lsc91

well I have a 93 cherokee and for the past 2 weeks I've had a little bit of a starting problem. Once it does start it runs fine. It also is charging at about 15 volts now instead of 14 where it wasa few weeks ago. It seems when its real cold it cranks for a long time and then starts and if you shut it off and try and restart it, it starts fine. When I turn the key on I hear the pump prime but I'm not sure how much pressure I've got, so if anyone has any ideas for me to try please let me know. Thanks for the input.

tjwalker

You could have two things going on here....

The target for the charging system is closer to 14 volts, so something is possibly wrong there. If you have a meter, I would verify that what you are seeing on your voltage gauge is the same as what you see on the meter.

Either the battery is marginal and the charging system is trying to compensate to keep it charged or the charging system itself is suspect.

Start by LOAD TESTING your battery. Any parts store will do this for you for free.

If you continue to have "extended crank time" symptoms only when cold, you will need to get a hold of a fuel pressure gauge (can be rented at many parts stores) and do some fuel pressure testing both cold before starting and when running. And also keep a gauge on the valve after turning the engine off and monitor it; called the pressure drop test. Consult the manual as the pressure should only drop a certain amount in a certain amount of time (can't recall off hand what the spec is for pressure drop test).

And of course, always be sure that tuneup hardware is fresh for crisp starts. Plugs, wires, distributor cap, rotor.

cpttuna

have you upgrades your cables?

lsc91

I did the load test on the battery today and it rad 12.44 and while the jeep was running it was anywhere from 14.25 to 15.01. I did a full tune up about 8 months ago but I didn't drive it for some time due to it being in an little fender bender and it took me some time to repair it.I guess I'll have to try the fuel pressure test in the next few days.

tjwalker

Did you simply check voltage on the battery? That is not a "load test", which has to be done with a LOAD TESTER. Your voltage numbers while the Jeep is running are a bit high. With a good fully charged battery, at idle you should see closer to 14 volts than 15 volts. That is why I suggested a load test because if your battery is marginal, the charging system will work harder to charge it to where it should be.

I'd still take this battery to a parts store and have them perform a free load test.

Yes, you can have a battery that is strong enough to start the engine, but marginal enough to give the engine management system problems.

lsc91

No I didn't just check voltage, I used a digital battery tester thatput a load on the cold cranking amps and that's when I came up with the 12.44 then I started it to get the other numbers. When I get home today I'll get my old time load tester and try it again

lsc91

Well when I got home this evening I grabbed my cornwell battery tester and connected the terminals to the battery and just the battery reads around 13 volts then I put a load on it for 10 seconds and it read 11.5 in the good portion of the tester. I guess I'm looking into the fuel pressure but if any one else has any ideas please tell me.