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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
While on vacation, I got a P0301 code (misfire cyl 1) and my 97 XJ has been running with a rough idle since and I've gotten the code even after some maintenance which I'll detail below.
I ended up replacing the distributor due to some shaft wobble. New Copper Plus plugs and new wires.
I've checked the injector harness plug for cyl 1 with a Noid light and it flashes. I've checked compression on cyl 1, 2, & 3 (125,135, & 130). I've checked for vacuum leaks and haven't found one. I've ordered a set of 4-hole injectors from K Suspensions as I'm suspecting the one is bad and the others aren't far behind. Below are the colors of the new plugs from Cyl 1, 2, & 3 after running for no more than 30 mins total during testing, etc.
Am I headed down the right road here? I sure hope these new injectors fix my problem. I figured if it was a coil or fuel pressure regulator problem it'd effect all cylinders, not just 1. Sorry the first pic is blurry.
The only troubleshooting weakness in there is that 1 variable (a possible single bad injector) is being replaced with 6 variables (the possibility that any of the new injectors are bad). But I don't blame you for going that route. A route with less variables is to move the suspected bad injector to another cylinder (swap it). If the misfires follow the injector you know its bad. If the problem doesn't follow the injector, then you would know to hold off on the injector swap until the real problem is addressed.
Last edited by jordan96xj; 08-08-2017 at 02:30 PM.
So, what if I did swap injectors 1 & 2 and the misfire doesn't move with it? What would that suggest? Reason I'd like to know is I intended to do so, but after setting the injector down that I was going to place in the #2 spot on the rail when I was interrupted by something, I wasn't 100% positive I swapped them. You see, like a dummy, I thought I could keep track of just two injectors without marking either one.
So, what if I did swap injectors 1 & 2 and the misfire doesn't move with it? What would that suggest? Reason I'd like to know is I intended to do so, but after setting the injector down that I was going to place in the #2 spot on the rail when I was interrupted by something, I wasn't 100% positive I swapped them. You see, like a dummy, I thought I could keep track of just two injectors without marking either one.
And the misfire is still on #1 only? Then swap them again. Then you can be sure you tried both injectors on #1.
If you swap injectors and the same cylinder misfires, its a connector or wiring problem (worse case scenario, the injector driver in the PCM). If you swap injectors and the misfire follows the injector, the injector is bad. A Noid light will only tell you if there is a pulse (check them all in case the injector being tested shows a weaker pulse than the others, ive seen this in a GM). A Noid light will not tell you if the injector is dirty. Also, check the injector body for any signs of splitting, which is bad. And when removing (or installing) injectors, you risk damaging the o-rings, which is also bad.
08-08-2017, 01:57 PM
Faulty Fuel Injector?
