Timing and running rich?
02-09-12, 07:29 PM
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Timing and running rich?
I need to do a quick and approximate tune up on my 1988 rx7 non-turbo. The timing marks have worn off and the car is running rich. I can adjust the position of the cam angle sensor but don't know which direction to turn it so it runs leaner (cw or ccw). Any other suggestions would be appreciated. Thanks
02-10-12, 01:35 PM
#2
Adjusting timing does not make it run richer or leaner. Timing dictates when the spark plugs fire, so if you play with it blindly, you can end up having very bad things happen.
Check the 2nd gen FAQ for links to the FSM. The procedure for setting the timing is detailed there, and will require removing the CAS, then re-stabbing it. To figure out where the timing marks are on the main pulley, find the 2 indentations & re-paint them. Nail polish works well, so steal some from someone female.
What are the symptoms that have led you to the conclusion that it is "running rich" ? "Rich" is subjective, and all FCs are tuned on the rich side at idle/cruise/under acceleration.
Check the 2nd gen FAQ for links to the FSM. The procedure for setting the timing is detailed there, and will require removing the CAS, then re-stabbing it. To figure out where the timing marks are on the main pulley, find the 2 indentations & re-paint them. Nail polish works well, so steal some from someone female.
What are the symptoms that have led you to the conclusion that it is "running rich" ? "Rich" is subjective, and all FCs are tuned on the rich side at idle/cruise/under acceleration.
02-10-12, 03:35 PM
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Adjusting timing does not make it run richer or leaner. Timing dictates when the spark plugs fire, so if you play with it blindly, you can end up having very bad things happen.
Check the 2nd gen FAQ for links to the FSM. The procedure for setting the timing is detailed there, and will require removing the CAS, then re-stabbing it. To figure out where the timing marks are on the main pulley, find the 2 indentations & re-paint them. Nail polish works well, so steal some from someone female.
What are the symptoms that have led you to the conclusion that it is "running rich" ? "Rich" is subjective, and all FCs are tuned on the rich side at idle/cruise/under acceleration.
Check the 2nd gen FAQ for links to the FSM. The procedure for setting the timing is detailed there, and will require removing the CAS, then re-stabbing it. To figure out where the timing marks are on the main pulley, find the 2 indentations & re-paint them. Nail polish works well, so steal some from someone female.
What are the symptoms that have led you to the conclusion that it is "running rich" ? "Rich" is subjective, and all FCs are tuned on the rich side at idle/cruise/under acceleration.
02-10-12, 03:39 PM
#4
always something to fix
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Get a wide band sensor kit, then you'll know exactly what your ratio is and you can tune it yourself with the handheld device
Innovate is popular, plx, aem, as cheap as 180 for a new kit, there's used ones on here as well
Innovate is popular, plx, aem, as cheap as 180 for a new kit, there's used ones on here as well
02-10-12, 11:03 PM
#5
Running rough at idle can be many things. Bag spark plugs, vacuum leaks or a bad TPS are typical causes. There is also a mixture adjustment pot near the airbox, but this should not need to be adjusted unless someone has previously messed with it. The initial set coupler (green 2-wire plug by the leading coil) needs to be jumped before doing anything. Let the engine idle, and slowly turn the screw either way. Find the mid-point where it runs the smoothest.
If it runs rough under load, it can be different issues, and there is no stock mixture adjustment. But you don't need one if all of the systems are working correctly.
"Eating gas" doesn't mean much to me. Rotaries don't get great gas mileage. If you drive the car the way it was meant to be driven, expect ~15 mpg with mixed driving.
Overkill if he's just needs to give the car a tune up.
If it runs rough under load, it can be different issues, and there is no stock mixture adjustment. But you don't need one if all of the systems are working correctly.
"Eating gas" doesn't mean much to me. Rotaries don't get great gas mileage. If you drive the car the way it was meant to be driven, expect ~15 mpg with mixed driving.
Overkill if he's just needs to give the car a tune up.
02-11-12, 02:34 AM
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Running rough at idle can be many things. Bag spark plugs, vacuum leaks or a bad TPS are typical causes. There is also a mixture adjustment pot near the airbox, but this should not need to be adjusted unless someone has previously messed with it. The initial set coupler (green 2-wire plug by the leading coil) needs to be jumped before doing anything. Let the engine idle, and slowly turn the screw either way. Find the mid-point where it runs the smoothest.
If it runs rough under load, it can be different issues, and there is no stock mixture adjustment. But you don't need one if all of the systems are working correctly.
"Eating gas" doesn't mean much to me. Rotaries don't get great gas mileage. If you drive the car the way it was meant to be driven, expect ~15 mpg with mixed driving.
Overkill if he's just needs to give the car a tune up.
If it runs rough under load, it can be different issues, and there is no stock mixture adjustment. But you don't need one if all of the systems are working correctly.
"Eating gas" doesn't mean much to me. Rotaries don't get great gas mileage. If you drive the car the way it was meant to be driven, expect ~15 mpg with mixed driving.
Overkill if he's just needs to give the car a tune up.
Also, what to I need for vacuum leak testing and how do I proceed?
Finally, what to you mean by air box (filter??)
Thanks.
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02-11-12, 10:30 AM
#8
You only need one multimeter to set the Green/Red wire of the TPS to 1 volt w/key to on and engine completely warmed up. Red meter lead to the G/R wire and the Black meter lead to a ground ( alternator housing or negative battery terminal) w/meter set to DC volts.
The air box houses the air filter.
The air box houses the air filter.
02-11-12, 11:00 AM
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You only need one multimeter to set the Green/Red wire of the TPS to 1 volt w/key to on and engine completely warmed up. Red meter lead to the G/R wire and the Black meter lead to a ground ( alternator housing or negative battery terminal) w/meter set to DC volts.
The air box houses the air filter.
The air box houses the air filter.
The car runs OK but needs a bit of tuning. It's rough at idle. My aim is to keep costs of tune up as low as possible since I'm only keeping it until June.
BTW, if I have a vacuum leak and it's some major gasket, is there a "quick fix" I can do that will last a few months?
02-12-12, 01:04 AM
#10
The simplest way to check for vacuum leaks is to spray carb cleaner around areas you suspect of leaking. Idle speed will change if it gets sucked in through an opening. If the intake manifolds have not been removed recently, a gasket leak is not likely. Hard/brittle or missing vacuum lines may be the case. You can always replace the rubber lines to rule them out. This was one of the very first things I did when I bought my car. If it's a gasket issue, you have to replace it.
For the TPS, you'll also want to measure resistance as you move the throttle/TPS plunger. There should not be any dead spots as it moves.
http://fc3spro.com/TECH/HOWTO/TPS/tps.html
For the TPS, you'll also want to measure resistance as you move the throttle/TPS plunger. There should not be any dead spots as it moves.
http://fc3spro.com/TECH/HOWTO/TPS/tps.html
02-12-12, 10:45 AM
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The simplest way to check for vacuum leaks is to spray carb cleaner around areas you suspect of leaking. Idle speed will change if it gets sucked in through an opening. If the intake manifolds have not been removed recently, a gasket leak is not likely. Hard/brittle or missing vacuum lines may be the case. You can always replace the rubber lines to rule them out. This was one of the very first things I did when I bought my car. If it's a gasket issue, you have to replace it.
For the TPS, you'll also want to measure resistance as you move the throttle/TPS plunger. There should not be any dead spots as it moves.
http://fc3spro.com/TECH/HOWTO/TPS/tps.html
For the TPS, you'll also want to measure resistance as you move the throttle/TPS plunger. There should not be any dead spots as it moves.
http://fc3spro.com/TECH/HOWTO/TPS/tps.html
Yesterday I did the volt meter test and set the throttle sensor adjusting screw so one side read about 12V and the other about 0V. Initially, they were about 1 volt each. The image is different in the manual from my 1988 non-turbo but found the right one here:
Did get some hesitation one time while driving around but it hasn't happened again.
Will try more tests on TPS again later today or tomorrow.
For vacuum lines, is there a picture where they are located?
Thanks again.
02-13-12, 02:03 PM
#12
Yes, the link above is for an S4 TII. But the TPS is identical.
Which wires did you back probe? The only one that matters is the one by itself on the 3-wire plug (should be G/R as satch mentioned. This is the one that should ready 1 volt with the engine fully warm.
For vacuum lines, there is a diagram in the manual, but it can be a bit confusing. All of the 3.5mm (and a couple 6mm) ID black lines in the bay can be replaced. Most are accessible with the engine assembled, but there are a few that require the intake manifold to come off. Around 15ft of hose should cover it, and you can buy it at dealership parts departments, automotive stores or online. I have some high-quality lines from BMW, and some silicon lines from an online vendor. For some of the special formed lines (like shown in your picture right behind the alternator), you should stick with OEM Mazda parts.
Which wires did you back probe? The only one that matters is the one by itself on the 3-wire plug (should be G/R as satch mentioned. This is the one that should ready 1 volt with the engine fully warm.
For vacuum lines, there is a diagram in the manual, but it can be a bit confusing. All of the 3.5mm (and a couple 6mm) ID black lines in the bay can be replaced. Most are accessible with the engine assembled, but there are a few that require the intake manifold to come off. Around 15ft of hose should cover it, and you can buy it at dealership parts departments, automotive stores or online. I have some high-quality lines from BMW, and some silicon lines from an online vendor. For some of the special formed lines (like shown in your picture right behind the alternator), you should stick with OEM Mazda parts.
02-13-12, 04:21 PM
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Yes, the link above is for an S4 TII. But the TPS is identical.
Which wires did you back probe? The only one that matters is the one by itself on the 3-wire plug (should be G/R as satch mentioned. This is the one that should ready 1 volt with the engine fully warm.
For vacuum lines, there is a diagram in the manual, but it can be a bit confusing. All of the 3.5mm (and a couple 6mm) ID black lines in the bay can be replaced. Most are accessible with the engine assembled, but there are a few that require the intake manifold to come off. Around 15ft of hose should cover it, and you can buy it at dealership parts departments, automotive stores or online. I have some high-quality lines from BMW, and some silicon lines from an online vendor. For some of the special formed lines (like shown in your picture right behind the alternator), you should stick with OEM Mazda parts.
Which wires did you back probe? The only one that matters is the one by itself on the 3-wire plug (should be G/R as satch mentioned. This is the one that should ready 1 volt with the engine fully warm.
For vacuum lines, there is a diagram in the manual, but it can be a bit confusing. All of the 3.5mm (and a couple 6mm) ID black lines in the bay can be replaced. Most are accessible with the engine assembled, but there are a few that require the intake manifold to come off. Around 15ft of hose should cover it, and you can buy it at dealership parts departments, automotive stores or online. I have some high-quality lines from BMW, and some silicon lines from an online vendor. For some of the special formed lines (like shown in your picture right behind the alternator), you should stick with OEM Mazda parts.
I adjusted that screw so one side was about 11 volts not 1 volt and the other side under 1 volt. Today's a rainy day and at idle the speed goes up then down over and over again. So is it near 1 volt or 12 volts on that connector?
02-14-12, 12:17 PM
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The simplest way to check for vacuum leaks is to spray carb cleaner around areas you suspect of leaking. Idle speed will change if it gets sucked in through an opening. If the intake manifolds have not been removed recently, a gasket leak is not likely. Hard/brittle or missing vacuum lines may be the case. You can always replace the rubber lines to rule them out. This was one of the very first things I did when I bought my car. If it's a gasket issue, you have to replace it.
For the TPS, you'll also want to measure resistance as you move the throttle/TPS plunger. There should not be any dead spots as it moves.
http://fc3spro.com/TECH/HOWTO/TPS/tps.html
For the TPS, you'll also want to measure resistance as you move the throttle/TPS plunger. There should not be any dead spots as it moves.
http://fc3spro.com/TECH/HOWTO/TPS/tps.html
What about the Green & Orange/Brown wires. I tried it there and it seems the reverse where resistance goes down from the 4-5K range to below 1K. Should I care about it being below 1K with fully opened throttle?
02-14-12, 02:23 PM
#15
The image you posted above comes from the 1st gen FSM in the GSL-SE section, which used an engine that is very similar to what's found in an S4 NA. The method described there is the "two-light" method. On the same page, they show using two 12v, 3.4w bulbs instead of multimeters. LEDs are more typically used for this, but I prefer the 1 volt / resistance checking method.
I don't think there are any specs for what resistance you should see on the other two wires. The G/R one is what goes to pin 2G on the ECU, where the 2nd gen FSM lists 1.0v as the spec.
I don't think there are any specs for what resistance you should see on the other two wires. The G/R one is what goes to pin 2G on the ECU, where the 2nd gen FSM lists 1.0v as the spec.
02-15-12, 01:26 PM
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The image you posted above comes from the 1st gen FSM in the GSL-SE section, which used an engine that is very similar to what's found in an S4 NA. The method described there is the "two-light" method. On the same page, they show using two 12v, 3.4w bulbs instead of multimeters. LEDs are more typically used for this, but I prefer the 1 volt / resistance checking method.
I don't think there are any specs for what resistance you should see on the other two wires. The G/R one is what goes to pin 2G on the ECU, where the 2nd gen FSM lists 1.0v as the spec.
I don't think there are any specs for what resistance you should see on the other two wires. The G/R one is what goes to pin 2G on the ECU, where the 2nd gen FSM lists 1.0v as the spec.
02-18-12, 10:07 AM
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TPS circuit checks out. Went on to check for vacuum leaks and found significant one due to hoses disconnected from the
switching solenoid valve
pressure regulator control solenoid valve
purge control valve
The vertical plastic tips off the solenoid valves where the short upside-down U-shaped hoses connect where snapped off inside the hoses. Likewise the plastic connector tip was snapped off inside the hose to the purge control valve.
I've temporarily glued these back with Gorilla Glue and this seems to work. If it lasts then I won't bother replacing the parts.
switching solenoid valve
pressure regulator control solenoid valve
purge control valve
The vertical plastic tips off the solenoid valves where the short upside-down U-shaped hoses connect where snapped off inside the hoses. Likewise the plastic connector tip was snapped off inside the hose to the purge control valve.
I've temporarily glued these back with Gorilla Glue and this seems to work. If it lasts then I won't bother replacing the parts.
02-19-12, 01:15 PM
#18
If the pressure regulator solenoid is improperly hooked up, you can end up with high fuel pressure at idle. When the vacuum line to an FPR is disconnected, it will see atmospheric pressure instead of vacuum from the engine. The result is an extra rich mixture & rough idle due to fuel pressure being as much as 10 psi too high.
02-19-12, 10:58 PM
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If the pressure regulator solenoid is improperly hooked up, you can end up with high fuel pressure at idle. When the vacuum line to an FPR is disconnected, it will see atmospheric pressure instead of vacuum from the engine. The result is an extra rich mixture & rough idle due to fuel pressure being as much as 10 psi too high.
However, I don't really know if any glue plugged the holes at those tips or if the solenoids are faulty.
I get a definite decrease in rpm after the engine warms up which I hadn't had for a long time. But the rpm goes lower than before and the engine starts idling rough. I plan to recheck timing and idle setting, is there anything else I should do or check?
Thanks.
02-20-12, 05:56 PM
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If the pressure regulator solenoid is improperly hooked up, you can end up with high fuel pressure at idle. When the vacuum line to an FPR is disconnected, it will see atmospheric pressure instead of vacuum from the engine. The result is an extra rich mixture & rough idle due to fuel pressure being as much as 10 psi too high.
Thank you.
02-23-12, 12:40 AM
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02-23-12, 02:28 PM
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I'll add a bit to my last post.
1. Starting the car after it's be parked overnight cause a rough idle even at the higher rpm.
2. As it warms up the idle does two things:
a) There is a decrease but no elimination of the "roughness."
b) A quick drop in rpm happens that goes below 500 (cars inside tach) then moves up to around 800-1100 depending (one day to the next).
3) Today I again noticed something I thought I eliminate, an oscillation (lower, higher, lower, higher) in rpm at idle for a short period of time.
If I need to go back and check vacuum with carb cleaner then where are some of the most suspect parts in the previous diagrams located? The diagrams aren't helpful in that regard.
Thank you.
1. Starting the car after it's be parked overnight cause a rough idle even at the higher rpm.
2. As it warms up the idle does two things:
a) There is a decrease but no elimination of the "roughness."
b) A quick drop in rpm happens that goes below 500 (cars inside tach) then moves up to around 800-1100 depending (one day to the next).
3) Today I again noticed something I thought I eliminate, an oscillation (lower, higher, lower, higher) in rpm at idle for a short period of time.
If I need to go back and check vacuum with carb cleaner then where are some of the most suspect parts in the previous diagrams located? The diagrams aren't helpful in that regard.
Thank you.
02-25-12, 10:34 PM
#25
When you get the idle bouncing around, it's the ECU trying to compensate for an inconsistency. The BAC is ECU controlled, and it'll change the amount of air it allows in, which increases/decreases idle speed. In addition to a vac leak or TPS issue, a bad AFM can also screw with the idle. I have an extra NA AFM that will make it idle rough and stall if I plug it in. There are resistance values listed in the FSM for it too.
As far as where to look for vac leaks, there are a ton of places. Any of the locations with gaskets or the larger hoses going into the manifold would be the most likely areas.
As far as where to look for vac leaks, there are a ton of places. Any of the locations with gaskets or the larger hoses going into the manifold would be the most likely areas.