Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

[cpjxh7]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

av8or09 - I'm not sure how to tell if the pump is a Holley or if it has an internal pressure regulator? It's a volvo part # 3857985 which I was told supersedes to 3858261. What should I look for?

Although I think I just made a discovery about half and hour ago. Had the boat running great after replacing the gas line, anti siphon valve and battery all of a sudden it started to hesitate? It pulled out of it for a couple seconds and then died and would not start. I pulled off the gas line from the carb and attached a rubber hose to it and ran it to a bucket. Cranked the engine and no gas came out. Then I pulled the relay to put a jumper on the pump and the pump still did not run. Checked voltage and I do not have any voltage to the relay housing on terminal #30, I do have low voltage to terminal #86. I will backtrack and let everyone know what I find. I did have a little better the 12v on #30 the other day when I checked.

Also the new anti siphon valve was much easier to suck air through. Don't know if this means anything, but sure felt like less suction was needed. Maybe just wishful thinking on my part.

bjcsc -- again thanks for posting the carb service manual! This may come in handy.

Off to find my short.

 

[bjcsc]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

No trouble...sounds like you're getting closer!!

 

[cpjxh7]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

Ok, need to slow down a little bit. Turns out the circuit breaker was tripped. Must have happened when I tried to jump the pump. Think I had the ignition switch in run when I tried to jump it.

Here is the current situation. I can jump the pump and it pumps gas with the ignition switch in the off position. When I crank the engine the pump does not run!

Previously Don S said "If no pressure, you need to check the #85 terminal on the relay and see if power is getting to the relay when the engine is cranking. If there is no power to the #85 terminal while cranking, it may have a bad diode in the orange wire going to that terminal." To do this do I pull the relay out and check voltage from #85 to ground while cranking the engine? Does it hurt anything to crank the engine while the relay is out?

While I wait for you responses I will follow the procedure for testing the relay and bjcsc provided.

Thanks.

 

[bjcsc]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

The diode checking procedure is on p. 2-60 in that first group of pages I posted. Basically just checking for continuity with a DVM...

 

[Don S]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

Forget what I said as a way of checking it, If you check it by the manual it will take you through the process step by step and you will quickly locate the problem.
Originally, I thought by reading your post that you had a pressure gauge hooked up. That is just a good way of seeing if the pump is running or not when the engine is cranking. Because you won't be able to hear the pump run while the engine is being cranked for starting.

 

[cpjxh7]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

I pulled the relay and it passed all the tests. Put the relay back in the boat and check the pump with the engine cranking it pumped gas just fine. Hooked the gas line back up and hit the key and the engine popped right off and ran for around 15 minutes. Turned it on and off a 6 times without any problem.

Guess I need to quit jumping around and take Don's advice and start over from the top and go through the manual step by step. Still have my doubts that it will uncover anything as this is such and intermittent problem.

My money is still on the relay having an intermittent problem as from the sounds of it there is nothing else that would be intermittent.

Comments? Suggestions?

 

[Don S]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

Relays are like solenoids, how often have you seen starters click a half dozen times then start. Eventually they will go bad. I would say take a spare relay with you. It's cheap insurance.

 

[cpjxh7]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

I picked one up today and plan on taking it with when we go out tomorrow. Just thought it would be nice to get this ironed out before going out.

Right now I can start and run the engine. Isn't this proof that the Alternator [Green] Lead Diode and the Assist Solenoid/Starter Relay [Orange] Lead Diode are good so there is no reason the check continuity?

And I've ruled out any restriction up to the fuel pump by replacing everything, checking the pick up screen and checking the gas tank vent.

Also is there any reason to check the fuel pump pressure? My problem has not been while the engine is running, it's only been starting. I've never had any issues while running at any RPMs. The engine has never killed, that is until tonight on the driveway.

So it's either got to be the relay, a short somewhere or a bad ground.

I'll let everyone know tomorrow night when we get back. Thanks for all the help and appreciate you all hanging in there with all my questions.

Thank! John

 

[goodlife]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

Relays are like solenoids, how often have you seen starters click a half dozen times then start. Eventually they will go bad. I would say take a spare relay with you. It's cheap insurance.

as i said a few post back mine was doing same thing and was bad connection where relay plugs in. looked nice and shiny but mashed plug in one at a time and has ran great all this year out onriver every weekend . still hard to believe connection could have pump run part time and other times not. mine did it on hose after chasing ghost most of last year. after all this still love those volvo engine with sx drive. good luck with your boat.

 

[Don S]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

Also is there any reason to check the fuel pump pressure?

As I said before, watching the gauge was a way of seeing if the pump was running or not since you can't really hear it or feel it run. I've tried, and it doesn't work.
So if it runs and you have no rpm problems no reason to check the pressure. Unless you just really want to know.

 

[cpjxh7]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

Here’s an update:

Out for the entire day, boating, tubing, skiing... engine never missed a lick. Burt probably 1/2 to 2/3 of a 30 gal tank. What a great day! Upper nineties and not a cloud in the sky. Even water was 84 degrees.

Will be out tomorrow again and see how it goes.

John.

 

[bjcsc]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

Great news and good job. In the interest of resolution, post what you think the problem was and how you fixed it before archiving this thread...

 

[cpjxh7]

Re: Fuel Problem? -- 97, 4.3L GL, 2Bbl Holly, electric fuel pump

We went out again Sunday for a repeat of Saturday and did not have one problem.

I’m not sure what the problem was and don't believe anything I did fixed it, permanently anyway. For the most part all I did was replace the battery, the anti siphon valve and gas line, took the hard line b/t the pump and carb off a bunch of times, trouble shoot the pump relay and checked the relay harness for power. Oh and I cussed a lot! I bet that’s what did it.

I still have not replaced the relay, but have a new one in the boat in case the problem presents itself again, which I think it will over time. Just didn't want to replace and then not know if it was the problem or not. This way if it happens again and I swap the relays and it works I will know for sure.

Best guess on the fix is that it is a bad connection somewhere either in the relay blades and harness or wires in the harness and playing around with the relay and stuff fixed it for the moment. Or as Don S said, it could be the relay itself.

I will be sure to give an update when/if it happens again.

Thanks for all the help!

John