tj21 Posted May 12, 2011 Share Posted May 12, 2011 '86 Comanche 2.5L TBI Compression test results, Rear to Front 130/132/148/140 What can I do to get the truck running better? Slow acceleration, very poor mileage 4 mpg, stinky exhaust, lots of emissions. Valve job? Piston rings? I ordered a throttle body kit, new fuel injector, timing chain & tensioner. Photos of gunk buildup: Link to comment Share on other sites More sharing options...
hick92 Posted May 12, 2011 Share Posted May 12, 2011 try using oil with detergent and change more often for a while Link to comment Share on other sites More sharing options...
Akula69 Posted May 13, 2011 Share Posted May 13, 2011 I used seafoam to clean the gunk out of the engine, oil passages and crankcase. It worked well and I did it several times to dissolve the built-up crud in my 87...it gave it new life. Just be sure that you don't use an engine cleaner that will release 'chunks' of build-up that can get lodged in the oil passages, and change the oil while it is still hot (to keep the sludge from re-forming in the oil pan). Link to comment Share on other sites More sharing options...
Dirteatr717 Posted May 13, 2011 Share Posted May 13, 2011 When's the last time you did a full tuneup and have you check your o2 sensor lately? That can help with the mileage :waving: Link to comment Share on other sites More sharing options...
tj21 Posted May 13, 2011 Author Share Posted May 13, 2011 When's the last time you did a full tuneup and have you check your o2 sensor lately? That can help with the mileage :waving: I don't know, what is a full tune-up? Currently I'm tearing apart and cleaning the throttle body, installing new fuel injector, then will install a timing chain & tensioner. I will do the O2 sensor as well. Then I guess spark plugs, wires, distributer & rotor. Air filter looks fine. Belts appear ok, but maybe I should replace to be safe. Anything I'm missing? I have driven the truck less than 1000 miles in the last 10 years. If I get the mileage to be decent I'll start driving it regularly and seafoam the oil and change it often to hopefully clear the gunk up. I'm concerned the gaskets / seals for the valves got dried up with the lack of use, which is why I ask about a valve job. Should I be concerned about the variance in compression between cylinders? Link to comment Share on other sites More sharing options...
tj21 Posted July 8, 2011 Author Share Posted July 8, 2011 I decided to get a valve job, and it cleaned up very nice. I will also be pulling the oil pan to replace a leaky gasket. Should I put on new piston rings, since everything is torn apart anyway? I have never replaced piston rings, but thought it would be a good time to do it as a preventative measure. Link to comment Share on other sites More sharing options...
stamp Posted July 12, 2011 Share Posted July 12, 2011 rings arent that easy to do a proper job you need new rings pistons and the block machined . its not really simple at all Link to comment Share on other sites More sharing options...
ParadiseMJ Posted July 13, 2011 Share Posted July 13, 2011 I decided to get a valve job... Should I put on new piston rings...I have never replaced piston rings ...sure, if you have a good mechanic. As a preventive measure you might wanna have them do the whole engine, while they're in there. Link to comment Share on other sites More sharing options...
banshee Posted July 13, 2011 Share Posted July 13, 2011 Above are all good suggestions I want to add one, You said you driven it about 1000 miles in the last ten years therein lies one of the largest problem 'DRIVE IT MAN', it doesn’t get hot enough to clean itself, change the oil to detergent, drive it change the oil again after several hundred miles, After several times, I think you’ll be surprised in how it reacts in both cleanliness and performance… Again just one man’s rant… B… Link to comment Share on other sites More sharing options...
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