I've got a 94 3/4 ton ford pickup with a 460. On saturday, I was driving it and it started to idle rough and then I noticed the tach started to surge. I got out of my pickup to pop the hood, but noticed the smell of raw fuel. I went to my tail pipe and noticed that everytime my engine surged back to life after almost choking itself out it would shoot out a blue flame about 8 inches past the tip. The surging cleared up as I drove it, but the flame then became constant.

I let it sit that night and started it up the next day, and it idled fine, but still really really rich. I took it for a test run and once it got to tempurature, it started shooting out flames again.

There is no check engine light, and I put my code reader on it and it didn't show anything either. So I don't really know where to start. I was just going to check resistance at any sensor that might relate to fuel and compare it to my chilton manual.

If anyone has a better idea where to start, it would be very helpful.

 

chek the Vacuum line to the MAP sensor.. or the map sensor itself

 

or the fuel pressure regulator.

 

agreed,,

one way to chek this is cheking the fuel pressure at the rail.. the range must be about 34-36 .. if way more.. its the fuel pressure regulator

 

The fuel pressure with the key ON engine OFF should be 41psi, with the enging RUNNING 35~38psi. Pull the vacuum line off the regualtor, does it squirt fuel when you turn the key on? If so replace it.

 

Sorry it's been so long since I've updated, but I only get to work on my truck on the weekends. Checked the trottle positioning sensor, it was fine. I checked the inlet air temp sensor, it was also fine. I did the running test with my code reader and it came up with a code 72 with the running test. The code shows problems with the MAP Sensor. It's a hundred dollar part, so I'm kinda hesitent. I tested the the pullup voltage of the MAP sensor and it passed according to my Haynes manual. I pulled off the vacume line off of the fuel regulator, no fuel. Thanks for the advise though.