no fast idle/mas air flow ohms off

flipskid · 05-07-2005, 02:57 AM

I recently bought a 87 4runner with the 4 banger. supposedly new motor in it. I noticed that when i start it, it does not have a fst idle. so i have been looking at all the tech threads. I get an ohm meter and start testing stuff. the throttle position sensor seems to be out of speck as well as the mass air flow sensor above the airbox. I stopped there because i began to wonder if everything I was going to test would be broken or was it just my tester> anyway, the air flow had been messed with, the seal was gone and the plastic came right off. there was some mineral deposits in there and looks like wheel may have ben adjusted. will that cause a different ohm reading? also, while the truck runs good and idles around 700-800 rpm, does not seem as if it has a lot of power. Iknow it isn't going to be a race car, but what should I be looking for? gears are stockers for now, the 410 or 411 I think because it came with the small tires. has 31's on it, and I know that will cuase some of the lack of power I am imagining. Gonna take it to a friend and see what readings they get, but any suggestions on any of this stuff?

Grim Reaper · 05-07-2005, 08:56 AM

If your read the repair manual you have half your questions you would not have asked.

The 22RE in those years does not use a IAC. It uses a heated Aperture bypass deal. Under the water neck you will see a black plastic square with two very small coolant lines and two air lines about 1 inch OD. Thats the part that controls cold idle speed. It has a bi metal spring that is heated by the coolant and closes the aperture as it heats. They suck and often don't work very well and get stuck in the closed position. If it starts when its cold and idles under 900 RPM hot then leave it alone your doing good.

Set the IDL-E2 circuit on the TPS. www.4crawler.com has a nice write up. If the TPS is not right and the idle is higher then 950 it will have a surging Idle when the brakes are applied (It senses the brake lights so that it knows its at Idle and stopping). You may need to clean out the workings of the throttle assembly. The way Toyota does their PCV they often gum up with oil vapors and sometimes hang partly open leaving the ECM with not IDE trigger and you will get that surging idle as well. Also make sure the dash pot that keeps it from slamming shut is working or you will get a stall problem when you blip the throttle.

When testing the TPS and the AFM the critical part is that they have a smooth linear sweep as you open them up (be careful with auto ranging digital VOM's they will jump as the auto range and make you think you have a dead spot). Any jumps or dead spots will give a run problem. As long as you see a smooth sweep then I wouldn't worry a lot about being out of the range the book states.

The AFM is your real concern. Its what really controls the fuel enrichment. The TPS just tells the computer your input then the AFM tells it the fuel needs by how far the engine has sucked the door open. To much adjustment one way or the other and your going to have a poor mixture. Putting in a GOOD air fuel meter in is about the best way to adjust that thing if you are daring enough to mess with it. It sounds like the last person tried and may have got you messed up.

22RE is not a power monster. Its a little bit of a dog especially if you have put over sized tires on it and not corrected the gear ratio it will be a slug for sure. It really likes to be running around 3k for its happy spot.

You might surch for FSM or factory repair manual. Somebody posted a link to FACTORY manual in PDF here a few months back. 60 megs

WELCOME NEWBIE

duffdog · 05-08-2005, 09:18 PM

whomever messed with the AFM probably f$%ked it up--if someone has played around with the spring retainer in there and accidentally let out some tension, the whole thing needs to be replaced. Also, DONT mess with the new afm if you get one--it is possible to slightly shift the powerband upward for the impression of more power, but that just decreases your low end tq. Just replace both the afm (with a good used one) and the TPS (with a new one)--that was the first thing I did on my 88 considering it had 220000 miles.

T

05-07-2005, 02:57 AM	#1
flipskid Registered User Join Date: Apr 2005 Member # 46731 Posts: 112	no fast idle/mas air flow ohms off I recently bought a 87 4runner with the 4 banger. supposedly new motor in it. I noticed that when i start it, it does not have a fst idle. so i have been looking at all the tech threads. I get an ohm meter and start testing stuff. the throttle position sensor seems to be out of speck as well as the mass air flow sensor above the airbox. I stopped there because i began to wonder if everything I was going to test would be broken or was it just my tester> anyway, the air flow had been messed with, the seal was gone and the plastic came right off. there was some mineral deposits in there and looks like wheel may have ben adjusted. will that cause a different ohm reading? also, while the truck runs good and idles around 700-800 rpm, does not seem as if it has a lot of power. Iknow it isn't going to be a race car, but what should I be looking for? gears are stockers for now, the 410 or 411 I think because it came with the small tires. has 31's on it, and I know that will cuase some of the lack of power I am imagining. Gonna take it to a friend and see what readings they get, but any suggestions on any of this stuff?

05-07-2005, 08:56 AM	#2
Grim Reaper Registered User Join Date: Aug 2001 Member # 6726 Location: United Socialist States of America Posts: 3,498	If your read the repair manual you have half your questions you would not have asked. The 22RE in those years does not use a IAC. It uses a heated Aperture bypass deal. Under the water neck you will see a black plastic square with two very small coolant lines and two air lines about 1 inch OD. Thats the part that controls cold idle speed. It has a bi metal spring that is heated by the coolant and closes the aperture as it heats. They suck and often don't work very well and get stuck in the closed position. If it starts when its cold and idles under 900 RPM hot then leave it alone your doing good. Set the IDL-E2 circuit on the TPS. www.4crawler.com has a nice write up. If the TPS is not right and the idle is higher then 950 it will have a surging Idle when the brakes are applied (It senses the brake lights so that it knows its at Idle and stopping). You may need to clean out the workings of the throttle assembly. The way Toyota does their PCV they often gum up with oil vapors and sometimes hang partly open leaving the ECM with not IDE trigger and you will get that surging idle as well. Also make sure the dash pot that keeps it from slamming shut is working or you will get a stall problem when you blip the throttle. When testing the TPS and the AFM the critical part is that they have a smooth linear sweep as you open them up (be careful with auto ranging digital VOM's they will jump as the auto range and make you think you have a dead spot). Any jumps or dead spots will give a run problem. As long as you see a smooth sweep then I wouldn't worry a lot about being out of the range the book states. The AFM is your real concern. Its what really controls the fuel enrichment. The TPS just tells the computer your input then the AFM tells it the fuel needs by how far the engine has sucked the door open. To much adjustment one way or the other and your going to have a poor mixture. Putting in a GOOD air fuel meter in is about the best way to adjust that thing if you are daring enough to mess with it. It sounds like the last person tried and may have got you messed up. 22RE is not a power monster. Its a little bit of a dog especially if you have put over sized tires on it and not corrected the gear ratio it will be a slug for sure. It really likes to be running around 3k for its happy spot. You might surch for FSM or factory repair manual. Somebody posted a link to FACTORY manual in PDF here a few months back. 60 megs WELCOME NEWBIE __________________ [COLOR="Black"]Did you expect to find something deep and meaningful here?[/COLOR] "He has all the virtues I dislike and none of the vices I admire." -- Winston Churchill

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05-08-2005, 09:18 PM	#3
duffdog Registered User Join Date: Sep 2004 Member # 35463 Location: sacramento Posts: 52	whomever messed with the AFM probably f$%ked it up--if someone has played around with the spring retainer in there and accidentally let out some tension, the whole thing needs to be replaced. Also, DONT mess with the new afm if you get one--it is possible to slightly shift the powerband upward for the impression of more power, but that just decreases your low end tq. Just replace both the afm (with a good used one) and the TPS (with a new one)--that was the first thing I did on my 88 considering it had 220000 miles. T