koolkats

I have a 5.7l efi high performance engine and had fuel leak out of a pressure switch. On one side of the engine there is the fuel regulator at the fuel rail and on the other fuel rail there is a pressure switch. This is where I need some advice.

Merc part number 87-14355, this part is no longer avail.
Does anybody know who has one? Tried alot of places and no luck.
Has anybody found a part that will work for a substitute?
Thinking of removing and putting a plug in that spot, will this cause any issues?

cjcs

Ttt

tunertech

I don't have a service manual in front of me but I think it is a 2 wire sensor where the normal running condition is an open circuit. Low pressure signals a ground resulting in an alarm and guardian mode.

To turn this monitoring capacity off you would reprogram the ECU to ignore. But in your case isn't really required

So In the KOEO,
1 - Leave the circuit open - test the result
2 - close the circuit - test the results

In one of those cases you should notice an alarm or definitive change in engine performance resulting in Guardian Mode.

koolkats

Yes you are right, the circuit is normally open. Sure seems like that part is nowhere in the nation,
I would like to have something in that spot instead of a plug, I have found some pressure switches
that are mostly used for nitros applications that seems like they would work.

Problem is the options are 15psi or 30psi and I believe the switch part number 87-14355 is 25psi.
Which one would you recommend? Higher or lower psi.

mr3dman

he is saying to plug the hole and wire around the sensor. If you want to "make it work" with another switch then it is up to you. I'd go with a lower 15psi if it were me. I hate guardian mode

andyt25

what engines do you have if they're the 320 efis I have 2 complete intakes and computers

koolkats

I hate gaurdian mode!
I have never had ecu go into gaurdian mode but sure don't like the sounds of it.

If I plug it (pressure switch) and keep circuit open and for some reason I lose fuel pressure will
this cause damage to engine or injectors? (thinking ecu wont adjust air/fuel mixture, don't know if this pressure switch would play any part of that or not?)

Also if ecu goes into gaurdian mode,
to get it back to normal, is it as easy as removing the terminals from the battery
or does it have to be re programmed?

bikercrze1

So if I read that right on my 2001 6.2L MX in the event of low fuel pressure the alarm should sound?

tunertech

If the pressure is monitored and it drops below the switches designed trigger level and you have a MEFI controller, yes you will get an alarm

koolkats

tunertch

What do you think about that gaurdian mode you had mentioned?
Once pressure is back up and switch is open ecu will automatically
go off gaurdian mode or does it need to be reprogrammed?