New CPS, cranks but still no spark
05-11-2018, 08:19 PM
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Model: Cherokee (XJ)
New CPS, cranks but still no spark
Hey I’m pretty new to this, but i have a 1999 Jeep Cherokee sport 4.0l that isn’t getting spark and I’m stumped. So i might’ve taken it for a dip in a river and had to get towed out. I changed the oil and oil filter the next day and drove it around and it died on me twice but started right up both times. I parked it in my garage and it hasn’t started since. It just cranks and cranks and cranks but no spark. I know it isn’t getting the 12v to the coil, in fact it’s reading next to nothing. It is getting pulse from the signal wire, we tested that with a test light. But I’ve cleaned up all the grounds, changed the crank sensor with a genuine one from the dealership, and i replaced the camshaft sensor as well. After about a week the CEL came on and i rented an obd2 scanner and got the codes p0122 and p1694. We changed out the TPS with a new one and cleared the code and the cel hasn’t came back on. Well it still isn’t getting spark and i am just stumped. Where should i turn to next? I’ve been browsing forums for weeks and i can’t seem to find something that works.
05-12-2018, 11:24 AM
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From what i can tell no. I drained the oil the day after and it didn’t look like any water got in the motor, and i drove it around after i put new oil in it and it drove great (for about 20 minutes)
05-12-2018, 11:34 PM
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When you turn the key to -on- without cranking, do you observe any weirdness with the fuel gauge or volt gauge? (like reading no value?).
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05-13-2018, 12:12 PM
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Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
How did you determine there is no spark?
But I’ve cleaned up all the grounds, changed the crank sensor with a genuine one from the dealership, and i replaced the camshaft sensor as well. After about a week the CEL came on and i rented an obd2 scanner and got the codes p0122 and p1694. We changed out the TPS with a new one and cleared the code and the cel hasn’t came back on. Well it still isn’t getting spark and i am just stumped.
What is the order of events here?
05-13-2018, 07:19 PM
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Sorry if i made it kind of confusing, but i know there isn’t any spark because i pulled the middle plug off the distributor and put a spark plug in it and got nothing. But yes the check engine light came on after it had been sitting a week in my garage. So there’s two wires that go to the coil, a white wire and a green wire. The white is the 12v constant, and the green is the signal wire. We probed the back of the signal wire with a paper clip and then used a test light to see if the signal wire is getting the pulse and it is, but the 12v constant wire is not getting any voltage, so the ignition coil isn’t getting voltage, which is causing the no spark issue. And i can’t seem to find any place on the harness where it has shorted out
05-13-2018, 08:16 PM
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Year: 1989
Model: Cherokee
Engine: 4.0L
Had the same issue on my Daughter's 97. It turned out to be the camshaft position sensor.
Pop the distributor cap off, remove the camshaft position sensor and look for damage to the part that gets signal from the pulse ring. You'll know it if you see it.
Pop the distributor cap off, remove the camshaft position sensor and look for damage to the part that gets signal from the pulse ring. You'll know it if you see it.
05-14-2018, 05:53 PM
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i already installed a new camshaft sensor and still no spark
05-14-2018, 06:26 PM
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Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Was the spark plug grounded?
What does "shorted out" look like to you? Serious question, which I ask because people who don't know a lot about electricity (which is most people) throw that word, "short" around like a young sailor throwing money at a local stripper. The problem is, they really don't know what it means. If I can get a radar fix on your level of understanding, I can help you better than if I assume......
05-14-2018, 06:54 PM
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Model: Cherokee (XJ)
Was the spark plug grounded?
What does "shorted out" look like to you? Serious question, which I ask because people who don't know a lot about electricity (which is most people) throw that word, "short" around like a young sailor throwing money at a local stripper. The problem is, they really don't know what it means. If I can get a radar fix on your level of understanding, I can help you better than if I assume......
05-14-2018, 07:20 PM
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Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Okay, good, you know what a short is. For a lot of people, "short" is some vague electrical thing that explains all electrical problems.
The problem with looking for a short is, they normally show up as a blown fuse (or fusible link).
More likely there is a bad connection or bad relay upstream of your coil.
I *think* the coil setup is the same up until they went to the coil-over-plug in the 2000 model year, so this section from my 94 manual is probably correct for your 99:
If so, that means I was completely wrong in responding to Turbo that the ASD has nothing to do with a no-spark condition. I was remembering that the ASD controls the fuel supply.
So, in fact, it looks like the ASD is your prime suspect.
The problem with looking for a short is, they normally show up as a blown fuse (or fusible link).
More likely there is a bad connection or bad relay upstream of your coil.
I *think* the coil setup is the same up until they went to the coil-over-plug in the 2000 model year, so this section from my 94 manual is probably correct for your 99:
AUTOMATIC SHUT DOWN (ASD) RELAY The automatic shut down (ASD) relay is located in the Power Distribution Center (PDC) near the battery (Fig. 1 or 2). As one of its functions, it will supply battery voltage to the ignition coil. The ground circuit for the ASD relay is controlled by the Powertrain Control Module (PCM). The PCM regulates ASD relay operation by switching the ground circuit on-and-off.
So, in fact, it looks like the ASD is your prime suspect.