SWMItoyota

I'm a new guy here and I need some help!

I've tried searching the forums for this problem and haven't come up with anything.

Here's the deal, I just purchased a '91 pickup 22re 4x4 about a week ago and I'm having problems getting the engine to stay at normal operating temperature.

On the test drive everything was OK, the engine warmed up to normal op. temp. and stayed. About an hour into the drive home, (I live in Michigan, bought the truck in Pennsylvania) I noticed the temp. dropped to cold and it stayed there. Also the idle characteristics went haywire, started running rich.

Got it home and figured the thermostat stuck open. Took it out tested it in boiling water, it works fine, replaced it anyways, 195 deg.

Took the intake tube off the throttle body and noticed the previous owner had once put tape over the idle control valve hole, but it looked like it had come off and got sucked into the engine. Covered up the hole and it idled back down to normal. Figured the idle control valve was stuck open. Took it off and tested it in boiling water. It worked fine. Put i back on assuming the coolant temp. wasn't getting warm enough to close the valve.

The fan clutch was stuck engaged so I took it off and threw on an electric fan with 185 deg. kick on.

No codes by the way.

Tested the antifreeze mixture, previous owner had filled it up with complete straight, tested at -60, drained some of the green, added water and got the mixture to around -10. At idle the engine will warm up to just about normal op. temp. and I have decent heat through the blower. When I hit the road, drops back down to cold.

Put some cardboard in the radiator. Still runs cold as can be going down the road. Still has idle issues and runs rich due to the cold coolant temp, I think...

I'm stumped...
Am I missing something?

Has anyone had this problem with a 22re running cold?
How can I get this engine to stay at normal op. temp.?

Any input would be greatly appreciated. Thanks!

My99

Doesn't make any sense. Only way I can see that happening is due to a thermostat that is malfunctioning. Did you test the new one before you put it in? Assuming you installed it right-side up.

RustBucket

iTrader: (1)

Go ahead and replace the coolant temp sensor. Aftermarket ones are like $15. I got one from AutohausAZ for $35 that is the same manufacturer as what you would get straight from Toyota but like half the cost.

Sounds like you know what you're doing though, you already eliminated a lot of potential problems.

My99

You can do that, but it's easy enough to tell if it's your temp sensor or if indeed the coolant is that cold & temp sensor is reading correctly. Go drive around on the highway for about 15 minutes and if you're able to feel hot air out of your vents (heater on, of course) and your coolant temp is showing full cold, you have an issue with the temp sensor. If it's blowing cool/cold air after that long on the highway, sounds like the coolant temperature really is low and somehow getting circulated (bad thermostat).

BTW, what makes you think it's running rich and what are the "idle issues" you're getting?

SWMItoyota

I did not test the new thermostat before I put it in... I suppose I could, or should have tested it prior to installation. However the top rad. hose stays cold until the thermostat opens and it slowly warms up.

Today I talked to some guys I used to work with, one of them suggested I burp the cooling system in case air pockets might be causing the cold running and idle issues. I thought this may work since I do have a gurgling noise coming from around the heater core and strange temp. changes from the blower. I've had air pockets in previous vehicles and it usually caused the motor to run warmer than normal, but since I'm not all to familiar with the flow characteristics of this motor, it was worth a try...

I parked it on a slight incline and jacked up the front end, ran it until the thermostat opened popped the rad. cap and noticed the coolant was flowing well. It was a little foamy, but not to bad. Topped off the coolant and drove again, unfortunately with the same problems, pulsating high idle, cold engine.

Also, keep in mind the average outside temp. here in Michigan right now is around 30 deg. F. Is it just too cold outside?
Should I try a different rad. cap? Will that make a difference?
Should I create a small resistance in the cooling system flow to keep coolant in the motor longer so it can warm up more?
Are the 22re's naturally cold blooded motors?

I am going to try RustBucket's idea and get a temp. sensor since it's cheap. It does blow warm air when the gauge reads cold, sometimes, it's very inconsistent. That was one of my next things to try.

My99, on the way home from purchasing the truck my dad was following and had to fall back due to fuel fumes from the exhaust, it was giving him a headache. It was black around the tailpipe. The oil was grayish and thin, like gas may have gotten mixed in. Gas mileage was HORRIBLE. My dad's V-10 Ford got better mileage. I checked the O2 sensor, it looked like it needed to be replaced. That may be the reason it's running rich. I assumed since the engine isn't warming up properly, the computer is making it run rich, or, the cold start injector is spraying all the time. But I don't too much about the cold start injector system.

If I fix the cold running issue and it still runs rich, I will go for the O2 sensor. But that's the least of my concerns now.

My dad and I have been racking our brains for the last couple days, he's a retired mechanic. I thought it was going to be an easy fix. I just don't get it, never seen anything like this problem before.

Thanks for the input so far. I really appreciate it. I thought people were going to think I was crazy. I might be... but this PROBLEM sure is!

Any more tips would be great. Oh and if by some miracle I fix this issue you'll hear about it right here.

My99

22RE should warm up fine. Mine is much slower to warm up than more recent machines, but 10 min of steady driving in the mornings here with 20 degree temps can get it warm "enough". More like 20 min until it really gets to operating temp.

Burping wont be the cause of your problem. May cause a idle rev issue, but not these other problems.

Based on what you are describing, these symptoms are not just as a result from a faulty temp sensor or faulty thermostat.

I'm starting to suspect something with your mass air flow sensor (intake) and or TPS. Double check the plug on your mas air flow sensor. Do a search and download the FSM. It will show you how to test the mass air flow sensor.

Not saying your coolant temp issue is not an issue, but these symptoms sound extreme for just a faulty temp sensor. O2... Again, not convinced this could be re culprit of such extreme issues.

I'd check to ensure both the TPS and mass air flow meter are working okay and then start looking into other issues - O2, temp sensor, etc.

BigBluePile

iTrader: (3)

Just to clarify, 22R-E's do not have MAF's but have AFM's....totally different.....

sam333

I had a similar problem with mine.

I knew my thermostat was stuck open because the engine temp gauge never got much above cold( 50's-60's outside).I got heat out of the heater core, but not much.

This started about a month ago , but I did not have time to replace it before I took it up to the cabin and temps were in the 20's. I had no heat there, luke warm air at best , not even enough to defrost.

Truck ran very rich. Coolent temp sensor told the ECM that the engine was always cold( which it was) and richend up the mixture accordingly.

I got about 9 miles to the gallon on that tank.

When I got home I pulled the plugs and they were covered in soot. I replaced my thermostat,( which was stuck open) the temps returned to normal and no more rich running.

If you want to know whats really happening with your cooling system , buy an IR temp gun, it will tell you the temp of every part of the engine, radiator and what temp your thermostat opens at.

Do you still have the stock radiator( larger aftermarket)? Some of the after market thermostats are junk( not accurate/ dont close and open reliably).

My99

Thanks for the correction, it should help the original poster in his searching unfortunately I was responding from my phone and didn't have the luxury to seek out the technical term and it's been a while since I worked on mine.

SWMItoyota

Yeah I need to do some more testing. The VAFM is a dreaded "junk yard special" with those yellow markings that most yards put on before they sell them. I will get some specs and test it. I will also test the TPS. The previous owner said he had tested it and had played around with the idle, so that may have messed something up.

The radiator is not factory, but it appears to be the correct size and fit. Even if it was a larger unit, covering it up would possibly create some results. It did not.

I do have an IR temp gun. I will do some testing with that at various points on the hoses and engine.

Maybe the after market thermostat I put in IS faulty? I know it's opening, but maybe it's opening too soon? I need to bench test it again in boiling water with a separate temp gauge to see exactly what temp it opens.

I haven't compared rad hose pressures from cold to hot, or from when the thermostat is closed to open. I will test that as well and post my findings. It's morning right now and maybe after work today I'll start testing some stuff...

I was hoping all of my issues were being caused by a cold running engine, but it may be more than one problem. I'll get it figured out in time.

This site is great! I'm glad I decided to join, the info I have received so far has been a big help! Thanks again everyone!

I'll keep you posted on what's going on.

RustBucket

iTrader: (1)

This may be a dumb question... but when you've been driving for a while and the temperature reads "cold" and the truck is running/idling poorly, if you pop the hood, are things actually cold? Mainly, the upper rad hose? If the motor IS hot and the computer THINKS it isn't, then we know we're talking about sensors.

The sensor for the gauge ("temp sender", middle of intake manifold) is different than the one for the computer ("temp sensor", front of intake manifold) and also the sensor that tells the cold start injector when to run (also front of intake).

SWMItoyota

No I haven't felt the top hose after driving. I will do that as well as get some temp readings from the IR gun. A sensor may be the reason it's running rich, but the idle either pulsates if I adjust it down, or gets way to high if I adjust it up. I need to try covering that idle control hole in the throttle body again to see if that fixes the idle like it did before.

Since the idle is mainly controlled by coolant temp, I am convinced that the coolant isn't getting warm enough to close the idle control valve, or, the valve itself may be faulty. Even though I did bench test it.

I read in a different thread that someone just sealed up that idle control passage with JB weld or something. I don't want to do that due to the climate I live in. Should I try and snag one from a junk yard and try that to fix my idle problem? Is it worth trying to find a NEW one?

I am going to try and tackle the coolant temp and idle issues first. Then move on to the rich running issue.

Once again, I'll do some more testing and record my results.

skypilot

iTrader: (1)

Mine eats thermostats. Once a year or more, sensor is fine. Just flush the system and keep putting thermostats in until you get one that stays hot. The aluminum block seems to keep things cool even in summer, but I use the V6 radiator also.

My99

Vafm page from the service manual. http://personal.utulsa.edu/~nathan-b...33volumeai.pdf

Indeed, the upper radiator hose (and top of the radiator) should stay cold until the thermostat opens. When this happens the hose should get hot really quickly as 195 degree coolant comes flowing through when the thermostat opens. If you feel that it is warming gradually while your heater is still pushing out cold or just barely warm air from the vents, this would indicate a faulty thermostat opening too soon or stuck open.

BigBluePile

iTrader: (3)

so they're the same.......... ....? But they're not REALLY the same thing physically are they?

BigBluePile

iTrader: (3)

Doesn't one utilize a mechanical means to measure air flow whereas the other electrical?

sam333

You dont even have to pull the thermostat to test it, just run the engine up to temp while pointing the IR gun at the thermostat housing and hose . You will know when it opens by the temp drop.

SWMItoyota

Well I think I fixed the problem.

It's embarrassing posting this but I'm doing it anyways.

The thermostat seal was bad...

I took off the housing to try another thermostat and the seal was damaged. Coolant was getting past. It all makes sense now.

I got a new seal put it in and burped the cooling system again. The engine reaches normal temp at idle, and I have great heat. Also my idle is back to normal. On the road temp drop slightly but everything else remains good.

I fixed it last night so I'm not sure if this restored my fuel economy, but we'll see. The exhaust doesn't smell rich anymore, so I'm hoping for the best.

I CANNOT THANK EVERYONE ENOUGH FOR TAKING THE TIME TO HELP ME OUT. Even though it was a simple problem, I was convinced it was something deeper, and I overlooked a $1.50 seal.

When my vehicle is running horrible, I feel horrible.

I'm sooooo happy my truck is running good!

borincano

I have a 95 4runner with the same problem. I changed the coolant temp sender, and went to change the t-stat and noticed it didnt have one, so i thought i just found the problem. Two t-stats later and no joy. The first t-stat was 182 and the second 195 since I thought maybe it would make the engine run hotter. The engine warms up at idle to operating temp in about 10 mins and will stay like that at idle as long as the engine is running. But as soon as I start driving, it starts droping until it no longer would shift past 3rd gear. Oh, and I did test the first t-stat thinking that it was faulty but it tested good. I know i installed a good seal but could it have gotten kinked or damaged while intalling the t-stat? what are the odds of it hapening twice?
Recomendations would be greatly apriciated!
Thanks!

toyota4x4907

Once you stop driving, like at a stop light or just stop and idling, does the temperature rise back up?

Could be the fan clutch sticking, leaving the fan on while driving so it cools the engine too much.....