Hot Weather woes

[macebus]

Just checking to see if anyone else has issues with carbs loading up in hot weather where one is caught in stop and go traffic.

The 66 275GTS I have, and another 275GTS I know of both had a similar issue coming home from a concours on the same road about 20 min apart. Since then, Ive had two time where I was forced to wait for 30 minutes or so before the car would run again.

Jim

[Michael Bayer]

Jim:There are a rich set of threads on this, it may be a tired mechanical fuel pump or in my weird case a blocked rear fuel filter that only occluded at temperature, there are several courses of action.

[Yale]

I am getting more confident in my ignorance to repeat the same two words when I read posts like this, ready? Vapour lock. Turn on your electric fuel pump in city driving and in traffic. Yale

[Rudy van Daalen Wetters]

My brother had issues with his 365 2+2 loading up in the stop and go traffic in Santa Barbara on the way home from the Monterey weekend. Ran terrible when quite hot and then after cooling, ran great again.

Rudy van Daalen Wetters
1963 GTE s/n 4001
1966 330 GT s/n 8705

[Jimmyr]

Jim, what do you mean "plugs loading up"? If it is vapor lock then there is no fuel getting to the carbs. This sounds like a classic vapor lock problem. Do you keep the electric pump running when it gets hot, and is the electric pump working correctly? Jim Riff

[macebus]

Indeed, I usually turn off the electric pump after the intial start up. Living in Washington State, the heat is not normally a problem and I suppose I just neglected to try that. In the future I will keep that pump on and see what happens.

I do think its a bit odd that the vapor lock could occur at the temp that it did.. Perhaps its mostly engine heat that is the issue, although it never does this in cooler weather.

Jim

[tyang]

Hi Jim,

What was the altitude? I remember evaporation is dependent on temperature, and altitude.

Tom

[Jimmyr]

Jim, vapor lock can happen anytime anyplace, there are many factors that can contribute to this problem. As Tom indicated altitude can be a factor, carb tuning - possible silghtly lean, timing - running a little hotter cyl temp, weak mechanical fuel pump - low fuel pressure, location of fuel lines, exhaust heat shields not in place, increased vapor pressure from some fuel blends. As our cars get older some or all of these factors contribute little by little to produce vapor lock. Since I live in AZ and 112 degree days are common, I keep my electric pump on all the time. A word of caution though, modern cars that also use electric pumps only have a crash switch to turn the pump of in case of a crash. If you choose to use your electric pump all the time keep in mind that a crash could possibly have some fire associated with it. Jim

[Matt F]

Indeed, I usually turn off the electric pump after the intial start up. Living in Washington State, the heat is not normally a problem and I suppose I just neglected to try that. In the future I will keep that pump on and see what happens.

I do think its a bit odd that the vapor lock could occur at the temp that it did.. Perhaps its mostly engine heat that is the issue, although it never does this in cooler weather.

Jim

Hi Jim. I used to turn off the electric pump after the intial start up, too. Then, my car stopped in around-town driving. The cause was vapor lock, and was solved by keeping the electric fuel pump on.

Even though the ambient temperature may not be that hot, if your Ferrari isn't moving very quickly, a lot of heat can build up within the engine compartment.

Good luck with keeping the Autoflux on. I think it will solve your problems.

--Matt

[lukek]

i rebuilt my mechanical pump and the "vapor lock" I used to get in traffic is all gone. Parts are available and not outrageaous. Mine was marginal, and I got tired of having to turn on the electric pump at every stop, or to keep it on all the time. I have also done a cooling upgrade, similar to Tom's electric fans, but with a twist. See his log or search for my "mother of all cooling upgrades" post. I am also about to install different plugs, with a heat range more suited to stop and go traffic.

[donv]

My 365GT 2+2 electric pump is wired to be on all the time, regardless of switch position (done by a previous owner). However, your mention of fire hazard is a very good point-- maybe I should rethink this.

[quote="Jimmyr"]If you choose to use your electric pump all the time keep in mind that a crash could possibly have some fire associated with it. Jim[/quote]