| Author |
Message |
Edward Gault (Irfgt)
Intermediate Member
Username: Irfgt
Post Number: 1165
Registered: 2-2001
| | Posted on Sunday, April 21, 2002 - 2:35 pm: | |
This system is crude and the adjustments are critical and no two of these system can be made identically due to the complexity of the design ,therefore there will be some differences between seemingly identical cars. Please do not try to compare these 80s cars to todays as the are light years of difference. I would hook up the 02 sensor if it were my car. |
Dr Tommy Cosgrove (Vwalfa4re)
Junior Member
Username: Vwalfa4re
Post Number: 114
Registered: 5-2001
| | Posted on Sunday, April 21, 2002 - 11:49 am: | |
Does anyone know if these cars "misidled" when they were new? Back in 87 had a Volvo P1800 that did the same thing until warm and I hated it. I never knew what it was doing until now.
Edward-do you have any idea why some 308's would do this and some won't? I was going to take your advice and reconnect the O2 on mine but I don't want to re-live my Volvo years. |
Edward Gault (Irfgt)
Intermediate Member
Username: Irfgt
Post Number: 1118
Registered: 2-2001
| | Posted on Friday, April 19, 2002 - 2:37 am: | |
The thermotime switch has nothing to do with the 02 sensor. What you are seeing is the engine varying between rich and lean conditions now that the 02 sensor is working. These systems are crude as compared to todays and without upgrading to a more modern system, That's the way it is, or was. |
cory mitchell (Mitch328)
New member
Username: Mitch328
Post Number: 21
Registered: 8-2001
| | Posted on Friday, April 19, 2002 - 1:45 am: | |
Donny,
The thermo-time switch should be directly below the intake manifold and behind the oil filter. Big switch right on top of the block. From what I understand it only operates for about the first 8 to 10 seconds after the car is fired up. If it is stuck closed the car would flood, if stuck open you might just have a low or rough idle for a short time. This switch will always be in the system regardless of the Lambda sensor being present. Thermo switch should have markings on it indicating what temp. the contacts are open or closed. A continuity test should be the way to go. I also had a problem with fluctuating idle but only after the car was warm. A throttle microswitch adjustment as Magoo suggested helped a little bit. If you find the problem, let us know. One more thing we can add to our troubleshooting charts. |
BretM (Bretm)
Intermediate Member
Username: Bretm
Post Number: 2401
Registered: 2-2001
| | Posted on Friday, April 19, 2002 - 12:43 am: | |
Having a misidling (is that a word) car is the most annoying thing in the world. It's right next to a car that doesn't run at all. I too am having interesting idle things, when I get all this back together and somehow it works, I'll make sure to tell all what I did. |
magoo (Magoo)
Advanced Member
Username: Magoo
Post Number: 2531
Registered: 2-2001
| | Posted on Friday, April 19, 2002 - 12:27 am: | |
Donny, I know how you feel. I wouldn't want my car jackin' up and down on the idle either. Just hang in there some of the guys here on the F.C. who know more about it then Dave or me will solve your problem. |
magoo (Magoo)
Advanced Member
Username: Magoo
Post Number: 2530
Registered: 2-2001
| | Posted on Friday, April 19, 2002 - 12:18 am: | |
As I said, Just a wild guess. Well got a F in that class. |
Dave328GTB (Hardtop)
Junior Member
Username: Hardtop
Post Number: 97
Registered: 1-2002
| | Posted on Thursday, April 18, 2002 - 11:35 pm: | |
Donny,
You have inadvertantly discovered why sensors are often disconnected. QV's are often searching for the perfect mixture and just alternates from rich to lean with the change in idle speed. 328's are known to do this as well, though not as bad. The computer is not a factor as Magoo suggested. QV's had primitive electronics. I would just drive it and not worry about it. I drove mine many 1000's of miles without one, no hitch, but it does seem to get another MPG or two with it hooked up. It's also propbable that cats will last longer with it than without it. I did pass emissions easily even when it wasn't hooked up.
DAve |
magoo (Magoo)
Advanced Member
Username: Magoo
Post Number: 2520
Registered: 2-2001
| | Posted on Thursday, April 18, 2002 - 9:58 pm: | |
Donny, I certainly am not a expert either but just a thought, Did you disconnect the battery and clear the computer since you hooked the sensor back up? If you have a Throttle Positioning Switch I have seen them act that way before. Just a wild guess. |
Donny Bridges (Wildcatfans)
New member
Username: Wildcatfans
Post Number: 47
Registered: 9-2001
| | Posted on Thursday, April 18, 2002 - 9:46 pm: | |
I found recently that the previous owner of my 84 308 had disconnected the O2 sensor. I replaced it with a new one since I didn't know if was disconnected because it was broken. Now, during a cold start, the engine fires right up, idles low (1200 rpm), begins to idle up after a couple of seconds (2200 rpm or so), then begins to idle up and down. The idle varies a couple hundred rpm every second or so. It doesn't appear to be flooding, the car isn't sputtering, just a smooth varing idle. After a complete warm up (10-15 minutes of driving), it idles back down to a normal speed and is steady. If the car is shut off of any length of time and restarted, the varying idle is back.
I ohmed the expansion tank coolant switch, both hot and cold. It didn't appear to change states from hot to cold, so I jumpered it out and restarted the engine cold. Same idle problem as before. I then disconnected the cold start injector, no change. Could this be caused by a faulty thermotime switch? Did reconnecting the O2 sensor place the thermotime switch back in the system? How is the switch tested and where is it located?
I'm new at troubleshooting this K-Jetronic system, so please let me know if I am looking in the wrong places.
As always, thanks
Donny |