nate2002

My 87 4runner still is getting hot. It seems to only overheat when for some unknown reason it idles up to between 1500-2000 rpms. Could it be that it is idling up to try and cool it off which would mean I am thinking about it backwards? Instead of idling up causes overheat, overheat causes idle up to cool down? Does the 87 yota have this kind of brain? I checked the timing to see if that was why it was overheating and I found out that it is advanced A LOT!!! I was looking for the timing mark with my light while it was running and it was 15-20 degrees advanced. So i loosened the thing and started turning it to retard it but almost immediately i could tell it was retarded to much. So the timing is where it should be according to how it runs but not according to the mark. Any ideas on that? Could it be a part of my problem? Is there any modification to engine that could have been done before I got it that requires the timing to be set that much more advanced? I am almost sure its not REALLY advanced that much because it hardly pings and if it was REALLY advanced 15 degrees more then spec I would imagine it would ping like crazy!?!?! Thanx for the input in advance!

rimpainter.com

OK, you need to slow down and stop turning knobs and adjustment screws.

Let’s start with the cooling problem.

When you shut down the 4Runner after a drive, can you turn the cooling fan by hand?

When was the thermostat done last?

How much coolant is in it? (check this cold obviously)

How about the water pump, when was it changed?

When was the radiator cap last replaced?

Let’s take it from there.

nate2002

it has a new fan clutch if thats what your getting at. I'll go take it for a drive and see if i can turn it tho. I just replaced the thermostat/no difference. Coolant is full. I do not know about the water pump. I thot about replacing it and even bought a new one but ended up not doing it and returning it. Altho it looks new and was told by the previous owner that he replaced it. I am not sure what can go wrong with the radiator cap but i dont know if it is new or not, altho i do know for sure that it is holding the pressure! Also forgot to mention that the temp gauge will jump up and down occasionally. Sometimes the gauge will say its all fine but i can hear the huge water pressure pushing water out the overflow when i stop which means its really got to be hot. I also replaced what i at least thot was the temperature sender. It screws straight up and out and only had one wire attached to it and the replacement looked similar enough and fit so i put it in. Dunno if theres more then one or what. I also noticed when i filled my gas tank that when i took off the gas cap after driving around i had to catch it in order to not have it fly away from the truck....is this much pressure normal?

bulldog-yota

Any mods done on the engine?

Start as 96 Runner suggested and check all the components of the cooling system and make sure they are fine. Is it loosing any coolant? If you can try to swap some the common components with known good ones, like the radiator cap. First make sure your cooling system is A OK.

Also in terms of tuning, I would recommend that you go to factory spec on timing, etc. Also check all your vacuum lines, for cracks, etc. Does the 87 use vacuum for timing advance? If it does cracks or breaks in the vacuum line cause erratic idling, sometimes people adjusts the timing a bit at idle to compensate for the lack on advance from the vacuum. This can lead to all sorts of idling and tuning problems. But first check the cooling system.

nate2002

cooling system seems ok, water is definitely circulating well. As far as factory spec for timing.....YA RIGHT! I parked it and havnt drivin it since i did that because I couldnt go up hill with it at factory spec timing. It wouldnt go!!!!! Also, i wouldnt really call this eratic idle....well in a way yes but its so much of a idle difference change that it goes from 800 to 1800 rpms...1000 rpm difference! And it usually stays that way until i drive for a few minutes then idles back down. Or sometimes if i turn it off it will idle back down when i start it back up and even sometimes will still be idling high when i start it back up.

rimpainter.com

You must have a problem with the temperature sending unit. Somehow this part seems to be telling the vehicle it's hot when it's not, and vice versa.

I know you said you just replaced it, but that also scares me.

BTW: I would never adjust the timing if you could not get the idle to settle down. You will never get it to spec that way.

Focus on the temp sending unit again. There has got to be something with that.

How did you know the previous unit was bad?

nate2002

i didnt know it was bad....just the needle jumping quickly from hot to cold gave me an idea some kind of temp sending unit wasnt right. It still does the jump tho after replacing the unit. Apparently according to the manual there is more then one temerature sensor on this rig tho. Do you know anything about that?

rimpainter.com

It would also help to know what engine we are talking about...

(I am guessing 22re)

nate2002

yes sorry I have the 22re.

SoCal4Running

Have you checked the TPS?

Are you grounding out the check terminal before adjusting timing?

nate2002

how do you ground out the check terminal? Thot about the TPS but dont know how to adjust it.

AgRunner06

According to my manual, it's the same for the 22re as the 3.0. You have to jumper T and E1, or TE1 and E1 on the diagnostic connector which is located near your fuse box. Then the check engine light will flass constantly if you don't have any codes. If you do have codes, it will flash the codes to you. You really should fix your timing and then go from there.

I would go ahead and replace the radiator cap if you are having overflow when your temp sensor is reading normal.

As for the idle problem, I had a problem very similar to that. It's on a different motor but the same principle. I took mine to the dealership and a tech spent almost 3 hours hunting it down. It turned out the throttle cable was adjusted too tight. Sometimes when the vehicle was hot it would idle at almost 2K rpms and sometimes it wouldn't. Sound familiar? Sometimes I could get it to come down if I revved it really high. It usually occured whenever I started the vehicle after it had been sitting for short period of time (like after I made a run into a store).

Let us know what happens after you adjust your timing.

Birdman

WTH!!!!!!

SoCal4Running

You have to ground out the check terminal when you time your engine, this disables the computer control of the advance so you can set Base Timing which is what is on your underhood label. If you dont ground out your computer you are doing it wrong.

Hey Birdman I used to live around Santa Cruz. I loved that place, but now down in Northern Mexico (San Diego) :cry: