Mullins_j

Here is my issue, I've been having some pinging going on with my '94 XJ. I went through it today, and now it's misfiring. Just here and there at idle, and when it get to temp. But at WOT it stubble's and misses alot, can hardly get out of it's own way.

I'm leaning towards the Crank shaft position sensor. I've already changed the plug's, wire's, cap, rotor, coil, Coolant temp sensor.

Anyone help?

Thanks,
J

Mullins_j

Anyone?

dmndd26

check the injectors i just had the same problem and thats what it was

Mullins_j

So an update. I have still yet to find the problem, but, it seems like it hardly misses at idle and low RPM's, Maybe 1 cyclinder. But when I hit WOT, it goes to hell. Checked the CPS, seems to measure right (per the hanyes manual I have), TPS is reading 3.8V at WOT, the book says alittle under 4.8V, does that qualify? and 738mV at closed throttle, book say alittle over 200mV.

Also measured resistance at all injectors, each read right around 13.6 Ohms.
Coolant temp sensor, works. MAP sensor measured fine and triped a code when unplugged.

I'm pretty much lost at this point? I have no check engine light on, but it still runs like *****.

Oh, and I changed the vac line going to the MAP, and FPR. They looked alittle ify.

Any idea's guys?

Thanks,
J

dmndd26

take the injectors out and clean the tips of them with carb cleaner spray or break cleaner and clean the injector ports i guarentee thats the problem, they may get voltage but they are most likely dirty trust me this will work

jeepxjho

it sounds like it might be a few things first thing i would do since its free is to clean the injectors by taking them out and cleaning the tip like suggested.

If that doesnt fix it i would look into that TPS sensor some more piggy back the connector and go thru closed throttle to full throttle also only getting 3.8 v at full throttle is low in my manual it shows 4.8v +/- .2 volts so if your getting only 3.8 at full throttle the servic maual says it is out of specs.

And if that doesnt fix it for some reason yo might have a clogged cat the symptoms of a clogged cat is that it falls on its face at mid to full throttle since the engine cant get all the exhaust gases out how many miles do you have on yours.

drgnhrt1979

In addition, I would also have the cylinder compression test done, I was in the same boat as you, couldnt figure mine out till i had that done and sure enough my misfires were caused by my head being cracked or warped.

Mullins_j

Finally figured her out last night. So, a buddy of mine came over and we went started trouble shooting all the sensors, came down to unplugging the Cam position and nothing changed while running. Went to the parts store, and got another for $37. Went back tried it, didn't work. By this time it was dark out, my buddy told me to start it up, then told me to go where he was. Then we saw it, I had a F*@#en cracked spark plug, brand new! CHanged that one, and she's back on her feet again.


Thanks for all guys,
J

fireman85p

I'm at a loss and about $1200 deep. HELP! My 1994 Cherokee sport 4.0 has been giving me problems for months. At first it was dying at idle and low speeds, I found out later it was the throttle body. Now After I have replaced and cleaned the #3 cylinder is misfiring and it runs sluggish. I have replaced:
Fuel Injectors
Fuel pump
Fuel Filter
Rotor and caps
Exhaust manifold gasket
Map sensor
Coolant sensor
Cam shaft, cam gaskets, Lifters.

I'm not even getting a check engine light?
I did a rebuild of the engine and it only has about 65,000 on the rebuild.
HELP! It is my only vehicle