After a miserable day, yesterday where my Pantera vapor locked a half dozen times in a 30 miles trip home from a friend's automotive workshop, I was not very happy. I was scheduled to participate in a very small car show celebrating Tarzana's (community in the San Fernando Valley part of Los Angeles)., but I was really nervous about driving the car to the event even though it was only a few miles from my house. I decided to chance it and figured it would sit for several hours and cool down enough that I could get home afterwards. It was a very small show with maybe 45-50 cars that ranged from rat rods to Ferraris. I parked my car in a row that had several 240z cars, a couple of vintage pickups etc. One of the 240Zs was exceptional with its magnificent bright orange paint. As I was getting ready to leave, there was an announcement that awards were going to be given at that time, so I stayed. A lot of people stopped to admire my car, so I just wanted to see if there was any chance of picking up one of the awards. And lo and behold, the first announced award was to my car for BEST PAINT OF SHOW. I was very surprised. My paint is very nice but not perfect and didn't (I thought) have the impact of the orange 240Z although it garnered a lot of attention from onlookers and nice comments from everyone who stopped to talk with me. So, I guess I can now say tht I have an "Award Winning" Pantera. Go figure!
When you're hot, you're hot!
Are you sure it was a vapor lock? Do you have an electronic ignition? If so, what ignition do you have? MSD? Mallory? PE EIS?
When it "vapor locked," how long did you have to let it cool before you could restart it? I've never been able to restart a vapor locked vehicle in less than 30 minutes of cooling time. If you could restart it after 5-10 minutes, you may actually have an ignition problem. Some electronic ignition systems have internal thermal cutoffs to protect the electronics if things get too hot. And MSD's and Mallory 6AL's are both known to fail in high heat.
If it's actually a vapor lock, a quick-fix is to carry a can or two of computer keyboard duster (the little compressed air in a can). The next time it happens, turn the compressed air can upside down and spray the fuel pump and fuel line. they will instantly be coated in frost! This will rapidly cool the vaporized fuel and return it to a liquid state, allowing you to restart your car.
Thanks for the advice, I will have a computer duster can in my car tomorrow. Unfortunately, when I'm stuck in the middle of an extremely busy intersection, frozen like an ice statue, it's not the first thing that comes to mind. I believe it's vapor lock but I'll bring up your suggestion with my mechanic tomorrow when I see him. It won't start in 5 minutes, but after about 15 minutes I can get it to start and at least get me out of the intersection. On Saturday it happened 3 times within a few blocks, and I was only about 6 blocks from home. The interesting thing is that engine temperature at the time was about 180* not some 220*+ temps that my car used to run into. It's frustrating because we've tried a number of things to try and improve it, to no avail. About 10 years ago, I essentially stopped driving my Pantera due to the pain in the rear starting sequence that made just getting started such a chore, I didn't want to do it anymore. Especially after I got my 5.0L XKR that was quicker, more comfortable, easier to manhandle on the track, and supremely reliable. And at about 600hp, it was no slouch. This lack of wanting to drive it prompted me to start the process of making it more user friendly by switching to fuel injection, and then once in the shop, we did everything else I ever wanted to do to the car. I am nearing the point of not wanting to drive it again because of this vapor lock issue, and this is a more dangerous issue. It has kept me from ever leaving the right lane on the freeway so that I could have enough time to drift onto the shoulder if it stops. I was a nervous wreck driving the car less than 5 miles from my house yesterday, and even more so home in the afternoon heat and traffic. I'm tempted to build a tray around the EFI and carry a cooler with ice around with me and dump a load of ice into the tray everytime I'm out in traffic. Seriously, we will find a solution to this or I won't drive it except for very early cold air mornings. I'll keep everyone updated on how we will have finally solved this.
Your symptoms sound identical to my electronic ignition getting heat soaked and shutting down. I could restart after about 10-15 minutes, but it was likely to happen again within a few miles. And this happened to me when I drove down to LA for the Pantera Palooza a couple years ago, driving on busy congested LA freeways and city streets on a 90-degree day. Not fun! So I totally understand what you're feeling! Except I also had my wife in the car who was not a great sport about it all and only wanted to add to the stress.
Anyway, I found that if I did NOT use the AC, it was less susceptible to heat soaking the ignition. But as soon as I turned on the AC, I was guaranteed it would die within a couple miles. Also, you mentioned you have fuel injection. Vapor lock is almost non-existent with a fuel injected car because the fuel lines are substantially pressurized. I would definitely try swapping your ignition box.