Oil switch or fuel pump?

[digbystar]

Hi Guys,

I'm new here and could use a bit of help. I will try and make it short. We went out on the lake , cruising great and the nothing. Engine dies, won't start. I take a little fuel and drop it in the throttle body and it fires right up then dies. I got towed back, anyway, I am trying to trouble shoot it now.

I have a Bayliner 2003 5.0 MPI alpha 1 ser.# Om615005

I have hooked a VOM to the fuel pump power leads and when I first turn the key I get power for 5 sec.s or so (when hooked up I can hear the pump run and stop). I have a 3 lead sensor and a 2 lead switch.
I tried jumping all combination's on each of them and could never get the pump to stay on.
Thanx in advance for any help, Digs

 

[Don S]

Re: Oil switch or fuel pump?

You have an MPI engine, only the carbed engines use the oil pressure switch so that can be eleminated as a problem.

You need to download manuals #31 and #36 here http://forums.iboats.com/showthread.php?t=251571 and follow the troubleshooting charts. Way too much to just start a hit and miss testing method. The pump is supposed to run for 2 seconds, when you turn the key on. When you start cranking, the ECM needs to see spark from the distributor before it will allow the injectors to fire. Do you have spark?

 

[digbystar]

Re: Oil switch or fuel pump?

thanx Don, I will check for spark today.

 

[digbystar]

Re: Oil switch or fuel pump?

You know what, If I pour some gas in the throttle it will fire. So I'm thinking I must have at least some spark?

 

[digbystar]

Re: Oil switch or fuel pump?

OK I do have spark , but I don't think I have any fuel pressure at the rail. I can push the Schrader and nothing. Even when the fuel pump is "running" I get no pressure, at least not noticeable. I don't have a gauge for that size schrader valve.
I have read the trouble shooting manual and the bast I can understand It is telling me to replace pump with a known good one. Any other suggestions ?

 

[digbystar]

Re: Oil switch or fuel pump?

Just a follow up. I bought the fuel pump and installed it today. Oh what a pain. I left about a quart of blood in the bilge. But the pump did the trick. I got it online for about $260, instead of the $425 the shop wanted. It is a new part number 861156A03 as the other is discontinued. Well I hope this helps someone later.