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Discussion Starter #1
OMG!!! When will it end? I got about a weeks worth of driving out of my samurai, and now something else goes wrong. now it's backfiring. consistently on one cylinder when the engine is under load. I pulled the plugs and the plug from the #1 cylinder had a lot of oil on it. I'm just about ready to throw in the towel and take it to a mechanic.
 

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If you have oil fouling the plug. You need to find out where it's coming from. Is the oil inside the cylinder or is it just pooling in the plug well and it ran down the plug when you pulled it out?
 

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Discussion Starter #3
the valve cover was loose, and leaking oil. I'll do everything i can to clean it up and replace the plug we'll see what happens then. gotta replace the timing belt again too, the oil leak has the belt practically soaked in oil.
 

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if the oil is burnt onto the plug it might that the piston is moving to far up and to far down that was the problem in 93 sierra oz version of the samuria it was making tapping noise when idleing and even worse when under load means the bearing on your con rod is warn out and that means a rebuild of the engine
 

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Are you definetly sure its oil on the spark plug and not unburnt fuel?
I had the same problem in my 93 sammy, one of the HT leads had a fault in the middle somewhere and was arcing inside the insulation losing spark power to the plug
It was fine when idling or light driving but when i needed power it would missfire.
I ended up replacing all of them while I was at it
 

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the valve cover was loose, and leaking oil. I'll do everything i can to clean it up and replace the plug we'll see what happens then. gotta replace the timing belt again too, the oil leak has the belt practically soaked in oil.
Fix oil leak, check oil, replace spark plug w new one . drive.
If water is leaking all over the place fix that leak too and check water level in radiator
I cant belive your timing belt is damaged What you got 20 miles on it?

What ever you do dont start taking the carburator apart or your gona have more trouble
 

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if it was leaking that much oil that it filled the plug well it was probably causing a misfire which would result in fuel on the spark end of the plug. If the belt is saturated with oil then it will need to be replaced eventually. Oil or coolant can cause the rubber to break down prematurely, but you should still have quite a few miles left on that new belt, (even if it did get soaked with oil) if you don't want to tear the whole front apart again.
 

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Discussion Starter #8
I figured the timing belt would be ok for a little while. once i get her back on the road, i'm going to order a spare anyway since it takes three days for any parts store near me to get one. I threw in the towel and took her to a mechanic. Since the shop was only 100 yards down from where i have her parked, it wasn't much of an issue to drive there with a poor running engine. they checked valve lashing and compression, she passed both tests. that brings us to an electrical/electronic issue. i've replaced the plugs, wires, cap, and rotor. the ignition coil looks to be brand new. i can't really think of anything else in the ignition system that could be malfunctioning. i'll pull all the plugs and visually confirm that i'm getting spark on all of them. any other ideas if all four pass this test?
 

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if you have compression and you have spark, and the timing is right, then the next thing is the air/fuel mixture. If you have the vacuum lines routed incorrectly or if you have a faulty component then you could be running too lean. This will make the engine misfire and fuel will be dumped into the exhaust and can cause back firing and also ruin your catalytic converter. I've pulled my carburetor more times than I care to think about and I swear I could run the vacuum lines on it with my eyes closed, but the last time I did my vacuum lines, I hooked two of them up to the wrong ports. It's easy to mess up and the results are a poor running or not running engine. Another thing that can cause a Too-lean mixture is a faulty EGR valve or EGR modulator. I had an EGR modulator go bad on me and it was drawing air straight through it when it shouldn't have even been open.

Check all of your vacuum lines and make sure they aren't cracked or hardened, check them against the diagrams on Ack's FAQ (print them out and put them in your repair manual) and make sure they are all routed correctly. Test the EGR modulator and make sure it's working. (do a search for it, there's a topic on it with a link to a page telling you how to check it)
 

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Discussion Starter #14
No worries. I finally get time to work on it tomorrow. Even though the check engine light doesn't stay on, will the computer have the errors that triggered it saved. Hopefully it does, Android that will give me some insight to what's causing the problems.
 

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Discussion Starter #15
OK, some hopefully good news. I ran the diagnositc system and only one code pulled. the "intake air temperatur" sensor (IAT). according to my haynes manual, this can cause the mix to run rich, the rich mix is flooding the engine and causing the backfires, as well as depositing carbon on the plugs. sensor is on it's way to me. new, working, sensor and some clean plugs, i should be back in business. I hope.
 

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Discussion Starter #17
lol, thanks. that part was a pain in the butt to track down. no shops around me had one. and i checked 8 sites before i found one that had the part. autozone was the only place open last night. no store in america had one, no dc in america had one, and their supplier didn't have one.
 

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Discussion Starter #18
yeah, new sensor didn't do a lick of good. she still backfires while under load. on a huch, i hooked up a timing light and found i was able to get the best idle at 20 - 25 degrees BTDC. Way off from what it should be. I brought it back to 10 deg, and idle speed went way down. keep in mind that while the ingnition timing was this far off, it ran for a couple dayw without backfiring. I'm going to check the lashing on the valves tonight. My thought process is that the intake valve on one of the cylinders is not closing when it should. the process of checking and adjusting the lashing is simple enough for me to understand. but the fundamentals of how much of a difference it makes with the engine is a little beyond me, i'm just cheking because it has been suggested a few times on here. if this could possibly be a valid cause for the problems, let me know. or, let me know if i'm looking in the wrong direction and should check elsewhere.
 

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Discussion Starter #19
The problem has been identified!!! But I can't fix it yet. :( I didn't even get to checking the lashing, pulled the valve cover off I noticed the #1 exhaust valve was about a quarter inch from the adjustment screw com the rocker! I thought to myself WTF!? The end of the rocker that rubs the lobe broke off. I ordered a new rocker tonight, but I won't have a free day to do the work until next weekend.
 
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