[zjrog]

And the other day, I BEAT IT!!!!

While taking my daughter to college with it, it started running poorly and losing power. Was hard to keep at an idle and just wasn't wanting to rev. So, time to troubleshoot. Its a 1990 Jeep Cheroke with 4 liter 6 banger and automatic. Because I had spark at all six plugs I ruled out basic ignition issues, though I replaced the distributor cap and rotor, and plugs and wires. I used a timing light to see if the timing chain was at issue, nope, rock steady. I had fuel at the fuel rail. I went through the tangles mess of vacuum lines, checking everything. No problems there. So I started looking at sensors.

With 199,000 miles on it, it had been running strong to this point and the motor had always sounded good. No ugly crankcase noises. Replaced the O2 sensor and the Throttle Position Sensor. No change. Ran a compression test. Well, had two cylinders down on compression. OK, headgasket. Took me a while to finish this task as I became ill and then had minor surgery to my ear and sinus. And of course, there was some level of don't care too.

Finished the headgasket, but no change when I started it up. I have a parts Jeep that I'm stripping, and so I started grabbing parts and swapping them around. I swapped fuel injectors and fuel rail and fuel pressure regulator, and the throttle body and checked and cleaned the Idle stepper. Then I bought a Crank Position Sensor. No change again. I swapped from the parts rig, the ignition control module, and then the distributor (which has the cam sensor inside it...), all to no change. All I had left was fuel pump or computer, and computers don't normally go bad in these.

So pulled the fuel pump out. Hey whats this? There is this little 3" piece of 3/8" hose between the pump and the output tube. And it was rotten, cracked, and very soft. In fact, without loosening the clamps, it was pulled off the fittings with a finger. On one side it was just barely making contact with the tube. Well this MUST be the problem... Replaced the hose, and just for my own edification, ran both that pump and the one from the parts Jeep and both pumped fuel between gas cans. Very nicely at that. I put the original pump back in with the new section of Goodyear fuel injection hose and a new clean strainer.

And the Jeep started and settled into a nice smooth idle. Took it for a drive, and it is quite nice to drive, better than anytime since I bought it. So while my peformance is better than ever, I imagine fuel mileage will be better too.

Next tool purchase will be a fuel pressure gauge. I could see I had fuel pressure at the rail, but now realize that with a gauge, I'd have a better picture what was going on.

On the other hand, I now have a bunch of spare parts in case something happens to me or a buddy on the trail. And the Jeep got one helluva tune up.

Rock on guys.