99SportX
Explorer Addict
- Joined
- May 14, 2003
- Messages
- 2,009
- Reaction score
- 25
- City, State
- Duluth, MN
- Year, Model & Trim Level
- 1999 Ex & Mounty
Hello,
For the past year I have had a warm start issue with the SOHC. It starts perfect every morning. It also starts just fine after sitting all day at work. It only has issues starting when warm. It will crank for an extended period of time (5+ seconds) before starting with a bit of a stumble. Sometimes it will quit just after starting but then start the next time. I can get it to start faster and more reliably by holding the gas pedal down about half way. It has always started so I never really cared to fix it, but now it is starting to get old. This weekend I got a misfire cyl 6 (P0306) code just after one of the rough starts.
I purchased a fuel pressure gauge from harbor freight. I hooked it up and when I turn the key to on, the pressure rises and settles at 65 psi. When cranking I can see the gauge pulsing between around 50 and 65 psi. Once the truck starts it stays steady at 65 psi and I can hear the fuel pump humming away when I listen near the tank. I have not revved up the engine much, but it didn't seem like it changed a lot when I let the rpm's rise some. Once the engine is shut off, the pressure immediately drops to 60 psi. After that it starts to slowly drop. I would say it loses 10psi in the first 5 or so seconds, and is down to 30psi after about 30 seconds. When I came back after 30 mins it was down to 10 psi.
As far as I know, this rate of leakdown is not normal. I am assuming the pressure leaks down whether it is cold or hot. Why does it only have hard starts when the engine is warm? I cycled the key many times and let the pressure drop from 60 to 30 multiple times. I would assume that if there was an external leak, that I would have seen something dripping. That leaves internal leakage. I don't even want to think about a leaking injector. I found this post about an internal tank leak : http://www.explorerforum.com/forums/showthread.php?t=222895
Once the truck gets running, it runs just fine. The idle may be just a little bumpy, but nothing severe. When climbing a hill at lower rpms under load, the truck sounds a little funny, kind of has a raspy crackling tone to the exhaust. I think I may have a hole in the muffler somewhere though. Could this be a pinging noise due to running lean? Why no codes? Under load there is obviously more fuel demand so I may have to watch my fuel pressure when climbing a hill.
When I bought this truck about 3 years ago, the fuel tank was in the rear cargo area. The owner started to change the fuel pump and gave up on it due to ongoing transmission issues. I installed a used fuel pump I got from a fellow member along with a new strainer and a new inline filter. The tank was inspected and was quite clean inside. I did not replace the short sections of hose between the pump, pressure regulator and hard output line. Everything was fine and dandy for quite some time, but now it just doesn't want to run as well.
Any thoughts or suggestions are appreciated.
For the past year I have had a warm start issue with the SOHC. It starts perfect every morning. It also starts just fine after sitting all day at work. It only has issues starting when warm. It will crank for an extended period of time (5+ seconds) before starting with a bit of a stumble. Sometimes it will quit just after starting but then start the next time. I can get it to start faster and more reliably by holding the gas pedal down about half way. It has always started so I never really cared to fix it, but now it is starting to get old. This weekend I got a misfire cyl 6 (P0306) code just after one of the rough starts.
I purchased a fuel pressure gauge from harbor freight. I hooked it up and when I turn the key to on, the pressure rises and settles at 65 psi. When cranking I can see the gauge pulsing between around 50 and 65 psi. Once the truck starts it stays steady at 65 psi and I can hear the fuel pump humming away when I listen near the tank. I have not revved up the engine much, but it didn't seem like it changed a lot when I let the rpm's rise some. Once the engine is shut off, the pressure immediately drops to 60 psi. After that it starts to slowly drop. I would say it loses 10psi in the first 5 or so seconds, and is down to 30psi after about 30 seconds. When I came back after 30 mins it was down to 10 psi.
As far as I know, this rate of leakdown is not normal. I am assuming the pressure leaks down whether it is cold or hot. Why does it only have hard starts when the engine is warm? I cycled the key many times and let the pressure drop from 60 to 30 multiple times. I would assume that if there was an external leak, that I would have seen something dripping. That leaves internal leakage. I don't even want to think about a leaking injector. I found this post about an internal tank leak : http://www.explorerforum.com/forums/showthread.php?t=222895
Once the truck gets running, it runs just fine. The idle may be just a little bumpy, but nothing severe. When climbing a hill at lower rpms under load, the truck sounds a little funny, kind of has a raspy crackling tone to the exhaust. I think I may have a hole in the muffler somewhere though. Could this be a pinging noise due to running lean? Why no codes? Under load there is obviously more fuel demand so I may have to watch my fuel pressure when climbing a hill.
When I bought this truck about 3 years ago, the fuel tank was in the rear cargo area. The owner started to change the fuel pump and gave up on it due to ongoing transmission issues. I installed a used fuel pump I got from a fellow member along with a new strainer and a new inline filter. The tank was inspected and was quite clean inside. I did not replace the short sections of hose between the pump, pressure regulator and hard output line. Everything was fine and dandy for quite some time, but now it just doesn't want to run as well.
Any thoughts or suggestions are appreciated.