1991 2.3L crank won't start, EEC draining battery dead

[dow]

Ranger died on the road and now won't start. Here is what I've done:
Timing belt and CPS were both replaced 1 month ago when the belt broke. Rechecked that the belt is still good and turning correctly
Exhaust side is sparking.
Sprayed fuel in throttle assembly and still won't want to start.
Can hear fuel pump when I turn key
Battery is a few months old. I checked the voltage and it was in the mid 12V. However, after waiting a few days to troubleshoot, I went out and battery was dead. Started removing fueses, and the EEC was causing the drain. Interesting to note that there was a parasitic drain also a few weeks ago, and traced that one back to the a fuse under the dash. With that fuse out, the voltmeter didn't work anymore, but the battery stopped dying, and the truck ran fine until it died a few days ago.
Had the alternator checked and it seemed fine. I understand that it could still be bad if it is checked on the car, so I also disconnected it and there was no battery drain, so from that I am assuming there are no bad diodes causiing a drain. Starter was also checked.
Not sure how to check the EEC or where to go now with that idea that the EEC is draining the battery

 

[RonD]

Welcome to TRS

Yes, the 1989-1994 2.3l will only have spark on the exhaust side until engine starts, above 400 RPM, then intake side will start to work, this is normal

But you don't have spark on either side if engine didn't start when you added fuel manually
Or you don't have compression
These are the only two options if there is a "no fire" when you added fuel manually to the intake, 50/50 test


After recharging battery it should show voltage above 12.3v
While cranking engine battery voltage should drop to 9v, no lower, if it does battery could be getting too old or has an internal short so self draining, no parasitic drain

EEC and radio both have power when key is off, it holds memory for both, thats normal but not enough of a drain a good battery

I would get engine running first then look at battery and charging system
There is just 3 wires you need to test on alternator
And a car battery has 12.8v new, 12.5v when 3 years old, 12.3v when 5 years old and time to watch for battery sales
12.2v and lower is a bad battery

Test battery after recharging, with it disconnected from truck and charger, write down volts
Wait a 1/2 hour and retest it, write it down, wait another 1/2 hour, write it down, if voltage is dropping battery has internal short, this is common on older batteries but can also happen on new batteries

 

[wcurtin1962]

If your battery has water caps you can test each cell by placing the positive lead tip into the acid the negative to ground. Look for a balance in the readings cell to cell. A dead cell will be lower or zero volts.

 

[wcurtin1962]

Also try pulling the fuel pump relay and cranking it. If it tries to run or pops you could have a leaking fuel injector. If so unplug the injectors one at a time and if the engine runs, that's the bad one.

 

[tomw]

Vaguely, if you are getting spark, the computer is alive and functional. A cranking engine will pull down system voltage, and my understanding was that anything below 10V while cranking indicated a weak battery or a starter that was too hungry and likely on the way to failure.
I would check for starting with fuel added to the intake and the throttle just off idle. IOW, open the throttle and squirt in some fuel, or add some via a vacuum line, and then try to start the engine with a little foot action on the gas pedal. If the IAC is not opening up, the engine will get no air, and will not start. Pull codes. I had a failing MAP cause a no-start. Never heard that one, but it would run for 1/2 second after cranking, and then die. Could not get it to run any longer. Un-plug the MAP and it started right up and ran. Not perfect, but it ran.
I do not know if you have a 'power distribution box' or have multiple fusible links on the starter relay, but in either case you can attempt to find your power drain by placing an ammeter in the circuit(do NOT try to start or run the engine with the ammeter installed) from the battery to all 'power eaters'. Remove the fuses one at a time, or the relays, ditto, and observe when the current ceases. That circuit would be the drain. The EEC can send power to other items(injectors/COP/etc) which should not use power with the ignition in OFF, but if they have a problem, the current can flow via the EEC, so be aware.
If you have a fuel pressure gauge, attach and observer pressure. Key ON, the pump should run for a few seconds, build pressure, and stop. Pressure should maintain for a while. Immediate leakdown of pressure indicates several possible failure points, including leaky injectors(did it flood the engine), leaking pressure regulator, leaking check valve(sometimes multiple). If no pressure developed, check fuel pump relay, etc.
You can borrow a fuel pressure gauge from some auto parts stores, and incur no charge if returned in good working order.
tom