93 Aerostar 3.0

Has been giving me intermittent problems (usually during wet weather) (note this is now our extra workhorse vehicle,.. does college hauling .. and the boys drive it when back) at the first part of winter it was giving me issues with not starting and occasionally killing... pulled the cap and rotor cleaned off the build up that occurs, started it, let it run till warm .. all good

next day .. wouldn't start no matter what I did.. decided that I would tackle it in the spring .. so of course .. 3 months later after sitting outside it starts right up .. WTH

starts three days in a row

Pulled codes OBD1 ( and I am using the codes results off the linked page above as they do not match the haynes manual)

KO engine off 172, 542
KO engine running 173, 538

172 --Oxygen sensor not switching - system is or was lean - Single, Right or Rear HO2S - Fuel control

542 - Fuel pump open, bad ground or always on - - Power / Fuel Pump Circuits

173 --Oxygen sensor not switching - system is or was lean - Single, Right or Rear HO2S - Fuel control

543 -System did not receive "goose" test - TESTS

I think 542 is my Key as my fuel pump has a lower pitched "drone" then I am used to (running fuel pressure (just under 40) key on pressure (35) (note it took three key ons to initially achieve this .. but I forgot to bleed the air from the tester at first)

once achieve and after bleeding air all key ons gave me 35 psi

So.... do you agree it may only be a bad ground and if so .. where would I find that ground??

or what do you think?

Thanks
Dan

 

The fuel pump is mounted on a plate that covers a big hole at the top side of the tank. Usually that's a pretty safe area, as not much gets up there. But if you live in humid climates, it's possible water can accumulate and cause corrosion.

You can look at the connectors in that area (the level sensor wires are there too) by lowering the tank. If you jack up just that side of the van, you can then lower just the left side of the tank enough to take a look. You can try to follow the wiring forward to see if there are any bad connections or chaffed wiring.