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94 4.0 someone please help

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Old 07-02-2021, 08:57 AM
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Default 94 4.0 someone please help

Im new to this so forgive me if I make some mistakes. I have got to get this thing going it's my only ride. Im losing work,and money! I drove it into our barn/shop. Reason, while driving when taking off it would backfire an pop. I got it home changed plugs, wires,cap was new didn't change it. Changed the IAC, throttle position sensor,even the throttle body. It will turn over an putter like it wants to start then when you let off the key it stutters an backfires. Do that a few times then play with the gas pedal an you can keep it running somewhat but not enough to move it. Then it'll rev up itself and suddenly drop rpm an backfire so loud then die. I'm stuck and have no help or another way to get around any ideas or suggestions would be very appreciated
Old 07-02-2021, 09:04 AM
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Default 4 ohhh crap!

Fuel pressure, crank sensor maybe. Any codes?
Old 07-02-2021, 09:17 AM
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Did this start happening "all of a sudden"? Have you done anything to it recently?

Cap is new? How new? Verify the firing order. Make sure the rotor is on securely.
Old 07-02-2021, 11:24 AM
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Default Cap maybe a month

Fuel pressure seems ok, and idk if I'm doing this correctly so sorry if I'm not. Firing order seems on spot I read a few post stating the 94 it's kinda hard to mess the timing up. But I've even changed the computer an does the exact same thing. The only code if had if I counted the check engine light flashing correct was IAC fault due to hight or low voltage
Old 07-02-2021, 11:35 AM
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Did you check to make sure the timing is set correctly? Dont just assume that it is.

Old 07-02-2021, 12:33 PM
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Originally Posted by connallycody
Fuel pressure seems ok,
Actually measured?
Old 07-02-2021, 01:35 PM
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Originally Posted by lawsoncl
Actually measured?
35 pounds, and I got cylinder one tdc. An set the rotary a little before the point for wire one. Took me about 7 trys.when it finally starts I can only gently tap the throttle if I try to give it more then a tap it instantly starts backfiring. I let off an it dies then takes forever to start again.
Old 07-02-2021, 10:53 PM
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Note from DJ

We need more information on your backfire problem.

Is it backfiring through the through the throttle body?

Or is it backfiring through the through the tail pipe?

This information will give a hint as to cause of your problem.

Backfires through the tail pipe is generally caused by a rich condition.
Backfiring through the intake is generally caused by a lean condition.
Old 07-04-2021, 04:41 AM
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Default Backfiring

Originally Posted by djgrayxj
Note from DJ

We need more information on your backfire problem.

Is it backfiring through the through the throttle body?

Or is it backfiring through the through the tail pipe?

This information will give a hint as to cause of your problem.

Backfires through the tail pipe is generally caused by a rich condition.
Backfiring through the intake is generally caused by a lean condition.
Sorry for late response it's backfiring through both. Not at the same time. And this is while turning over. Once it finally starts it'll idle at around maybe 200 rpm then when I give it gas it pops an sputters an backfires. Then when I let off it'll idle high then drop rpm an backfire extremely loud then rev itself back up an do the same then die
Old 07-04-2021, 02:17 PM
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Default Timing

I've played with the distributor, and it is definitely my timing. I have fought with it for the past 5 hours an I get close real close but still off! I've never had this much trouble. It's just me minimum tools no timing light no help
Old 07-04-2021, 02:18 PM
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Default Timing

I've played with the distributor, and it is definitely my timing. I have fought with it for the past 5 hours an I get close real close but still off! I've never had this much trouble. It's just me minimum tools no timing light no help
Old 07-04-2021, 06:38 PM
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Originally Posted by connallycody
Im new to this so forgive me if I make some mistakes. I have got to get this thing going it's my only ride. Im losing work,and money! I drove it into our barn/shop. Reason, while driving when taking off it would backfire an pop. I got it home changed plugs, wires,cap was new didn't change it. Changed the IAC, throttle position sensor,even the throttle body. It will turn over an putter like it wants to start then when you let off the key it stutters an backfires. Do that a few times then play with the gas pedal an you can keep it running somewhat but not enough to move it. Then it'll rev up itself and suddenly drop rpm an backfire so loud then die. I'm stuck and have no help or another way to get around any ideas or suggestions would be very appreciated
The problems I've had with idle (cold) were the IAC sensor and (hot) the forward O2 sensor. My 98 suffered the failure of both at the same time. If the engine starts I doubt the crank position sensor is the culprit. My 96 suffered from that failure as an intermittent condition at first and then a complete shut down after a few weeks. I didn't know what it could have been at first but after some head banging got it figured out.
Old 07-04-2021, 08:24 PM
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Originally Posted by connallycody
I've played with the distributor, and it is definitely my timing. I have fought with it for the past 5 hours an I get close real close but still off! I've never had this much trouble. It's just me minimum tools no timing light no help
Not sure what you're doing, but these instructions might help. Beware some of the drawing for firing order are wrong, including the one in Haynes. The one on Cruisers site is accurate.
https://www.jeepforum.com/forum/f12/timing-4-0l-508405/
http://cruiser54.com/?p=68
Old 07-06-2021, 07:00 PM
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Originally Posted by lawsoncl
Not sure what you're doing, but these instructions might help. Beware some of the drawing for firing order are wrong, including the one in Haynes. The one on Cruisers site is accurate.
https://www.jeepforum.com/forum/f12/timing-4-0l-508405/
http://cruiser54.com/?p=68
I've came across about 50 of em, thank you I'll give this one a try. Wanted to thank everyone that has tried helping it's appreciated
Old 07-12-2021, 10:16 PM
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Default Done with it, engine swap

Originally Posted by connallycody
I've came across about 50 of em, thank you I'll give this one a try. Wanted to thank everyone that has tried helping it's appreciated
I've done everything every timing order I've seen. Lined it up as detailed an still it either turns over an literally idles like it's got one tell of a cam then dies or it backfires through intake an doesn't run. How hard is it to put a Chevy motor in?


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