Aerostar relay questions
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From: East Coast USA
Aerostar relay questions
I own a 1991 Aerostar 3.0 V6 with 125k and a few months ago,my fuel pump relay stuck,draining the battery-I had it replaced and it kept acting up.We replaced the computer(PCM?) and it still was not activitating the fuel relay-we could manually kick in the fuel pump by connecting the points on the fuel relay so...we start checking other relays and there is one that is on the same wire tail as the fuel pump relay and we examined to to find that it had completely corroded inside.Basic wiring diagrams list it as a "PCM Relay"but the part # on it does not cross reference and so I have no idea where to being to replace it-any tips?If it is the PCM relay then obviously the new pcm isnt going to start the van without it.Im at my wits end because its been laid up for 2 months already.Does anyone have the specs for this particular relay?Thanks!!!
MJ
MJ
Former ******
Joined: Nov 2004
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From: Salt Lake City, Utah
There are replacement relays that have all 5 pins in them, and they will replace all three relays with the same standardized part. Just get an AC or fuel pump relay and check to see if it has all the pins. The factory relays are keyed so they won't interchange, but the new ones won't have the keys. The old ones have some of the pins inside cut off, the new ones will have all the pins.
Question, what led you to replace the computer?
Question, what led you to replace the computer?
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From: East Coast USA
Yeah we put another relay on that terminal that was the same as the fuel relay and it wasnt working-it had 5 plugs too but when we opened up the old pcm relay,the inner "trigger" was different from the one in the fuel relay-We suspected the computer,had it tested and it was bad so we had hoped that would solve it.It started,ran very briefly and then cut off-after cutoff,it will not start again.I called a cousin who runs a garage and he mentioned the "other relay" next to the fuel relay and referred to it as a power relay"which led me to check and see it was corroded beyond hope.
Im an amatuer as u can tell....my father and uncle have been helping me with it and we are stumped
MJ
Im an amatuer as u can tell....my father and uncle have been helping me with it and we are stumped
MJ
Post Fiend
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From: Washington state
STANDARD MOTOR PRODUCTS Part # RY46T More Info {TRU-TECH}
5 Blade Terminal; Powertrain Control Relay
STANDARD MOTOR PRODUCTS Part # RY46 More Info {RELAY - FUEL PUMP}
STANDARD MOTOR PRODUCTS Part # RY70 More Info {RELAY - MULTI PURPOSE}
to view>
http://www.rockauto.com/catalog/raframecatalog.php
elec. diagram
http://www.autozone.com/az/cds/en_us...rInfoPages.htm
5 Blade Terminal; Powertrain Control Relay
STANDARD MOTOR PRODUCTS Part # RY46 More Info {RELAY - FUEL PUMP}
STANDARD MOTOR PRODUCTS Part # RY70 More Info {RELAY - MULTI PURPOSE}
to view>
http://www.rockauto.com/catalog/raframecatalog.php
elec. diagram
http://www.autozone.com/az/cds/en_us...rInfoPages.htm
Last edited by 96_4wdr; Sep 9, 2007 at 06:54 AM.
Post Fiend
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From: Kiev, Ukraine
I tried to do it and finally I had to cut connector away, installed headlight relay connector and 40A headlight relay.....
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Senior User
Joined: Mar 2006
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From: North Carolina
Most cars now seem to have standardized to using the little square Bosch style relays I first saw on 1970s era European cars. Other than having 4 or 5 pins I think they are pretty interchangable.
That used to be one way of testing for a bad fuel pump relay is to swap it out with a horn or similar less necessary relay nearby on the same car. Even across different car brands these relays may well interchange.
Of course some may have higher amperage ratings like the 40 Amp headlight relay Pablo mentioned, or have other features I'm unaware of.
That used to be one way of testing for a bad fuel pump relay is to swap it out with a horn or similar less necessary relay nearby on the same car. Even across different car brands these relays may well interchange.
Of course some may have higher amperage ratings like the 40 Amp headlight relay Pablo mentioned, or have other features I'm unaware of.
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Post Fiend
Joined: Oct 2005
Posts: 5,242
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From: Kiev, Ukraine
Yeah, now nearly all the relays are Bochs style, used for all the europeaan trucks and cars and for a half of modern american cars and trucks, like my '01 Ranger.
All the european cars and new american cars now have integreted in Fuel filter FPR.....
All the european cars and new american cars now have integreted in Fuel filter FPR.....
Lead Driver
Joined: Sep 2003
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From: SoCal
A lot of those Bosch type relays actually have their circuits embossed onto their case, so you can see exactly where each pin connects to. If necessary, you can rewire the connector so that the activating wire from the key switch goes to activate the coil, and run the power wires to and from the EEC to the correct pins.
The only thing I would watch for is that some of these relays (especially Ford OEM) have a reverse-biased diode on the coil to absorb back-emf during switch-off. If you apply current across it in the forward direction (reverse of how the relay should be activated), the diode will blow spectacularly, and probably ruin the relay. You might be able to check this with an ohm meter; one direction will read lower resistance than the other. You want to apply power in the direction of greater resistance.
The only thing I would watch for is that some of these relays (especially Ford OEM) have a reverse-biased diode on the coil to absorb back-emf during switch-off. If you apply current across it in the forward direction (reverse of how the relay should be activated), the diode will blow spectacularly, and probably ruin the relay. You might be able to check this with an ohm meter; one direction will read lower resistance than the other. You want to apply power in the direction of greater resistance.
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Update Aerostar Sport 1991 v6 3.0/relay issues
We finally found an ECM relay thru Autozone & last night we plugged it in and held our breath,then turned the key.It didnt catch at first because the battery was low(its been sitting for weeks)but then it started and idled roughly,and about 45 seconds later the idle smoothed right out-boy was that old relay corroded-the rust was making it stick,which probably is what fried my ECM and 2 fuel pump relays....thanks for all the advice and help!!!!
MJ
MJ
