4.8l suddenly issues.
 

So I have had my 4.8l swap going now for around a year with no issues and suddenly I'm having problems. It will start up just fine and run for 20 to 30 mins then it dies and does not want to start. My setup is:

2001 4.8l 140k miles on it.
returnless rail
Wix regulator/filter
rear install FI tank with walbro pump

The last time it did this I pushed the schrader valve on the fuel rail to see if I was getting fuel and it shot a little out and I went to try to start it and it fired up. So I figure my fuel injectors were bad, I replaced them and added a pressure gauge to the rail and it fired up fine. Drove for 20 mins and it died again. I had my wife turn the key on but not start it and I noticed that the fuel pressure went right up to about 55 and then very quickly went down to 0. From what I understand it should not do this, so I'm wondering what is failing. Fuel pump? Regulator? Something else?

Any help would be great.

Thanks,

Rich

Re: 4.8l suddenly issues.
 

If its an in tank pump, the hose between the pump and pick up tube could have a hole in it. There a specific submersible fuel hose for the application but most guys use the regular stuff and it can come apart.

Could also be a bad filter/regulator. What brand is it?

Re: 4.8l suddenly issues.
 

It's intank pump, fuel lines and setup is less than a year old. If it was a hole in the line I would assume I would see fuel coming out of the line and smell gas. Thinking its the regulator.

Re: 4.8l suddenly issues.
 

He may be talking about the rubber connection on the fuel pump in the tank

Re: 4.8l suddenly issues.
 

I would hole that after less than a year it would not be damaged on the pump side.

Re: 4.8l suddenly issues.
 

I bought a new Wix regulator/filter and I will replace it tomorrow and see what happens.