Dual O2's??????
New User
Joined: Dec 2002
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From: Bowling Green USA
Dual O2's??????
I have a question that y'all might be able to answer.
I pulled my motor(4.0L) out of a 93 Areostar.
I have heard that some motors run dual O2 sensors. one in front of the cat and one after.
does this motor have that?
also would the absence of the rear or any O2 sensor stop the computer from starting in an open loop?
have y'all ever heard anything about running a 5.0 injector in the 4.0?
thanks!
Daniel
I pulled my motor(4.0L) out of a 93 Areostar.
I have heard that some motors run dual O2 sensors. one in front of the cat and one after.
does this motor have that?
also would the absence of the rear or any O2 sensor stop the computer from starting in an open loop?
have y'all ever heard anything about running a 5.0 injector in the 4.0?
thanks!
Daniel
Posting Guru
Joined: Apr 2000
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From: PNW
Dual O2's??????
It's my understanding that the dual O2 configuration came with OBD II, which was '95 or '96 depending on which model car/truck/van you have. My '95 Aerostar is still OBD I. Your motor should not have OBD II. OBD II included more sensors to monitor the emissions equipment so it was easier to detect failed emissions equipment (but some might argue it was done to introduce more failure modes). I suspect the absence of the rear O2 sensor would not prevent it from starting in open loop. I think that's primarily temperature dependent. The absence of the front O2 sensor will probably force it to run in some fail safe mode so that there is no damage to the motor, but I can't say for sure that the fail safe mode is the same as "open loop". I don't know enough about the logic inside that little box used to control the engine.
Concerning the 5.0 injector, why would you want to do that? I don't know anything about it, but I'm curious as to your motivation for doing such a thing.
Concerning the 5.0 injector, why would you want to do that? I don't know anything about it, but I'm curious as to your motivation for doing such a thing.
New User
Joined: Dec 2002
Posts: 24
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From: Bowling Green USA
Dual O2's??????
well the reason for the 5.0 injector is I would like to increase the fuel, spark and port the upper and lower intake to get more performance. also a buddy has some that he'll give me, and one of mine is broken so I figured free is better then $60 for a new one. I'm thinkin' it might have been the cause of the violent jerking that I was discribing in my previous post
the reason for the O2 sensor question is it seemes that my motor is not going into open loop when I start it. it idles at like 750 from cold start and wants to die. I replaced the O2 when I got the motor runnin but I am going to check it in the morning to see if it is bad.
I know that the O2, IAT, and the coolant temp sensor all control this but I can't test the IAT and the coolant temp is good(tested it yesterday).
do you think the injector will work?
the reason for the O2 sensor question is it seemes that my motor is not going into open loop when I start it. it idles at like 750 from cold start and wants to die. I replaced the O2 when I got the motor runnin but I am going to check it in the morning to see if it is bad.
I know that the O2, IAT, and the coolant temp sensor all control this but I can't test the IAT and the coolant temp is good(tested it yesterday).
do you think the injector will work?
New User
Joined: Dec 2002
Posts: 24
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From: Bowling Green USA
Dual O2's??????
here is what it is doing.
first crank:
doesn't start just rolls over.
second crank:
it starts but only runs at 750 and dies
third crank:
same as second but if you tap the gas it will stay runnin at 750
it never idles any higher.
the way I understand it is open loop is when the computer ingnors all the sensors and just plugs numbers to make it idle high so the motor will warm up. after the computer sees the motor is warm(via the coolent temp sensor) it will then read all the sensors(O2, stuff like that) and idle down.
the way it is acting is what is making me think it's not going into open loop.
first crank:
doesn't start just rolls over.
second crank:
it starts but only runs at 750 and dies
third crank:
same as second but if you tap the gas it will stay runnin at 750
it never idles any higher.
the way I understand it is open loop is when the computer ingnors all the sensors and just plugs numbers to make it idle high so the motor will warm up. after the computer sees the motor is warm(via the coolent temp sensor) it will then read all the sensors(O2, stuff like that) and idle down.
the way it is acting is what is making me think it's not going into open loop.
Posting Guru
Joined: Apr 2000
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From: PNW
Dual O2's??????
Another thing that will affect idle speed is the IAC valve. Even if the computer is in open loop, if the IAC is not working, idle speed will not increase. Have you checked that out?
Regarding the injector, I have no idea if it will work. I understand your desire to save money, but if you think you'll need more fuel flow due to your mods, the stock injectors will keep up unless you're making serious power.
Regarding the injector, I have no idea if it will work. I understand your desire to save money, but if you think you'll need more fuel flow due to your mods, the stock injectors will keep up unless you're making serious power.
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Hotshot
Joined: Aug 2002
Posts: 12,679
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From: BC, Canada
Dual O2's??????
Until the engine is warm the PCM stays in open loop. It defaults to open loop if there is a problem too. I've never heard of one not going into open loop. I think Mikeman is on the right track. Take a good look at the IAC and maybe clean the MAF while you're there and check for vacuum leaks, particularly at the fuel rail gaskets...top and bottom.
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New User
Joined: Dec 2002
Posts: 24
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From: Bowling Green USA
Dual O2's??????
well my friend came up short on the injectors so I 'm getting a stock one today and planing on putting it back to gether this afternoon. I'm getting new upper and lower gaskets for the fuel rail. how do I check the IAC?
Posting Guru
Joined: Apr 2000
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From: PNW
Dual O2's??????
Remove the IAC and inspect for crud buildup. If present, then give it a good cleaning. The manual I have mentions that there are some out there that have plastic bodies and that these can't be cleaned without damaging the plastic. Don't overlook the passages on the manifold/throttle body.
Here's a link with some other info on the IAC.
http://www.geocities.com/MotorCity/Flats/3349/idle.htm
Here's a link with some other info on the IAC.
http://www.geocities.com/MotorCity/Flats/3349/idle.htm
New User
Joined: Dec 2002
Posts: 24
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From: Bowling Green USA
Dual O2's??????
I got it back together today. bad news. it is still acting up. I installed the injectors, cleaned the MAF, and cleaned the IAC. nothing. I can tell all the sensors above are working because when I unplug them one at a time the motor wants to die.
the reason I pulled the injectors was I got a bank 1 "lean" code.
now after I cleaned the MAF I have a code saying that it is showing a low voltage?????? I made sure not to break the smll resisters so is there any thing else I could have broke? I have it installed on the bottom of the intake would that make a difference?
the reason I pulled the injectors was I got a bank 1 "lean" code.
now after I cleaned the MAF I have a code saying that it is showing a low voltage?????? I made sure not to break the smll resisters so is there any thing else I could have broke? I have it installed on the bottom of the intake would that make a difference?
Posting Guru
Joined: Apr 2000
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From: PNW
Dual O2's??????
The motor should not die when you uplug one sensor, so something isn't right. The low voltage at the MAF sensor could be a wiring problem or some other problem. Have you reset the computer after replacing and cleaning various senors? What do you mean when you say you have it (the MAF?) installed on the bottom of the intake?
New User
Joined: Dec 2002
Posts: 24
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From: Bowling Green USA
Dual O2's??????
[updated:LAST EDITED ON 01-16-03 AT 12:45 PM (EST)]when I installed the motor I didn't have an air box for the 4.0L but I did have an air box for a 3.0L. so I turned the MAF body so the MAF is on the bottom of the body insted of the top that way it would bolt on to the air box. would that cause a change in the reading that it would give?
with every thing pluged in the jerking only happenes about half of the time and suddenly it will go away. I don't get it. also the only codes that are poping up are:
these are auto trany codes but I am running a mitsu 5spd so they shouldn't matter:
522
629
566
these are the motor codes that show up in the second set of codes:
157-MAF signal voltage is to low
158-MAF signal voltage is to high
I reset it with the code scanner but I haven't reset it at the battery yet so I will try that.
with every thing pluged in the jerking only happenes about half of the time and suddenly it will go away. I don't get it. also the only codes that are poping up are:
these are auto trany codes but I am running a mitsu 5spd so they shouldn't matter:
522
629
566
these are the motor codes that show up in the second set of codes:
157-MAF signal voltage is to low
158-MAF signal voltage is to high
I reset it with the code scanner but I haven't reset it at the battery yet so I will try that.
Posting Guru
Joined: Apr 2000
Posts: 1,746
Likes: 4
From: PNW
Dual O2's??????
I wouldn't think that having the MAF upside down would matter, as long as it's installed downstream of the filter. If it affected the motor, I would expect that you would notice it all the time, not intermittently. Have you tried the wiggle test? When the engine is running OK, wiggle various connectors and wires and see if you can cause the symptom to appear. Since you are getting the MAF code, I would concentrate on those connectors and wiring in the MAF circuit, checking as much as you can. Another thing you could do when it acts up is to check continuity and resistance in as much of the MAF circuit as you can when it is working properly and when it's acting up and see what turns up. I'm not sure what the resistance should be, but if it changes, then you've got a clue as to what's going on and can troubleshoot from there.