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Old 04-01-2012, 01:22 PM   #1
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tj not running good need help

new wires new distributor cap new rotary button and plugs still skipping backfire ?

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Old 04-01-2012, 02:05 PM   #2
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Please fill in your vehicle info on your profile. Too many variables otherwise.

You could have bad gas, bad TPS, Crank Sensor etc.

We will be here waiting

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Old 04-02-2012, 06:49 AM   #3
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I put a new crank sensor in last night still no change . It's good gas . I had to replace fuel pump 2 months ago I just wonder if the pump is floating inside the aluminum tube .
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Old 04-02-2012, 11:15 AM   #4
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Is it backfiring through the intake or exhaust?

If backfiring through the intake it is generally an indication of either running too lean or the exhaust could not be getting out of the combustion chamber due to flat cam lobe or restricted exhaust system.

If backfiring through the exhaust it is generally one of two things, either running too rich and the unburned fuel is igniting in the hot exhaust or more commonly there is an ignition problem where the spark is intermittent. When the spark is reacquired it will burn the fuel in the exhaust causing a backfire.

Narrow it down to intake or exhaust backfire first so you are not chasing your tail trying to diagnose it.

Also, post up any more information as the more information and the more detailed the better chance we have of helping you diagnose this properly.

Mike.
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Old 04-02-2012, 12:14 PM   #5
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It is through the intake and then it will run good for a bit. I had a problem with the switch in 2009 I installed a push bottom to start it after you turn the key on . Some time the air bag light will come on and all the gauges quiet working . But you can blow the horn and everything starts working again. and thanks for all your help so far bud .
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Old 04-02-2012, 12:25 PM   #6
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and you can tell I'm very new to this lol
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Old 04-02-2012, 12:27 PM   #7
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It is through the intake and then it will run good for a bit. I had a problem with the switch in 2009 I installed a push bottom to start it after you turn the key on . Some time the air bag light will come on and all the gauges quiet working . But you can blow the horn and everything starts working again. and thanks for all your help so far bud .

Man, that sure sounds like you have a wiring issue but generally a spark related (or lack of spark rather) issue is going to backfire out the exhaust. Intake is almost exclusively lean or a restricted exhaust.

If you have access to a vacuum gauge I can walk you through a quick and easy check for a restricted exhaust system.

Hook up a vacuum gauge to a manifold vacuum port. At idle depending on what kind of elevation you are at it should read fairly high teens on a good healthy engine, something around 17-20 inches of vacuum.

If it is lower than that check for leaks as this could also cause a lean condition.

Once connected and you have your vacuum reading, slowly rev the engine to approx. 1500-2000 RPM and hold it. As you are reving the engine with the throttle the vacuum will drop somewhat, once the RPM stabalizes at the desired RPM, the vacuum should come back up slightly (probably not all the way back up to where it was at idle).

Once the vacuum comes up watch it and see if it holds or starts to drop off. If you are holding the throttle steady and the vacuum starts to drop this is a good indication that the exhaust system has a restriction. Either a smashed exhaust, plugged catalytic converter or worst case scenario a camshaft with a flat lobe which is not opening one or more of the exhaust valves far enough and letting the exhaust out.

Think of the engine as an air pump. In order to let more air in the air must get out.

A vacuum pump is fairly cheap from NAPA or any local auto parts store and they are very good to help diagnose the health of an engine.

In my opinion the vacuum gauge is one of the most under-used tools anymore yet one of the most inexpensive to own. Once you get good at reading one you can detect things from lean or rich to too much or too little ignition timing to a sticky valve or broken valve spring.

Hope that helped.

Mike.
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Old 04-02-2012, 12:28 PM   #8
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and you can tell I'm very new to this lol
No problem.

We are here to help and we can all benefit from learning more.

Mike.
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Old 04-02-2012, 01:29 PM   #9
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In my opinion the vacuum gauge is one of the most under-used tools anymore yet one of the most inexpensive to own. Once you get good at reading one you can detect things from lean or rich to too much or too little ignition timing to a sticky valve or broken valve spring.

Mike.
X2 Mike.
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Old 04-02-2012, 04:21 PM   #10
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Thanks my friend will try it this weekend if I don't half to work
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Old 04-04-2012, 05:21 PM   #11
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Also when I got the hood open it seems It's trying very hard to get air through the breather box . And I've held my hand over it and it cleared up. almost like you had the chock on

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