Lean Idle condition; HELP
03-10-12, 09:44 PM
#51
porting won't affect your idle AFRs much at all, even large street ported motors will idle fine with all the stock components.
as Hailers keeps alluding to you need to eliminate air pumped into the exhaust to get an idea of exactly how rich or lean the engine is running, especially when it is attempting to or is stalling out.
if you believe the injectors are the root issue, swap the primaries with the secondaries.
as Hailers keeps alluding to you need to eliminate air pumped into the exhaust to get an idea of exactly how rich or lean the engine is running, especially when it is attempting to or is stalling out.
if you believe the injectors are the root issue, swap the primaries with the secondaries.
03-10-12, 09:56 PM
#53
Also, is there a write up anywhere on how to set a S5 TPS? Everything I have ever found has been for S4 or it has been instructions on how to set it via the light method. I can't find the instructions on how to make the lights anywhere either...
Aside from this thread which doesn't make it clear if it should be set to 1V or 1 ohm.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/tps-adjustment-multimeter-s5-n-739191/
Aside from this thread which doesn't make it clear if it should be set to 1V or 1 ohm.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/tps-adjustment-multimeter-s5-n-739191/
03-10-12, 10:00 PM
#54
Rotary Freak
By the way.........the two elect plugs on the ACV have nothing to do with the afr. They can be cut off and laying in the backyard as far as that goes. It's vacuum from the relief and swtiching soleoids that control the ACV under normal conditions.
*********Just put in AEM FPR. Cranking up the fuel pressure helps, but not much. It idles at 1500 rpm 16:1 AFR's. Then when I adjust the TPS to lower the idle: right when it reaches about 1300 RPM it suddenly goes full lean again -19:1- and idle drops to 500-700 rpm.
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Remember what I said how the TPS setting determines when the Relief solenoid ports vacuum to the ACV?????????? Most likely when you were turning the screw on the TPS in the above quote, you turned the TPS to a point where it outputted one volt to the ECu and the ECU in turn energized the RELIEF solenoid which then ported vacuum to the ACV which in turn ported fresh airpump air to the exhaust ports which in turn diluted the exhaust gasses prior to the 02 sensor locationg which then made the afr show much leaner (higher figure on the gauge).
*********Just put in AEM FPR. Cranking up the fuel pressure helps, but not much. It idles at 1500 rpm 16:1 AFR's. Then when I adjust the TPS to lower the idle: right when it reaches about 1300 RPM it suddenly goes full lean again -19:1- and idle drops to 500-700 rpm.
************************************************** ***************************
Remember what I said how the TPS setting determines when the Relief solenoid ports vacuum to the ACV?????????? Most likely when you were turning the screw on the TPS in the above quote, you turned the TPS to a point where it outputted one volt to the ECu and the ECU in turn energized the RELIEF solenoid which then ported vacuum to the ACV which in turn ported fresh airpump air to the exhaust ports which in turn diluted the exhaust gasses prior to the 02 sensor locationg which then made the afr show much leaner (higher figure on the gauge).
03-10-12, 10:09 PM
#55
Rotary Freak
Also, is there a write up anywhere on how to set a S5 TPS? Everything I have ever found has been for S4 or it has been instructions on how to set it via the light method. I can't find the instructions on how to make the lights anywhere either...
Aside from this thread which doesn't make it clear if it should be set to 1V or 1 ohm.
https://www.rx7club.com/showthread.php?t=739191
Aside from this thread which doesn't make it clear if it should be set to 1V or 1 ohm.
https://www.rx7club.com/showthread.php?t=739191
About all I will say about setting the TPS is this...............if one looks in the factory service manual..........the FUEL AND EMISSIONS section and then find the page that shows the input/output of each pin on the ECU plugs..........he will find it says that the INPUT to the ECU from the TPS is APPOX ONE VOLT DC.
No matter whether you use the ohms method.............two LED light method........or just use a meter to backprobe the input wire at the ECU..........the end result is a figure of APPROX ONE VOLT from the TPS to the ECU at IDLE.......when the TPS is actually set right by either method. A figure of 1.10 vdc IS appox one volt and a figure of 0.95 vdc is APPROX one volt. Approx is ..well approx. I can use any of those figures and the car idles just the same. .
Engine MUST BE FULLY HOT to ensure the fast idle cam is off its roll pin reuslting the the throttle shaft/plates being fully CLOSED when setting the TPS. Because on a cold engine the water thermowax's piston will extend and push the throttle linkage to a slight open positon resulting in the plates/shaft not being in the fully closed position. Note the TPS piston rides on the throttle shaft so any movement of the shaft reslults in the TPS plunger moving and outputting a figure other than one volt (idle is one volt i.e plates fully closed.
03-10-12, 10:44 PM
#56
green wire off the TPS plug is the narrow range signal wire for both series 4 and 5, backprobing it and set to 1 volt with the engine fully warmed up. as mentioned, the engine doesn't actually have to be running.
also do a slow sweep of the throttle and watch the voltmeter and see if you get any erratic dips or peaks in the reading.
also do a slow sweep of the throttle and watch the voltmeter and see if you get any erratic dips or peaks in the reading.
03-11-12, 08:29 AM
#57
Rotary Freak
03-16-12, 07:32 PM
#59
Rotary Freak
Yes. But the ACV seems to be doing what they are supposed to do.........feed airpump air to the exhaust port during idle therefore diluting the mixture that the 02 sensors read.
No real idea why you thing the ACV is a bad actor.
No real idea why you thing the ACV is a bad actor.
03-16-12, 09:36 PM
#61
weirdest thing ever. took it for a drive. it got dark, and cold. I turned on my headlights and my heater and the car started to idle correctly for a few minutes. perfect 900rpm idle and afr's in the 16 range. (everything hooked back up) once turn off either my heater of headlights it goes lean again and will not idle.
03-17-12, 12:03 PM
#63
Rotary Freak
Misconception number one: the TPS does not determine the fuel delivery at idle.
Your post #28: the BAC is NOT a on/off device like you mentioned in a earlier post of yours. The BAC has a duty cycle that varies do to load and has not much of any effect if the rpms are over approx 750 rpm.
Your post #21: No, the injectors should have batt voltage on one pin and the other pin goes to the ECU which pulses a GROUND to that wire to open/close the injector.
You tried your friends fuel injectors and that failed to fix the lean. I think you tried another air flow meter and that did not fix the problem. If you ddn't then try your friends air flow meter. Airflow meter check outs per the factory service manual do NOT mean the airflow meter is rigged right. On a series four airflow meter is someone fiddles with the spring tension of the vane OR fiddles with the bypass airscrew and does not know up from down..........the idle can be messed up really easily. I'm not familar with series five airflow meters and whether or not they have a airbypass screw that could be messed up.
Normal idle afr on a RX with no airpump air being injected is what I said it should be in a earlier post, approx 13afr for a decent idle.
Your say the afr are rich while driving the car at speed. That leads me to believe, like others on this thread, that there is a air leak. Could be as simple as a misrouted vacuum hose or cracked vacuum hose. Nobody on this forum can tell if you have the vacuum/air hoses routed right or not.
Turning the headlights on would indicate to the ECU that there is a load being put on the engine (page F1-40 of the online FSM) so it seems that would riched up the mixture at idle a bit. Might be a clue. That act also causes the BAC to up its duty cycle.
Leaking grommets at the bottom of the fuel injectors will cause a crummy idle. They should not be rock hard grommets but have some pliability to them so they will not let air bypass at the injectors bottom seat. The leaking grommets won't been noticed once driving. How seafoam could effect that is beyond me.
ACV causing a vacuum leak?????? I don't see that happening myself. The only way I see that happening is if the ACV gasket is kaput causing a leak around the gasket. But remove it and put the blockoff plate on with a good gasket and see what happens. While at it make a blockoff plate for your BAC. Something as simple as a solid piece of aluminum inserted between the body of the BAC and where it mounts with a good gasket to prevent air leaks. Just drill two attach bolt holes in the piece of alumimun so you can mount it b/t the BAC and the manifold.
Not all nipples on a throttle body are vacuum. Some are metered air sources like for the spider for the oil injectors (those hose on the oil injectors good?). So if you have a vacuum line going to a source of air instead of vacuum that could cause idle problems but not driving problems.
Your post #28: the BAC is NOT a on/off device like you mentioned in a earlier post of yours. The BAC has a duty cycle that varies do to load and has not much of any effect if the rpms are over approx 750 rpm.
Your post #21: No, the injectors should have batt voltage on one pin and the other pin goes to the ECU which pulses a GROUND to that wire to open/close the injector.
You tried your friends fuel injectors and that failed to fix the lean. I think you tried another air flow meter and that did not fix the problem. If you ddn't then try your friends air flow meter. Airflow meter check outs per the factory service manual do NOT mean the airflow meter is rigged right. On a series four airflow meter is someone fiddles with the spring tension of the vane OR fiddles with the bypass airscrew and does not know up from down..........the idle can be messed up really easily. I'm not familar with series five airflow meters and whether or not they have a airbypass screw that could be messed up.
Normal idle afr on a RX with no airpump air being injected is what I said it should be in a earlier post, approx 13afr for a decent idle.
Your say the afr are rich while driving the car at speed. That leads me to believe, like others on this thread, that there is a air leak. Could be as simple as a misrouted vacuum hose or cracked vacuum hose. Nobody on this forum can tell if you have the vacuum/air hoses routed right or not.
Turning the headlights on would indicate to the ECU that there is a load being put on the engine (page F1-40 of the online FSM) so it seems that would riched up the mixture at idle a bit. Might be a clue. That act also causes the BAC to up its duty cycle.
Leaking grommets at the bottom of the fuel injectors will cause a crummy idle. They should not be rock hard grommets but have some pliability to them so they will not let air bypass at the injectors bottom seat. The leaking grommets won't been noticed once driving. How seafoam could effect that is beyond me.
ACV causing a vacuum leak?????? I don't see that happening myself. The only way I see that happening is if the ACV gasket is kaput causing a leak around the gasket. But remove it and put the blockoff plate on with a good gasket and see what happens. While at it make a blockoff plate for your BAC. Something as simple as a solid piece of aluminum inserted between the body of the BAC and where it mounts with a good gasket to prevent air leaks. Just drill two attach bolt holes in the piece of alumimun so you can mount it b/t the BAC and the manifold.
Not all nipples on a throttle body are vacuum. Some are metered air sources like for the spider for the oil injectors (those hose on the oil injectors good?). So if you have a vacuum line going to a source of air instead of vacuum that could cause idle problems but not driving problems.
03-17-12, 12:06 PM
#64
Rotary Freak
Also when the rpms get over 1100 rpm the ECU advances the timing quite a bit which can effect idle mixtures in the driveway.
Someone on this or maybe another post on this forum suggested backprobing the ECU pin by pin and comparing that with the section the FUEL AND EMISSIONS seciton of the FSM that lists the proper readings for each pin.
Another tack would be to pull the air/vacuum lines off the throttle body and cap the nipples and the hoses and then try to idle the engine. IF a major difference is seen then that would be a clue.
Also the AWS valve might have a hose leaking or it's gasket isn't sealing..
Also the ACV is controlled by vacuum from the switching and relief solenoid. They pull vacuum on diapharms inside the ACV so if a diaphram was toast, then that would cause a bit of a unauthorized air leak. There is also something called a anti afterburn diaphram/valve in the ACV that gets its vacuum from one of the intake runners directly opposite that valve (can't be seen with the ACV installed). So if the antiafterburn valve internal to the ACV was bad.........irregular idle.
And or.............fully heat the engine up. PUll the vacuum line off the fuel pressure regulator. ON a stk car that would make the fuel pressre go up from appox 28 psi to 39psi and enrichen the mixutre.
I'm guessing bad lower grommets on the fuel injectors.
Someone on this or maybe another post on this forum suggested backprobing the ECU pin by pin and comparing that with the section the FUEL AND EMISSIONS seciton of the FSM that lists the proper readings for each pin.
Another tack would be to pull the air/vacuum lines off the throttle body and cap the nipples and the hoses and then try to idle the engine. IF a major difference is seen then that would be a clue.
Also the AWS valve might have a hose leaking or it's gasket isn't sealing..
Also the ACV is controlled by vacuum from the switching and relief solenoid. They pull vacuum on diapharms inside the ACV so if a diaphram was toast, then that would cause a bit of a unauthorized air leak. There is also something called a anti afterburn diaphram/valve in the ACV that gets its vacuum from one of the intake runners directly opposite that valve (can't be seen with the ACV installed). So if the antiafterburn valve internal to the ACV was bad.........irregular idle.
And or.............fully heat the engine up. PUll the vacuum line off the fuel pressure regulator. ON a stk car that would make the fuel pressre go up from appox 28 psi to 39psi and enrichen the mixutre.
I'm guessing bad lower grommets on the fuel injectors.
03-17-12, 12:31 PM
#65
Rotary Freak
Water temp sensor can cause lean problems but usually just on starting the car. IF disconnected the car will act normal once the water temps get around normal (180* F). Might just check to see if it's connected up good and also read its output at the ECU pin when the car is hot (approx a half volt fully warmed up, much higher readings when the water is cold, like 2-3vdc).
04-13-12, 07:29 PM
#66
Been back probing and monitoring everything all day. Looks like almost everything is normal at the ECU, which is leading me to think that the wiring harness is the problem.
The only things I found out of spec was the MAP sensor and Fuel pump were odd. The MAP was reading 4.5V with key on, per FSM testing procedure, as opposed to 2.5-3.5v, however I was thinking that could be caused by my elevation and lower atmospheric pressure. Not sure if the ECU even uses MAP for idle, anyway...
I was monitoring the Fuel pump voltage at the ecu and it is only showing 9.5V when cranking and .7V at idle. While part throttle driving around it's either at .7V or 12V when I'm getting on the throttle. FSM say's at idle it should be below 2v, but it doesn't list a lower limit. Is the voltage to the fuel pump supposed to regulate per driving conditions with the voltage varying, or does it just sit at 1v and 12v, per driving conditions?
The only things I found out of spec was the MAP sensor and Fuel pump were odd. The MAP was reading 4.5V with key on, per FSM testing procedure, as opposed to 2.5-3.5v, however I was thinking that could be caused by my elevation and lower atmospheric pressure. Not sure if the ECU even uses MAP for idle, anyway...
I was monitoring the Fuel pump voltage at the ecu and it is only showing 9.5V when cranking and .7V at idle. While part throttle driving around it's either at .7V or 12V when I'm getting on the throttle. FSM say's at idle it should be below 2v, but it doesn't list a lower limit. Is the voltage to the fuel pump supposed to regulate per driving conditions with the voltage varying, or does it just sit at 1v and 12v, per driving conditions?
04-14-12, 09:53 PM
#67
If you measured the voltage at the ECU plug w/key to on the light Green wires (all four of them) will have battery voltage (plug must be secured to the injector and the wires in the plug must not be pulled back in the plug causing a faulty connection). The Black/Yellow wires at the injector plugs will all have battey voltage w/key to on as well.
Originally Posted by HAILERS2
Your post #21: No, the injectors should have batt voltage on one pin and the other pin goes to the ECU which pulses a GROUND to that wire to open/close the injector.
If I'm looking at the wiring diagram correctly the injectors get the keyed 12V from the training ignitor. If it has a short in it somewhere then that may be the problem, but my tach registers fine, so... It's either a short in the wiring harness or trailing coil/ignitor.
04-15-12, 12:25 AM
#68
The Light Green injector wires have 12 volts until the ECU places a ground on the wire to fire the injector. If you're driving at low rpms the secondary injectors would not be used so the secondary ECU injector wires would always have 12 volts on them while the primary injectors would constantly be sent a brief ground pulse so as to fire the injectors.
The injectors are powered by the EGI INJ fuse via the Main Relay.
The injectors are powered by the EGI INJ fuse via the Main Relay.
04-15-12, 07:17 PM
#72
The only reason why the Light Green wire has voltage is because the voltage from the Black/Yellow wire passes through the injector plug onto the Light Green wire (backfeeding). W/o the plug being on the injector, the voltage would not pass from one to the other.
04-16-12, 07:14 PM
#74
Okay, just to confirm. I tore it down again and the black and yellow wires to each injector plug has 11.95V. the green wires to the primaries have no voltage, and the green wires to the secondaries have 11.3 volts. This is done with the injectors unplugged from the harness. Is this correct?
Also noticed the BAC was humming like mad. Is that normal? Can I unplug the thing and will the ecu not notice it? Maybe that this is the issue.
Also noticed the BAC was humming like mad. Is that normal? Can I unplug the thing and will the ecu not notice it? Maybe that this is the issue.
04-17-12, 05:39 PM
#75
Rotary Freak
The green/red, green/black, green/white and light green wires go from the injector plugs directly to the ECU's small plug.
The ECU pulses a ground on the light green wire of the injectors to make them open/****.
Unplug the small ECU plug to see if the voltage on the injector plugs goes away. Should. The other wire will have batt voltage anytime the key is ON. Normal
IF your reading voltage on the light green wires AT the injector plugs with the small plug on the ECU attached, then I suggest your backreading some voltage from a injector driver inside the ECU and there is probably no meaningful current on that line.
I don't know that for sure since I've never read volage on a light green wire on an injector plug with key ON ...because I know how stuff works and would not be expecting volage on a light green injector wire. A wire that in normal operation pulses a Ground to the injector plug.
BAC's will vibrate with key ON engine OFF. Normal as can be. Operates at about 120hz in normal operation, give or take some hz. Called a duty cycle. I would not disconnect the BAC myself. It helps hold a 750-800 rpm idle speed.
The ECU pulses a ground on the light green wire of the injectors to make them open/****.
Unplug the small ECU plug to see if the voltage on the injector plugs goes away. Should. The other wire will have batt voltage anytime the key is ON. Normal
IF your reading voltage on the light green wires AT the injector plugs with the small plug on the ECU attached, then I suggest your backreading some voltage from a injector driver inside the ECU and there is probably no meaningful current on that line.
I don't know that for sure since I've never read volage on a light green wire on an injector plug with key ON ...because I know how stuff works and would not be expecting volage on a light green injector wire. A wire that in normal operation pulses a Ground to the injector plug.
BAC's will vibrate with key ON engine OFF. Normal as can be. Operates at about 120hz in normal operation, give or take some hz. Called a duty cycle. I would not disconnect the BAC myself. It helps hold a 750-800 rpm idle speed.