91 Jeep won't start - but battery should be good. It turns like normal but won't "catch". 91 Jeep Cherokee

Hi,

My 91 Jeep Cherokee only has 70k miles on it. I only put 500 miles on it a year at most but have the oil changed and use premium gas in it. It's been super faithful.

For the last two months I've noticed that it was taking longer to start up than usual, though it doesn't make that dying battery sound you get when it's your battery. Finally, last night, it wouldn't start at all. A jump start got me going.

Details: It's had the usual repairs over the years, exhaust systems, brakes, pads, belts, new radiator, spark plugs. It gets yearly check ups but it doesn't get much use. I checked all of the connectors under the hood that I could find. I read here that it wouldn't be the alternator because the alternator isn't used until the car actually starts (catches, gets going, does more than make the normal pre-start noises). I'd also like an idea of what I might be charged to repair. there are several shady auto shops here and I have "idiot" stamped on my forehead.

Thanks much.

Update:

Thank you all for your suggestions. UR all super fast.

The shop where I dropped it off just called and here's the deal. Pls let me know if the price looks right , okay ?

3 fuel relays (need replacing)

1 "Cam" sensor

Tune up

The cost is $665.00

If I skip the tune up it's : 328.00

Since I can't afford $665.00, I said they could start the work but skip the tune up. I remember seeing coupons for much less (tune up) in the mail . Unless those are tricky coupons... I asked which work was absolutely manditory because I can't afford $665 and they said the Jeep would start up okay 'for a little while' if I okay the relays and cam sensor replacement.

They did $700 of repair work just to pass inspection in December (which I authorized). Back then , the shops would give me different diagnosis' and I didn't know who to believe. So I went with the lower $500 one . Jiffy Lube tells me they give me a tune up every year (not just topping off the fluids).

How much should a tune up cost ?

6 Answers

Relevance
  • bobweb
    Lv 7
    1 decade ago
    Best Answer

    Eventually when your cranking the engine and the starter motor is running, you'll run down the battery if the engine won't "catch" and run normally. So you need a good battery to "start" with, and if your battery is 5 or more years old, it's wise to buy a new battery. Otherwise, you can have your battery tested at the auto parts store to see if it holds a charge and is still good. Even with a new battery, you have to clean your battery cable connectors with a wire brush or metal file inside the connector where it slides down on the battery post (clean the battery post too). Some cars have a bolt up type battery connection that needs to be cleaned metal bright too. If your going to work on your car at home, you need a battery charger, because even a good battery won't hold up for long when you need to crank the engine to test it, but it won't start. Buy a battery charger like the Sears charger below and follow the directions.

    Next, you need to test to see if you have ignition spark when the engine is cranking over ok, but won't start. Disconnect one of your spark plug wires and hook it to the Napa spark tester shown below to make sure your engine has spark. If the tester shows spark, then you can start checking the fuel delivery system including the fuel pump to see if it is running and delivering the required fuel pressure etc.

  • Anonymous
    1 decade ago

    Above are good answers...but let me add one more. If you can get a fuel pressure gauge, connect to the Schrader valve on the fuel rail. Just turn the key on. The system should pressurize to 35-39 PSI. The pump will run for 4 seconds if you do not crank. No pressure..crank the engine and watch the gauge..MAKE SURE THERE IS NOT SPILT GAS!!. STill no pressure. Unless you have a wiring problem, you have lost a pump.

    OK>>Pressure,but will not start. Check as suggested above for spark. No spark...you have a crank position sensor in the drivers side bellhousing. Disconnect the wire at the connector and reconnect and see if it will start. No, pull the sensor..from under the car, about the only way to reach it. There should be NOTHING on the magnetic tip. If ANYTHING on it clean it, but would consider to replace it at this point. A continutiy tester will tell you if it has an open circuit, or a GOOD VOM would show a very tiny A/C output if you waved it past a steel object. Testing on the car is a bit risky.

    Good Luck

  • 1 decade ago

    If This Happens After the truck has Sat For A while, You May Be Losing the Prime in your Fuel System ( Needs to Crank a while to Build up Pressure).You Can Check this also by Only letting it sit For 2-3 mins, (after you had it Running) And restarting it( it Should Fire Right up real fast) I Know they Are Electric Fuel Pumps And they Are to Build Pressure & Always hold it, But this does happen on older jeeps. Get Them To Check your fuel Pressure On the Fuel Rail With out Starting the truck just turn the KEY on(they May need to let it sit 2-3 hrs for the Prime to be lost to check the pressure. If they Don't Let it sit It May Still Be Holding Pressure, Misleading them). This Will Show How Much Pressure Is In the Line/Rail Prior to Start-up. Then Start It And See Where the pressure is at. If they tell you You Need a fuel pump, You will need A new fuel Screen,Pump,Lockring and Gasket. As the Pump is in the Gas Tank. they will Probly Take it Off to Change it.

    I've Had 6 Jeeps And I've had that problem it was a Combination of old gas lines and weak pump. If they Are Fixing it ask About REPLACING THE FUEL LINES From the tank to the Fuel Rail.

    Pumps Are $150-250 + all the Other Little things.

    Oh Yes I Solved the Long crank(no start) By Feathering the Gas Pedal As you Crank it over ....I KNOW you are not to touch the gas Pedal in a Fuel Injected Car As it will flood it. But this did work to get it started Quickly Until I Made Proper Repairs Without having to get A Boost(Although I do Not Recommend this )

    Good Luck with this

  • 1 decade ago

    No idea about the repair charges, but it sounds like it may be a fuel pump. I might suggest buying a "chilton's" repair manual from your local auto parts store and buying the fuel pump, IF that is what it turns out to be. With the chilton's manual, it gives you the chance to be independent of the auto shops that you may believe are shady and do the work yourself. You will also have a sense of accomplishment. I would most definitely call the service guys at the local jeep dealership and tell them exactly what it is doing. Good Luck.

  • How do you think about the answers? You can sign in to vote the answer.
  • 1 decade ago

    You need a buddy for this. Take loose by twisting then pulling on the boot of the wire (not just the wire itself) to remove it from a spark plug. Take a long, PLASTIC handled screwdriver (you hold the plastic), place the blade in the boot and hold the metal shaft about a 1/8 inch or less from (not against) a metal edge that is grounded. The metal line from the master cylinder works well. Have your buddy, making sure the car is in park, crank the engine. If there is no fire jumping it means your have no fire to the plugs. You need to have the module, rotor, and the pick-up in the distributor checked. It takes fire, fuel, and compression for a vehicle to run.

    There is also a 'limp in' mode that only allows about 50 starts and that is controlled by the computer under the dash..

  • 3 years ago

    we can frequently advise that any one that dislikes rattles or vibrations no longer purchase a Jeep. The older ones look fairly vendors to them. Many Jeep Cherokee coolant reservoirs will crack and leak antifreeze, i'm no longer particular if 1991 is roofed. based on the engine, you may adventure and exhaust leak. If the Jeep became fairly maintained and pushed responsibly, you're able to do alot worse.

Still have questions? Get your answers by asking now.