xj yj

I noticed that my 99 cherokee doesn't have the power that it used to. I have to downshift on hills that I used to be able to go up in fifth gear. Also several times it took some nursing to get it started. I had to keep it revved for the engine to stay alive. It seems to be idling rough too. The other day I went to start it and it acted like the battery was dead. When I turned the key, nothing happened. I let it sit for a minute then tried again. IT started up but everything was reset as if I had disconnected the battery. The clock was set to 1200 and the radio went to some random am station. This morning it did the same thing and I had to jump start it to get it going and had to rev it for it to stay running. I don't think it is the battery cause I replaced it not even a year ago. Plus it is a Diehard battery from sears so I am thinking that isn't the problem. Any ideas?

Thanks

phoenix901223

prob the battery, my friend didnt bolt his down and it only lasted about 6 months. autozone will do load tests for free

Gee oh Dee

Almost sounds as though the battery isn't getting recharged, but that has nothing to do with the loss of horsepower.

dukie564

Freshen your grounds and replace your battery terminals. I bet your problems all go away.

Gee oh Dee

This would explain the slow cranking and such, but what of the loss of power?

Could it be that the grounds are not good enough to give the injectors or ignition system full power?

dukie564

correct. Every electrical component requires the grounds to be good, including all the sensors and injectors.

Gee oh Dee

Understood. It just seems to be rather unlikely, ya know?

I know bad battery connections cause slow cranking as they don't let full power reach the starter. But once the motor is running the alt should toss 12+ volts, more than enough to power the entire truck, esp in stock form (no extra lights or accessories).

So this would lead me to think its got something to do with the ALT connections.

tjwalker

1. Check ALL connections, but battery connections are always more suspect for corrosion. You must remove the battery terminals and clean both the cables and posts until they are SHINY. Can't tell by looking at em......

2. Load test the battery. Load testing is the ONLY accurate way of determining battery condition. It is not that unusual to have a battery fail prematurely.

3. What is the voltage gauge reading on the dash? Should be around the 14 volt mark, give or take. If not, you have a charging system problem.

xj yj

The volt gauge reads 14 as usual. I just drove it around to do some errands and it ran ok. Bout ten minutes into the ride though the idle dropped really low and I had to rev it to keep it going. After that I had no problems starting it or idling. IT seems like a random problem so maybe there is a wire loose or dirty somewhere.

Thanks

tjwalker

Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea!

You can't just check or look at these grounds. You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. The one on the back corner of the head, and where it attaches to the firewall. Scrape the paint from the firewall. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support. Scrape the paint off first.