1990 4 runner 3.0 problems.
Jun 30, 2021 | 08:12 PM
#1
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From: Okanogan, WA
1990 4 runner 3.0 problems.
Just picked this up 2nd gen. Can’t get it to stay running unless I keep on the throttle or move the MAF sensor back and forth. Just replaced the stock fuel filter. Rebuilt motor hasn’t even been broken in yet. Someone tell me how to upload a video and you’ll see what I’m talking about but here is an
imgur link: https://imgur.com/gallery/fnHhkOm
Jul 6, 2021 | 08:56 PM
#3
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From: Okanogan, WA
Tps problem
no.. I think I have the tps adjusted wrong and I’ve never had to adjust one like this. Cant just run the MAF richer because that just hides the problem.. thinking about taking it to a shop because I don’t wanna ˟˟˟˟ the new motor up
Jul 7, 2021 | 02:12 PM
#5
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From: exo-reality -wave if you see me; Front Range, CO
I can't recall off the top of my head, but there was a thread in the past year(?), someone had a thread about adjusting the MAF I think.
You might also could maybe track down wiring, and then test your wires, including ground paths. IIRC, the MAF has to show flow (I think the switch must be closed inside), making the ECM 'see' airflow, and that grounding of that switch provides the ground for the COR to provide power to the fuel pump. No air flow - no ground - no power thru CO relay - no pumping fuel.
Safety feature; engine not running, no fuel pump running. Works good if you're in a wreck.
You might also could maybe track down wiring, and then test your wires, including ground paths. IIRC, the MAF has to show flow (I think the switch must be closed inside), making the ECM 'see' airflow, and that grounding of that switch provides the ground for the COR to provide power to the fuel pump. No air flow - no ground - no power thru CO relay - no pumping fuel.
Safety feature; engine not running, no fuel pump running. Works good if you're in a wreck.
Jul 7, 2021 | 02:25 PM
#6
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Joined: Jun 2021
Posts: 14
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From: Okanogan, WA
Tps
Jul 7, 2021 | 02:27 PM
#7
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Joined: Jun 2021
Posts: 14
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From: Okanogan, WA
I can't recall off the top of my head, but there was a thread in the past year(?), someone had a thread about adjusting the MAF I think.
You might also could maybe track down wiring, and then test your wires, including ground paths. IIRC, the MAF has to show flow (I think the switch must be closed inside), making the ECM 'see' airflow, and that grounding of that switch provides the ground for the COR to provide power to the fuel pump. No air flow - no ground - no power thru CO relay - no pumping fuel.
Safety feature; engine not running, no fuel pump running. Works good if you're in a wreck.
You might also could maybe track down wiring, and then test your wires, including ground paths. IIRC, the MAF has to show flow (I think the switch must be closed inside), making the ECM 'see' airflow, and that grounding of that switch provides the ground for the COR to provide power to the fuel pump. No air flow - no ground - no power thru CO relay - no pumping fuel.
Safety feature; engine not running, no fuel pump running. Works good if you're in a wreck.
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Jul 8, 2021 | 12:43 PM
#8
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From: Chiloquin, OR
The MAF normally doesn't take any alignment. They CAN be adjusted for the mixture, but seldom require it. It never requires adjustment for the COR switch. That either works, or it doesn't. You can ohm the switch to test it. It's just as easy, if not moreso, than voltage. Safer for you, too. You can't get "bitten" by ohms, like you can by volts.
First step is to pull the battery terminals off. BOTH of them. It only takes a very little amount of volts on the leads, in the meter's ohms mode, to cause the meter to fail. Reason being, that the meter uses it's internal battery when in OHMs, to apply a very LOW level voltage to the leads, then reads the resulting current flow to determine the resistance. Uses OHM'S LAW. Look it up, sometime. Anywho, an external voltage on the leads in ohms mode will burn up the sensor in the meter. That's why you make absolutely certain there's no way to get any voltage in the system when ohming things.
Switch the meter to "ohms" setting, the one marked with a symbol that looks like a horse shoe with the open end down. Or it might be labeled "OHMS".
Set the meter to the lowest ohm reading. Frequently that's 2 ohms, max. Then it goes up in powers of 10. IE: 2, 20, 200, and so forth.
With the leads not touching anything, including each other, the meter will indicate "infinity" ohms. Different meter meters have different ways to show that, so just look at your meter's display with the leads not touching anything to see what it uses. Then, touch the leads tips together to see what they show. Should be a 0 (zero).
Now, simply pull the plug off the MAF, and move it out of the way. DO NOT loosen the screws that hold it together. Use the metal bale that holds the plug in place. Now, touch the meter's leads to the first two pins of the MAF, on the left. It should be infinity with the vane closed all the way. Then, with vane opened, even slightly, the meter should read 0.
You can't read the ohms to ground, as, with the plug off, the MAF is isolated from ground.
There you go, now you know how to use OHMS part of the meter
You can use it to check if a wire is broken, too. Just put on lead at one end of the wire, and the other at the wire's other end. You may need to build an extender wire to reach. Simple: Take a piece of wire, long enough to reach back to the meter from the far end of the wire. Strip both ends of the wire. Now, touch one end to the far end of the wire, touch the other to one of the meter's leads. Touch the meter's other lead to the near end of the wire. Now, you have a complete circuit, and can read the ohms the wire has. Anything much more than 0.01 ohms is bad. It may be very slightly higher if it's a very long wire, and WILL read higher if there's are dirty/corroded plugs in the wire anywhere.
Those should be cleaned out, and a small dab of silicone dielectric grease applied to them prior to reconnecting them. Easiest to just put a little bit into the female side of the plug. That stuff is a wonderful thing to prevent further dirt or corrosion from building up. I use it in any and every wire I touch. That includes both ends of the plug wires, any plug I ever unplug, you name it. Great stuff to use.
Okay, shutting up now...
Pat☺
First step is to pull the battery terminals off. BOTH of them. It only takes a very little amount of volts on the leads, in the meter's ohms mode, to cause the meter to fail. Reason being, that the meter uses it's internal battery when in OHMs, to apply a very LOW level voltage to the leads, then reads the resulting current flow to determine the resistance. Uses OHM'S LAW. Look it up, sometime. Anywho, an external voltage on the leads in ohms mode will burn up the sensor in the meter. That's why you make absolutely certain there's no way to get any voltage in the system when ohming things.
Switch the meter to "ohms" setting, the one marked with a symbol that looks like a horse shoe with the open end down. Or it might be labeled "OHMS".
Set the meter to the lowest ohm reading. Frequently that's 2 ohms, max. Then it goes up in powers of 10. IE: 2, 20, 200, and so forth.
With the leads not touching anything, including each other, the meter will indicate "infinity" ohms. Different meter meters have different ways to show that, so just look at your meter's display with the leads not touching anything to see what it uses. Then, touch the leads tips together to see what they show. Should be a 0 (zero).
Now, simply pull the plug off the MAF, and move it out of the way. DO NOT loosen the screws that hold it together. Use the metal bale that holds the plug in place. Now, touch the meter's leads to the first two pins of the MAF, on the left. It should be infinity with the vane closed all the way. Then, with vane opened, even slightly, the meter should read 0.
You can't read the ohms to ground, as, with the plug off, the MAF is isolated from ground.
There you go, now you know how to use OHMS part of the meter
You can use it to check if a wire is broken, too. Just put on lead at one end of the wire, and the other at the wire's other end. You may need to build an extender wire to reach. Simple: Take a piece of wire, long enough to reach back to the meter from the far end of the wire. Strip both ends of the wire. Now, touch one end to the far end of the wire, touch the other to one of the meter's leads. Touch the meter's other lead to the near end of the wire. Now, you have a complete circuit, and can read the ohms the wire has. Anything much more than 0.01 ohms is bad. It may be very slightly higher if it's a very long wire, and WILL read higher if there's are dirty/corroded plugs in the wire anywhere.
Those should be cleaned out, and a small dab of silicone dielectric grease applied to them prior to reconnecting them. Easiest to just put a little bit into the female side of the plug. That stuff is a wonderful thing to prevent further dirt or corrosion from building up. I use it in any and every wire I touch. That includes both ends of the plug wires, any plug I ever unplug, you name it. Great stuff to use.
Okay, shutting up now...
Pat☺
Jul 8, 2021 | 12:53 PM
#9
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Joined: Jun 2021
Posts: 14
Likes: 2
From: Okanogan, WA
The MAF normally doesn't take any alignment. They CAN be adjusted for the mixture, but seldom require it. It never requires adjustment for the COR switch. That either works, or it doesn't. You can ohm the switch to test it. It's just as easy, if not moreso, than voltage. Safer for you, too. You can't get "bitten" by ohms, like you can by volts.
First step is to pull the battery terminals off. BOTH of them. It only takes a very little amount of volts on the leads, in the meter's ohms mode, to cause the meter to fail. Reason being, that the meter uses it's internal battery when in OHMs, to apply a very LOW level voltage to the leads, then reads the resulting current flow to determine the resistance. Uses OHM'S LAW. Look it up, sometime. Anywho, an external voltage on the leads in ohms mode will burn up the sensor in the meter. That's why you make absolutely certain there's no way to get any voltage in the system when ohming things.
Switch the meter to "ohms" setting, the one marked with a symbol that looks like a horse shoe with the open end down. Or it might be labeled "OHMS".
Set the meter to the lowest ohm reading. Frequently that's 2 ohms, max. Then it goes up in powers of 10. IE: 2, 20, 200, and so forth.
With the leads not touching anything, including each other, the meter will indicate "infinity" ohms. Different meter meters have different ways to show that, so just look at your meter's display with the leads not touching anything to see what it uses. Then, touch the leads tips together to see what they show. Should be a 0 (zero).
Now, simply pull the plug off the MAF, and move it out of the way. DO NOT loosen the screws that hold it together. Use the metal bale that holds the plug in place. Now, touch the meter's leads to the first two pins of the MAF, on the left. It should be infinity with the vane closed all the way. Then, with vane opened, even slightly, the meter should read 0.
You can't read the ohms to ground, as, with the plug off, the MAF is isolated from ground.
There you go, now you know how to use OHMS part of the meter
You can use it to check if a wire is broken, too. Just put on lead at one end of the wire, and the other at the wire's other end. You may need to build an extender wire to reach. Simple: Take a piece of wire, long enough to reach back to the meter from the far end of the wire. Strip both ends of the wire. Now, touch one end to the far end of the wire, touch the other to one of the meter's leads. Touch the meter's other lead to the near end of the wire. Now, you have a complete circuit, and can read the ohms the wire has. Anything much more than 0.01 ohms is bad. It may be very slightly higher if it's a very long wire, and WILL read higher if there's are dirty/corroded plugs in the wire anywhere.
Those should be cleaned out, and a small dab of silicone dielectric grease applied to them prior to reconnecting them. Easiest to just put a little bit into the female side of the plug. That stuff is a wonderful thing to prevent further dirt or corrosion from building up. I use it in any and every wire I touch. That includes both ends of the plug wires, any plug I ever unplug, you name it. Great stuff to use.
Okay, shutting up now...
Pat☺
First step is to pull the battery terminals off. BOTH of them. It only takes a very little amount of volts on the leads, in the meter's ohms mode, to cause the meter to fail. Reason being, that the meter uses it's internal battery when in OHMs, to apply a very LOW level voltage to the leads, then reads the resulting current flow to determine the resistance. Uses OHM'S LAW. Look it up, sometime. Anywho, an external voltage on the leads in ohms mode will burn up the sensor in the meter. That's why you make absolutely certain there's no way to get any voltage in the system when ohming things.
Switch the meter to "ohms" setting, the one marked with a symbol that looks like a horse shoe with the open end down. Or it might be labeled "OHMS".
Set the meter to the lowest ohm reading. Frequently that's 2 ohms, max. Then it goes up in powers of 10. IE: 2, 20, 200, and so forth.
With the leads not touching anything, including each other, the meter will indicate "infinity" ohms. Different meter meters have different ways to show that, so just look at your meter's display with the leads not touching anything to see what it uses. Then, touch the leads tips together to see what they show. Should be a 0 (zero).
Now, simply pull the plug off the MAF, and move it out of the way. DO NOT loosen the screws that hold it together. Use the metal bale that holds the plug in place. Now, touch the meter's leads to the first two pins of the MAF, on the left. It should be infinity with the vane closed all the way. Then, with vane opened, even slightly, the meter should read 0.
You can't read the ohms to ground, as, with the plug off, the MAF is isolated from ground.
There you go, now you know how to use OHMS part of the meter
You can use it to check if a wire is broken, too. Just put on lead at one end of the wire, and the other at the wire's other end. You may need to build an extender wire to reach. Simple: Take a piece of wire, long enough to reach back to the meter from the far end of the wire. Strip both ends of the wire. Now, touch one end to the far end of the wire, touch the other to one of the meter's leads. Touch the meter's other lead to the near end of the wire. Now, you have a complete circuit, and can read the ohms the wire has. Anything much more than 0.01 ohms is bad. It may be very slightly higher if it's a very long wire, and WILL read higher if there's are dirty/corroded plugs in the wire anywhere.
Those should be cleaned out, and a small dab of silicone dielectric grease applied to them prior to reconnecting them. Easiest to just put a little bit into the female side of the plug. That stuff is a wonderful thing to prevent further dirt or corrosion from building up. I use it in any and every wire I touch. That includes both ends of the plug wires, any plug I ever unplug, you name it. Great stuff to use.
Okay, shutting up now...
Pat☺
so the whole issue with this thing was the air intake plenum bolts were not tightened at all causing a massive vacuum leak
Jul 8, 2021 | 02:24 PM
#10
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Registered User
Joined: Jun 2021
Posts: 14
Likes: 2
From: Okanogan, WA
Switched the MAF
The MAF normally doesn't take any alignment. They CAN be adjusted for the mixture, but seldom require it. It never requires adjustment for the COR switch. That either works, or it doesn't. You can ohm the switch to test it. It's just as easy, if not moreso, than voltage. Safer for you, too. You can't get "bitten" by ohms, like you can by volts.
First step is to pull the battery terminals off. BOTH of them. It only takes a very little amount of volts on the leads, in the meter's ohms mode, to cause the meter to fail. Reason being, that the meter uses it's internal battery when in OHMs, to apply a very LOW level voltage to the leads, then reads the resulting current flow to determine the resistance. Uses OHM'S LAW. Look it up, sometime. Anywho, an external voltage on the leads in ohms mode will burn up the sensor in the meter. That's why you make absolutely certain there's no way to get any voltage in the system when ohming things.
Switch the meter to "ohms" setting, the one marked with a symbol that looks like a horse shoe with the open end down. Or it might be labeled "OHMS".
Set the meter to the lowest ohm reading. Frequently that's 2 ohms, max. Then it goes up in powers of 10. IE: 2, 20, 200, and so forth.
With the leads not touching anything, including each other, the meter will indicate "infinity" ohms. Different meter meters have different ways to show that, so just look at your meter's display with the leads not touching anything to see what it uses. Then, touch the leads tips together to see what they show. Should be a 0 (zero).
Now, simply pull the plug off the MAF, and move it out of the way. DO NOT loosen the screws that hold it together. Use the metal bale that holds the plug in place. Now, touch the meter's leads to the first two pins of the MAF, on the left. It should be infinity with the vane closed all the way. Then, with vane opened, even slightly, the meter should read 0.
You can't read the ohms to ground, as, with the plug off, the MAF is isolated from ground.
There you go, now you know how to use OHMS part of the meter
You can use it to check if a wire is broken, too. Just put on lead at one end of the wire, and the other at the wire's other end. You may need to build an extender wire to reach. Simple: Take a piece of wire, long enough to reach back to the meter from the far end of the wire. Strip both ends of the wire. Now, touch one end to the far end of the wire, touch the other to one of the meter's leads. Touch the meter's other lead to the near end of the wire. Now, you have a complete circuit, and can read the ohms the wire has. Anything much more than 0.01 ohms is bad. It may be very slightly higher if it's a very long wire, and WILL read higher if there's are dirty/corroded plugs in the wire anywhere.
Those should be cleaned out, and a small dab of silicone dielectric grease applied to them prior to reconnecting them. Easiest to just put a little bit into the female side of the plug. That stuff is a wonderful thing to prevent further dirt or corrosion from building up. I use it in any and every wire I touch. That includes both ends of the plug wires, any plug I ever unplug, you name it. Great stuff to use.
Okay, shutting up now...
Pat☺
First step is to pull the battery terminals off. BOTH of them. It only takes a very little amount of volts on the leads, in the meter's ohms mode, to cause the meter to fail. Reason being, that the meter uses it's internal battery when in OHMs, to apply a very LOW level voltage to the leads, then reads the resulting current flow to determine the resistance. Uses OHM'S LAW. Look it up, sometime. Anywho, an external voltage on the leads in ohms mode will burn up the sensor in the meter. That's why you make absolutely certain there's no way to get any voltage in the system when ohming things.
Switch the meter to "ohms" setting, the one marked with a symbol that looks like a horse shoe with the open end down. Or it might be labeled "OHMS".
Set the meter to the lowest ohm reading. Frequently that's 2 ohms, max. Then it goes up in powers of 10. IE: 2, 20, 200, and so forth.
With the leads not touching anything, including each other, the meter will indicate "infinity" ohms. Different meter meters have different ways to show that, so just look at your meter's display with the leads not touching anything to see what it uses. Then, touch the leads tips together to see what they show. Should be a 0 (zero).
Now, simply pull the plug off the MAF, and move it out of the way. DO NOT loosen the screws that hold it together. Use the metal bale that holds the plug in place. Now, touch the meter's leads to the first two pins of the MAF, on the left. It should be infinity with the vane closed all the way. Then, with vane opened, even slightly, the meter should read 0.
You can't read the ohms to ground, as, with the plug off, the MAF is isolated from ground.
There you go, now you know how to use OHMS part of the meter
You can use it to check if a wire is broken, too. Just put on lead at one end of the wire, and the other at the wire's other end. You may need to build an extender wire to reach. Simple: Take a piece of wire, long enough to reach back to the meter from the far end of the wire. Strip both ends of the wire. Now, touch one end to the far end of the wire, touch the other to one of the meter's leads. Touch the meter's other lead to the near end of the wire. Now, you have a complete circuit, and can read the ohms the wire has. Anything much more than 0.01 ohms is bad. It may be very slightly higher if it's a very long wire, and WILL read higher if there's are dirty/corroded plugs in the wire anywhere.
Those should be cleaned out, and a small dab of silicone dielectric grease applied to them prior to reconnecting them. Easiest to just put a little bit into the female side of the plug. That stuff is a wonderful thing to prevent further dirt or corrosion from building up. I use it in any and every wire I touch. That includes both ends of the plug wires, any plug I ever unplug, you name it. Great stuff to use.
Okay, shutting up now...
Pat☺
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