For the love of god please help
03-10-2019, 10:39 PM
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For the love of god please help
Hello, in need of some serious help here. So I’ve been having a no start issue (sort of) for a better half of a year. It’ll start once in a while and stall sometimes run rough. Ive been itching to wheel and dumping money into this thing and it just doesn’t wanna run. I’ve replaced almost everything and tried just about everything. I’m just going to list everything I’ve done/replaced and see if anyone else wants to shout out some idea and could possibly help me solve my issue. Anything would be greatly appreciated! Thank you in advance!
so I’ve replaced the following. Distributor and (4 switch plates + cap and rotor)(timed right) timing sprockets + chain (set right) CPS (3 times and spaced with the factory sticker spacer) coil, spark plugs (gapped right) spark plug wires, TPS, throttle body (newGasket)
ive replaced the whole engine harness, Ive checked all the grounds and cleaned them. I replaced the fuel pump and pressure was fine and cleaned the tank with fresh fuel. Vacuum lines are good, compression is great. I just replaced the starter must of burnt out from me cranking it so many times for the last year) only 2 things I haven’t replaced are the map sensor and the computer. I have a code that comes on and off sometimes it’s low circuit to CPS or something but it hasn’t popped up in a bit. I’ve tried other things as well just can’t think of them but if anyone has any idea I’d appreciate it.
1997 Jeep Cherokee 4.0
so I’ve replaced the following. Distributor and (4 switch plates + cap and rotor)(timed right) timing sprockets + chain (set right) CPS (3 times and spaced with the factory sticker spacer) coil, spark plugs (gapped right) spark plug wires, TPS, throttle body (newGasket)
ive replaced the whole engine harness, Ive checked all the grounds and cleaned them. I replaced the fuel pump and pressure was fine and cleaned the tank with fresh fuel. Vacuum lines are good, compression is great. I just replaced the starter must of burnt out from me cranking it so many times for the last year) only 2 things I haven’t replaced are the map sensor and the computer. I have a code that comes on and off sometimes it’s low circuit to CPS or something but it hasn’t popped up in a bit. I’ve tried other things as well just can’t think of them but if anyone has any idea I’d appreciate it.
1997 Jeep Cherokee 4.0
03-10-2019, 11:01 PM
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Year: 90,84
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Engine: 4.0,2.5
Maybe a bit more info for those that might help. It does always crank, but too often doesn't start? (BTW, try floor-boarding the throttle. That cuts of injector pulse to start a flooded engine) Any smell or smoke? The CPS, (crank position sensor) is a booger to change there on the bell housing. I'm not familiar with any "spacer". Were all three from the same source?
The vacuum line to the MAP is supper crucial and a common booger in earlier Jeeps with the MAP up there on the firewall with the green wire connector. Your symptoms might match a problem with that line, but I think your MAP is on the throttle body with maybe a little elbow tube to it. The MAP is first in line to start roughing out how much fuel is delivered, if it doesn't get proper vacuum or is fubar, you won't be having a good day. (I gather with a spendy or analogue meter one can watch "the sweep" of voltage as you pull the handle on a vacuum pump.
Bummer dude, I feel for you!
Edit.....my 90 will sometimes, and sometime not start with the MAP unplugged. (might have to do with temp?
The vacuum line to the MAP is supper crucial and a common booger in earlier Jeeps with the MAP up there on the firewall with the green wire connector. Your symptoms might match a problem with that line, but I think your MAP is on the throttle body with maybe a little elbow tube to it. The MAP is first in line to start roughing out how much fuel is delivered, if it doesn't get proper vacuum or is fubar, you won't be having a good day. (I gather with a spendy or analogue meter one can watch "the sweep" of voltage as you pull the handle on a vacuum pump.
Bummer dude, I feel for you!
Edit.....my 90 will sometimes, and sometime not start with the MAP unplugged. (might have to do with temp?
Last edited by DFlintstone; 03-10-2019 at 11:04 PM.
03-10-2019, 11:39 PM
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Year: 1998
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Have you checked out your ASD relay? Does your check engine light atleast illuminate when you turn your key to on when it doesn’t start? Do you have any way to check for crank signal from the PCM when it won’t start? Any way to check for fuel pressure? Definitely would help to narrow down what it might be if you can narrow it down to fuel or spark issue.
03-10-2019, 11:42 PM
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Also, if you changed a bunch of things have you cleared the adaptive memory to rest things such as the steps for your idle air control and fuel trims?
03-11-2019, 07:49 AM
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Thank you everyone for replying yes I have replaced the IAC valve as well and checked all fuses, It doesn’t have to do with anything heat related. It’ll just run randomly when it wants to. Lately (within the last I’d say 4-5 months just hasn’t ran at all. I’ve also done a few re-learns and factory resets and all that stuff. I had a few member from my NEA club come down and they were even confused. Guess I’ll try the computer guys. Thank you very much everyone I appreciate it
03-11-2019, 08:33 AM
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Year: 1992
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The leads from the battery can be internally corroded in the wiring or at the terminals on the posts. What is the fuel pressure at the fuel rail? What is the resistance across the negative and across the positive lead? I think that the 1997 is just distributor cap thru wires to plugs. It'd be aweful easy to remove each plug and place a teaspoon of fresh gasoline into each cylinder before trying to start. That will confirm that you have decent spark and compression. Sometimes that creates enough of a vacuum to allow it to run. Running allows non-varnished gasoline to clean the system.
Giving us the fuel pressure at the rail helps to eliminate the pump and filter. Starting with gasoline in the cylinders helps to eliminate spark and to a lesser degree compression. The fuel pressure tester is free to rent from O'Reilly's. If you are eager, then you could do a dry and wet cylinder compression test while preparing for your with gasoline in cylinders starting test.
Giving us the fuel pressure at the rail helps to eliminate the pump and filter. Starting with gasoline in the cylinders helps to eliminate spark and to a lesser degree compression. The fuel pressure tester is free to rent from O'Reilly's. If you are eager, then you could do a dry and wet cylinder compression test while preparing for your with gasoline in cylinders starting test.
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