Awwwwe, Pretty blue flame.
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Junior User
Joined: Feb 2008
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Awwwwe, Pretty blue flame.
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.
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.
Posting Guru
Joined: Dec 2006
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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
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
Lead Driver
Joined: Feb 2003
Posts: 8,140
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From: Oak Harbor, OH
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.
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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.
