Vapor Lock? Anyone experienced it?
 

Has anyone experienced "vapor lock" and could share the symptoms of it?
I have been troubleshooting my car for the last year due to (what I thought) was coolant overheating. I replaced the radiator with a champion, replaced my thermostat (again), switch (again) & even added new autometer gauges for an accurate reading of temp. The radiator keeps the car somewhat cool, my fans are now both turning on before 200* due to my new switch and everything seems OK. Both my temp gauge & fan switch are now mounted directly into my manifold vs the stock head positions (no more header melting plastic).

But tonight I was cruising youtube and watched a video of a guy with a turbocharged IROC talking about how his fuel lines were too close to the headers which in turn was locking his car up (turning fuel inside the lines to vapor instead of gas and going into the injectors that way in turn shutting the car down).

Hmm?

-What my car has been doing-.

1) It would start and idle fine, but after a while in dead stop traffic, it would start to chug...eventually dying and shutting off completely.
2) My starter would not engage whatsoever (what I thought was heatsoak from sitting at idle and in hot temps?).
3) The ignition would turn on fine and the fans would kick on, but the starter would not engage.
4) If I let the car sit for about 20 minutes, it would start up and act like normal....but once the thing got hot again, same thing. chug chug, turn off. No start. Let it sit for 20 minutes and try to gun it home.

Is there a chance that the overheating could be due to my aftermarket fuel line(s) placement? Could they possibly be too close to the header which are making them soak up the heat (the headers get hot as hell) and get too hot...turn into vapor and making the car shut down?

Here are a few pictures of the fuel lines next to my driver side header.
Any advice?


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P.S. I do have a new powermaster starter waiting to go in vs the autozone to hopefully get rid of the starter heat soak issue...

Re: Vapor Lock? Anyone experienced it?
 

i had the same problem with mine....except mine used to be a mechanical fuel pump...i imagine you have an electric one.....



anyway i had my mechanical fuel pump changed to an electric on...the mechanic insisted on putting the fuel pump in the engine compartment near my headers...instead of the rear...even though i told him.... ( mechanical fuel pump sucks fuel - electrics push fuel ).....the car would shut of once it hit 220* and would do the same...it would be fine on the highway....heres a video



I had him put the fuel pump in the rear and the problem was gone !

It may not be the same situation we both had,,,but it was the heat being to close to my fuel pump at the time......You should just route the fuel lines where they originally go through...they look pretty close to your engine...to close....Maybe they are getting to hot...

Re: Vapor Lock? Anyone experienced it?
 

thanks for your comment! Yes my fuel pump is actually in my gas tank. My OEM was replaced with a Walboro 255 back in 2005 when I upgraded my tpi to a stealth ram. Unfortunately I did not replace the fuel filter at the same time and it eventually clogged burning my Walboro. I now have BBK 255 in the tank and a new OEM fuel filter FWIW.

Re: Vapor Lock? Anyone experienced it?
 

They look way to close to the headers, try re-routing them along the fender over the booster.

Re: Vapor Lock? Anyone experienced it?
 

The lines should be re-routed for safety, but vapor lock in EFI systems is pretty rare and almost impossible (notice the almost).

Fuel in a pressurized line is going to resist flashing into vapor. Old carbureted engines with the mechanical (or electric) line in suction and no pressure in the system were a lot more susceptible. Since the TPI EFI systems also flow more fuel due to the constant return from the regulator, liquid fuel doesn't stand in the fuel line very long and doesn't get heated as much as in the older systems.

Re: Vapor Lock? Anyone experienced it?
 

Could be good 'ol ign module, rather than a fuel issue - symptoms pretty much fit.

Re: Vapor Lock? Anyone experienced it?
 

Put a heat shield or blanket around your new starter. It does sound like fuel issue. Ive never had good luck with stock starters near headers.

Re: Vapor Lock? Anyone experienced it?
 

OK, maybe the car was just overheating then, do you think I should still move the hoses away from the header anyway?


Running the stocker, I've read a symptom of one going bad was it wont rev past 2k unless thrown back in park...Mine doesnt do that. It revs fine, just turns off when it gets hot lol.

Definitely, I bought a powermaster XS a few years ago and snapped the terminal off tightening one of the connectors...and threw in a autozone one as a quick fix. Re-soldered the inside of the powermaster but never put it back in. I will definitely use a Moroso heat shield plus some wrapping this time!

Re: Vapor Lock? Anyone experienced it?
 

That's the classic ign module symptom. Nothing to do with rpms. Also part of which is not restarting for 20-30 mins until it cools down, which is not typical of vapor lock. At least in my experience with vapor locked carbs - they usually start back up within seconds to a minute or so.

Re: Vapor Lock? Anyone experienced it?
 

same thing with me,,,,, carb with vapor lock,,,but it will start right back up..

Re: Vapor Lock? Anyone experienced it?
 

So I should look into possibly replacing the module?

Sorry for my lack of knowledge but if I had to guess, the IGN module is inside the distributor cap? Is this the curved circuit board looking thing or the actual plug the wiring harness snaps into? My distributor is stock but has an MSD cap & rotor.. MSD wires, coil and digital 6 ignition installed as well for further info.

What would make this thing get hot and start screwing up to begin with?
Looking at the MSD website they only offer an HEI module and my coil is seperate from my dizzy.

Steve

Re: Vapor Lock? Anyone experienced it?
 

The module is mounted in the dist below the rotor, not inside the cap. Like any electronics subjected to repeated extreme heat stress, it's life will become limited, Or the dielectric grease under it fails or was badly applied by a PO etc, leaving it prone to overheating. Anecdotally, the best replacement seems to a stock Delco.

Could still be vapor lock of course - just thowing the module out there too. When it dies - can you still crank it? If so - see if you have spark during the no-start - will rule the module in or out.

Re: Vapor Lock? Anyone experienced it?
 

No. When it dies, turning the key does nothing but surge the battery. No clicking, no nothing. That is why I thought the starter was somehow becoming heat soaked.

Re: Vapor Lock? Anyone experienced it?
 

Sounds like you've got 2 different issues - heat kills the engine thru whatever means, and then subsequently kills the starter or it's solenoid by the heat soak.

Just for giggles, when it's dead check the voltage at the batt terminals and starter post, make sure it's not something like cables, batt terminals or some such.

Re: Vapor Lock? Anyone experienced it?
 

Agreed on both counts.

Go drive it around for 20 minutes some day that it DOESN'T do this, and then turn the car off and try to turn it right back on. If it's heatsoak in the starter ANY situation to get the starter warm will cause it to not turn over or be VERY sluggish.

The problem that causes the car to chug and shut off is unrelated. Could be an ignition module. Just get a cheap factory-sounding replacement one. I've burned through a few aftermarket modules when my $20 borg warner one has lasted a long time now. If it makes absolutely no difference, put the old or new module aside for the day that it DOES happen to you, because it's nearly inevitable, maybe next week, maybe in a few years.

Now for the starter not working, the common solution is a ministarter. They are smaller and much less likely to heatsoak. A factory option is an LT1 starter. Don't bother with a parts store reman LT1 starter, it costs more than brand new performance ministarters from summit or jegs. But if you get a used one or a chinese one on ebay you may have good luck with it. I got a junkyard one for $25 on ebay and it lasted about a year before it crapped out. I figure that was worth it since it fixed the heatsoak problem I had. I at least knew that was how to fix it.

Re: Vapor Lock? Anyone experienced it?
 

Just so were on the same page I do have a powermaster XS starter. Bought it a few years ago and never put it in because I snapped the soldered terminal off when putting it in. Fixed it, just never put it in.

Re: Vapor Lock? Anyone experienced it?
 

Just FYI for anyone who stumbles upon this post. There was a lot going on with this car and it took me a very long time to get it all figured out.
1) My distributor had a dying ICM, and no I did not know it needed to be replaced. This thing would work fine cold, but extra hot temps out in certain days + header heat would fry it to the point my car would stall at stop lights. It always seemed out of nowhere.
I replaced everything you could think of except that stupid module since I thought I had a fuel pressure problem. Fuel pump (twice), fuel filter (twice), new chip burned, drained gas, etc. I thought maybe it was a heat-soak issue and moved my fuel lines around.
2) My stock starter and then the replacement auto zone starter would get heat soaked to the point that once the ICM started to fail, I also could not even re-start the car unless it sat for a few hours and cooled down...

So, I replaced the starter with a power-master XS along with an aftermarket aluminium heat shield. Then the restarting problems were gone...but the car kept stalling.
After replacing the ICM, the issue was taken care of. The original ICM had zero thermal paste left on it from 1988 and was rusty.
https://cimg6.ibsrv.net/gimg/www.thi...86d5637c84.jpg
https://cimg7.ibsrv.net/gimg/www.thi...7746c5e7cf.jpg

What sucked for me was the stock ICM 2 prong connector was so burnt/deteriorated that simply touching it caused it to shatter into several pieces and I had to install the new one wrapped with electrical tape.
I also used Arctic Silver thermal paste (used for high end gaming computers) instead of the stock white grease that came with the replacement ICM to help pro-long the life of the replacement.

This stupid $50 part drove me insane for several years and kept my car in the garage because of it.

So, replace the ICM with an original Delco brand and enjoy. I hope this helps.

7/30/19 Update, I cut the old ICM connector plug off (what was left) and spliced in a much newer donor plug and soldered it in-line. FYI these weird bare wires hate sticking to solder even when fluxed so be warned. Also the top of the dizzy is very, very corroded and may need a rebuild soon so if your stock dist. ICM is taking a crap you might want to pull the entire unit out and re-build it with a fresh icm/cap/rotor all at once.