Thread: Vapor lock or fuel pump?

So on my recent trip to Vegas I experienced problems with my P10 VE. The problem first occurred 160 miles into my 220 mile trip. The temperature was in the 110's and I had the A/C on going 75-80 or so up an incline. The car began to lose power and bog. I pulled over and the idle was erratic. At this point since I was 100 miles from my destination, I called AAA was towed into Vegas. The tow truck driver said he sees a lot of vapor lock in that area due to the heat and load on the cars. So when we got to Vegas I him drop me off at a gas station. The car started up fine, I topped off with gas, then went to the hotel. So two days later I hit the road figuring I would baby it home and not run the A/C. Again the temps were in the 110's in the desert. I only made it 50 miles this time....same problem. After being on the phone with AAA and having to wait, I decided to start it up and see if I can get further down the road....which I made it to Baker which was another 35 miles or so. I pulled off the freeway, topped it off and let it rest for a bit. (at this point I was averaging 36mpg since I was driving about 60-65mph). Once I got on the freeway again I only made it another 25 miles before it did it again. At that point I had it towed home since I was 106 miles from home. I've taken a 300+ mile trip to the bay area with 3 people in the car with the A/C on going up the grapevine (mountain pass going up interstate 5) with no issues, but then again it probably was only in the 90's.

So my question is, could it just be vapor lock due to the heat or could it be the cheap aftermarket TRE 190lph fuel pump I'm using? What things should I check? It's been too damn hot the last couple days to look at it and I have a full tank of gas which sucks. Would I be better off with a new/newer stock fuel pump? This is my daily driver, so I don't race it... will a stock fuel pump keep the VE happy? The only reason I replaced the pump in the first place was because it had 207K miles when I put the VE in.

edit: Also forgot to mention that this happened at an altitude of 3000-4000 feet.

Could be that fuel pump going out on you. You could just slap in another 190lph in it or try and find a denso pump that isn't a fake. Stock DE fuel pump is fine for a VE, Ran mine it till that pump died of old age.

Thanks. That's what Mac said as well. I might try and get a Walbro or Denso....but the Denso's are expensive! :o

If u get another walbro don't run it dry, it seems to kill them faster.

Yeah, I think that's what killed this cheap TRE. I did it a couple times in the last few months.

I think it's the pump really going out. just go with a Walbro 190lph, can't go wrong with the price and quality. That reminds me, I need to replace the fuel pump on Barney as well...

I went ahead and ordered the Walbro 255lph yesterday. I might need to replace the one on my B14 too. I think it's starting to act up.

i didnt think most modern cars suffered from vapor lock anymore. the position of the fuel pump and the fuel injection system itself, by design pretty much eliminates it. it probably had more to do with the altitude and load more than anything else.

x2
Vapor lock happens with older cars that have mechanical fuel pumps on the engine. The pump has to suck gas from the fuel tank. When the gas gets too warm, it starts to vaporize in the fuel line and the vapor "bubbles" stop the flow of the fuel.
Any car with an electric fuel pump in or at the fuel tank runs with a pressurized fuel line which keeps the "bubbles" from forming.