86 Ford Range weak spark, no fuel prime, slow crank

[Bootz1385]

Hello everyone. I have been on the forum for days reading post about issues that I have going on. I have tested my little heart out and am now turning to you guys to see if I missed anything.

The Truck: 1986 Ford Ranger 2.9L manual 2wd extended cab. odometer read 59,883 but am 1000% sure it is 159,883

The story: I bought the truck off a guy that was selling two of these trucks. the single cab had a bent frame from the wreck, So I only bought the extended cab. The truck has been sitting for about 6 months as the guys kid went to prison and left the truck. The guy said the truck was stalling out on him so he started to figure out what was going on as he went back to prison. I got the truck home and the wires were just twisted together for the fusible links and what not. So I busted out the ranger bible ( the Hayne's manual) and put the wiring back to normal and soldered everything back up. then I started the testing, These are my issues.

The Issues:
1. Very slow crank. The truck just doesn't want to turn. I pulled three different batteries from around the shop that are all good. None of them changed the crank speed so I bought a brand new 56 series and still nothing. reading up on the forums, I change the battery wires from the battery to the starter solenoid, from the solenoid to the starter, the ground to the frame and from the frame to the battery. Still nothing. So then I changed the starter solenoid to see if that would help and nope. The Starter looks to be new as everything on the underside of the truck is caked in oil and the starter is shiny still. so that's where I am at with that.

2. Very weak spark. before I started changing parts. I had weal spark but it was yellow. So I figured it was a bad cap and button. Took them off and cleaned them both up. No change. Changed on the TFI to see if that is bad as the forums say they go out a lot and I know this from a old Escort I had. still and it got worse. The spark is now very faint and yellow if it does spark.. Went and got a coil even though I tested the coil and it was good but thought "what the heck". Still nothing. That is where I stopped with that.

3. No fuel Prime. This is the first issue I looked at as it was what the guy I bought it from said the issue was. I first started at the pump. No power. So I went the the inertia switch. No Power. So I went to the relay. boom I have power at the main port (yellow wire). I have ground at the ground port (orange/light blue stripe). The switch port ( red wire) and the switch ground port (brown/ light green stripe) there is nothing. With the key on I still have main power and ground ( yellow and orange/light blue stripe), the switch (red wire0 gets 12volts but has no prime cycle. The ground switch (brown/light green stripe) still has no power or ground. I jumped the relay from main power to main ground ports ( yellow to orange/light blue) and pumps come on strong. I can also jump main power to switch (yellow to red) and pumps come on. If I jump ground to any of them, I get nothing. Tried to ground the obd1 fuel pump port and got nothing. went down by the computer and the computer hold down screw was loose and there was a broken ground. fixed the ground and it was still the same. I changed all three relays and still the same. I have headlight and tail lights ( read in a forum that was a sign of something I can't remember now). So this is where I turned to Y'all to help a guy out after 2 days of headaches.

So I pulled the computer and it is a remanufactured unit. The number on the paper is -4258 as it is worn and can't read the whole number. The DC Code is 0603** as that is worn too. There was a piece of tape over the bar code. Don't know if that is when the remanufacture painted it or if the guys son did that. The 2 letter code is RP which the look up says is from a Ranger/BII 2.9L auto. Mine is a Manual. Would that cause all my issues? Only thing I haven't tried is the EGR sensor as I read that was an Issue for another guy. I really need to get this truck running good so I can start the Frame off resto of my 88 Ranger with the 2.3L That I will be picking up next week. Thanks in advance for all your help and look forward to figuring this all out with y'all.

P.S. This is my first forum post ever and sorry for that long post. Wanted to put as much info as I could.

 

[Bootz1385]

 

[gaz]

Bootz,

Sometimes a summary is best. Sounds like you don't know if you have spark or fuel.

Do the 50/50 test, crank the engine. Did it start, yes or no. If no, shoot starter fluid in the intake and try again. If it doesn't start, fuel isn't your primary issue; if it does start with starter fluid, fuel is your primary issue.

 

[Bootz1385]

I did the 50/50 test and it did not start. there is no to little spark. Before I can get that far, I have to figure out the very slow crank. I added a ground straight to the starter to see if that would help and it did not. The engine turns over normal by hand. I may try a new starter and see if that clears it up and then move on from there. Thank you for getting back to me and helping out

 

[RonD]

Batteries are easy to test
Key off
12.8v is a new battery
12.5v is a 3 year old battery
12.3v is a 5/6 year old battery and time to shop for battery sales

12.2v or lower is a done battery, replace it

Since your spark is already disabled, lol, easy to do a load test on battery
Have volt meter connected to battery and WATCH voltage when someone cranks engine
Should be about a 2volt drop, 1.5volt is better
If voltage drops below 10volts then either battery is bad or large battery cables are corroded internally, after load test run you hand down BOTH positive and negative cables and feel for hot spots, thats from internal corrosion, replace that cable
Can also be a bad starter motor, drawing too many amps

Because starting an engine requires alot of AMPs/voltage, a weak battery WILL cause weak spark
So testing for spark WILL show weak or no spark if voltage drops below 10volts when cranking
I would address this problem first, the slow cranking, as that could be the ONLY problem you have

Once engine can be started test your charging system
Battery should show 13.5volt to 14.8volt after engine is running
That's from the alternator, it powers the WHOLE vehicle when engine is running, battery is ONLY used for starting
If voltage is lower than 13.5v then charging system needs repair

Its very common for a bad battery to ruin a good alternator and a bad alternator will ruin a good battery
So TEST BOTH

 

[Bootz1385]

@RonD Thank you for your help. I got a new battery yesterday from Advanced dated 11/20. Yesterday I also changed all the power and ground wires out to a 4g wire to let plenty of power through and to get this 34 year old girl something new. Yesterday I also replaced the starter solenoid. I just did your test. I have 12.5v with key off. gave her a crank and it fell to 8.2v. I pulled off the starter and am taking it down to get tested/ get a new one. Thank you for the test. I'll keep you updated in a bit.

 

[Roert42]

Could jumper a battery straight to the starter, and see if it cranks any faster, that would tell you if the problem is with the starter or something before that.

 

[Bootz1385]

I did a quick bench test and it fried the power wire. Took it to advanced and it failed for amps. Picked up a new one and got it in the truck. Didn't hear the fuel pumps prime but she fired right up. Could be left over starter fluid as I added a clear inline filter to help clean out the bad from it sitting for 6 months and the fuel filter is empty. However the starter stayed engaged. I saw a few posts about it so I will look those up unless you guys know a quick fix on it. After I get the starter normal I will check back on the fuel.

Thank you guys for all your help.....at least we are making progress!


EDIT: I Changed back to the old starter solenoid and boom......no more excessive crank. I got it to fire off the starter fluid. Spark is yellow but strong. Now to figure out the no fuel issue. Here is what I posted above:

3. No fuel Prime. This is the first issue I looked at as it was what the guy I bought it from said the issue was. I first started at the pump. No power. So I went the the inertia switch. No Power. So I went to the relay. boom I have power at the main port (yellow wire). I have ground at the ground port (orange/light blue stripe). The switch port ( red wire) and the switch ground port (brown/ light green stripe) there is nothing. With the key on I still have main power and ground ( yellow and orange/light blue stripe), the switch (red wire0 gets 12volts but has no prime cycle. The ground switch (brown/light green stripe) still has no power or ground. I jumped the relay from main power to main ground ports ( yellow to orange/light blue) and pumps come on strong. I can also jump main power to switch (yellow to red) and pumps come on. If I jump ground to any of them, I get nothing. Tried to ground the obd1 fuel pump port and got nothing. went down by the computer and the computer hold down screw was loose and there was a broken ground. fixed the ground and it was still the same. I changed all three relays and still the same. I have headlight and tail lights ( read in a forum that was a sign of something I can't remember now). So this is where I turned to Y'all to help a guy out after 2 days of headaches.

EDIT #2: i have no check engine light and have 12v to the grounds at port 16, 20, 40 and 60. Which are all supposed to be grounds (with key on) and no power or ground at port 22 on the computer.

 

[RonD]

In a 1986 you will use Fusible links instead of fuses for the EEC Relay and the Fuel pump relay

The fender mounted Starter Relay(often called starter solenoid) is where ALL vehicle 12 volts comes from
One of the larger posts on this relay will have the Battery Positive cable, AND with it, the alternator wire, fusible link wires and any other 12volt wires to power ALL devices in the vehicle

Just FYI, the other larger post on this relay should only have ONE wire, ONE WIRE, it goes to starter motor
There is no "polarity" for these 2 large posts, either can be the battery positive side or ONE WIRE starter motors side

On the same side of engine bay will be 2 or 3 regular relays
EEC relay, it will have a BROWN base
Fuel pump relay, it will have a GREEN base
AC Relay(WOT relay), it will have a BLACK base

EEC relay is turned on by key on
It powers EEC(computer), fuel injectors, spark system, and the relay part of fuel pump relay
Your EEC relay is working because you have spark

Fuel pump relay should be pulled out and inspect for corrosion
Test the GREEN base for slots with 12volts
Key OFF, you should find one slot that has 12volts, that's from a fusible link hooked to starter relay post(see above)
Key ON, should see another slot that now has 12volts, thats 12v from EEC relay being on

Ford used 2 different types of relays
Mini-relay base looks like this: http://www.gtsparkplugs.com/images/mini-relay-diode-wiring.jpg

Micro-relay looks like this: http://www.gtsparkplugs.com/images/micro-automotive-relay-wiring.jpg

Easy to tell the difference

Slots 85 and 86 are the "relay power" for either
One needs to be 12v and the other a ground to activate the relay, no polarity, either can be 12v and the other a ground but has to have BOTH to activate

Slots 30 and 87 are for the "Load", 30 and 87 are connected together when a relay is activated, in this case one would have 12volts all the time, and the other slot runs to Fuel pump to power it, again, no polarity, either can be the 12v and the other runs to fuel pump

You can jumper 30 and 87 to see if fuel pump comes on, and if engine then starts and runs, thats what computer does

Locate your OBD1 connector in engine bay, should be passenger side on main computer harness
Connector looks like this: https://www.therangerstation.com/tech_library/images/eec-iv_testing2.gif

Fuel pump slot is labelled in drawing, this is the GROUND wire from computer TO Fuel pump relay, computers pin 22 wire loops thru this slot on its way to fuel pump relays GREEN Base
Key on, this slot should show 12volts(relay plugged in)
If you have 12v, then if you ground this slot the FP relay should close and fuel pump should come on
A relays coil is just that, a coil of wire, so 12v IN = 12v OUT of that coil of wire, if you ground the OUT then relay activates, its not a short because the coil is a "load" a small one but still a load so not a short



Just FYI, 87a is not found on all relays, 87a is connected to 30 when relay is OFF, the WOT relay(AC Relay) uses this, in vehicles with AC the 12volts for compressor clutch runs thru this, 30-87a, so has 12volts when AC is on and relay is OFF, when driver pushes gas pedal to the floor, Wide Open Throttle(WOT) the computer activates this relay, which cuts power to AC compressor to give engine MAX. power, for passing or ???


If you are wondering about the Relay numbering.................industry standard numbers, lol
Make no sense whats so ever
Common thinking is that it came from VW wiring which were the first to use these types of relays

 

[Bootz1385]

Awesome! Thank you @RonD. I picked up the new computer, ignition switch and a new plug for the in tank fuel pump connector as it was intermittent. Put the key in and had fuel pump. Gave her a crank and she started right up. runs a little rough but new plugs, wires, cap, rotor, injectors and cutting the cats and blown muffler to straight pipe ( I don't have emissions). She'll be right as rain. I did go back and check over the wiring to make sure I had the right volts and grounds as you posted just to double check. Thank you for all your help, I couldn't have done it without y'all. Now to get the 88 and rebuild the locked up 2.3L.

 

[RonD]

Good work