Reading voltage on inertia switch | Page 2 | Ford Explorer - Ford Ranger Forums - Serious Explorations
  • Register Today It's free!

Reading voltage on inertia switch

shamaal

Explorer Addict
Joined
April 25, 2005
Messages
1,248
Reaction score
5
City, State
Friensdwood, Texas
Year, Model & Trim Level
91 Mazda Navajo
Well, I started out this morning ready to perform trouble-shooting and take pictures. After locating the fuel pump relay under the power distribution box, under the hood, on the passenger side of the vehicle; it dawned on me that I still don't know if you have the 4.0 OHV or 4.0 SOHC engine. Is our battery on the driver's side or the passenger's side?

Your reply in #16 leads and your replacing the relay leads me to believe that the problem is in the control circuit. When you put the jumper in the inertia switch connector, did you check it with the test light. It should have come of 1-2 seconds when the key was switched on. From my reading on your #16 it did not.

To answer your question regarding jumpering the relay (looking at the diagram AND you have the 4.0 OHV engine), the jumper would go between the contacts corresponding to C109 (BK/Y) and C100 (DG/Y). Your pump should come on. Do this only for a short period, you don't want to fill the cylinders with gas. I'd feel better if there was a picture so the correct pins are confirmed.
 

Attachments

  • Relay Box.JPG
    Relay Box.JPG
    99 KB · Views: 23,421



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





WECALLHERDORA

Active Member
Joined
April 16, 2006
Messages
50
Reaction score
0
City, State
michigan
Year, Model & Trim Level
1994 ltd
I feel like maybe I am testing the inertia switch improperly.there is definately power at the relay. I also banged on the fuel pump and got nothin. I think I am just going to replace the pump and see what happens. Anyone want to buy a 94 explorer in MI?! I cant keep messin with this thing.
 






WECALLHERDORA

Active Member
Joined
April 16, 2006
Messages
50
Reaction score
0
City, State
michigan
Year, Model & Trim Level
1994 ltd
sorry did not see last post. my battery is on passenger side. as far as connecting the inertia switch for testing I connected the test light to ground and unhooked the wires at the bottom. I put the tester on each wire terminal and I get no light with key on. Also I dont want to jumper the wrong thing so I havent done it yet. I am still studying it.
 






WECALLHERDORA

Active Member
Joined
April 16, 2006
Messages
50
Reaction score
0
City, State
michigan
Year, Model & Trim Level
1994 ltd
I see your relay box under power distribution but i dont know if I can reach mine as there is hardly anyroom. My underhood looks much more crowded than yours!
 






WECALLHERDORA

Active Member
Joined
April 16, 2006
Messages
50
Reaction score
0
City, State
michigan
Year, Model & Trim Level
1994 ltd
WAIT A MINUTE! Something has just occured to me after reading your question about the inertia switch. . . should I be testing a jumper wire? because I am not. I am just putting the tester on each seperate wire terminal with no jumper wire present? Maybe I am just a retard!! Please Heelp !
 






shamaal

Explorer Addict
Joined
April 25, 2005
Messages
1,248
Reaction score
5
City, State
Friensdwood, Texas
Year, Model & Trim Level
91 Mazda Navajo
Chill, no damage done.

Yes you can test the jumper in the connector. Touch the jumper with the tester. Have assistant turn key on, the light should come on for 1-2 seconds, then go off. If this happens (off, on, off) it's the fuel pump (most likely) or wiring.

If this does not occur, then it's time to check the relay side. I'm curious about what relays you have been checking. Perhaps there is that great a difference between the 91s and the 94s. In the picture of my 91, on top of the relays is the power distribution box, it contains fuses. Underneath the fuse box (the whole box lifts up after pinching the bracket) is the relay box, which lifts out in a similar manner.

:D Can someone confirm the arrangement of the 94 ltd,
perhaps post a picture? Of particular interest is the pinout of the relay socket.

In the meantime what relays have you been looking at? The later models have the relays and the fuses in the same box, perhaps this is yours.
On top of your engine, is there a plastic cover that says: 4.0 L EFI?
 






WECALLHERDORA

Active Member
Joined
April 16, 2006
Messages
50
Reaction score
0
City, State
michigan
Year, Model & Trim Level
1994 ltd
My explorer has the fuses and relays in the same box, so you can see I was even more baffeled when I saw your picture, cause i dont have that box underneath. I will check the inertia switch like you said with the jumper and see what happens. The relays I have been testing are the fuel pump relay and the EEC relay. I swapped each one out with heater/blower relay and no change I also purchased a new fuel relay( to the tune of 13$ at autozone) and no change. I am also very curious about a picture of the pin jump. I am not ready to do it until I am certain I am doing it properly. Thanks for all your help, it is appreciated.
 






shamaal

Explorer Addict
Joined
April 25, 2005
Messages
1,248
Reaction score
5
City, State
Friensdwood, Texas
Year, Model & Trim Level
91 Mazda Navajo
There is a difference between the 91s and the 94s in regards to the component location.
Let us know how testing the inertia switch jumper works. I too am adverse to any relay jumping unless I know exactly what to do, if anyone has a picture of the socket, please post.
Swapping the EEC relay was a good idea, that is where the voltage comes from for the fuel pump relay control.
 






WECALLHERDORA

Active Member
Joined
April 16, 2006
Messages
50
Reaction score
0
City, State
michigan
Year, Model & Trim Level
1994 ltd
I have tested the switch and I get the off on off so, I am now making the assumption that it is the pump. I dont think that I can drop the tank myself and will have to get somebody to do it. Best place to purchase the pump? someone told me they were on ebay for 50$ but I am not certain about how good the parts will be when I get them.
 






410Fortune

Truck Season!!
Staff member
Moderator
Joined
August 3, 2000
Messages
28,728
Reaction score
5,107
City, State
NORTH IDAHO, 7B
Year, Model & Trim Level
B2 "Slightly" Modified
Callsign
FOURTEN
Napa or carquest for the pump, stay away from Autozone, Checker for fuel pumps.

You can drop the tank yourself, seriously it takes like 4 bolts and a few hoses, takes an hour tops......dont pay more then $200-300 MAX to have a new pump installed.

If you have power at the relay your inertia switch is working, as I said they RARELY ever go bad...
 






WECALLHERDORA

Active Member
Joined
April 16, 2006
Messages
50
Reaction score
0
City, State
michigan
Year, Model & Trim Level
1994 ltd
Thanks again for all help I will let you know how it turns out. I am wondering if there is a thread with specifics about changing the fuel pump? I will start searching. Are there any special tools required. I know i could get off the bolts but I am concerened about the Hoses.
 






DeRocha

NEX Vice President
Elite Explorer
Moderator Emeritus
Joined
July 5, 2003
Messages
6,674
Reaction score
56
City, State
Brockton, MA
Year, Model & Trim Level
'93 XLT 4x4
Use the search button and enter "fuel pump" and you'll get lots of info such as
Fuel pump and Sending unit replacement
Dropping the fuel tank
Using Fuel line Disconnect tools
Although a fuel pump costs $50 or so the fuel pump sending assembly (the part the fuel pump connects too) maybe rotted out... It is only made of zinc plated steel and the lines running outside the tank often rust out. As such it maybe better to get the entire assembly (pump & sending unit) and just drop it in...

btw more good info can be found in the repair link in my sig line..
 






shamaal

Explorer Addict
Joined
April 25, 2005
Messages
1,248
Reaction score
5
City, State
Friensdwood, Texas
Year, Model & Trim Level
91 Mazda Navajo
Way to go!
Your call regarding the tank, it's a tough one person job, but it is doable; get a friend to assist. DeRocha has researched some good links. The ones with TAS98xlt's pictures are especially informative. It may be time to purchase a Haynes repair manual for your Explorer.
Read the book, threads and ask questions of things you do not know.
A couple tips:
- There may be pressure in the fuel line, see pic. Wrap a rag around the fuel scrader valve on top of the engine (I've removed the cap) and depress to relieve any pressure; like a tire valve.
- Use a siphon hose to remove the gas from tank, the less gas in the tank, the easier it is to drop and raise.
- Back your Explorer on to ramps to gain lots of clearance. Block the front wheels. You can use the ramps later to change your oil.
- The special fuel connector tools are demonstrated in TAS98xlt's pictures. You will need two sizes. They will come in the kit or you can get them as loaners at your car store. The tools insert easily, but sometimes the fittings stick. No pliers or other tools are required. As a last resort use a pick to remove the retaining ring. Replacements are available at an autostore.
- Did I mention ask questions if somrthing's unclear?
 

Attachments

  • Fuel schrader.JPG
    Fuel schrader.JPG
    60.7 KB · Views: 7,048






CDW6212R

Hauls the mail.
Elite Explorer
Joined
June 17, 2004
Messages
23,662
Reaction score
4,170
City, State
Knoxville, TN
Year, Model & Trim Level
98 Limited AWD
The fuel tank line fittings can be easy, and they can also be an awful task. If you do the pump, have the vehicle high enough to have an object(like tool box) able to fit under the tank to rest on. It takes a lot of patience to disconnect those line fittings.

I have worked on a couple of tank lines which someone else had previously abused, making the fittings much tougher to remove. The plastic line tools work better than the steel or aluminum versions. They are deeper, reach deeper into the connectors.

A used pump assembly and fuel level sender should be about $50. They may last many many years, or not long at all. I haven't had a used pump fail yet. Good luck,
 






WECALLHERDORA

Active Member
Joined
April 16, 2006
Messages
50
Reaction score
0
City, State
michigan
Year, Model & Trim Level
1994 ltd
Very helpful information. I will be doing my homework before I tackle this on my own. Also about the schrader valve, I have pressed it in already to see if I was getting any fuel pressure but there was nothing, not even a single drop of gas. i am assuming this is because it has been sitting for quite a few days now.
 






CDW6212R

Hauls the mail.
Elite Explorer
Joined
June 17, 2004
Messages
23,662
Reaction score
4,170
City, State
Knoxville, TN
Year, Model & Trim Level
98 Limited AWD
The fuel pump keeps pressure in the lines, but it bleeds away after some time. When you get the pump working again, turn the key on, and off, a few times, to bring the pressure up. Change the filter also if you don't know how old it is.

BTW, the object that you set the tank on(lower it down slightly onto), will be the height where you will reach above the tank for the line fittings. Make that object the right height and strong enough to hold up the tank there.

I had to change the pump in my 93 Limited and my 91 XLT, they are no cake walk, but you get used to them. Good luck,
 






budwich

Explorer Addict
Joined
May 4, 2005
Messages
3,243
Reaction score
7
City, State
Ottawa, Ont
Year, Model & Trim Level
96 XL
dora... before you go after taking the fuel tank / pump out. Try directly jumping the fuel pump. Yes I know you have been jumping wires here and there but run a wire all the way from your battery terminal to the other side of your inertia switch (ie. the side going to the fuel pump).... and listen for your pump. Of course, you should also check this with your test light to ensure that you are getting voltage all the way to the point in the circuit. If you don't get a pump sound then you are likely looking at the cabling to the pump. But don't give up and start replacing things quite yet. Lift up your back end, crawl under and inspect the wiring going to the pump / fuel sender. Wiggle things to see if you get pump noise happening with your long jumper wire still attached as it still could be just a poor connection. Good luck.
 






CDW6212R

Hauls the mail.
Elite Explorer
Joined
June 17, 2004
Messages
23,662
Reaction score
4,170
City, State
Knoxville, TN
Year, Model & Trim Level
98 Limited AWD
You can check for down wiring yes, but the wiring from the inertia switch back is well sealed or protected. The connector near the pump being removed would be the most likely wiring issue there, and it would be obvious. Good luck,
 






budwich

Explorer Addict
Joined
May 4, 2005
Messages
3,243
Reaction score
7
City, State
Ottawa, Ont
Year, Model & Trim Level
96 XL
Tha't what I figure too... that way with her own jumper wire directly from the battery to "just past" the inertia switch takes basically everything out of the circuit except for the connector at the pump and the pump. If she doesn't hear anything, then its got to either be the connector (loose or otherwise) or the pump. She can then address this directly. If the pump runs, then she can save herself a lot of lost effort and money.

PS.... if you can't find any wire long enough, use a normal house extension cord with a couple of small wires at each end.... remember to check for voltage with your test light to ensure your "jury rigged" jumper is good.
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





WECALLHERDORA

Active Member
Joined
April 16, 2006
Messages
50
Reaction score
0
City, State
michigan
Year, Model & Trim Level
1994 ltd
I will give it one last shot with the jumper wire. let me make sure I got it right, wire from positive battery terminal to inertia switch fuel pump side which I believe is green wire? and listen for pump to prime. also the wiring is super sealed and it would be hard to tell if any thing was loose. I did a bit a wiggling but no change. i am pretty sure that if there is a loose connector near the pump I will need to drop the tank anyway to get at it and if thats the case she is getting a new pump wether she needs it or not (119,000 miles.) I dont think I am going to want to take it off again.
 






Top