1989 Ranger no start/ Positive engine at run position

[177CIOfPureLove]

Alright, 89' ranger, 2.9 v-6, m5od, 2wd.

This truck has never ever let me down. I was leaving work (a little backround, a month or two ago sometimes sporatically the starter would not engage, everything else would go as normal, solinoid clicked and all that good stuff. Being at work and school i did not investigate it very much, because at the very worst i could always rollstart it, which wasnt often. It also always started when hot or warm after running) and the truck would not start on its own. roll started it out of the parking lot and drove away. the truck ran perfectly as it always has. Then about 400 yards away down the street the gauges and the battery light went nuts; then the engine stopped. Pushed it into a parking lot and checked what i could with my tools, voltage good, fuses good, everything works lights fuel pump relays ect. no starting it. Had to get it towed home. Got it home load tested the battery, its perfect. I find out that once you key the ignition to run, the block becomes positive. Ignition off everything is grounded. i took the starter, starter lead off and completely out of the car. bench tested starter, its working. the starter lead is great, no shorts or anything. I put it all back, and took a jumper cable to the positive on the battery right to the one lead for the starter, and it does not crank, but instead turns everything on, and ungrounds the block. my voltmeter showed the block go from 0.0 volts to 12. Also arcing is heard once you turn the key back from run. I ent out in the dark with the ho dclosed over my head, and i cannot see spark. It sounds like it is on top of the motor. This truck is my DD, and i cant use my moms van forever. Me and the truck have been through a lot...but my god it took me less time to put the motor and clutch, ect. into it a year ago......lol. I replaced the alt. and the solinoid. Any ideas or advise would be greatly appreciated. I am not sure the best way to continue, other than pulling the harnesses and checking each wire for flaw. Thank you so much everyone in advance.

 

[Mark_88]

Well, it sounds like you know way more about this already than I do...but what I did catch was the gauges going nuts...that happened on both my Ranger and my Tempo and both times it was the alternator...guy at the shop said that the alternator was out of phase (apparently there are three phases)...also looks like you just replaced the alternator so that could mean a bad wire or connector on the alternator circuit...other than that I wouldn't know where to start...

 

[177CIOfPureLove]

yea.......thats not my problem. something is arcing to the block, so it is no longer grounded which means everything connected to the block would not work.....of course only when the ignition is put to run and start. I need some advise on how to find this fault or anywhere else it could be (EEC,ect) although i pray its just a wire and i dont need an ecu. I really cant fry this truck, it is all i have in this world, and i have far too much into it to abandon it. I hope someone out there has defeated a problem like this...

 

[Jorley]

Looking at a wiring diagram and I can suggest some things to check.
Pull the starter and see if you still have the problem. I know it won't start, but check the arcing and things coming on.
Disconnect the neg. battery terminal and measure resistance to the engine. Should read 0 or very low ohms.
On the under hood fue block pull fuses #7(50A) & #3(60A). This will isolate the allternator and its wiring. I know you replaced the alternator, but this will eliminnate the wiring to it.
Do each of these one at a time. Check the resistance 1st.
If none of these work, let us know or if they do work. I know how you feel about your truck. I feel the same way about my Bll, it can be aggrevating, but I wouldn't get rid of it for the world.

 

[RobbieD]

Have you checked the engine's grounding? You're saying "I find out that once you key the ignition to run, the block becomes positive. Ignition off everything is grounded."; if so, it sounds like the block is not properly connected to the battery Negative post. A quick test for you- with the truck exhibiting the symptom, take one jumper cable and connect it to the battery Negative post and the engine block. If the engine then starts OK, simply put a new ground cable on her. Good luck.

 

[88BlackHorse]

My Bronco II is doing the exact same thing and i cant fix it, maybe the starter cable is shorting to ground on the block?

 

[gbadgley]

Sounds to me like you lost a ground. Ground the battery directly to the block with secondaries to the frame & body. Greg

 

[RobbieD]

My Bronco II is doing the exact same thing and i cant fix it, maybe the starter cable is shorting to ground on the block?

If the engine is properly grounded, which is its normal state, if the starter wire was shorted to the block you'd have a major short circuit. You'd get sparks and smoke while cranking it, just about like a battle scene from Star Wars.

The block itself can only show as having Positive voltage if it is not grounded to the battery post. Period. Plain and simple.

There should be three primary grounding means- to the engine, the frame and the body. BUT, Ford has used several arrangements through the years of how these three things are connected to the battery Negative post.

On an '89 BII, there's three ground leads at the battery. The thick one goes to the frame, then continues on to the block. There's a short one to the radiator support, and a third which goes to a round connector. In a lot of these cases, a previous owner has done a half-assed primary ground cable replacement which has worked for some time, then craps out years later on a different owner. Now the poor new guy doesn't have much to work with, as to how the original primary grounds were originally designed by Ford.

I really suggest that anyone having these kinds of electrical problems start with checking the grounding cables from the battery Negative post. Basically, troubleshoot it by starting at the beginning, the battery itself, and then working your way downstream. A quick and easy way to test the primary grounds is to use jumper cables. Clamp one or both clips on one end to the battery ground post, and the other end's clips to the block and frame or body. In essence, you're jumpering over a suspect existing cable with a known good one (temporarily), and if the problem becomes corrected then the indication is that the existing cable is bad. There's other more precise tests, such as checking voltage drop, but the jumper cable method will work fine and can be done quickly.

Usually it's the simplest problem areas that cause the weirdest symptoms, and can really throw the repairman for a loop. Cables and wires can look fine externally, but be dead as a doornail inside. Good luck, and I hope that both ya'll's aggravations turn out to be something simple, and easy to fix.

 

[Donnie strickland]

+1 on what RobbieD said. And you will save yourself a LOT of grief if you go with Ford factory cables. They cost a little more, but they are well worth it. I know -- BTDT. I got mine from directfordparts.com.

 

[177CIOfPureLove]

Your right.I fiddled with my main ground, and i assume somewhere there is a break in the wire. And seeing how the terminal end has the other ground wire in it as well i know i am going to have to go for the factory ford replacement. In the end I am glad it was that simple. Thank you all for your help, it is as always very appreciated. And I will definetly check out that site Donnie, thank you so much for the info. Sounds very good.

 

[RobbieD]

Cool! Glad to hear that you're on the right track, and that it'll be an easy fix. Thanks for letting us know how it turned out.

 

[88BlackHorse]

My problem was also the ground cable, I changed it today and my B2 started right up. Thank you guys very much for the help! Sometimes you get so wrapped up in the problem you forget to go back to the basics

 

[RobbieD]

Wow; that's a classic example of killing two birds with one stone.

My thanks to both you guys, 177CIOfPureLove and 88BlackHorse, for posting back what you found. A lot of times you try to help a guy and never know if you did or not . . . .

I'm just really glad that both ya'll got 'em going again. Keep On Truckin, dudes!

 

[MAKG]

Bad battery cables (ground or hot side) go bad far more often than people realize. Replacing those was the first thing I did to my Exploder (aside from changing all the fluids) when I got it. It was 2005, and they were all original (1991), showed significant voltage drops, and the computer was flipping lean codes.

FYI, what you did measuring the voltage at the engine block is a standard technique called a "voltage drop test." The fault in a single nonfunctional circuit usually lies at the measured voltage drop. In this case, between the engine block and negative battery post. Had you wished to, you could have located the exact location of the internal break, with a needle-probe. It's a very powerful technique.

You can also understand this in terms of Ohm's Law -- and it's a nice exercise for it. An open circuit is infinite resistance, so the entire hot side of the break goes to battery voltage, even if it has a really big resistive load on it (no current through the load means the voltage drop across the load is zero).

 

[177CIOfPureLove]

Wow, MAKG that is some good info. True about the lean codes, I had thought I had fixed the problem by just cleaning the negative end to the block, she started and ran, but it lost partial ground soon after and started running real lean, then threw the lean code. Terms like Ohm's law were all good in chemistry, but it is a good feeling to apply them into mechanics as well (well, there really is no choice anymore) I hope to really learn to use these methods and have a better understanding as well. But glad like hell shes herself again.