dead cylinder?
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dead cylinder?
so awhile back i made a post about my 92 f150 302, having poor acceleration and power. i pulled the plug wires off while the engine was running to see if the cylinder were all firing, and when i pulled the plug wire off the right/front plug (#5 cylinder i believe) idle didn't change at all. so it seems as if the cylinder isn't firing at all. the plug and plug wire is good, how could i check to see if its getting fuel from the injector?
Postmaster
Joined: Aug 2005
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From: Cleveland, TN
Why not get a compression gauge and find out?? No matter how much fuel you have it ain't gonna fire without compression...
Fleet Owner
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From: Kentucky
It might be low compression. As noted above it is time for a compression check.
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right after i made the post i went outside and did a compression test on the cylinder. after i disabled the fuel system, i held the throttle open and cranked it over, and the best i got was about 120psi, is this really low?
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From: Garden City
I would say yes, it is low. You have to compare it to the other cylinders, though. The engine I just took out had a couple cylinders that were that low, while others were up to 150. In my case, I knew without doing a compression check. There was so much blow-by that oil was draining from the air filter box, soaking the filter, and dripping oil residue from the tps. Very little smoke from the exhaust, however.
Other indicators were an uneven/rough idle and if I had the a/c on, it would stall the engine when going from drive to reverse gear unless I tapped the accelerator. Under light acceleration, it would have kind of a "surge" until the rpms built up a bit.
If any of this sounds familiar (especially the blow-by), then I suggest a rebuild/replace is due.
Other indicators were an uneven/rough idle and if I had the a/c on, it would stall the engine when going from drive to reverse gear unless I tapped the accelerator. Under light acceleration, it would have kind of a "surge" until the rpms built up a bit.
If any of this sounds familiar (especially the blow-by), then I suggest a rebuild/replace is due.
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From: Garden City
I just read your low power thread. It seems that you lost power after an evening of horsing around, correct? One thing I didn't see you mention is the timing. It may have retarded during the rough driving. If it is still firing before TDC, the engine will still rev while not in gear somewhat normally, but it will be sluggish under load. Might as well verify that is good also before condemning the engine, right?
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From: Kentucky
You need to check the rest of the cylinders to determine if that reading is low or in line with the rest of the others.
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From: Garden City
Even if your compression ratios are variable, setting the timing properly will help it run as good as it can until it is overhauled or replaced. I would use a light instead of the ear tune method.
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From: Garden City
This gets you close. There is no real way to know without a timing light.