78 SC fuel(?) problem at the track..
#1
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Just got home from a dissapointing two days at the NNJR Summit Point DE. My 78 SC with stock fuel system and stock 3.0 was running perfectly, then a couple oddball things happened. On my 2nd run group my oil breather popped off and spewed a little oil into the reaf of the engine compartment and onto the right header, causing smoke and a black flag. Apparently the hose clamp wasn't put back on (it was loosely laying down on the other end of the breather hose) when the engine was removed to replace the tranny (I'm assuming it was removed anyway, as my mechanic said it was his fault)... Annnnyyyway, put that back on, brake-cleaned her all up, and the next run no more smoke.Ran perfect for about 4 laps (8+ miles) and then a large loss of power, wouldn't rev much past 4000. Came in, checked all connections, fuel level, oil, (new) gas cap for vacuum when removed, etc. Tried it again, exact same thing, ran fine then crappy running after about 4 laps. Kept messing with it all day (blew out the fuel filter along the way) and always the same problem. Let it sit, it's fine for a bit, then runs for crap. Brought it to a local shop last night and he put a new fuel filter in, drained the tank, cleaned the screen, flushed the tank a couple times, and reassembled. He had no fuel pump but he didn't think that was it anyway. Today first run, exact same results..ran great then pukes on the 4th lap. It's going into the shop tomorrow but just wanted to hear if anyone has seen this problem before?
Thanks!
Thanks!
#2
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Gary: How bad (dirty) was the tank? This problem sounds like it might be the fuel distributor, but I would only lean that direction if the fuel tank was really scroungy. I've never experienced a fuel pump behave this way, but you never know. You're not using Platinum plugs, are you? Do you have a spare CD and coil to plug in as a test (maybe a loaner from the shop)?
Pete
Pete
#3
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Hi Pete, thanks for the quick reply!
The tank had a small amount of what appeared to be dissolved black material in it, which when smeared would dry into an almost paint-like result. The screen had very little gunk on it at all and after a couple of 5-Gal. flushes nothing else came out. We also cut open the filter and saw no major contamination. I noticed that when the line was disconnected from the fuel pump it flowed VERY freely and when I opened the fuel tank fill it almoset doubled the output.. Is that normal? The guy at Summit seemed to think so as the tank vent is quite small compared to the wide open fuel filler mouth. Either way there is no way the car could consume that much flow even at 6500 RPM on the track, so I figured the whole tank cleaning thing was academic but couldn't hurt at that point. It's just odd that if I just let her sit for a minute it will run full out fine again for a short time. If it sits for an hour (or overnight, dosn't matter) I get the "8 minutes of fame"..
The tank had a small amount of what appeared to be dissolved black material in it, which when smeared would dry into an almost paint-like result. The screen had very little gunk on it at all and after a couple of 5-Gal. flushes nothing else came out. We also cut open the filter and saw no major contamination. I noticed that when the line was disconnected from the fuel pump it flowed VERY freely and when I opened the fuel tank fill it almoset doubled the output.. Is that normal? The guy at Summit seemed to think so as the tank vent is quite small compared to the wide open fuel filler mouth. Either way there is no way the car could consume that much flow even at 6500 RPM on the track, so I figured the whole tank cleaning thing was academic but couldn't hurt at that point. It's just odd that if I just let her sit for a minute it will run full out fine again for a short time. If it sits for an hour (or overnight, dosn't matter) I get the "8 minutes of fame"..
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#4
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Well, if the pump is known to be old replace it, but I'd rather see you plug in a different coil & CD first... unless you have Platinum plugs in the car, which should be exchanged for a set of Bosch Copper Core plugs first.
Pete
Pete
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Thanks, i'll be sure to post what the final fix is! Something that crossed my mind this morning as I got a message about a possible semi-chronic SC oil scavenging problem giving the same issues. The car's first problem at the track was the oil breather blowing off the air cleaner and dumping oil onto the engine, tray, and exhaust. I replaced it, found and tightened the clamp, and it stayed on but from that point on the car had the "other" symtoms. I also remember a very strong "gurgling" sound (think an upside down gallon bottle draining out) when I pulled the car off the track hot, shut it off, and opened the hood. It was obviously oil traveling "somewhere", either back into the tank or back from the front cooler, dunno if that gurgle is normal or not as I don't usually jump out of the car and stick my head in the engine compartment...
Anyway, to the shop she goes..
Anyway, to the shop she goes..
#6
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Well.... the fix is when an oil breather line pops off be SURE you put it back on where it belongs!!! There is a plastic fitting on the bottom of the air cleaner box sticking out, VERY invitingly, and THAT is where the breather line lined up with and fit on like a glove. BIG DUH. Problem was the breather line goes to a fitting behind the oil tank fill neck!! I effectively BLOCKED the breather and after 5 minutes or so was pressurizing my crankcase.. not a good thing to do. Amazingly I didn't do any damage, blow any seals, or anything else. I had my original stock 915 rebuilt and a new LSD put in and they even checked my RMS for any seepage, all A-OK.. To think I had a shop look at it at Summit, SHOWED them the line I replaced and they didn't catch it. At least I have a clean tank and new fuel filter!!
On to WGI 6/7-6/8!!
On to WGI 6/7-6/8!!
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