Hello i have a 1993 jeep cherokee ive had a bunch of problems but fixed most of them now my concern is its not starting period i have chancged the starter and the fuel pump and im going to be changing the battery as well we have chexked the fuses under the hood and everything and do not know what it could be can someone help
my jeep
- Thread starter jessylynn
- Start date
Tison78_CJ5
New member
Hi, Does it crank, do you have fire to the plugs?
carb, or fuel injection?
Sorry, but I got to narrow the list down.
Tison
carb, or fuel injection?
Sorry, but I got to narrow the list down.
Tison
Yes it cranks i have power it sparks i have fire to all those as well my dad thinks its the computer
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greg92jeepxj
Official Supporter
Just would like to add as Tyson 78_cj5 will suggest to check the fuel injector wiring harness . It is best to check any wiring on any vehicle that connects to an ecm , PCM or module with a computer safe test light. They're inexpensive and should be found at a parts store. The PCM grounds which injector it intends to fire through a firing order much like the spark plugs on its compression stroke. Each injector will have its own wiring harness plug with power and ground. The power should be on at all times ( hot with ignition on) but the ground will only be active when the PCM is firing that injector. SPFI ( sequential port fuel injection) is used on your jeep.
use the test light to look for power with key on engine off ( KOEO) and try to look for ground on an injector ground wire when cranking. Check the instructions on your new test light but when checking ground , the alligator clip is on the batt + . Alligator clip on negative when looking for power. A quick check is to look for reference ( 5 volts ) and ground on the TPS wiring harness if you suspect the PCM may be the problem. Hope this helps. Greg
use the test light to look for power with key on engine off ( KOEO) and try to look for ground on an injector ground wire when cranking. Check the instructions on your new test light but when checking ground , the alligator clip is on the batt + . Alligator clip on negative when looking for power. A quick check is to look for reference ( 5 volts ) and ground on the TPS wiring harness if you suspect the PCM may be the problem. Hope this helps. Greg
mud4feet
New member
Well, that pretty much narrows it down to a fuel delivery problem at least. Should get you on the right track.
Tison78_CJ5
New member
Yep, Something is keeping it from putting fuel to the injector.
Could be computer, or something the computer wants to see before opening the fuel supply.
Could be computer, or something the computer wants to see before opening the fuel supply.
greg92jeepxj
Official Supporter
Agreed . If it runs for any length of time , spark quality is probably fine but can be checked later if need be . I am leaning toward fuel delivery since this is sounding less of a PCM issue ( or not at all ) and more of an electric fuel pump issue. Fuel pressure regulator should also be checked .
As posted , if the engine runs off the starting fluid which is like temporary fuel and engine stalls after you quit spraying starter fluid than absolutely its a fuel delivery problem. A fuel pressure gauge will confirm that but at this point I think we've all agreed its time to pull the fuel pump.
Fortunately , it's an easy job in a cherokee. Jack the back up high and with jack stands under the body the rear axle will hang low enough to access the sending unit which is on the top side of fuel tank facing forward. No need to drop the tank in your cherokee.
P.S. - as Previously posted , something is preventing fuel from getting to the injectors. One step should be taken before going after the fuel pump ; verify voltage at the wiring harness disconnect under the jeep near the fuel tank. It won't be to far from the fuel filter. Back probe with a test light while cranking the engine.
As posted , if the engine runs off the starting fluid which is like temporary fuel and engine stalls after you quit spraying starter fluid than absolutely its a fuel delivery problem. A fuel pressure gauge will confirm that but at this point I think we've all agreed its time to pull the fuel pump.
Fortunately , it's an easy job in a cherokee. Jack the back up high and with jack stands under the body the rear axle will hang low enough to access the sending unit which is on the top side of fuel tank facing forward. No need to drop the tank in your cherokee.
P.S. - as Previously posted , something is preventing fuel from getting to the injectors. One step should be taken before going after the fuel pump ; verify voltage at the wiring harness disconnect under the jeep near the fuel tank. It won't be to far from the fuel filter. Back probe with a test light while cranking the engine.
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greg92jeepxj
Official Supporter
If fuel pressure is satisfactory and fuel pressure regulator is good , please let us know if voltage is read at injector harness and if ground is read while cranking. We must know if the PCM is responding .
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