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1986 4runner 22re hot start isuues with AFM?

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1986 4runner 22re hot start isuues with AFM?

Old 02-10-2019, 12:46 PM
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Question 1986 4runner 22re hot start isuues with AFM?

I have a 1986 4runner with the 2.4L 22re. the body has 219,000k and the engine is rebuilt with around 40,000k.

The problem is that when the vehicle is up to operating temperature if it is shut off it will go into a no start condition. Sometimes using a generous amount of starter fluid tends to get it started, or oddly enough unplugging the air flow meter allows it to start for about 4-5 seconds, (giving me enough time to plug it back in to keep it idling).

After i figured out unplugging the AFM allowed it to start i figured that was the cause of my problems. I followed the testing procedures and found out that the resistance between the pins were all in spec. I've tried adjusting the air flow meter thinking that would help, and it has with the idle of the engine but no change when trying to start when the vehicle is up to temp.

I am at a loss, I've checked all the vacuum lines with starter fluid, even though there are two lines coming from the intake manifold that the original owner just plugged up with screws and i'm not able to find out where they go. there was a ground wire for a vacuum line solenoid that connects to the egr system that i connected and after that it seemed to start up at warmer temperatures, but after reaching full operating temperatures it still wont start.

I'm just not sure if its the AFM still or not. with the afm cover off i can move the needle off of the switch and hear the fuel pump relay activate, and what sounds like a little pump activate as well. While holding the AFM and having someone in the car crank it, it will start up with a little throttle. It just doesnt make sense to me that the car will start while the AFM is unplugged and that fuel pump relay not activating. If anyone has any advice or anymore knowledge on if its the AFM or another issue id appreciate the help.
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Old 02-10-2019, 01:02 PM
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You smelling gas after it cranks back up?

Test the ECU temp sending unit.

Also, test the cold start injector thermo time switch. This switch went bad on my 92, and hot starts were a big PITA.
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Old 02-10-2019, 02:20 PM
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yes there is a smell of gas while the vehicle is running.

I will have to look up the procedures on the temp sending unit.

the cold start injector works fine, but from my understanding it shouldnt be operating once the vehicle is up to operating temperature, correct?
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Old 02-11-2019, 03:16 AM
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Originally Posted by jmac321 View Post
yes there is a smell of gas while the vehicle is running.

I will have to look up the procedures on the temp sending unit.

the cold start injector works fine, but from my understanding it shouldnt be operating once the vehicle is up to operating temperature, correct?
not correct. the CSI only operates within a certain temperature range and with the keyswitch in the start position. it does not operate with the switch in the "on" position.
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Old 02-11-2019, 05:11 AM
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Originally Posted by snippits View Post
You smelling gas after it cranks back up?

Test the ECU temp sending unit.

Also, test the cold start injector thermo time switch. This switch went bad on my 92, and hot starts were a big PITA.
Is the ECU temp sending unit located on the thermostat housing to the right of the intake manifold? if so i found out that there aren't any wires connecting to it. I found a loose green wire hanging around and i just grounded it to the body, i was wondering if that may have been for the temp sending unit? This could be he cause of my problems considering the ecu wont even be getting the signal.
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Old 02-11-2019, 05:20 AM
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that's it
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Old 02-11-2019, 05:27 AM
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Old 02-11-2019, 05:27 AM
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Originally Posted by 87-4runner View Post

that's it
There is no connector going to mine, original owner must of broke the connector or forgot to put it on there. i need to know the wire colors that come from the ecu to that harness.
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Old 02-11-2019, 06:05 AM
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My bad about the cold start injector thermo time switch.

It's been right at two years ago when I changed the switch, and it was cold starts that were a PITA.
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Old 02-11-2019, 09:00 AM
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Originally Posted by 87-4runner View Post
that parts diagram looks nothing like the efi setup for '86-87 22re 4wd setups.
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Old 02-11-2019, 09:31 AM
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Originally Posted by wallytoo View Post


that parts diagram looks nothing like the efi setup for '86-87 22re 4wd setups.
no it does not.
i plugged in the loose green/black wire to the ECU temp sending unit and it didnt seem to make too much of a difference. What still doesnt make sense to me is that when the AFM is unplugged, the car starts right up?
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Old 02-11-2019, 10:25 AM
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Originally Posted by wallytoo View Post


that parts diagram looks nothing like the efi setup for '86-87 22re 4wd setups.
oops wasn't paying much attention... just saw the sensors without looking at detail ... sorry
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Old 02-11-2019, 10:39 AM
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The thermo switch on top of the thermostat housing is for the fuel pressure up system.

The hot start issue has a TSB, it requires a thermo switch with a different range.

There is at least one detailed thread here with the tests you want to run. In short make sure your switch works
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Old 02-11-2019, 11:21 AM
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Originally Posted by Co_94_PU View Post
The thermo switch on top of the thermostat housing is for the fuel pressure up system.

The hot start issue has a TSB, it requires a thermo switch with a different range.

There is at least one detailed thread here with the tests you want to run. In short make sure your switch works
i know that the thermo switch isn't working because it has no connection going to it. i"m not sure if its because the original owner broke it off during the engine swap, or if he forgot to plug it in and the connector is tucked away somewhere underneath the intake manifold. there was a green/black wire that was broken off and ust dangling that i put a spade clip on and connected to the thermo switch on top of the thermostat housing, but im not sure if that is the correct wire or not (didnt make any difference). when the wire is connected to a ground you can hear the switch on the egr vaccum line on the rear of the valve cover. ill post pictures the next time i have a chance.
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Old 02-11-2019, 11:28 AM
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This might help, shows how AFM is tied to VSV, sensors & ECU for an '87:


Last edited by Paul22RE; 02-11-2019 at 11:29 AM.
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Old 02-11-2019, 11:35 AM
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Here is the rest of the AFM circuit:

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Old 02-12-2019, 05:56 PM
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Originally Posted by jmac321 View Post
i put a spade clip on and connected to the thermo switch on top of the thermostat housing, but im not sure if that is the correct wire or not (didnt make any difference). when the wire is connected to a ground you can hear the switch on the egr vaccum line on the rear of the valve cover. ill post pictures the next time i have a chance.
This indicates to me your vacuum lines probably aren't routed correctly.

I'm pretty sure this green black wire is the TSW signal, but don't take my word for it. Put your voltmeter on it and probe the location out at the ECU connector.
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Old 02-25-2019, 04:08 PM
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checked the wire continuity to the ecu on the green/black wire. i was getting continuity to more than 8 pins on the ecu. ill need to go through the wiring harness to see where its shorting out to the other wire. other than that i did notice rust on the ecu, meaning its been in some contact with water, does anyone know the ecu testing procedures?
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