backfire thru intake?

[mmink]

My 120K mile 1993 Ford Explorer acted up this morning. I started it normally but right as I released the key, I heard a 'bpooff' sound and it quit running. It seemed like a backfire at first and I could smell unburned fuel. I tried to start it again and it started but ran at 2700-2900 RPM for about a second and a half and then stopped. I thought a sensor or something may have sent a wrong signal to the computer, so I took the battery cable loose to reset the computer and then tried it again. Same result, running fast only for a short period. I gave it some gas as it went to stall and it seemed to run roughly for a bit but I was concerned there may be something wrong with the timing chain or something of that nature so I promptly quit giving it gas and let it die.

I bought this vehicle new and have maintained it flawlessly for its whole life. The only real problem (besides the damn brake wear) has been the thermostat I replaced last summer. Also last summer I replaced the entire airbox with a high flow filter unit similar to a K&N type.

I was thinking it the timing chain may have slipped a tooth or something similar since the way it is now running, it seems it is either the timing or perhaps something to do with a damaged sensor from the ?backfire? I may have let go of the key too quick when I was first starting it which may have caused the "backfire". Its never "backfired" before and it was running perfectly last night when I parked it.

Any advice somebody can provide me would be greatly appreciated. I have a young special needs child who requires most of our limited resources and will have to perform any needed repairs myself.

Thanks,
Mark C. Mink

mailto:mmink@prestonphillips.com
Phone: (770) 396-8752 Direct: (770) 396-1144 x217
Fax: (770) 396-4767

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All who wander are not lost!
Mark '93 Sport

 

[Gigantor]

My first double post, my bad.

[This message has been edited by Gigantor (edited 04-03-2000).]

 

[Gigantor]

MARK,
How long did you disconnect the battery for? In order to reset the computer you need to have it off for a WHILE. I would say 10 min. Once you do that you need to let the truck idle about 3 min. There is an ongoing debate about resetting the computer however this is what I do and it works for my 93.
Good luck, I hope this works. If not, try checking the spark plugs and wires.

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Nick
'93 XLT 4 Door 4x4
Bosch Plat+4's with SplitFire Dual Core wires and a
K&N Air Filter with a Modified Air Box

 

[Maniak]

One thing to check would be the vacume lines on the driver side of the intake. Our vacuum lines were a little soft due to a bad vacuum modulator in the tranny (which allowed tranny fluid into the hoses). One morning when we tried to start our '92 we got a kinda pop sounding backfire from under the hood. After that it ran but barely. I noticed a new sound and I found one of the vacuum lines had popped off. It did it two more times before I got tired of it and replaced the vacuum line with a new one.

I hope your problems is as simple as ours was.



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Mark
mark@legendz.com
http://mark.legendz.com
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