Always lean and in open loop??
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Joined: Feb 2003
Posts: 77
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From: Boone Iowa
NEED HELP!!!!!!!!!!!!1
My 85 L98 had codes 13, 34 and 43. I found out that the idiots who put my new clutch in removed the dist. and did not time the car when the job was complete. There was real bad detonation under a load which caused the 43.
When I timed the car, I cleared out the codes and the 43 and 34 never came back. The 13 was still there. I put in a new oxygen sensor hoping it got disturbed when the clutch was put in, but the problem is still there.
My diagnostic scanner shows the car to be in open loop all the time, even at 200deg after a 5 mile drive. The exhaust is always lean. Is it poss. that the MAF is bad and not giving a code for some reason? If the ECM is not getting the proper air readings from the MAF it should go into default mode and possibly create a lean condition.
I had no probs when I took the car to have the clutch put in. Is there something that they might have unhooked in the process and not hooked back up.? My check engine light in intermitent.
Please help before I decide to dig a hole and bury this thing.
Sturtzy :confused: :confused: :confused: :confused: :confused:
[Modified by sturtzy85L98, 8:02 PM 3/20/2003]
[Modified by sturtzy85L98, 8:03 PM 3/20/2003]
When I timed the car, I cleared out the codes and the 43 and 34 never came back. The 13 was still there. I put in a new oxygen sensor hoping it got disturbed when the clutch was put in, but the problem is still there.
My diagnostic scanner shows the car to be in open loop all the time, even at 200deg after a 5 mile drive. The exhaust is always lean. Is it poss. that the MAF is bad and not giving a code for some reason? If the ECM is not getting the proper air readings from the MAF it should go into default mode and possibly create a lean condition.
I had no probs when I took the car to have the clutch put in. Is there something that they might have unhooked in the process and not hooked back up.? My check engine light in intermitent.
Please help before I decide to dig a hole and bury this thing.
Sturtzy :confused: :confused: :confused: :confused: :confused:
[Modified by sturtzy85L98, 8:02 PM 3/20/2003]
[Modified by sturtzy85L98, 8:03 PM 3/20/2003]
Drifting
Joined: Nov 1999
Posts: 1,801
Likes: 2
From: St. Paul MN
Re: Always lean and in open loop?? (sturtzy85L98)
Won't your scan tool show you exactly what the maf is doing while driving it? This would let you know if the maf is okay. I think from checking everything while driving it with the scan tool hooked up you should be able to figure out what isn't working. What about the temp sensor? I think there is one that sends the signal to the temp. guage in the dash and a different one that sends the signal to the ecm. So, if that were bad your ecm wouldn't know that engine is warmed up and go into closed loop, would it? And, I thought if it were in open loop doesn't it default to rich rather than lean since you can cause some serious engine damage running lean can't you? I'm very limited in my knowledge here but thought maybe this might get some others to chime in. What, exactly, is code 13 on your car?
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Joined: Feb 2003
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From: Boone Iowa
Re: Always lean and in open loop?? (Bob86ZZ4)
Code 13 is the oxygen sensor circuit. If the MAF is bad, and the ECM goes to default mode, when you accelerate or rev the car the ecm will not compensate for the added air. That is my understanding anyway.
The scanner does give readings for the MAF, but I do not know what they mean or how to tell good from bad?????
Also, if I'm not mistaken, whenever codes 13,44 or 45 are set the car will run in open loop. So what i need to do is find out why I have the 13 code and fix it hopefully allowing the car to switch over to closed loop.
Come on all you sandbaggers. I read this forum a lot and know there is somene out there with the answers.
Thanks for the response..
Sturtzy
The scanner does give readings for the MAF, but I do not know what they mean or how to tell good from bad?????
Also, if I'm not mistaken, whenever codes 13,44 or 45 are set the car will run in open loop. So what i need to do is find out why I have the 13 code and fix it hopefully allowing the car to switch over to closed loop.
Come on all you sandbaggers. I read this forum a lot and know there is somene out there with the answers.
Thanks for the response..
Sturtzy
Drifting
Joined: Nov 1999
Posts: 1,801
Likes: 2
From: St. Paul MN
Re: Always lean and in open loop?? (sturtzy85L98)
Okay, so code 13 is oxygen. What does the scan tool show then for o2 sensor readings. Shouldn't your o2 sensor voltage fluctuate above and below .5 volts? It is't not doing that doesn't it mean the o2 sensor is bad?
Oopps, just realized you put in a new o2 sensor. Does it show the correct voltage then?
[Modified by Bob86ZZ4, 6:27 PM 3/20/2003]
Oopps, just realized you put in a new o2 sensor. Does it show the correct voltage then?
[Modified by Bob86ZZ4, 6:27 PM 3/20/2003]
Thread Starter
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Joined: Feb 2003
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From: Boone Iowa
Re: Always lean and in open loop?? (Bob86ZZ4)
It shows 456 mV. There is no fluctuation in ths figure either. I just put in the new sensor yesterday and 10 mins later I had the 13 code again.
I think that there are quite a few factors that can cause the oxygen sensor to be open which gives the 13 code. The only prob is finding out what. With the o2 sensor open I don't think it sends the proper commands to the ECM to allow it to compensate for the rich or lean readings by changing the fuel mixture.
Prob. something real simple, but what a pain.
Thanks Bob
Sturtzy
I think that there are quite a few factors that can cause the oxygen sensor to be open which gives the 13 code. The only prob is finding out what. With the o2 sensor open I don't think it sends the proper commands to the ECM to allow it to compensate for the rich or lean readings by changing the fuel mixture.
Prob. something real simple, but what a pain.
Thanks Bob
Sturtzy
Drifting
Joined: Nov 1999
Posts: 1,801
Likes: 2
From: St. Paul MN
Re: Always lean and in open loop?? (sturtzy85L98)
Is this what happens if the o2 sensor doesn't get heated up enough? I know when I put on long tube headers my o2 sensor wouldn't get warmed up enough to work so it wouldn't set the ecm into closed loop. I had to put in a heated 3 wire o2 sensor. Somebody around here should know if that low reading is indicative of the sensor not getting hot enough.
Instructor
Joined: Mar 2003
Posts: 187
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From: Aztec NM
Re: Always lean and in open loop?? (sturtzy85L98)
If the voltage is fixed at .453, that's why it won't come out of open loop. It stays in open loop till the ECM sees the voltage at the O2 start moving around. If you have access to a scan tool, disconnect the O2 sensor and ground the harness connector, the scan tool should read close to zero volts for the sensor. I don't think it has to be running or even warmed up. If it doesn't read close to zero you have an open in the circuit between the sensor and ECM, or they forgot to hook up the sensor ground wire. That ground should be on the back side of the driver's side cylinder head, near as I can figure. But I don't know why they would have disconnected it.
Hope that helps, holler if you need more info.
:seeya
Hope that helps, holler if you need more info.
:seeya
Racer
Joined: Jun 2002
Posts: 411
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From: Palm City FL
Re: NEED HELP!!!!!!!!!!!!1 (sturtzy85L98)
Check your grounds! If they pulled the clutch, there is a number of grounds conected to that area. Perhaps they missed one. The aluminum head cars have a big ground on the left side of the block. The iron head cars I beleive are grounded to a trans mount bolt or a bolt in the back of the drivers side head. If you have a problem that doesn't make any sense, than odds are a ground problem. :crazy:
I also had a MAF problem at one time, and the car still went closed loop.
I also had a MAF problem at one time, and the car still went closed loop.
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Thread Starter
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Joined: Feb 2003
Posts: 77
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From: Boone Iowa
Re: NEED HELP!!!!!!!!!!!!1 (severe-1)
Thanks for all the advice guys. It sounds like the winner so far is a grounding problem. This would kind of make sense since I am also having probs with the digital tach only working part of the time.
I'm headed out into the garage right now and check it out. I'll update whatever I find.
Thanks again everyone.
Sturtzy
I'm headed out into the garage right now and check it out. I'll update whatever I find.
Thanks again everyone.
Sturtzy
Safety Car
Joined: Feb 2002
Posts: 4,212
Likes: 10
From: Sun City West Az
Re: NEED HELP!!!!!!!!!!!!1 (severe-1)
If your o2 sensor is maintaning .450mv, you car is stuck in open loop. when the O2 heats up to 600*+- that allows the ECM to go closed loop. The readings should be "swinging" widely over the .450 mark. (250-800) It sounds like the O2 signal isn't geting to the ECM or the ECM isn't recognizing it. Could the O2 sensors been damage during the installation of the clutch?... or not connected back in to the harness properly...or contaminated by vapors from an improper sealer? Or maybe the ECM has a problem. Also, check your knock sensors that the harness is correctly pluged onto the sensor. This will also prevent closed loop and give the same symptoms. Just a few things to check.
[Modified by ittlfly, 7:08 PM 3/20/2003]
[Modified by ittlfly, 7:10 PM 3/20/2003]
[Modified by ittlfly, 7:08 PM 3/20/2003]
[Modified by ittlfly, 7:10 PM 3/20/2003]
Thread Starter
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Joined: Feb 2003
Posts: 77
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From: Boone Iowa
Re: NEED HELP!!!!!!!!!!!!1 (drive it)
Now I'm really irritated. I checked the car over for bad grounds and found nothing. Everything is connected properly.
I took the car out for a drive to try and get it to go closed loop with no success. It stays in open loop and shows lean. The o2 sensor never moves from 456mV.
Now that I am back home, I put the scanner back on and now I have a 13, 34, and a 43. WONDERFUL!!! The car is pinging again, which I assume caused the 43. It will not go to closed loop under any circumstances.
I have unhooked the MAF and still the lean condition exists and the car is in open loop.
Anyone want to buy a car???
Sturtzy
I took the car out for a drive to try and get it to go closed loop with no success. It stays in open loop and shows lean. The o2 sensor never moves from 456mV.
Now that I am back home, I put the scanner back on and now I have a 13, 34, and a 43. WONDERFUL!!! The car is pinging again, which I assume caused the 43. It will not go to closed loop under any circumstances.
I have unhooked the MAF and still the lean condition exists and the car is in open loop.
Anyone want to buy a car???
Sturtzy
Safety Car
Joined: Feb 2002
Posts: 4,212
Likes: 10
From: Sun City West Az
Re: NEED HELP!!!!!!!!!!!!1 (sturtzy85L98)
Has th eQ2 sensors been changed out since the car was new? If not, then replacing them (if nothing more than for maintance) is a good idea. Get OEM from Jeff Koop and go from there.
Drifting
Joined: Mar 1999
Posts: 1,931
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From: Norcross GA
Re: NEED HELP!!!!!!!!!!!!1 (ittlfly)
Real simple,... w/o an operating O2 signal, the ECM will never go closed loop.
That said, I'd suggest you concetrate on getting the O2 signal working. I'll guess you have a 2 wire O2 sensor. One is from the ECM, the other probably goes to a head bolt ground. Did you try the "grounding the wire test" mentioned above? You did this w/ the O2 sensor disconnected, right? If you didn't and the O2 was warm enough to operate,.. the sensor is now dead. Anyway's lets start w/ this.
Engine OFF
Disconnect the O2 connector.
Key to ON positon (not running)
Read O2 voltage w/ scanner.
It should be 0.5V
On the O2 sensor connector, (not the sensor side),....
Short the 2 wires together w/ a paper clip or something.
Read the O2 voltage w/ scanner.
It should now read 0V.
If not,.... you have a wiring problem.
If you do, you have a sensor problem.
That said, I'd suggest you concetrate on getting the O2 signal working. I'll guess you have a 2 wire O2 sensor. One is from the ECM, the other probably goes to a head bolt ground. Did you try the "grounding the wire test" mentioned above? You did this w/ the O2 sensor disconnected, right? If you didn't and the O2 was warm enough to operate,.. the sensor is now dead. Anyway's lets start w/ this.
Engine OFF
Disconnect the O2 connector.
Key to ON positon (not running)
Read O2 voltage w/ scanner.
It should be 0.5V
On the O2 sensor connector, (not the sensor side),....
Short the 2 wires together w/ a paper clip or something.
Read the O2 voltage w/ scanner.
It should now read 0V.
If not,.... you have a wiring problem.
If you do, you have a sensor problem.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Re: NEED HELP!!!!!!!!!!!!1 (sturtzy85L98)
Ground for the O2 is via the ECM. Generally a tan wire, Pin D6 to the left side of the bell housing. If there's continuity from the sensor lead to the ECM, check this ground. Whoever did the clutch, may have left this wire disconnected so look around and verify that it's connected.
Safety Car
Joined: Feb 2002
Posts: 4,212
Likes: 10
From: Sun City West Az
Re: NEED HELP!!!!!!!!!!!!1 (sturtzy85L98)
Thanks SunCr. I'll check it out.
Steelblue- I just replaced the sensor with a new one. No luck.
Thanks guys
Sturtzy
Steelblue- I just replaced the sensor with a new one. No luck.
Thanks guys
Sturtzy
Instructor
Joined: Mar 2003
Posts: 187
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From: Aztec NM
Re: NEED HELP!!!!!!!!!!!!1 (ittlfly)
Did you ever take the sensor wire from the ECM and ground it while watching the scan tool? I know it was mentioned a couple of times. Don't worry, it won't hurt anything, in fact it's one of the tests that the service manual says to do for this code. That will tell you if the the wiring is good and also if the ground is good. It should read very close to zero on the scan tool when grounded. Before you throw an ECM at it, try that.
JIM
JIM