Fuel pump or ?????

[belsie]

Drove car Sat. perfect with solid pull thru out, parked overnite and within 5 miles cranked up and fell on it's face and would not boost over 12 lbs. !!

Parked hooked up fuel gauge turned on ignition and 0, turned off re-turned and relay kicked up to 42 lbs then when relay stopped fuel pressure dropped to 0. What is the prognosis ??? Dead pump, reg, or ??? new tank & sending unit with a 4 year old RED'S XP ! Went E-85 200 miles ago, question is: Could E-85 have killed pump? is it a coincidence? Was calling on this pump a death sentence?

 

[trbojo]

modern fuel is hard as hell on fuel systems anymore much less e85.....at 4 years i'd guess yours is done! i only got 2 out of my reds, if that, running regular fuel.

 

[Hanny87]

If the fuel pressure is not holding after the fuel pump turns off then it's a regulator problem. The regulator will normally hold pressure for a good while after the pump shuts off. Easy way to check is to put 12v to the fuel pump wire behind the alternator, this will turn the fuel pump on. Check the fuel pressure, if it's holding steady while the pump is on, and then drops as soon as you shut it off, I would say it's a regulator problem. If the fuel pressure drops while the fuel pump is running, then it's likely the fuel pump.

 

[belsie]

I thought the check valve in the pump was for the purpose of holding pressure (preventing drainback), is that not correct? After car sits a while it will take 2 cycles to build any pressure on the gauge and after cranking car will start. Since the car won't boost over 12# I can't see if pressure is climbing as it was 1 day earlier. I have a Kirbans billet reg. app. 2 1/2 years old, what would fail there causing this?
Thanks to all...............

 

[Hanny87]

You are correct about the check ball, I was mistakenly thinking of another vehicle that I worked on recently that had the check ball in the regulator. Another possibility that it could be is the rubber hose between the fuel pump and the sending unit. If the clamps came loose or the hose has a hole in it, that would cause the symptoms you're describing. I personally had that happen to me on my truck. If you didn't change out that hose when you switched to e85, and the hose was marginal to begin with, that would definitely do it.