we left Nebraska July 1st for Colorado springs co. then onto Albq NM. once into CO. all i could get was ethanol in the gas, then the vapor locking with ethanol in the gas started. it was near 100 degrees outside, in the evening it did not vapor lock. from the springs to Albq NM. is a 6hrs drive, and it was vapor locking, on the interstate, it run but not good & when i slowed down it died, and if i filled up the cool gas outa the tanks in the ground, it helped for a 30mi stretch or so. all the gas in CO. and NM. had Ethanol in it, i tried 85 octain 87 & 93, i normally run 85 or 87 on my way home i took I40 east outa Albq to tucumcari NM (i know sp) then 54 north through dalhart TX. then to liberal KS. once i got to dalhart TX. they han gas with out any ethanol (and the station said for 2 weeks they have had people coming from the south, tucumcari NM. asking about additives for there fuel, the station thought people were getting bad fuel in NM. butt everyone was vapor locking) once i gassed up at Dalhart TX. with no ethanol no more vapor locking. it's a 95 Ford E150 Conversion Van with the 5.8 V8 and i've owned it since it had 6mis on it, it now has 121,000mi. what can i do when i can only get ethanol ? in NE I can get gas with or with out ethanol.

thanks.

often installing an electric fuel pump near the tank will help. My van would always vapor lock in the summer when the engine was shut off. I added an electric fan with a thermostat due to a 134a freon conversion. With the fan cooling off the engine bay after the is shut off the vapor lock ended.

the van is factory fuel injected and the factory fuel pump is in the tank. this vapor locked with the AC on or off. i had the van checked out on a diagnostic machine after a new cap rotor & plugs, plug wires, and the fuel pressure checked out on the diagnostic machine also and everything checked 100% this was checked prob 8 or 12months b4 we went on this trip, the van prob was drove 3000mi since it was checked out.

thanks

Mustangsaly

If you are really sure it is a vapor-lock condition,and everything else checks ok,try wrapping some thermal barrier material around the fuel lines in the engine bay.Also double check the return line to the fuel tank,since on FI motors it keeps the fuel recirculating and thus cool.

i'm not aware of a situation where efi can have a "vapor lock" scenario? isnt "vapor lock" where the fuel in the float bowls boil? in a fuel injected vehicle, the fuel pressure is too high to allow boiling anywhere, not to mention not having a place to boil other than the fuel lines or fuel tank? i have an early model mustang with a carburetor, running a mild compression ratio, generating a lot more power than your van. i can drive to vegas in the summertime and not vapor lock....

EFI's cant vapor lock... drop in a can of dry gas or octane booster and see if that helps.

i did put in octane booster, sure acted like it was vapor locking, and only did it when it was Hot outside and when i run ethanol gas and mostly in high altitude i guess. it gets damm Hot in Nebraska and humid too. i spent most of last yr in N Carolina with no problems. it did this about 4yrs ago in a summer trip when i was in Albq NM. after that time i tuned it up, plugs plugs wires, cap rotor fuel filter, hasn't been all that long on this tune up i will look 4 a collapsed return line and replace fuel filter, maybe i have a fuel pump problem, butt the fuel pump pressure will show on diagnostic check. sure acts like its vapor locking.

any other ideas ?

Mustangsaly

Yes, they can. Usually caused by a fuel pump nearing the end of its life. The fuel literally boils in the line, and the pump cannot push it through. What was your actual pressure read? If it was at the lower end of the spectrum, this could be your cause. Also, what percentage of alcohol was in the fuel? The more alcohol, the easier the fuel will boil.

well buddy... your the ONLY one i've heard say that an EFI engine can vapor lock. i've even tried looking it up and cant find anything about it. I even checked with the guys at the garage i work at and they've never heard of an EFI vapor locking bacause theres too much pressure in the sustem for the fuel to boil. if you can find some info on the net about it let me know. because i would really like to see what is said about it.

i was told by a Ford Tech in the mid 90s, that if you run your tank low on gas that the pump can over heat,and damage the pump. although i try not to let it get low in these high temp days in the summer. i'm sure it's happened. i don't know what the fuel pressure was, as i was just told it checked out fine. when i have it put on the diagnostic machine in the next week or two, i will know what it is. most if not all pumps in NM and CO. did not show the percentage of alcohol in the gas. most pumps here show a 10% plus ethanol sticker on the pump. i've been wondering about the pump, but i think it's been replaced once under warranty and one other time, i'm not sure.


thanks


Mustangsaly

Well, it's not info on the net that I am going by, it's nearly 12 years of hands on experience. They will vapor lock, and the symptom in very much like that of a faulty fuel cap on an old carbed vehical. On a hot day, the car will start and run fine untill it is hot, then it will hesitate, buck/stall, and then quit with no restart. Let it sit for 20-30 minutes, and it will run for another 20-30 miles, untill the fuel gets hot again. The return fuel being pumped back to the tank is at engine temperature and will heat the fuel in the tank. If the fuel pump pressure is at the bottom end of the range, vapor lock is possible.


Vapor lock is rarer with newer EFI units due to the pressure being increased to 65lbs+. But on older set ups, where the max pressure is around 45psi, and the low is 35psi, adding the 210* fuel to the weak pump, vapor lock can occur.

what you said is 100% on the money what mine did. whats the fix ?


Mustangsaly

well, its like i said, nobody i work with or that i know ever heard of it, so i guess its just one of those things i'd have to see to believe. the weak pump part i can understand....

The fix is to drop the fuel tank, remove the sending unit assy., and replace the fuel pump. At the same time, clean out the tank, as the new pump warrenty will require this, as well as a new fuel filter. Time consuming, but you can DIY, flat rate is 2.0 hours, but it is not a hard job.

Smblkchevy and whoever said vapor lock can occur in a fuel injected engine are very right. I have an Olds '87 2.5l TBI fuel system. I have the same symptons. My TBI system uses only 9 lbs - 13 lbs of pressure.
I will check the fuel pressure when I can get an adapter that substitutes for the fuel filter.
ONE SUGGESTION FOR OTHERS:
Do what you can to get cool air to the air cleaner. Make sure your air cleaner has a snorkel that is picking up cool air from the front of the vehicle. I have temporarily dissconnected mine, and the vapor lock happenns a lot more as the engine is sucking in very hot air from the engine compartment heating up the air cleaner AND THROTTLE BODY.
If the fuel pump pressure checks out OK, I might install a 3" inline duct fan to blow cooler air from the front thru the air cleaner to cool things.
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