Vapour Lock Definition

[2ManyZs]

If it just started suddenly, I doubt it's vapor lock, unless you still have the water line connected to the intake that is.

Sounds like either an ignition problem, bad tank of gas, fuel filter clogged, plug fouled, plug wire shorting across another wire..... if it were vapor lock, it would have been doing it all along, or at least to the point you would have noticed it.

Probably end up being one of those things that make you slap your forehead and ask yourself, "Why didn't I think of that"....:cheeky:

[NR240]

I tend to notice vapour lock during exessive periods of idling, say at traffic lights on a hot day. It occurs when attempting to take off at high speed. It is often quite hot in Australia so its no surprise. I have a heat shield, plus my extractors are HPC Coated to prevent heat transfer...It still happens despite this.

Trick is, to know when it might happen, so you dont end up getting smoked off the line!

[tanny]

Unfortunately I can't tell you which of the following fixes worked for my vapor locking 73 Z because I did them all at once: Re-installed the mechanical fuel pump(already had the electric running), fabricated a heat shield, hooked the fuel recirculation back up, and insulated all of my fuel hoses with 1/2 inch copper pipe foam insulation from the hardware store. Absolutely no vapor lock anymore. Victor.

[v12horse]

Hmmm... Well I replaced the gas filter and there was a bunch of rust in it. It is wierd because when I first got the car in 99 it sat for awhile and I had the filament and rust removed from the tank. Now it is there again. Also, the diaphragm in the gas pump is sucking in air with the gas. I took it on a drive yesterday and it did not have the problem, but it did feel a little shakey. As regards to gas, I go to this generic place all the time just to support a small business near my home. I am going to start using brand name gas from now on.

I will keep you guys posted on how the car is running.

-Ben

[v12horse]

I just went on a drive and the car drove fine. I didn't go on a long one, but the weather was hot, I went up hills on the freeway, got on the gas some, and drove it around town in traffic. I am hoping that it is the gas filter like 2manyzs said. The car felt like it had a lot of power, but if it was the gas filter, why did it all of a sudden start doing this? The only time that the car would get bogged down was in the heat, on the freeway, and usually uphill. I would think that is when I need the most fuel. I am going on a drive with some guys from the forum tomorrow. that will be the true test. Thanks for everyones comments.

-Ben

[TomoHawk]

V8 engines sometimes get vapore lock because the carb is too close to the intake manifold and the guel in the carb boils. So they put a non-heat-conducting spacer under the carb to keep it a little cooler.

If you remove the webbing from the intake for the fuel-inject Z, would heat from the exhaust affect the injectors?

thx.

[jmark]

My 78 280Z exhibits some bucking but only below a half a tank of gas. I has been explained to me that the fuel hose in the tank may have a hole in it and when the fuel gets low it starts sucking air & fuel. I fill the car up & it runs fine. The gas tank has been redone, fuel filter cleaned etc. The only way to fix is to pull the hose and basket by drilling another hole in the tank. The fuel tank seems to be a weak point on these cars especially when the car isn't driven much and allowed to sit. I have been told to keep the tank full when storing.

[jalexquijano]

On ‎03‎/‎20‎/‎2004 at 6:36 AM, tanny said:

Unfortunately I can't tell you which of the following fixes worked for my vapor locking 73 Z because I did them all at once: Re-installed the mechanical fuel pump(already had the electric running), fabricated a heat shield, hooked the fuel recirculation back up, and insulated all of my fuel hoses with 1/2 inch copper pipe foam insulation from the hardware store. Absolutely no vapor lock anymore. Victor.

Have you got pictures of the heat shields? what material did you use to insulate the metal fuel rail and fuel lines? I have the exact same problem and need a solution to percolation at the fuel bowls!

[Mark Maras]

@240znz, are you still with us? We haven't forgotten you.

Jalex, As I recall your heat shield is two piece. (can't remember which thread the pic was in.) It's possible that the gap in the shields between the carbs is defeating the intended function. Just a theory.  Instead of all this guesswork on everyone's part (don't get me wrong, treasure hunts are fun) have you, (or any other member with the gremlin), considered using an infrared thermometer to measure the temp of the the fuel system components under the hood? You are still connected to the fuel rail by the valve cover aren't you? I think this was suggested by another member a while back. I'm sure that everyone (including you) would love to have raw data to peruse. I'd start at the firewall and work my way forward to the float bowls. The findings would invaluable to you and others with the same problem.

[240znz]

Yep. still here, but not at all often.

[Pop's Z]

Hey all. Be aware that 240ZNZ has been sidetracked by kids, catamarans, mountain biking, craft beers, etc, etc, etc. Plus living in New Zealand itself is a major distraction. Many lame excuses for why his "zed" is still in pieces. Oh, yeah, now it's winter again...just sayin..............

Cheers, Mike

[siteunseen]

Anyone heard from the other New Zealander whose avatar was his wife holding a white poodle?  Super nice guy that was a lot of help to the members here. 

Can't think of his name and hadn't seen any comments from him in a year or so. Seems like he had a 2.4 in an Austin Healey?