NewZed Posted January 23, 2013 Share Posted January 23, 2013 The AAR has no effect on the air-fuel ratio. It only lets air past the throttle blade, not the AFM. All air should pass through the AFM, if the AAR is plumbed correctly. 70 ohms is correct for the AAR, that's the resistance of the heater wire on the bimetallic strip. And the AAR only opens when the bimetallic strip cools off. Even so, it's only effect is on idle RPM, not AFR's. The AAC also only affects air flow, not air-fuel ratio, but through a different control mechanism. EGR will affect the amount of fuel, but it only dilutes both air (O2) and fuel equally. There's a great chart on page EF-49 of the 81 Turbo Supplement. EF-35 has a nice diagram of the inputs to the ECCS. 81 was the early days of the ECCS Analyzer though, so much of the FSM assumes it's being used. Makes it a pain to figure things out., but there's still some good clues in there. For example, at mid-throttle, mid-RPM on a warmed-up engine the ECCS should go to closed-loop control, using the O2 sensor. Maybe your O2 circuit is showing a constant lean condition and the ECCS is compensating. Might also explain the jerky behavior, and good perfromance under load. cg knows more about the closed-loop control since he's installed a few complete systems. Just a possibility. Quote Link to comment Share on other sites More sharing options...
SDgoods Posted January 23, 2013 Author Share Posted January 23, 2013 The AAR has no effect on the air-fuel ratio. It only lets air past the throttle blade, not the AFM. All air should pass through the AFM, if the AAR is plumbed correctly. 70 ohms is correct for the AAR, that's the resistance of the heater wire on the bimetallic strip. And the AAR only opens when the bimetallic strip cools off. Even so, it's only effect is on idle RPM, not AFR's. The AAC also only affects air flow, not air-fuel ratio, but through a different control mechanism. EGR will affect the amount of fuel, but it only dilutes both air (O2) and fuel equally. There's a great chart on page EF-49 of the 81 Turbo Supplement. EF-35 has a nice diagram of the inputs to the ECCS. 81 was the early days of the ECCS Analyzer though, so much of the FSM assumes it's being used. Makes it a pain to figure things out., but there's still some good clues in there. For example, at mid-throttle, mid-RPM on a warmed-up engine the ECCS should go to closed-loop control, using the O2 sensor. Maybe your O2 circuit is showing a constant lean condition and the ECCS is compensating. Might also explain the jerky behavior, and good perfromance under load. cg knows more about the closed-loop control since he's installed a few complete systems. Just a possibility. Im almost certain the AAC does affect idle AFR's. I forgot to mention my EGR is blocked off (more specifically the pipe coming off the intake manifold has been welded shut). at idle the 02 sensor is reading .3 V and i recently replaced it with a new one. Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 23, 2013 Share Posted January 23, 2013 It might be a correlation, not a cause. The attached diagram shows that the AAC only bypasses the throttle blade. The EGR gas might affect the O2 reading, since it as adding O2 depleted air to the intake system, which is not the same "reference" air that the O2 sensor is calibrated to. The AAC and EGR system are tied to the same VCM. Looks complicated and the variables probably interact. Regardless, the 81 Turbo Supplement is a good document to study. Quote Link to comment Share on other sites More sharing options...
SDgoods Posted January 23, 2013 Author Share Posted January 23, 2013 It might be a correlation, not a cause. The attached diagram shows that the AAC only bypasses the throttle blade. The EGR gas might affect the O2 reading, since it as adding O2 depleted air to the intake system, which is not the same "reference" air that the O2 sensor is calibrated to. The AAC and EGR system are tied to the same VCM. Looks complicated and the variables probably interact. Regardless, the 81 Turbo Supplement is a good document to study. Ive studied it thoroughly as When i get the car it was completely missing the VCM and associated vacuum hoses so I acquired a VCM and hooked up all of the hoses. How would the EGR affect 02 reading? All it's doing is diluting the combustion chamber and like you said, AFR should be the same just a lower proportionate volume of air and fuel. I will re test the 02 sensor circuit but is .3 at idle normal? I will also check it's voltage while revving as even with no load and car just sitting there it will shoot to 10 AFR with enough throttle Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 23, 2013 Share Posted January 23, 2013 (edited) A though - are you testing your TPS at the TPS or at the ECCS connectors? Better to test at the ECCS connectors so you know what the ECCS sees. As far as 0.3 volts, I think that the narrow band sensors jump rapidly from .2 V to .8 V when they go rich (low O2). But Ithink that when the mixture is way off, the sensors can foul and don't work right anymore. The wide bands apparently go the other way, in a more linear fashion, from high V to low V when the mixture gets rich. You're not using the same type of sensor for your AFR gauge and the ECCS are you? They're different. And there's a newer type of sensor that uses resistance, not voltage to calculate the ratio. You're probably right on the EGR effect, since there is no extra fuel added with the added EGR gas. I got my gases mixed up. I still can't see any reason for the AAC or the AAR to affect the fuel-air ratio. Good luck. At least you have a good reason to dig in to all of technology behind the system. Edited January 23, 2013 by NewZed Quote Link to comment Share on other sites More sharing options...
SDgoods Posted January 24, 2013 Author Share Posted January 24, 2013 A though - are you testing your TPS at the TPS or at the ECCS connectors? Better to test at the ECCS connectors so you know what the ECCS sees. As far as 0.3 volts, I think that the narrow band sensors jump rapidly from .2 V to .8 V when they go rich (low O2). But Ithink that when the mixture is way off, the sensors can foul and don't work right anymore. The wide bands apparently go the other way, in a more linear fashion, from high V to low V when the mixture gets rich. You're not using the same type of sensor for your AFR gauge and the ECCS are you? They're different. And there's a newer type of sensor that uses resistance, not voltage to calculate the ratio. You're probably right on the EGR effect, since there is no extra fuel added with the added EGR gas. I got my gases mixed up. I still can't see any reason for the AAC or the AAR to affect the fuel-air ratio. Good luck. At least you have a good reason to dig in to all of technology behind the system. More findings, One the 02 sensor was pretty lose, turnable by finger. pulled it out and cleaned it off, tightened back up. Reads around .7 volts at idle now with my wideband reading right around 12. Also the downpipe gasket is leaking at the bottom of the flange worse than i thought. Im wondering if this is skewing outputs on both the wideband and/or the stock 02 sensor. Quote Link to comment Share on other sites More sharing options...
cgsheen Posted January 24, 2013 Share Posted January 24, 2013 (edited) You are correct about the vcm controlling ecu through vacuum however the air regulator is what allows the air to get to the aac when vacuum is applied to it. The vcm only applies vacuum to te aac diaphragm, it doesnt supply bypass air Directly Oh, we're talking two different things. The Air Regulator is a completely seperate device. The A.A.C. does not get it's air supply from the Air Regulator. The FSM describes the A.A.C and it's function in depth. The Air Reg. is supplied voltage by the fuel pump relay. It has a bi-metal "arm" inside that moves a shutter. It's wrapped with a coil, and when power is applied it heats the bi-metal which slowly bends. As it bends, it moves the shutter. As I recall, the shutter is open when the engine is cold to supply by-pass air and raise idle speed, then closes within a couple of minutes. And, you're right, neither of these should be the cause of your overly Rich condition. The L28ET relies on it's "base map" a great deal. It will only poll the O2 Sensor if it can get into "closed loop" mode. It will only try to get into "closed loop" mode under certain conditions - above a certain RPM, below a certain RPM, when the CHTS is above a certain temperature, and if it's getting proper signal from it's other sensors... All that stuff is outlined in the FSM and it's mostly "all sensors working, warmed up, and at cruising speed". At idle it doesn't poll the O2 Sensor, over 3500 RPM or under heavy load, it doesn't poll the O2 Sensor. You know when it's in closed loop mode because the LED on the side of the ECU will start flashing. The ECU is then polling the O2 Sensor and trying to pulse the injectors so it runs just on the edge of just Rich and just Lean and the LED is signaling the change being reported by the O2 Sensor. I don't think a downpipe leak would skew the O2 Sensor reading. It's still a pressurized pipe and most of the exhaust gases are still going down the pipe past the sensor(s). It's oxygen content is not going to change because some of the exhaust gases are going out a different hole. Because it's pressurized, no external air is going to get in there and change the composition of the exhaust gases. Edited January 24, 2013 by cgsheen Quote Link to comment Share on other sites More sharing options...
SDgoods Posted January 26, 2013 Author Share Posted January 26, 2013 I forgot to mention something else I found (or lack there of) On the underside of the distributor theres a 2 pin connection (nothing plugged into it) Anyone know what this is for? Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted January 26, 2013 Share Posted January 26, 2013 When I suspect any of the usual suspects on the intake manifold, I simply remove the crazy T section (or is it F shaped) and replace it with two hoses. One goes from the valve on the intake manifold of cylinder 4 to the J pipe and the other goes from the regulator to the idle air control actuator. Most of the hoses are probably cracked anyway. Easy test. http://farm7.staticflickr.com/6066/6116930413_17e6c40377_b.jpg Quote Link to comment Share on other sites More sharing options...
SDgoods Posted January 27, 2013 Author Share Posted January 27, 2013 When I suspect any of the usual suspects on the intake manifold, I simply remove the crazy T section (or is it F shaped) and replace it with two hoses. One goes from the valve on the intake manifold of cylinder 4 to the J pipe and the other goes from the regulator to the idle air control actuator. Most of the hoses are probably cracked anyway. Easy test. http://farm7.staticflickr.com/6066/6116930413_17e6c40377_b.jpg That wouldnt really explain my problem. It would cause a lean problem. Not to mention i pull 20 in/hg Quote Link to comment Share on other sites More sharing options...
cgsheen Posted January 27, 2013 Share Posted January 27, 2013 (edited) Edited out, sorry, I forgot we were talking about an '81 turbo engine... Edited January 27, 2013 by cgsheen Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted January 27, 2013 Share Posted January 27, 2013 What I described above is a test and it pretty much disables anything the hoses are connected to on the intake manifold other than the "vacuum control valve" which is actually a small blow off valve. It's a good setup for testing but I've been running it that way for 40,000 miles. I would also clean the throttle body with a rag and some carb cleaner which can bring down your base idle to something that won't idle at all. Quote Link to comment Share on other sites More sharing options...
SDgoods Posted January 27, 2013 Author Share Posted January 27, 2013 What I described above is a test and it pretty much disables anything the hoses are connected to on the intake manifold other than the "vacuum control valve" which is actually a small blow off valve. It's a good setup for testing but I've been running it that way for 40,000 miles. Ill try it although like ive stated a couple times through out the thread the idle is the least of the problems. Its mainly the fact that it goes pig rich any time i even slightly get on the throttle. I dont believe its going into closed-loop I would also clean the throttle body with a rag and some carb cleaner which can bring down your base idle to something that won't idle at all. Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 27, 2013 Share Posted January 27, 2013 (edited) You haven't said if you're taking your resistance readings at the ECCS connector or right at the various components like the idle switch, AFM, CHTS, etc. It doesn't matter that the component measures right if the ECCS can't see it, or gets the wrong information. You could help your dilemma by measuring those three things, and others like air temperature, at the ECCS connector and reporting what you get. Start at page EF-16 of the 81 turbo supplement. And, to be sure, do you know that it's "pig rich" or does it just feel like it's rich. [Edited out - waste of words] Maybe the AFRs are a symptom not a cause. Edited January 28, 2013 by NewZed Quote Link to comment Share on other sites More sharing options...
SDgoods Posted January 27, 2013 Author Share Posted January 27, 2013 Did you read the thread? Ive said numerous times that 1. I have a quality aem wideband 02 sensor with a gauge so i know its running rich. 2. Ive checked readings at both the sensors and at the ecu. By pig rich i mean pegged to as rich as the gauge will go- 10 afr which means its probably even more rich. I have questioned the wideband however the gas mileage backs it up, under 10 mpg. Today i confirmed that its not going into closed loop. The light on the ecu turns on when the key is in on positin but driving around low rpms low load it never does. The afm over all test is 80 ohms under spec. The chts is in spec, and i get the same resistance reading for it at the ecu and at the sensor. The idle switch checks out as well. I might be getting my hands on another ecu to try out. Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 28, 2013 Share Posted January 28, 2013 I guess you missed my point about the difference between actually "running rich" (too much gas, not enough O2) and high AFR numbers? The gauge is just showing you what's coming out of the exhaust system. What went is in inferred from the number. It's an assumption. No guarantee that it means what you think it does. Your mileage is a good indicator, but you didn't mention it before. Good luck. Quote Link to comment Share on other sites More sharing options...
loy Posted January 28, 2013 Share Posted January 28, 2013 I'd try another AFM also since it ohms out of spec. Quote Link to comment Share on other sites More sharing options...
SDgoods Posted January 29, 2013 Author Share Posted January 29, 2013 Yay more problems! I switched AFMs to a free one I got and the afrs were sporadic from 13's to 18's and super lean. So I changed back to my original AFM and while I was at it I cleaned off the external CAS as well as tried to measure the gaps with a makeshift feeler gauge. the pick up was at a diagonal and not parallel to the disc so I (stupidly) bent it straight.... As of now the car won't start. It cranks but floods itself. A couple of times it ran for a few seconds a 500 or less RPM. So did i destroy the CAS or what? Also already asked this but can anyone confirm I have an 82-83 distributor? It has the 4 pin/prong connection on the underside of the distributor but nothing plugged in Quote Link to comment Share on other sites More sharing options...
cgsheen Posted January 29, 2013 Share Posted January 29, 2013 (edited) Not the best picture, but this is what the '82-'83 Turbo Distributor looks like. It has a 4-pin (spade) plug covered (normally) with a black rubber weather seal, and a bracket which is bolted to the dist. to hold it in place. The wire is 10 to 12 inches long and connects to the ECCS harness just behind the thermostat - same connector that the external CAS uses... If you unscrew the distributor cap and remove the rotor, you should see a metal plate covering the stainless steel optical wheel and the electronics that make it all work. If you actually have a turbo dizzy, you need to get that thing hooked up! You'll need the connector though. If you don't have it, it may be tough to find another... HowlerMonkey put an L28ET in his F31. I put F31 engine management on my L28ET... Edited January 29, 2013 by cgsheen Quote Link to comment Share on other sites More sharing options...
SDgoods Posted January 29, 2013 Author Share Posted January 29, 2013 Not the best picture, but this is what the Turbo Distributor looks like. It has a 4-pin (spade) plug covered (normally) with a black rubber weather seal, and a bracket which is bolted to the dist. to hold it in place. The wire is 10 to 12 inches long and connects to the ECCS harness just behind the thermostat - same connector that the external CAS uses... If you unscrew the cap and remove the rotor, you should see a metal plate covering the stainless steel optical wheel and the electronics that make it all work. If you actually have a turbo dizzy, you need to get that thing hooked up! You'll need the connector though. If you don't have it, it may be tough to find another... turbodizzy.jpg it appears I do have one. Although is the end of the black thing with the yellow line the end of the connector that actually plugs into the distributor? And is that plugged in? Im missing that but do have that little prong coming off the dist. as well as the 4 pin connection underneath Quote Link to comment Share on other sites More sharing options...
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