THUNDERZ

I know someone has ssomething out there

I put an 82 L28 into a 74 260Z Manual trans and using dizzy from the 82. My car runs fine but havent had any tach action sinse the swap.I am trying to figure out what wires to hook up to make my tach work again. I have wiring diagrams but they dont sem to help with this. Anyone who has done it please shoot me some advic e.

Still nothing?

I just painted my Z and want to make a stencil of the Z emblem so I can paint it on the car. I am thinking of the emblem just behind the small window on the side. I need aquality image so I can print it out and make a stencil. Any ideas? Thanks

I am not saying to run out and get another pump. I would absolutely get everything else set correctly first. I think jmortensen is on the right track. If you are using a stock return on a 280z it probably doesnt have a small enough inner diameter hole to hold pressure at the carbs with a low pressure low volume pump. Check the line that you are using for return. On my 260 the return line looks like it is the same diameter as the supply but upon closer inspection it come to a head and really only has a pin hole that returns fuel to the tank. Check it out and let us know.

Sooo... Is it that since the return line is clamped and the system is essentially "dead headed" that it works? If so that means that your fuel pump is not adequate for the system. :

I am thinking that you need to start eliminating things as far as what the real problem is. Check the floats, check the fuel pressure, maybe your relay for the fuel pump is going out. Double check to see that you dont have a loose wire somewhere that could be grounding out your spark.

I would double check to see that the fuel pump is keeping up at those revs. You can hook a cheap fuel pressure gauge in line and run an extension fuel line out of the hood so you can see the gauge when you drive. If the fuel pressure dives at those rpm's you know where the problem is. Absolutely check and or replace your fuel filter. If it is really dirty or clogged you most likely have some crud in the gas tank.

yes they are balanced... I realized I wasnt checking valve lash with correct #'s. Will do that in A.M. with cam specs.

If I wasnt so frustrated by this problem I would laugh at your comment

I did a search with no luck on this. I have a misfire at mid to high rpm's. I have a 1980 L28 with triple dellorto carbs, .020 bore, medium cam , ported head with a header to 2.25 inch exhaust. My ignition is 1980 stock. This is in a 74 260z. It has a holley blue fuel pump and regulator set to 5 psi. with a return flow configuration. I have played with jetting and every combonation doesnt affect the misfire. I just rebuilt carbs and checked float levels which are right on. I checked valve lash today and it seems tighter than what the book said it should be but this is the way it came from the shop that built it and I havent had this problem until I rebuilt carbs and put in a new fuel pump. I cant imagine that valve lash can get tighter on its own right? My timing is set at 15 dbtdc static. The engine is running fantastic at idle and about a quarter to half way through the rpm's. At this point it stumbles a little to where it interferes with the power. Its like a series of little back fires in the carbs, not loud but little muffled pops. Any ideas would be appreciated.

What is the maximum advance you can run on an L28?

I am pretty sure I found out what was happeneing in my situation. The gauge was not reading right. In reality I was pumping like 15 psi when it sad 5 and blowing open the needles in the carbs. There goes the pressure. I am not positive yet though.

I would check with Holley as far as PSI. Check out Summit Racing .com for in line fuel pressure gauges. Gauge kits for inside the car have been pretty pricey from what I have seen, but maybe they are out there for reasonable prices if you look in the right place

Tony What pressure is your fuel pump putting out? It is very likely you are running too much pressure and it is blowing open the needle and flooding the carb. A regulator is needed, and running a fuel pressure gauge is a good idea to get your pressure dialed in right where it should be. Good luck.

All the testing that I am doing now is out of a 5 gal. bucket so the fuel lines arent next to anything hot.

Not sure what you mean...I have a pressure regulator....I dont think the pump is adjustable and I have had the same results with two completely different pumps. :

I HAVE A 260Z WITH A 1980 L28 AND TRIPLE DELLORTO 40MM'S. I AM RUNNING A HOLLEY BLUE PUMP W/REGULATOR. THIS PROBLEM HAS KEPT MY Z IN THE GARAGE FOR MONTHS NOW. THE CAR RUNS FOR ABOUT 5 MINUTES AT CORRECT FUEL PRESSURE(3.5) AND THEN SLOWLY DROPS OFF THE SCALE. I THOUGHT IT MAY BE A CLOGGED TANK OR LINE. I DROPPED THE TANK AND IT WAS SPOTTLESS. I BLEW OUT THE LINES ETC. I RAN A TEST WHERE I PUT THE PICK UP AND RETURN LINES IN A 5 GAL. BUCKET(TO ELIMINATE THE TANK AS A SUSPECT). STILL DID THE SAME THING. THE PUMP IS NEW AND JUST IN CASE I RAN A SPARE PUMP IN THE SAME TEST AND IT REACTED EXACTLY THE SAME. ANOTHER INTERESTING DETAIL IS THAT RIGHT AROUND THE SAME TIME THE PRESSURE STARTS TO DROP, THE RETURN LINE STARTS TO BLOW A FEW BUBBLES IN THE BUCKET OF GAS. THAT WOULD MAKE ONE THINK IT MIGHT BE PULLING IN AIR BUT FROM WHERE? THE ONLY PLACE THAT THERE MAY BE SOME VACUUM WOULD BE IN THE FEED LINE AND THAT IS SNUG. TAKE A STAB AT IT! :malebitchslap:

I just took one out of a 78 and all I had to do was take the screw out of the front face and then under the dash there is one lonely screw in line with the tach to take out. You dont have to go to deep either. Should be the first phillips screw you see logically in line with the tach. Then pull it out. Good Luck. Jim

I agree with you . Initially I had no pressure running it wide open to the return line. Thats why I put a valve in...so I could back it up and increase pressure. Now that I installed a different fuel filter in the back I somehow have 3-4 psi with the valve wide open. Now that I have pressure to work with I will put in a regulator.

Tim...I filled it up with gas I had in the garage to a little over 1/4 tank...I wasnt paying attention. That made a difference. It couldnt have been the problem all along because I have had the same amount of gas in it when it acted up before. Somewhere along the line it seems like something worked. I am not going to get my hopes up yet but I went for like a 7 minute drive and watched the gauge maintain 3-4 psi. I guess it would behave different now running a high volume pump and return line than it would act with a reg pump and dead head set up...I mean on a low tank, because it is constantly sucking up gas compared to intermitantly moving it with a dead head set up. It would be more sensitive on a low tank with the gas sloshing about.

Good idea Tim...I will try it. I just installed a different filter at the rear and for some reason it maintained a 3psi level at idle in the garage wth the gate valve wide open! I love adding in little things to the soup that make no sense. Oh... now get this...I do the ceremonial test drive and it drops off the scale as soon as I give it gas(as usual) . Then I hit the brakes kind of hard in frustration and the gauge shot up! I gave it gas and it zeroed ...hit the brakes and it shot up! What the heck does that say???

Don, I am thinking something similar. I have drained the tank 3 times, The pump is brand new...has ran for about 20min.I am going to try pulling from the original pick up and the drain plug fitting...see what happens. Oh! I wanted to ask about the third line. I think it went to the charcoal canister to the expansion tank or to the top of the gas tank. Does that need to be uncapped or doesnt it matter?

OK this started out with hot wires to the pump, this problem was cured with larger wire. Now...The fuel pressure continues dropping to 0 after it drives for 2 minutes. At this point I can see into the glass fuel filter and it look like someone pouring a glass of ginger ale ( lots of bubbles). OK. This is after I relocated the pick up line hose to a fitting that I made to go into the drain plug hole in the bottom of the tank. I did this because I suspected that there may be a "sock" on the end of the original pick up tube that may be clogged. So...I am still experiencing a problem that I cannot define exactly. Any ideas will help. Oh yeah ...this car is a 74 260 with a Holley blue pump to a built L28 with tripple Dellortos(40mm)and I am running a return line. I also have a gate valve in line after the carbs to create pressure at the carbs. Other wise it runs at 0 through straight 5/16 line.

ok I am going to start a new post since this one has changed direction from electrical to plumbing I think. Wires are not hot anymore.