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I THINK I can do it ??

989 views 11 replies 5 participants last post by  ozark1 
#1 ·
A couple days ago I was doing some tidying up under the hood on the '79..and noticed the small vacuum line was not attached to the WUR. FD and WUR were rebuilt by Larry 3 years ago. After I plugged it back on, I noticed the cold idle was better..and the WUR was just right. I have been driving it more lately, and today I noticed this..The cold start was perfect..idled down to about 6-700 in gear. I drove it about 10 miles..shut it off for about 15 minutes. When I attempted the start, it sounded like an old radial engine..like one cylinder..then another..then another, etc. It evened out, but idles so low that it died..Started it again..still low idle...even the battery light came on. Went back home, and adjusted the idle screw. (big white one) to about 700 in park. From what I've read..I think I'm too rich..and need to lean the A/F mixture.It smells like rich exhaust too. I have never touched the air/fuel screw. Before I do..does anyone have any other advice before I have to call for a flatbed ?..or should I just call my mechanic ?...thanks..j..'
 
#2 · (Edited)
I just rebuilt my fuel system and one of the things I read is the oxygen sensor aids in setting the fuel mixture. My car has 200K miles and so I decided to replace my oxygen sensor as a matter of being thorough. You might pop it out and take a look at it. Mine had been in there so long it looked like it had melted.
 
#7 ·
OK... I'ma gonna chime in here. I am a member of the camp that believes one cannot set the mixture by "ear", "smell", etc. O2/gas analyzer, other instruments, etc are required to set properly. Does that mean one can't twiddle the screw and make things better? Of course not. Even a blind hog finds an acorn now and again...
 
#9 ·
RESULT..I figured I may as well look things over..so..found ANOTHER vacuum line unplugged ! (Tom H. told me once.."Vacuum lines are our friends !")...Then..better see if the screw comes out OK..no problem. comes out nicely..Probably should check to see if I have a 3MM allen..Got it!..Just couldn't stand it..I leaned the mixture a very small amount......less than 1/8 inch..reset the idle speed at about 6-700 in gear..and went for a drive. Got it warmed up..shut it off...and it started fine...and even ran better !..although I did notice my temperature gauge went up just a hair. I'll check it one more time, but the solution seems to be VERY small changes to the mix...Not sure what caused the Temp. increase ??
 
#11 ·
Probably won't be needing the old position.....(but I know where it was )..since that is where the problem arose after the aforementioned vacuum lines were reattached. Just drove it again..Cold idle is 1100..Warm idle about 850..Idle in gear ..6-700. I talked to Larry at CIS and followed his instructions to adjust air/fuel mix. I was overly cautious, but I wanted to try the fix myself. Worst case..I screw it up..and have to take it to my mechanic !
 
#12 ·
Did another test run this AM. Car was stone cold....started perfectly..idled by the book..Idled down in gear..Went about 10 miles..got it up to temperature and shut it off..Started right again..Seems to run better with the 2 vacuum lines reattached. One was to the WUR..the other was on passenger side..under air cleaner..So..the 3MM allen is back in the tool box..I think I got it !!..(another thanks to Larry at CIS.)
 
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