FJ62 Vapor Lock (1 Viewer)

[Grease Cruiser]

Here is the story: My brother-in-law has a 1990 FJ62 that he acquired last winter. It had been sitting for about a year. We could tell the gas was bad so instead of draining the tank (like I recommended) he ran the tank really low. When he filled it back up, the fuel pump went out. So after replacing the fuel filter and the fuel pump, he is still having problems.

Here is what's going on: The problem only happens when he is on a major highway or Interstate. He commutes 30 miles daily and the vapor lock does not happen. It only does it when he drives it on a weekend trip. He is driving along running great until he slows down, like exiting off the highway and coming to a stop sign. When the idle comes down, it sputters and then dies. It will not start for about a half hour. He has to sit there for 30 minutes and then it starts. And,,,,it only does this when the ambient temperature is fairly hot. Above 85 degrees.

Is this vapor lock? Anybody else have similiar experiences? What can he do? Any thoughts and comments are greatly appreciated.

 

[jesterb]

It sounds like the same thing that was happening to dd113's truck. He traced it down to some part on the ignition system. PM him if he doesnt chime in.

 

[FJ40Jim]

Can't be vapor lock. That's when high temps cause the fuel to boil in the carb or mechanical fuel pump, preventing the engine from running.

 

[dd113]

first thing I would look at is the fuel pressure regulator. Run the codes also.

 

[Grease Cruiser]

Yeah, I was questioning vapor lock myself. My brother-in-law took the Cruiser in to have it checked by a professional Toyota mechanic. They said they ran some computer diagnostics and everything came out good. They said to bring it back in if the problem gets worse.

Since the problem is intermittent, they could not pinpoint what was going on. I will look into the fuel pressure regulator. Any other thoughts?

 

[dd113]

Try this: Get a squirt bottle of cold water and when it happens pick one part of the EFI and squirt it down then see if it starts. On mine it was the ignightor but ti took me almost 2 years to isolate the problem.

 

[Shickalee]

I know this is an old thread but my 90 Landcruiser FJ62 is having the exact same issue. CruiserParts.net advised that it might be the vapor/carb cooling fan not working. Could this be the issue?

 

[dsmud4u]

Wait...62s have a carb cooling fan??? I thought all 62s were FI.

 

[Spook50]

Wait...62s have a carb cooling fan??? I thought all 62s were FI.

They are. Not sure why, but Toyota kept the carb cooling fan in place rather than eliminate it in the FJ62's design. Mine's been unplugged since shortly after my dad got it in '90, and later on I removed it completely. I still have it though, so I'm going to wire it up to a relay controlled by the IGN circuit and duct the outlet along the fender to have it blow cool outside air on the alternator whenever the truck is running. My intention is to keep the exhaust heat away from it and allow it to last even longer.

 

[FJ40Jim]

Wait...62s have a carb cooling fan???
I thought all 62s were FI.

No, they have an injector cooling fan. Like many other children of the 1980s (see Datsun, Audi, Porsche, et al.)
Yes, all USA 62s are EFI.

 

[Pin_Head]

Just to reiterate: No vapor lock on EFI engines because of the high pressures required for FI.
More likely it is an intermittent blockage due to the junk from the old gas floating around in the fuel system messing things up.

 

[NCFJ]

I do not agree Pin Head, vapor lock can and does occur on EFI engines. Granted, it is far more prevalent on systems without a return from the engine bay to the fuel tank. But even with a return it can happen if under hood temps are high enough and fuel flow is slow enough. This is why I use a loop system on an LSX swap, the fuel just stays cooler. Toyota continued to use the cooling fans on the EFI models for a reason.

 

[Pin_Head]

We can disagree. Vapor lock is uncommon even on carbureted engines that have a gravity feed to a mechanical fuel pump. The temperature required to vaporize fuel at 4 atmospheres of pressure are so high that you would have a lot of other temperature related problems first. The cooling fan isn't there for vapor lock.

 

[NCFJ]

No worries here, I agree that it is uncommon, just not out of the realm of possibility.

 

[FJ40Jim]

IMHO, the fan is there as insurance. When the system leaks down after shutdown, then the fuel rail can boil dry. The fan reduces that concern.

Some of the Audi cars w/ an injector fan run 80-90PSI in the mechanical injection system. They definitely don't need a cooling fan if everything is working right. But a leaky check valve or leaky injector can still make hot restarts a problem.

 

[TobyB]

Seems to me that the non- crossflow engines seem to get the fan- Nissan L series, especially.
Exhaust heat soak must have been a concern in some circumstances.

And I'm with Pinhead on a bypass EFI system getting 'vapor lock' as described by the OP-
it can only happen if the fuel boils in the tank...

t

 

[Shickalee]

Update the issue of my 90 FJ62 not restarting at operating temp was isolated to be a bad oxygen sensor.

The details:
The mechanic first replaced the water temp control sensor, as mechanic said the connector broke when he went to remove for testing, a new WTC sensor did not fix the problem. After further testing, I was advised the LC needed a new ECU, so I ordered a used one from CruiserParts. The mechanic installed but the the LC would not even start after installing. The mechanic then re-installed the old ECU and the testing equipment then displayed a code for a bad oxygen sensor, as reinstalling seemed to reset the codes. The oxygen sensor was replaced and the LC seems to be running good now with no starting issues at operating temp.