My 87 4Runner 22re idles very low 400-500 on a warm start. After a little bit of driving it goes and stays right where it should be.

I have done my research and found multiple threads on this issue but have not come up with a real fix or a cause of this problem. Lot of "I think it's better but still does it" or "it helped a little bit" I'll take any ideas tho.

This is currently the only issue I have with my rebuilt 22re and I've put way too much time and money into it for it to not run like it's supposed to. Lol then again, not a huge issue but I would like to correct it.

 

I drove about 70 miles, went to take care of some paperwork for about 20-30 minutes. Knowing my 4Runner does what you described, I took a pin and a wire to ground with and when it idled low, I shut it off and grounded the FPU switch and it fired right up and idled around 900-1000 RPMs. I let it idle for 20-30 seconds and pulled the wire and it idled normal. I have since wired in a toggle switch and can operate it manually. It's the switch above the thermostat, it goes to ground when the switch makes. In the research I've done there is a service bulletin that calls for a different part number switch to improve this, but that part number is no longer available. The bulletin is listed as Vol. 10, Eng. No. 11. It's working good so far.

 

What's working good so far?

 

I wrote that I wired in a toggle switch to operate the FPU manually. You can try it by jumping it to ground while it's idling low. I think it is worth a try.



Here is a picture of the Fuel Pressure Up switch (FPU). On the wiring diagram it's called Water Thermo S/W (4WD)

 

Just saw this. Thanks for the pic, I may give that a shot!!

 

I would so love to lay this one to rest.

If this is the solution, this should be stickied.

Unfortunately for me I removed my FPU VSV along with a bunch of other stuff. Thinking about adding my own custom VSV with a manual switch.. Hmmm.

One can also test this by simply pulling the vac line from the VSV that goes to the FPR, and capping it at the VSV.

Or in my case (FPU VSV deleted), pulling the line from the plenum that goes to FPR and capping it at the plenum to prevent vac leak.

 

Still have not got a chance to check this. Gonna give it a try here in a min. Now my donor 1989 4Runner does not have the FPU on the thermostat housing... Where would it be in the 89?

 

This is the TSB: http://www.toyotapart.com/22R-E,_22R...T-EG011-89.pdf

Note that not all 22re's have the FPU; I don't have the page that lists the applications.

Seems like a somewhat complex fix, but they wouldn't issue a TSB unless they thought they needed it.

 

Thanks scope103.
Grumpin mentioned you couldn't get them anymore?

 

That's what these guys say: http://www.toyotapartsdeal.com/oem/t...428-26020.html

Have you tried the "jumper wire" technique to see if that is actually your problem? If that is really the problem, and as "ghetto" as it sounds, a toggle switch will get you around the lack of replacement part.

 

Grumpin can you send me a picture of you toggle ground setup?

 

It will be a day or so. Actually busy this weekend. I soldered the wire and ran it through the firewall to the toggle switch, then to a ground behind the left kick panel. I used a hole with a nut behind it instead of stacking it under the one that is there.

 

i know this might be a dumb suggestion but i had a problem with rough idle when warm, and i just had to change my pcv valve. Runs great hot now. its probably not something that you overlooked but you never know.

 

Was it rough idle when warm or was it rough idle at warm start? Cause mine idles perfect when warm. It's only acts up (or down I should say lol) when I frist start it up when warm. It'll idle at about 400-500 until I start driving it goes right back to where it should be 750-800

And thank you I will check that regardless, no suggestion is a bad one in my eyes

 

I have a theory about this issue. I recently had it, and it is resolved. If it was just a matter of changing out the sensor because of the temperature rating, these problems would have been evident for you in the 80's. My theory is that the operating temperature and the heat soak from it has changed on your vehicle recently. Perhaps a plugged radiator or coolant passages. Maybe a water pump or radiator fan clutch. It doesn't seem to take much to create this issue. Mine was fixed by a new radiator. No new switch, no grounding it, no nothing. Problem solved.

 

hexrain, i believe there are no dumb questions or suggestions. Good point on the PCV valve, I did check it. jgod, another good point, I did check the coolant system. Also it did happen in the 80's, there is a service bulletin. http://www.toyotapart.com/22R-E,_22R...T-EG011-89.pdf I do not use the ground switch unless I have to. It happened today and I flipped it on for a bit and all was good. I've also noticed something else. After a long drive on the freeway and I would pull off and get gas, shut off maybe 5 minutes, when I started I would get a surge, up and down maybe 500 RPM. It hasn't done that since I took the switch out of the system.

 

Believe me, if this problem comes back I'll be grounding it for sure. It's horrible. Sitting at a stoplight trying to rev it up to stay running. So frustrating.

 

These symptoms exactly

 

My 3vze does this too. It's not an all the time issue and seems to occur a little more when its cold out, but the problem is so intermittent I haven't bothered with fully troubleshooting...

 

jgod, jennygirl and RSR, I have never had this happen at a stop light, or while it is warm and running. That service bulletin is exactly what it does. After shutting down and sitting for 15-30 minutes. On start up it idles real low, 2-300 RPM, may even die. I'm thinking these may be different issues. Worth a try of course.