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| rough idle after warming up, 'bucking' during cruising | |
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| Topic Started: Aug 19 2012, 10:38 AM (260 Views) | |
| Jbrown3912 | Aug 19 2012, 10:38 AM Post #1 |
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New Member
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Ok, i bought a 92 xfi fixer upper a few months ago form Geostalker, im trying to get it all road worthy before winter and having an issue. had to reset the timing belt when i bought it, did a tune up, and got everything back together no problem, ive been playing with the ign timing and think i got it about right (by ear, dont have a timing light) the car always starts normally and idles fine until it gets warmed up. when it gets warm it wants to die out and the idle drops so low that the whole car shakes violently and will usually die out within 10 sec. im a auto tech by trade and know my way around cars but dont have any experience with the diagnosis of geos lol the other problem im having is while cruising at city speeds, 20-30mph, it wants to kinda 'buck' like you let off the gas then hit it again, i dont know if its related to the idle problem or not the car seems to run great when you punch it (for 49hp) thanks in advance for any insight! |
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| brichter14 | Aug 19 2012, 01:58 PM Post #2 |
Elite Member
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help this guy out, hes got a nice car that just needs the kinks worked out |
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| Big Rhino | Aug 19 2012, 04:10 PM Post #3 |
 
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Did geostalker tell you what the compression numbers were on the engine? Recheck all your plug wires to make sure they are routed right just for giggles and recheck those timing marks and make sure they are still in time on the crank and cam. |
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| Jbrown3912 | Aug 19 2012, 09:40 PM Post #4 |
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New Member
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I started it up today and took it around the neighborhood and it seemed to idle like a champ... its still doing the running rough thing during part throttle tho, plug wires were right, im gonna get a compression gauge and timing light to set that tomorrow, any other ideas would be great! |
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| Jbrown3912 | Aug 20 2012, 09:29 PM Post #5 |
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New Member
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Well I did a compression test and have some bad news... 178/135/192. But I also have good news, I found the root of my problems, no. 3 spark plug was smashed over and almost touching the electrode, I regapped it and it runs way better, idle seemed ok, no bucking/hesitation during cruising and seems to run pretty smooth! I can't imagine how it would feel with cyl. 2 at full comp haha I think imma keep driving it and see what happens. Is it possible for the compression to restore its self? Or a g10 friendly additive I could try? |
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| cwatkin | Aug 27 2012, 03:21 PM Post #6 |
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It seems most people here either use Seafoam and/or Marvel Mystery Oil to clean out the G10. I flushed mine with some cheap oil and MMO/Seafoam when I first got it going and it seemed to make a big difference. Make sure you have clean oil and a clean filter when doing this. MMO isn't quite as aggressive as Seafoam but if you do the Seafoam, I would drive it a day and then change the oil again. The oil will get very dirty very quickly if there is a lot of crap to break loose and dissolve. Keep an eye on the color of the oil on the dipstick. These solvents will also evaporate and you will loose volume of oil so replace it with more oil if you aren't changing it right then. I put about 1/2 can in my engine, fired it up and ran it like 30 seconds to circulate the solvent but not warm the engine up and vaporize the solvents. I then let it sit overnight and then ran it for a day, came home, and changes oil and filter. If all works as planned, your day old oil will look worse than oil that has been run for thousands of miles in a cleaner engine. The reason I let mine sit overnight was to let the crap that might cause rings to stick a change to dissolve. Conor |
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