Fuel Pump Replacement on 1995 5.7 TBI

[tmothy07]

Sometimes the only solution is to figure out a real fuel pressure data logging solution. Not super cheap but useful.

Many generations of MEFI will allow you to disconnect a sensor and when disconnected fully the system will run off a "default" value so if a sensor is supposed to be reading say 1 to 5 volts - the unplugged value that is inserted might be say 3 volts. And that should be sufficient to provide a "normal" run condition or atleast faily normal.

Interesting, I'll have to give it a shot. Any idea where I can find a diagram for these sensors (or perhaps a TeamTalk post)? Or should I order a service manual?

[88 PS190]

There are only a few, engine coolant, idle air flow etc.

[ValveCoverGasket]

Think I need to have someone professionally check the injectors on this TBI 5.7?

I think it's worth doing and is really inexpensive. I don't think running cleaner through the tank is anything but a waste of money (imo) only takes a few minutes to pull them and send them out for cleaning and testing

[CantRepeat]

This is the MEFI 1.2 diag which I've been using on my 94. You might test the coil and the pick up.

MEFI 1-2 diagnostics

[tmothy07]

Thanks for that source Tim. I've got my replacement TPS, so hopefully that works to solve this issue.

[tmothy07]

Update: that didn't solve the issue and I threw in the towel. I let Ace Marine know everything that I had done to it so far with no change in behavior and they dug into it. Turns out, it was a clogged valve/fuel line issue in the in-tank pickup. The material was what confused all of us, it looked almost like a gray concrete-y mud, and had hardened inside of the old hose and filter. It was evidentally causing a partial blockage sometimes (which accounted for the inconsistency of the issue). Any way, a new anti-siphon valve to replace the original, and a new hose/filter, and a nice clean fuel tank has the boat running like it's brand new. I suppose I don't have to worry about any fuel system part replacements for a while lol.