weak spark and fuel but no start 93 xj HELP PLEASE
#1
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Model: Cherokee
Engine: 4.0
weak spark and fuel but no start 93 xj HELP PLEASE
hey i recently bought a 93 jeep cherokee 4.0 high output 150k miles clean title for 400$$
thing is it doesnt start the guy i bought it from said one day it just didnt wanna turn on anymore he changed the crank position sensor coil pickup rotor distribuitor and spark plug wires and still didnt start so he just wanted to get rid of it
towed it to my house ive bin trying to get it to start but it just keeps cranking n cranking it doesnt even backfire or anything but it has spark and fuel wat can it be??? shouldnt it atleast backfire or something since it has both spark and fuel? please help thanks
thing is it doesnt start the guy i bought it from said one day it just didnt wanna turn on anymore he changed the crank position sensor coil pickup rotor distribuitor and spark plug wires and still didnt start so he just wanted to get rid of it
towed it to my house ive bin trying to get it to start but it just keeps cranking n cranking it doesnt even backfire or anything but it has spark and fuel wat can it be??? shouldnt it atleast backfire or something since it has both spark and fuel? please help thanks
#2
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Year: 1998 Sport
Model: Cherokee
Engine: 4.0
hey i recently bought a 93 jeep cherokee 4.0 high output 150k miles clean title for 400$$
thing is it doesnt start the guy i bought it from said one day it just didnt wanna turn on anymore he changed the crank position sensor coil pickup rotor distribuitor and spark plug wires and still didnt start so he just wanted to get rid of it
towed it to my house ive bin trying to get it to start but it just keeps cranking n cranking it doesnt even backfire or anything but it has spark and fuel wat can it be??? shouldnt it atleast backfire or something since it has both spark and fuel? please help thanks
thing is it doesnt start the guy i bought it from said one day it just didnt wanna turn on anymore he changed the crank position sensor coil pickup rotor distribuitor and spark plug wires and still didnt start so he just wanted to get rid of it
towed it to my house ive bin trying to get it to start but it just keeps cranking n cranking it doesnt even backfire or anything but it has spark and fuel wat can it be??? shouldnt it atleast backfire or something since it has both spark and fuel? please help thanks
#5
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the guy i bought it off of said he thinks its like an auto shutoff sensor or something like that that prevents it from starting he said its by the shifter under it or something like that??
#6
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Year: 1999
Model: Cherokee
Engine: 4.0
1. As mentioned, you need a strong BLUE spark to start the engine. Yellow/orange/white indicates a weak spark, which may not be strong enough to start the engine. The primary cause of weak spark is a weak ignition coil.
2. Verify fuel pressure. This MUST be done with a fuel pressure gauge. I know you said you have fuel, but you must achieve a minimum fuel pressure to start the engine. For your 93, that is approximately 31 psi.
3. If the above two things check out (and only if), then run a compression test on all cylinders. Never rule out the possibility of an internal problem. The compression spec. for the 4.0 engine is 120-150, with no more than a 30 psi variation between cylinders.
2. Verify fuel pressure. This MUST be done with a fuel pressure gauge. I know you said you have fuel, but you must achieve a minimum fuel pressure to start the engine. For your 93, that is approximately 31 psi.
3. If the above two things check out (and only if), then run a compression test on all cylinders. Never rule out the possibility of an internal problem. The compression spec. for the 4.0 engine is 120-150, with no more than a 30 psi variation between cylinders.
#7
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even if it has the fuel pressure isnt right it should still atleast inetnt to start with starting fluid right???
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#8
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if the coil is weak should i just go buy a new one? the guy i got it from had changed it already he said and yea it has red spark so that means its weak spark? wat else can cause that
#10
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Year: 1996
Model: Cherokee
Engine: HO4.0 I6
As you mentioned before you think the PO said something about the ASD (auto shut down relay). There are relays located in this box too. Use that diagram mentioned above to locate the ASD. Notice the part numbers on that one and temporarily switch it with another with identical p/n.
These are just ideas. it doesn't sound like your problem, but it is way easier and way faster to check these since you don't need anything but your hands and eyes.
Let us know what you find.
#11
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i checked all my fuses from engine fuse box and under the steering wheel all fuses are good my fuel pump is turning on i have spark but its red and i keep reading that red/orange is WEAK SPARK that it needs to b blue wich means strong spark wats wrong with my jeep i need help please im in modesto ca if anyone close can help me ill pay $$$$ but im really hoping that the motor isnt bad since it atleast has weak spark it should atleast try to start atleast backfiring or something right???
#12
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Year: 1996
Model: Cherokee
Engine: HO4.0 I6
i checked all my fuses from engine fuse box and under the steering wheel all fuses are good my fuel pump is turning on i have spark but its red and i keep reading that red/orange is WEAK SPARK that it needs to b blue wich means strong spark wats wrong with my jeep i need help please im in modesto ca if anyone close can help me ill pay $$$$ but im really hoping that the motor isnt bad since it atleast has weak spark it should atleast try to start atleast backfiring or something right???
And don't mean to be a D-bag but try to use some punctuations. Makes it a lot easier on the brain.
#13
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im going to change the cps tomoro morning and ima take the coil to autozone to seeif they can tell me if its good idk wat else it can b im stuckkkkk
#14
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Year: 1996
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http://www.jeepforum.com/forum/f11/h...-4-0-a-803463/ Read that thread about how to test it. It will save you some time. And I also believe that if the CPS was bad that you would not have spark (don't know for sure though).
Then you can also check the ignition coil with the multimeter as well. If you are going to go to the zone for parts PLEASE pick up a manual. It will be your best friend. And you really just need to have some patience man, I know its frustrating to have a no start for a car especially after you take car of a vehicle. But throwing parts at it isn't going to make it work. Diagnose it first.
Basically this weekend I had a stall out and then a no start. Would crank and crank but not turn over. Had fuel at the rail and no spark. Everyone and their brother said CPS. Bought a multimeter and tested it and it said it was still good according to the test. But being an ignorant 21 year old I replaced it anyways. Didn't fix my problem. Went to the ignition coil (which everyone then referred me to) pulled it and ran test on it with the meter. Meter said it was good but again I was an ignorant young gun and replaced it anyways. Still no start. I then checked my fuses (should have been the first thing I did) and it was a little 30 mini amp fuse. Replaced it and it was fine. But I could have saved myself all that time had I of listened to my own tests. (I returned the parts for my money back and put the old stuff abck in now that I can replace both within a half hour...). Basically get a multi meter and start running some tests dude. And also, if you don't use at least three punctuation marks in your next reply you won't hear from me again!
#15
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hey i got it runnning just wana let u guys know what the problem was incase anyone goes thru this
i figured it would b a ground because it had spark good coil good cps it was just weak spark theres 3 grounds coming from the wiring harness that go on the side of the block by the dizzy and those grounds come from the coil
1 of those 3 grounds was broke off from being to old i guess put it on and started right up thanks for the help!!!
i figured it would b a ground because it had spark good coil good cps it was just weak spark theres 3 grounds coming from the wiring harness that go on the side of the block by the dizzy and those grounds come from the coil
1 of those 3 grounds was broke off from being to old i guess put it on and started right up thanks for the help!!!