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Backfire and poor/no idle
Posted: Fri Mar 06, 2009 11:53 am
by drawe
Hi All,
I have a 1975 710M. Had it on a LONG COLD trip from Colorado to Iowa and back in December '08. Air temps were constantly around -10 below (we almost froze to death). There was alot of problems (of course) like intermittent carb backgiring with even getting up to a reasonable operating temp while driving.
So now it's March and MUCH warmer (above 30 LOL) but I can't keep it idling at stops. It sputters and then dies unless I keep foot on the gas a little. So with all this backfiring and now poor idle does anyone think it's time to rebuild carbs?
This problem just started about a week or so ago.
Dave
Posted: Fri Mar 06, 2009 1:55 pm
by Jim LaGuardia
Start by checking the #10 breaker and then clean the molex connector terminals and try again. Sounds like the carb solonoids have lost power.
That is the most common cure for your symptoms.
Posted: Sat Mar 07, 2009 10:28 am
by dokatd
MAke sure both chokes are closing fully. Also check for fouled plugs. And if you have a civilian plug conversion, check your plug wires. Just one cylinder acting up can cause your problems.
Oops!
Posted: Sat Mar 07, 2009 10:38 am
by drawe
I took a close look at the front carb and noticed some fuel condensation/leakage around its' top section. Maybe I need to dig in. I have only a short time for this but will take a look.
Thanks for the suggestions
I'll report back if I find an 'easy solution'
Dave
Posted: Sat Mar 07, 2009 12:40 pm
by todds112
See if you can wiggle the upper part of the carb. There are 4 screws that come up through the bottom of the throttle body. Mine are always coming loose. It's a pain because you have to remove the carb from the engine to tighten them.
Posted: Sun Mar 08, 2009 6:57 pm
by pinztrek
dokatd wrote:MAke sure both chokes are closing fully. Also check for fouled plugs. And if you have a civilian plug conversion, check your plug wires. Just one cylinder acting up can cause your problems.
I can confirm this. What I thought was a carb issue that haunted me for a while turned out to be a wimpy coil. I had reasonable spark when I checked them out of the engine. But they would blow out under 2-3k rpm resulting in hard starting, poor idle, etc. Rev it up, voltage goes up, and it worked fine.
Put a $19 "Blue bosch" coil on and it ran like a top! (Or at least as good as the carb'd ones ever do :-> )
<
http://www.pinztrek.com/pinz/mods/pinz_mods.htm >
There is more than one "blue bosch" coil... you want the 3 ohm one as that's exactly what's in the military contained. Google blue bosch and you'll find the vw, bmw, mercedes crowd has all the info you need. Also is in the pinzgauer yahoo group forum, search the archive. Only works if you have done the civilian plug mod, at least for the coil wire. (or use a vw dist cap)
Have fun,
Alan