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#1 |
5 day ban, learn to behave.
Join Date: Nov 2002
Location: san diego, ca
Posts: 684
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when it rains it pours
needing to vent and maybe get some suggestions.....
weekend before last I tuned up my 77 K25 and had it running SO good for the desert trip that weekend (glamis)... first tune up since I had broken in the motor, (sbc400) and it was running great, I tell ya. smoothest idle you ever felt, timing was dead on and it was unstoppable. It was great... took it to glamis 3 hrs away, and was playing in the dunes.. I think I over revved it. it started missing on a cylinder or two, and just being shakey if I got on it.. I knew something was up. Hoping there was the smallest possibility that it was a bogus cap & rotor (been there done that) I went to the closest autozone and bought a new one, didnt help it.. well my truck was out for the rest of the weekend. luckily I had my banshee ![]() so last weekend or so I start to track down the problem... first thing I think is maybe its running lean.. It was, carb cleaner on the intake mating surface would bring the idle up enough to make me wonder... When I installed the intake my engine builder said use no silicone on the intake ports.. I disagreed but did as he said anyway. so that was my first suspicion.. So I yanked the intake and re-did the gaskets, this time with form-a-gasket.. put it all back together and as im doing this, notice that my tranny modulator line was disconnected (at the tranny side).. so I hooked that back up. that would have made a pretty large vacuum leak so I was pretty confident that one of those would have fixed it.. got it all back together the next day or so and took her for a test drive. Fired right up no problem.... but was still a little shakey.. it seemed better but somewhat different. hmm I thought. Maybe I need to tune it up. On the test drive it was acting funny.. one run it had NO power, and on a few others it was just acting funny. I dunno. I only set the timing by "eye" and who knows what else needed fixin'...... well at some point i bust out the timing light.. I had the timing set pretty far advanced, checked it, then revved the motor once to watch the advance kick in.. well the timing line disappeared and never came back.. the timing just moved a BUNCH just from revving the motor. Damn accel distributor (im 100% anti-Accel now, more on that later)... so today I take the distributor out.. check it out.. just for grins, I replace the module with a GM, and the coil with a GM... and cap & rotor with napa.. and I check the vacuum canister, its working good. greased and checked the mechanical advance weights with lithium grease. everything is great. the only thing in that distributor I didnt mess with was the pickup coil. Too much trouble and it was a longshot. So in other words I dropped in a whole different distributor.. was real anal about getting the rotor where I wanted it (instead of just close enough like usual)... and got it perrrfect. (after about 3 or 4 tries of moving the oil pump driveshaft)........ anyways I get her in.. hook up the plug wires.. they're new... new spark plugs (about 300miles actually but all look real good from the lean drive home) intake is fresh, I did a compression check on the motor the day before I removed the intake... good results there. get her all hooked up, new fuel filter since it was right there anyways, everything is ready to roar.. for some god forsaken reason my battery is now 100% dead. Yeah the new optima. WTF is draining the battery? I still dont know. This is the second time its happened, seems to happen when it rains. Get out the portable jump starter thing and hook up the remote starter switch... cranks and will only sputter for a few seconds. Wont stay running.. arghhhhhhhhhhhhh. Spray a little ether in the carb and she'll run on that *seemingly* fine.... for some reason it will not idle at all.. if I twist the throttle a few times to squirt some gas thru the accel pump, it will run off that but it wont run off the carb. at this point im irritated. pull the carb and check and double check everything. End up tearing down the carb completely and blowing out passages, and checking everything. Everything checks out O.K.... this carb has not so much as hiccup'd in the last 1 or 2 years since I rebuilt it. But it doesnt make sense. Its definately getting fuel and spark (I have a clear fuel filter right before the carb connection).... Now im thinking back to the motor thing now, I can get it to sputter on 6 or 7 cylinders for a few seconds then BAM it backfires thru the carb and dies... and will do what looks like dieseling sometimes for a second or two.. I have checked and double checked every !@#$ing thing.. The motor and everything on it is new or fresh. Could it be that my optima is so far gone that the alternator cant keep up with charging it AND providing 12v to the distributor? These optima batterys have done some wierd things. Thats one theory im going to toy with before I get into it too deep. Explain this: the day I did the compression check... I start with the passenger side bank, hot motor.. 160, 160, 160, 160... bam, quick and easy as that..... heres where it gets weird: in the time that it took for me to unhook the last cylinder on that side and hook up to the 1st cylinder on the drivers side, something happened to where Im only getting 140psi.. the 1st one I was like shoot... only 140?? then I goto the next one.. same. next one, same.. and same, 140psi for all 4 cylinders on that bank. what the?? so just for grins again, I go back to the other side, 140 over there now too!!.. i dismiss it as luck of the draw, and figure all my cylinders have good compression. so here I am. truck will not run at all now. It ran "fine" when I pulled it into the garage to fine tune it after messing with the intake.... Im 100% sure about the intake & vacuum lines, 100% about the distributor and ignition, and 75% about the carb. I do have an olddddd carb at my friends house that Ill have to pick up and see what happens. While I had the intake off, I cranked the motor over and watched all the valvetrain, it all looked xlnt. Definately no obviously weak cam lobes or anything. I dont really expect any help but if you're still with me, god help you ![]() good day! mike |
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