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battery died, now crank no start

ehall

NAXJA Member
NAXJA Member
I'm looking to get some ideas and inputs for a problem.

The battery in my '91 beater is a few years old and has been struggling to keep a charge for the last couple of winters. Last week it bottomed out on juice while trying to start, so I put it on the charger for the day. I put it back in the jeep the next day, and now the engine cranks over fine but does not start.

Actually it spudders at first and it will try to start if I hold the throttle down, but it does not fully engage. Otherwise its just turning over and not even trying. There's no weak misfire or anything (unless I hold the pedal down) and its just turning with no attempt at engaging.

What would cause this?

First thing I checked was spark on a test plug and it shows a nice white pattern, so I know the ignition system from the CPS through the distributor is functioning.

There is obvious pressure at the fuel rail when I depress the test valve (I don't have a working fuel pressure tester so I can't get precise numbers); the pump primes up and is just as loud as always. I squirted a teaspoon of starter fluid into the throttle body and it did not start with that either.

I also left the cowl intake tube from the throttle body so air was unrestricted, but it did not make a difference either.

The key-trick shows codes 12 (battery removed) and 55 (end of list), so the computer doesn't see any problem on any of the monitored circuits. I am going to test some of the sensors such as coolant temp and the rest to see if they are within expected ranges, since some of them could cause AFR problems that would have similar symptoms.

After that I will have to scare up another fuel pressure tester.

Other ideas? Maybe the computer was fried when the battery started going? Idle air controller needs to be reset maybe? Anything else?
 
im guessing that battery is just weak at this point. does it crank slow or anything? have you tried to jump start it?

just throwing out ideas
 
As it doesn't start with gas into the intake, I'd concentrate on quality of spark. And also ensuring that the injectors are firing (noid light helpful here).

You have spark so your crank sensor is working, but you should have a strong, blue, snapping spark. Yellow/orange/white can be a bit weak. I'd try testing your ignition coil for primary/secondary resistances.

Best for many reasons just to bite the bullet and get a new battery in there, considering how important it is to the engine management system.
 
I would look to the battery.

When you are cranking, what voltage does the battery drop down to?

Have you tried jump starting it with another battery/vehicle?

Before you go pulling plugs, and spending money to fix the problem, diagnose it properly first.
 
If you've been cranking without ignition, you may have "fuel fouled" the plugs. They won't spark for doodley-squat if they're wet.

1.) Pull them out and hit them with a bit of the ether/starting fluid (it'll evaporate quickly and clean them off) and re-install them.
2.) Throw a "known good" battery in her and go from there.
 
Got this worked out. It was the computer reset to defaults, and did not know the IAC position. Basically I jumped it off another car with the throttle open and it chugged to life, but when I let off the gas it would die immediately. Then I decided to ease off the gas over several seconds and it eventually settled into a stable idle. Now it starts and runs same as normal.
 
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