| From | Message |
Steve Wright
Dodge Dakota
11/02/2001
17:28:05
|
 Subject: Open loop/Closed loop
IP: Logged
Message:
I have been having intermittent starting problems. The engine will crank, with spark to the plugs, but will not start. After several tries over a couple of hours it starts like there is nothing wrong. The Check Engine light has not come on(but works). I got it to my mechanic who hooked up a scan tool. After replacing a clogged fuel filter and cleaning the IAC we checked his scan tool. It indicated an Open Loop condition. He said that it should be reading Closed loop, since the engine was at operating temperatures. He suggested that the Oxygen sensor be replaced. His scan tool showed that the rich-center-lean was fluxuating between all three, so I lost confidence and paid up and left.
This open/closed loop condition is Greek to me. What is indicated by the condition not going to closed loop?
I've read many past posts and have come up with some good leads, like corrosion below the fuse panel, the fuel pump not maintaining pressure, and a couple of sensors maybe going bad.
I once had a jeep that had similar starting trouble and the problem was a flywheel position sensor. What about cam or crank position sensors?
Would I not be getting a check engine light if the problem was with one of the sensors?
93 5.2L 4WD 105K
|
CW
Dodge Dakota
11/02/2001
19:47:37
|  RE: Open loop/Closed loop
IP: Logged
Message:
Here is a explanation as to what open and closed loop is. http://www.speedtweaks.net/Tips_Tricks.htm#openclosed
I doubt it is the O2 sensor that is forcing the open loop condition, they are supposed to fluctuate rappidly between rich center lean.
|
Neil
Dodge Dakota
11/02/2001
20:00:10
|  RE: Open loop/Closed loop
IP: Logged
Message:
You can check the codes yourself by turning the ignition switch on, off, on, off, on and then counting the times the check engine light flashes. It will flash 1 to 5 times, pause and then flash again. A code of 5 5 is the last code. I have the manual so you can e-mail me your results and I will look it up for you.
Neilkathyd@msn.com
|
Steve Wright
Dodge Dakota
11/02/2001
20:38:49
| RE: Open loop/Closed loop
IP: Logged
Message:
Neal,
I've done that test, there were no flashes. The check engine light only comes on during the prestart lamp check.
|
Steve Wright
Dodge Dakota
11/02/2001
20:47:37
| RE: Open loop/Closed loop
IP: Logged
Message:
CW,
I've been to that site and found another with a basic primer. I have a basic idea about how this open/closed concept works. I'm also beginning to think that open/closed conditions are not a clue to the solution of my no start problem, but more of something that needs attention to improve performance after I figure out how to get this thing started.
The first thing I need to do tomorrow is look for corrosion in the wires just below the fuse box, then hit the Chiltons.
|
CW
Dodge Dakota
11/02/2001
20:51:21
| RE: Open loop/Closed loop
IP: Logged
Message:
If it doesn't start tomorrow see if it has fuel pressure. Sounds like it is loosing pressure over night. Good luck.
|
Steve Wright
Dodge Dakota
11/03/2001
13:26:11
| RE: Open loop/Closed loop
IP: Logged
Message:
The cure for my no start condition was easily fixed. It would have been tough to find, had the problem not been discussed by Rascal on this board. Thanks Rascal
The cure involved corroded wires about 8-10 inches below the underhood fuse box. There are 4 red and white wires twisted together. They were so corroded that it broke apart when I removed the tape covering them. Among the things powered by these wires is the fuel pump. Wired everything back together and it started right up.
Once I got it started I got error code 35. Apparently the codes had been masked by the broken wires?
Thanks to everyone for their help.
|
CW
Dodge Dakota
11/03/2001
15:21:36
| RE: Open loop/Closed loop
IP: Logged
Message:
Glad to see you found it. Rascle is a good guy.
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
