Turns over, won't start
10-05-2018, 01:56 PM
#1
SCtruck
Thread Starter
Turns over, won't start
I have a 1998 Ford F150 Lariat 4.6l 4x4 with 198,000 miles which has been in the family for about 14 years. It was been dependable. Within the past year a problem has developed where after a period of driving, it will not restart, will turn over, but will not start. After about 10 minutes it generally will start again. It will start for the first cold start after a period of sitting. I have seen on numerous forums that this is not an uncommon problem but I have seen a variety of possible fixes. Any thoughts?
10-05-2018, 02:03 PM
#2
SCtruck
Thread Starter
Additional info
Things that I have done so far - New O2 sensors, new MAF, new PCV, replaced a vacuum hose with a large hole, new fuel pump relay, replaced ECU. Replacing the ECU made it run a lot smoother but still will not restart immediately after running for a while. Currently no codes are showing. Runs great right now, just an aggravation when it will not restart. I'm thinking now about replacing the fuel pump. Any thoughts will be appreciated.
10-05-2018, 02:06 PM
#4
Senior Member
No codes I take it?
Sounds like a leaky fuel pressure regulator to me. Next time you drive it, take the vacuum line off of the regulator and watch it for a bit. See if fuel comes out of it, and flooding it.
Sounds like a leaky fuel pressure regulator to me. Next time you drive it, take the vacuum line off of the regulator and watch it for a bit. See if fuel comes out of it, and flooding it.
10-05-2018, 02:23 PM
#7
Senior Member
Yep, regulator.
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10-05-2018, 02:39 PM
#8
SCtruck
Thread Starter
On another site (https://www.doityourself.com/stry/7-symptoms-of-a-bad-fuel-pressure-regulator) I read this about testing a fuel pressure regulator - "Remove the vacuum hose that attaches to the fuel pressure regulator, making sure the engine isn't running. If gas is in the line, your fuel pressure regulator is bad. Also, if there is none in the line, but, when you turn the switch on, fuel drips out of the hose, it is bad."
When I pulled loose the vacuum hose, there was no gas. When I turned the switch on, there was no gas. Should I continue with changing out the regulator?
When I pulled loose the vacuum hose, there was no gas. When I turned the switch on, there was no gas. Should I continue with changing out the regulator?
10-05-2018, 02:44 PM
#10
Senior Member
You take it for a ride with gauge attached and up on the cowl. You should read a constant and steady pressure (around 42 psi) throughout the rpms. If pressure varies, the reg is bad. If pressure exceeds 65 psi, the rail is shut down by the PCM.