|06-08-2011, 07:24 PM||#1 (permalink)|
Join Date: Mar 2011
Member # 187134
94 Jeep Wrangler Misfiring Neep Help
Tried posting over in the newbie forum, but didnt get to many responses.
I just recently purchased a 1994 Jeep Wrangler 4.0 HO, Auto with 94000. I knew it had the problem when I purchased it, but figured i would try to fix it and if i couldnt get it running it was cheap enough that I could replace the motor and still be fine for the price I purchased it for. i have read the threads and tried to find an answer and used some pointers, but it still isnt running right.
To start off it, the jeep will start and run but is misfiring bad, it had a rough idle and will drive but is still misfiring. It feels like it has power and pulls but probably wont go faster than 10 or 15 mph.
So here is what Ive tried and done so far:
1.New fuel pump
2. New Distr., wires, plugs, rotor button, Checked firing order many times
3. Fuel Filter
4. New air filter
5. Checked for intake leaks with starter fluid
Checked Computer codes and said some air sensor replaced it.
Tried checking fuel injectors, all had power, but when I pulled number 2 and 4 the motor didnt change idle so thought injectors were bad so I replaced 2 and still have same problem. Cleaned fuel rail when i replaced the 2 injectors.
Checked spark plugs all are firing when i pulled wires off and tested with diffferent spark plug and turned over to see if they were sparking. The plugs were a little wet with gas when i pulled them out.
Checked compression all had around 125psi
Checked fuel pressure at fuel rail and had about 35 psi and the 39-41 when unhooked the vacuum line on the fuel regulator.
Pulled valve cover and looked and rocker arms and springs looked as they were moving and nothing broke.
Im sure i left something out, but have tried everything I can think of and still cant get it running right. About ready to throw in the towel and take it to a mechanic or just replace engine. The only thing I can think of to replace is the fuel regualtor or computer. Any help would be greatly apperciated. Thanks
|06-08-2011, 07:38 PM||#2 (permalink)|
Join Date: Mar 2008
Member # 110248
Location: Western Maine
check the fuel injectors again. I had this problem a couple months ago and it was a bad injector. when you find the cylinders that are the problem swap the injectors around to the good cylinders. That will tell you if you have an actual injector problem or a wiring/computer issue.
The way I did it was pulling each plug wire till i found the cylinder that didn't change the idle, then did the same thing with the injector plugs and swapped the suspected injector to a known working cylinder and repeated the above process, in my case the problem moved so i knew it was the injector.
If the problem doesn't move but It is misfire/bad cylinder problem, check wires on the harness and noid lights, all of that crappy stuff. Also a compression test if it isn't electrical.
So the real question is, Are you sure it's a cylinder not firing?
Western Maine Mountain Jeepers
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