Mechanics

123000 MILES

1997 Jeep Wrangler

Lately, my Jeep has been breaking down quite frequently. While on the highway, traveling at normal speeds, randomly the car will just start slowing down. I still have the gas pedal pressed the same but it just starts to slow down on its own. When I pull over, because I cant continue to accelerate, the car cuts off. Then it wont start again for about 5 minutes or so. When it does start up it is fine for about another 10 minutes and then does the same thing again. I took it to a repair shop and they could fing nothing wrong with it. Help me!
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97Wrangler
January 13, 2007.



What size motor?

4.0 Liter 6 Cyl.

Tiny
97Wrangler
Jan 13, 2007.
Has there been a check engine light? Or any others.

If so, what codes?

How has your fuel economy been, if you know?

Is there anything in common when the problem happens, ie. Weather conditions, speed traveling, how warm the engine is?

Has the fuel pressure been checked?
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Has the idle air control motor been cleaned,

has an air induction service been done,

Fuel injection cleaning been done?

Have you looked for any loose or dirty connections?

How old is the battery?

How are the connections at the battery, alternater and ground? Clean and tight hopefully!

Last time fuel filter, ignition wires or plugs were replaced?

Need previous answers and these to go forward.

There have been no indication lights at all. Usually happens between 60 - 70 mph. Weather has varied. Just had the Cadillaic converter replaced. I have had the Jeep for a year and a half and don't really know all the other information.

Tiny
97Wrangler
Jan 13, 2007.
A magic bullet, I don't have on this. I need information that may be relevant to help. If you want to try to solve this yourself or give it you best shot then: Let's start with: What is weather varied mean? 10 degrees sometimes, 80 degrees other times, dry conditions, damp conditions?

HAve the codes read from the computer, best bet is buy a code reader.

Again: Have you looked for any loose or dirty connections?

How are the connections at the battery, alternater and ground? Clean and tight hopefully!

How warm is the engine when it happens?

Why was the converter replaced?

Has the problem been happening before the converter, if so how long?

If you want to try a few maintenance procedures instead that may or may not help then: Replace the plugs and wires, Have injectors professionally cleaned and do an air induction service.

Unplug the crank sensor and plug it back in. Could be intermittent, if that doesn't help, try changing it with know good crank sensor.

Tiny
Aacplus
Jan 13, 2007.
Lets not forget the basics, truthfully my biggest problem. I would do a quick ohms check on the coil. A guy can go nuts chasing down sensor issues and may be on the right track. But first I'm going to the coil on this one. It is a fast easy check and cheap to replace if its faulty. Check ohms flow when the coil is cold and hot, if you can, check it when you have those few minutes on the side of the road. You probably don't have much going right then anyway! If the measurments are within spec in all three conditions you ruled it out. A southward coil will not always throw a code and you can do this with a good volt meter or ohm meter and a manual to walk you through it. No scan tool required. Good luck.

Tiny
Cearl
Jan 19, 2007.
That's a great point Cearl and I don't disagree, not do I necessarily disagree with aacplus. My guess aacplus has been down this path with this solution as a winner. And I have seen the coil situation on other vehicles and it does fit. I can't say I have seen it on a wrangler 4.0, but that doesn't mean much. That's one of the great things about this site, is the different angles that folks take to solve a problem. So many times you can see someone running down the wrong path possibly and causing the poster greif instead of resolve, but another member can bring it back on course. Such as may the case here : D

From my view, I try to get as much info as I can to either find TSBs or something that supports or eliminates a theory before I state it. Thats just my style. Getting info on this one has been fruitless, killing any narrowed down insight I can provide. After looking at it again, we still don't no if it is a no crank or no start. Based on the no dashboard warning lights at stall I would assume that it is a no start, but that whole assume thing can be an achellies heel too! : )

I would check the fuel system before I go to Ignition on this sort of problem.

Fuel system head pressure: This checks the maximum output pressure of the fuel pump. With the return line pinched shut, the pump should produce two times its normal operating pressure at idle. If the pressure rating does not go up with the return line blocked, the pump may not be able to deliver enough fuel at higher engine speeds. Possible causes include a worn pump, low voltage at the pump, a plugged fuel filter or inlet sock in the tank, an obstructed fuel line or almost empty fuel tank.

Fuel volume: the pump should deliver a Qt of fuel in 30sec

Rasmataz
Jan 19, 2007.
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