2.9 hairpuller

[whit]

recently my son managed to put our '86 2.9 ranger on it's side - low speed no serious damage- now we have a won't start- decided to try an old trick and put the test jumper in to test fuel pressure (grounds relay)-all fine- so started engine with test jump in place -runs fine- pull test jump- no fuel- test relay- all fine test pcm relay -all fine-so as I understand it the ground for the fuel pump relay is applied by the ecm through terminal 22, would anyone be able to tell me what signals the ecm to provide ground for the relay? Thanks (going bald rapidly!)

 

[87Ranger4me]

There is an emergency fuel shut off switch, (inertia switch) just to the right of the hump behind the carpet inside the cab, that probably tripped and you will have to reset it.

 

[whit]

thanks but that has already been eliminated as a possibility as it is down stream from the relay

 

[gaz]

This sounds familiar

Good day Whit,
I have had many fuel problems recently and two in the past: the first was a clogged fuel filter=no gas. the second was a bad inertia switch in my Ranger (I got lucky, a buddy told me about it, I changed it and fuel was back). Recently I have had a tank pump go out, forgotten to hook up the ground and now yesterday after explaining to a buddy how I severly dought that the inertia switch was my problem because I was able to check it good, I traced it to the switch and it was at fault.

Here is what I did and the symtoms my Bronco II had. Cleaned and rebuilt injectors, fuel pressure regulator checked good, new inline fuel filter, new inline hi pressure fuel pump, new canister filter, new in tank low pressure fuel pump. I had no fuel, I went through it for 8 days then happily took it to a reputible local fuel specialist; 45 minutes later he finds the ground wire hanging from the battery cable terminal jog that I performed 9 days prior.

I drove the Bronco for 3 days, a hundred miles and then it started and stopped, started and stopped almost started/stopped, then wouldn't start.

This time I felt very confident that I could troubleshoot the problem:
1. I ran a hot wire from the battery to the power wire for the low pressure fuel pump in the fuel tank, it spooled right up (that is what I wanted to happen). Now I had a couple of plans on how to fix this but since things were going my way, I
2. I ran a hot wire from the battery to the power wire for the inertia switch (i had previously tested both my Bronco's inertia switch and another know good switch, the both worked, so I didn't expect to learn anything with this test but I had decided to work my forward from the tank, so...) upon connecting the power it did not spool up the pump (AH HA). I plugged in my known good switch and walla, all systems are a go. I installed the other switch and rotated the key, started up like a champ, no hesitation, no problem since.
3. I drove immediatly to Ford Parts department to buy a new inertia switch since my tester was from my Ranger; now I have only been able to purchase these from Ford and in my area the are about $55, so I hope you are right and your inertia switch is good as I WAS WRONG and it cost me several days of thinking and 20 minutes of trouble shooting.

I had an intermittent bad inertia switch, it worked when it wanted.

Good luck, gaz

 

[whit]

thanks for the reply GAz I guess I'll go through it all again just for luck but it still doesn't make sense to me as I have even temp. bypassed the inertia switch as a test. what I have is no ground for the fuel relay - it is supposed to be grounded through the brain but isn't doing so. the fuel pump test in an old book of mine manualy grounds the relay and this works -if i leave the test jumper attatched the truck will run fine- so ford strikes again- there is power from the ingitionswitch to the relay -there is power to the brain but some where the brain isn't providing the ground required to trigger the relay as I sayed i'll go through it all again to be sure but I think I am likely to provide the ground my self even if it isn't the right way. frustration is winning I think
whit

 

[rickcdewitt]

i've seen a few 2.9l trucks at work with broken wires in the harness that made it do that you might want to check continuity of the wires in that circuit with an ohm meter or by voltage drop.you could have someone wiggle the underhood harnesses while you have the meter hooked up to each circuit.the computer could be bad also

 

[whit]

thanks rick I hadn't thought about a broken harness - That will be my next test