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HELP! Backfiring, valve seals by powrmajik
Started on: 01-13-2004 02:46 PM
Replies: 5
Last post by: powrmajik on 01-14-2004 08:32 PM
powrmajik
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Report this Post01-13-2004 02:46 PM Click Here to See the Profile for powrmajikClick Here to Email powrmajikSend a Private Message to powrmajikDirect Link to This Post
Okay its not exactly back firing....yet. However when I let off the accelerator or really give it some juice it will let of a small sputter...almost like a very quiet backfire. I cannot hear it with the windows rolled down but when they are up and I listen for it it is very noticable. Any ideas on what to do to fix it? Also, as this might help, it is running very rich right now. I wanted to mess with the timing to adjust but the Fiero's computer would do most of the adjusting itself...problem is the guy I bought my car from has obviously messed with the distributor and I have a feeling it is no longer in its stock position. Can someone tell me the stock 2.5 distributor positioning? I want to get that right before I start with the timing. I have seen a few pictures of it and I am thinking it is about 5 degrees off (looks like he turned it counterclockwise).
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powrmajik
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Report this Post01-13-2004 02:48 PM Click Here to See the Profile for powrmajikClick Here to Email powrmajikSend a Private Message to powrmajikDirect Link to This Post

powrmajik

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Forgot to mention the valve seals....yes they are not great as I am burning oil. Could this attribute to the backfiring problem? Also, I have recently gotten a compressor, someone told me there is a tools to attach to the hose that compresses the cylinder so I can replace the seals. Can someone tell me what tool this is/where to get it, and how to replace the seals using it?
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dguy
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Report this Post01-13-2004 03:06 PM Click Here to See the Profile for dguySend a Private Message to dguyDirect Link to This Post
I have a carb'd motorcycle which burbles & pops on a closed-throttle decel from a high RPM; I know why it & other carb'd engines often do that, but I have yet to figure out why this happens on fuel-injected engines as well. I'll be interested to see any answers which other members have.

As for your question regarding compressors & changing valve seals, what you need is a length of hose with a threaded fitting that matches that of your spark plugs. Thread this hose in to the spark plug hole, and pressurize the cylinder to keep the valves from dropping in after you remove the retainers.

Another method of keeping your valves up, is to thread a bunch of rope in through the spark plug hole, then gently rotate the crank by hand until the piston compresses the rope against the faces of the valves, holding them in place. Once you've re-assembled the valve seals & springs, rotate the engine backward just enough so that you can extract the rope.

With either method, it's not a bad idea to ensure that the cylinder is on its compression stroke. It'll make life easier if you're using compressed air to hold the valves, and you're less likely to jam a piece of the rope between a valve & its seat with the othe rmethod.

-d.

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his: 1985 2M6 SE
poly'd, Koni'd, formula nose & factory sub

hers: 1984 2M4
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[This message has been edited by dguy (edited 01-13-2004).]

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powrmajik
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Report this Post01-14-2004 10:01 AM Click Here to See the Profile for powrmajikClick Here to Email powrmajikSend a Private Message to powrmajikDirect Link to This Post
Sounds like a plan with the rope trick, I've heard of that before. I thought there was an actual tool I could use with the compressor, but I think I'll go with the rope. Can anyone tell me the easiest way to check for the compression stroke, besides just crawling back there with a flash light and taking a look? Heck, maybe thats the easiest way anyway. What about the stock position on the coil?
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TNJ84se
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Report this Post01-14-2004 10:07 AM Click Here to See the Profile for TNJ84seClick Here to Email TNJ84seSend a Private Message to TNJ84seDirect Link to This Post
Valve seals wouldnt cause popping just oil burning. You might need a valve job if your valves arent sealing well, but that has nothing to do with valve seals.

did that make sense.???????

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powrmajik
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Report this Post01-14-2004 08:32 PM Click Here to See the Profile for powrmajikClick Here to Email powrmajikSend a Private Message to powrmajikDirect Link to This Post
Yeah that made sense. I was also thinking it might the cat...if thats clogged up, and it probably is as it looks like the original, that would be a good starting point. If the back pressure isnt flowing the way it should then I'll have problems.
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