minus. Going to see how this plays out and will reply back later.

Back to cold weather and a little snow.

[FastWoman]

I drove a '75 Z back in the 1980's. It developed a rust hole in the siphon tube inside the tank, so that when it got down to a half tank of gas, the pump would be drawing air.

A more common problem is that rust and debris can clog the intake screen as it sloshes around inside the tank. Then when you shut the pump down, the debris falls to the bottom again.

[bhermes]

Fixed gas leak and another 20-25 mile trip with no issue in regards to fuel pressure. Trying to determine if I need to replace battery (constantly putting charger on to start). The car did run rough at first yesterday and I am just curious if this can happen if the battery is not fully charged? After a couple miles everything seemed good. I did stop the car after about 5 miles for 2 hours and the car started up without charging.

Still need to get in a little longer drive and hopefully I will today. More ice and snow coming Sunday night.

[bhermes]

If someone can chime in. I have always wondered how a low charge on the battery could impact car performance. I guessing with the EFI it can cause problems but not sure.

Since I have not really seen an issue with fuel pressure, at least yet, I was curious if the battery could be the issue or at least an issue. After I made the alternator change, 60 AMP internally regulated alternator, I did not make the wiring change to the e-brake relay and therefore the light was coming on even when the brake was off.

Just trying to understand, obviously I can easily replace the battery and check to see what happens.

Thanks.

[Mark Maras]

Back to combustion basics. Fuel, air, ignition source. A lack of voltage can effect any of these especially in a F.I. engine. If you think the battery is low, check it with a volt meter. it should be a little above 12volts with the engine off. Engine running voltage should rise to 13 + volts if the alternator is charging. While on the road, if you think the voltage is down, turn on everything electrical; lights, heater fan, etc. If voltage is already down, this will make the engine run worse. Mark in Portland

[bhermes]

Thanks Mark.

I will continue to check fuel pressure and confirm voltage.

Is there an easy way to tell if I have something on all the time draining the battery? Not sure what a normal battery would drain just sitting for a few days.

It seems to only hold a charge at least enough to start the car for a few days max.

Again thanks. Waiting for next day without ice on road and above 40 degrees.