Code 44
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Joined: Nov 2005
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From: Austin TX
Code 44
I have this elusive issue at hand. Before when my 1991 6spd threw code 44 it was always the O2. This time is different. I am now on my third O2 and still having problems. O2 #1 was a heated Bosch that lasted about two months before throwing a code 44. O2 #2 was a Bosch 1 wire that lasted 80 miles then threw code 44. O2 #3 is a beautiful Denso 1 wire which lasted one five mile trip also throwing code 44. I have been skeptical all along, but especially after the Denso had problems. Tonight i ohmed out my injectors and checked the MAP. Both were perfect. TPS is set properly. The code is always thrown at low RPM. Mostly after driven, at idle, in closed loop. Car runs great in open loop and cruising, but when you let off the gas down a hill in closed loop it jerks and twitches. Any help would be appreciated. 
Last edited by ChevyPoweredByBen; Mar 7, 2007 at 12:24 AM.
Thread Starter
Navigator
Joined: Nov 2005
Posts: 9
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From: Austin TX
I also have a new cat, IAC valve, and AIR pump. EGR is disabled in tune, but valve is still in place and riser pipe is blocked off. It has had this setup for about 8 months with no issues.
Last edited by ChevyPoweredByBen; Mar 7, 2007 at 12:31 AM.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Do you have a FSM? If not you need one. Since replacing the O2 sensor did not fix the problem you may have a bad connetor, wiring to the sensor or from the ECM, mechanical problem, or water entering the fuel tank via stopped up drain. The FSM (factory service manual) gives a detail description on how to follow and fix the problem.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
http://members.shaw.ca/corvette86/Code%2044.pdf
AGENT 86 (forum member) was nice enough to do this for all of us. Just follow the link.
AGENT 86 (forum member) was nice enough to do this for all of us. Just follow the link.
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Simply cause you get a code to say its lean does not mean replace the sensor. There is a load of things that can cause it to think its lean. (doesnt even mean it is lean, just that the sensor says it is)
Check the EGR system to make sure its not allowing any air through into the intake. (i know youve got it disabled, but some of it is still there, so it can still leak.)
Check the AIR system to make sure its not blowing air into the exhaust stream when its not meant to. Also check to see there is no exhaust leaks between the header and the head, and make sure its not able to suck any air in anywhere else before the O2 sensor.
Get onto it with DATAMASTER so you can see what all the sensors are doing and saying at the time of the issue, measure the fuel pressure, measure the vacuum at idle, and check the connections at the ECM for a nice tight clean fit.
Check the EGR system to make sure its not allowing any air through into the intake. (i know youve got it disabled, but some of it is still there, so it can still leak.)
Check the AIR system to make sure its not blowing air into the exhaust stream when its not meant to. Also check to see there is no exhaust leaks between the header and the head, and make sure its not able to suck any air in anywhere else before the O2 sensor.
Get onto it with DATAMASTER so you can see what all the sensors are doing and saying at the time of the issue, measure the fuel pressure, measure the vacuum at idle, and check the connections at the ECM for a nice tight clean fit.
Drifting
Joined: Jun 2005
Posts: 1,781
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From: Swanton VT 2000 Navy Blue Mettalic M6 / 1991 Auto - Steel Blue 68,500 R.I.P
When I had the code 44 in my 91 it was the injectors . I ohmed them and they we're everywhere from 5. to 17. only 2 were were they should have been. I know u ohmed yours already and there fine but thought I'd share my experience with you . Once I replaced the injectors I haven't seen that code since ( about 2000 miles put on after the replace ).
Good-luck in your search ,
PatsFan
Good-luck in your search ,
PatsFan
Thread Starter
Navigator
Joined: Nov 2005
Posts: 9
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From: Austin TX
Checked out ECM wires tonight. It all looks good with no shorts and the ground is good. I re-routed them anyway to make sure everything was good and would stay that way. I checked the fuel door drain and it was very clogged. I cleaned it out and will drive the car before I add anything to the tank to see if the wires solved the problem. Then I will move on to the water issue. Thanks for all your help guys!!! I will keep you posted until we solve it completely.
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Burning Brakes
Joined: Nov 2002
Posts: 1,186
Likes: 264
From: Huntington Beach CA
I am having the EXACT same issue as you are. I'm interested to see if you figure yours out. I've had my car in the local corvette shop, and they couldn't pin point the problem either....mainly because when my car was in the shop the code wasn't being set, but as soon as I get the car back...code 44 every day.
I'm beginning to think it is injector related, because the code only comes on after the car has been sitting for some time (say during work, or over night). Then after driving it for a while the code goes away and the car seems to run great. I wonder if and injector(s) is leaking a tiny bit while the car is off. Although, with that condition it makes me think the car should be running rich (code 45 instead)....and I seem to be getting worse gas mileage lately.
I too have replaced the 02 sensor a few times, also the IAC, vapor canister, vapor canister solenoid, fuel filter, egr solenoid, checked for vacuum leaks, etc.
I'm beginning to think it is injector related, because the code only comes on after the car has been sitting for some time (say during work, or over night). Then after driving it for a while the code goes away and the car seems to run great. I wonder if and injector(s) is leaking a tiny bit while the car is off. Although, with that condition it makes me think the car should be running rich (code 45 instead)....and I seem to be getting worse gas mileage lately.
I too have replaced the 02 sensor a few times, also the IAC, vapor canister, vapor canister solenoid, fuel filter, egr solenoid, checked for vacuum leaks, etc.
Drifting
Joined: Sep 2005
Posts: 1,867
Likes: 3
From: Pasadena Maryland
Ohming the injectors only tells you if the coil is good or not. You could have an injector that is not functioning properly an still ohm out as good. An injector could be stuck?
Can you rig it up to read the o2 sensor as you drive?
Can you rig it up to read the o2 sensor as you drive?
Thread Starter
Navigator
Joined: Nov 2005
Posts: 9
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From: Austin TX
The car ran great on Thursday going to work, but it still felt a little "off". So at lunch I went by Walgreens and bought a couple of bottles of iso alcohol. I added about 3/4 of a bottle to a 1/4 tank of gas. I then drove it around stop and go for 45 min and it ran better than it has in months! I drove the car all weekend and it has not missed a beat. I am going to add a little to each tank for a while to make sure the water is all gone. Thanks for all of your help! That code 44 troubleshooting page helped tremendously. Thanks again.
Ben
Ben
Burning Brakes
Joined: Nov 2002
Posts: 1,186
Likes: 264
From: Huntington Beach CA
The car ran great on Thursday going to work, but it still felt a little "off". So at lunch I went by Walgreens and bought a couple of bottles of iso alcohol. I added about 3/4 of a bottle to a 1/4 tank of gas. I then drove it around stop and go for 45 min and it ran better than it has in months! I drove the car all weekend and it has not missed a beat. I am going to add a little to each tank for a while to make sure the water is all gone. Thanks for all of your help! That code 44 troubleshooting page helped tremendously. Thanks again.
Ben
Ben
So, your conclusion is that you are getting moisture in your gasoline? and adding isopropal alcohol to the gas tank will help get rid of the moisture?
Le Mans Master
Joined: May 2005
Posts: 5,214
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From: Queensland, AUSTRALIA
Le Mans Master
Joined: Feb 2006
Posts: 8,753
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From: Louisiana
Tech Contributor
Joined: Aug 2006
Posts: 9,933
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From: Peoria Arizona.. Resident Gold Cylon
Heet is the only moisture removal from a bottle method I have heard of to remove water from fuel. 
Burning Brakes
Joined: Nov 2002
Posts: 1,186
Likes: 264
From: Huntington Beach CA
After reading your post, on Monday I threw a can of HEET in my car, and (knock on wood) the SES light hasn't reappeared and has been running fine. I'm going to put another can in next fill up along with some Chevron Techron fuel system cleaner. Maybe the 18 year old fuel system just needs a little TLC.
Burning Brakes
Joined: Nov 2002
Posts: 1,186
Likes: 264
From: Huntington Beach CA