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260 Z wont start and run Any Ideas?

1712 Views 21 Replies 6 Participants Last post by  aj92033
So I put all the fuel lines back together, and added 5 gallons of 91 octane and Berrymans B12 fuel system cleaner (accordingly). The only way I can get the car to start is by spraying starter fluid into the carbs. So when I start the car with the choke on, it waill start then ide rough at low rpm's I also have to keep my foot on the gas to keep it going or else it will die. If I take the choke off, the car doesnt even idle it just dies. I HAVE ALREADY TESTED ALL THE FUEL PUMPS AND REPLACED THE FUEL FILTER. Gas is getting to the carbs. It has to be the air fuel mix ratio. BUT I DONT GET IT, THE CAR WAS ALWAYS A GREAT CAR UNTIL THIS ISSUE. THE CARBS SEEMED TO ALWAYS WORK CORRECTLY. DOES ANYONE HAVE ANY IDEAS?
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Where is the first part of the story? It's missing.

Fill in here...............So I put all the fuel lines back together...etc.
hopefully you didnt swap the feed and return lines or had a fuel filter installed the reverse direction of flow.
I had created a few other posts which are further down the line. I will try swapping the feed and return lines to see what happens. LONG STORY SHORT, I put some sour gas in my car and drove to work, came back out later to start it. It started and ran, I went back in to clock out, came back and the car had died, couldnt get it to restart until a few days later. But had to use starting fluid. I had it going two days ago but the IDLE WAS VERY ROUGH and the car would barely drive.
Now even when I use starting fluid it will start for a split second and die.
so you used different gas? did you remove fuel pump or etc. does your fuel pump whine when your prime it by putting key into on position?
Sorry, I didn't make the connection. Did you flush the float bowls? They might still be full of bad gas.
I went back on his posts, he has the flat top carbs. I would suggest getting the FSM for the 74Z and look up the carbs there. My paper 73 FSM has them starting on EF-7. (engine, fuel system, pg 7)

Bonzi Lon
Yes I did flush out the float bowls, and I also drained all the fuel and fuel lines and let it all dry out for two days, the I went and got 5 gallons of fresh 91 shell gas and also added half a can of Berryman B12 fuel system cleaner. You see, I was able to get it to start at that point, but the car ran like crap. The idle was very low and rough with the choke on. When I take the choke off the car would die. Now when I start it I wont start at all.
Whats your fuel pressure at?
I dont think I can check the fuel pressure since I cant even get the car to start. I spray starter fluid into the carbs and start it up. The rpms go up but then the car quickly dies a split second later. Iknow Iam getting fuel to the carbs though. I pulled the fuel lines off, cranked and saw fuel come out.
The fuel barbs into the carburetors have a fine mesh screen under them. The last filter before the float bowl. Have you checked these for trash? If they are OK, the only thing left that I can think of are the float settings themselves.
So when the mesh filters are there an seem to be clean, but when you meen the float settings, would that be a carb adjustment? Or a is a carb rebuild needed?
You need to get a Factory Service Manual for your year Z. It will explain setting the carburetor floats. If the floats are set improperly, the float valves can close, not letting enough fuel into the carburetor. I'm too far away from my library (300+ miles) to give you any specific information about your carburetors. Read the sticky at the beginning of this of this forum and get the FSM from Xenon's site.

Another possibility is that the float valve orifices are plugged with trash.
Now I knew it might have something to do with the carbs, I just didnt know what it was. The floats being improperly set is a very possible problem. Like I said previously the car will start idle rough then die. I dont know much about carbuerators. I put some sour gas and thats what screwed it up. I used starting fluid to get it started and was able to get it home, but it ran like crap. What do you suppose are some reasons why the floats would have come out of adjustment. Before I had this issue my car ran very well (no denial).
Maybe the sour gas plugged the filters on the carbs. Here is how one fixed his flat tops. http://www.zcar.com/70-83_tech_discussion_forum/flat_top_carbs_my_240z_898697.0.html

Bonzi Lon
Good Looking out bro, I will check the filters and get back with some results a little later. Thank You for the link, it helps to know someone had this similar issue and overcame it.
I checked the little fuel filters in tyhe carbs and they look cean, I even sprayed them with some carb cleaner. Now I am wondering if it is the floats? I found out at auto zone that I have a bad battery as well. Its supposed to put out 650 cold crank amps, and my battery is only putting out about 460ccc's could this be a possibility?
If it fires and runs on starter fluid, but will not continue running, it sounds more like a fuel feed problem.
Yesterday I went ahead and just pulled the carbs out. You told me previously that it could be the float settings. When I popped the carb plugs and cranked the engine to get the bad gas out, it is possible that the floats went back down. Then when I ran new gas into the carbs the floats never came back up. Thus leading to what you told me about the float valves closing. When I pulled the carbs out I flipped each one over (upside down) Now I think there was some more sour gas inside the carb sitting at the bottom of the float bowls. Sour gas that didnt get flushed out. The gas that came out of one carb when I flipped it over had that same sour stinch to it. Today I am going to try and clean the carb out using carb cleaner. I am trying no to take it apart cause I dont have the replacement gaskets to put them back together.
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If you have an art supply shop near you, they have a product for cleaning paint brushes that have dried acrylic paint on them. This stuff will clean the ... well, never mind that. It will clean out any deposits left by gas. I don't know what it will do to gasket material as I have always taken the carburetors apart before using it. If you get some, test it on a scrap piece of gasket material before using it on an assembled carburetor.

I can't tell you the name of the stuff because I can't find my bottle of it. Just moved into a house with a shop and I'm not organized yet. Too many cars, motorcycles and parts for the same. Someday I'll get it down to a manageable number.....Yea, right.

Found the bottle. It's called "Brush Cleaner & Restorer" For Dried Acrylic & Oil Colour, made by Winsor & Newton, Piscataway, NJ 08855, www.winsornewton.com A 4 fl. oz. bottle cost $6.29, but save it after you use it. It can be used a number of times. The bottle says it's non-toxic, biodegradable, water soluble, non-flammable, non-abrasive and low vapor.
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