Darkfire25

Anyone have any ideas what this problem could be?


It's correlated to the temperature. It has to be relatively warm outside (At the very least like upper 60s/low 70s and more likely if it's sunny) and the engine has to be hot too. So if i'm on the freeway going 70mph (and it's not too hot, I'm pretty much fine, but when you're stuck in traffic, that's when it starts acting up, especially. It gets progressively worse as the temperature outside increases. It idles rough (Like someone is very gently tapping the throttle) and if you drive it it will buck back and forth pretty hard. During the winter it was fine because it was cold, but I now need to address this problem. Also, I should note that the car runs and idles flawlessly otherwise. Had my oil changed today and told the mechanic, he said he thinks it's ignition related like the signal generator in the distributor or the igniter. I was thinking vacuum leaks myself, but he said the way I described it that's not what it would be. Any ideas?
Oh, and one more thing: A similar idle will happen after you start it when it's warm (When the engine is warm). Like if I go for a drive, shut it off, and then start it say 5-20 minutes later, it will idle low and fluctuate a bit, but goes away within 30-60 seconds

Here is what I have tested so far:

Ignition coil: It was out of spec. Primary coil resistance was supposed to be between .5-.7 ohms, it was like 1-1.2. So I replaced it with a brand new one. Didn't fix the problem

Igniter: Seems to be fine. The power source line voltage is just under 12V, same with the power transistor (They fluctuate from like 11.75V and up). I did the battery test (Where you hook up a 1.5V to the connector) and I got 5.8V (Supposed to be 5-8V) when it was cold. When hot (I got it to do the bucking problem for a little and then checked it), I got 5.4V, so it went down just a little, but still within spec. The FSM does not say whether to check hot or cold.

Signal generator: Possibly bad. The FSM also doesn't say whether to check it hot or cold. I get 168 ohms when cold. It's supposed to be 140-180 so that is good. However, right now I just got 196 ohms when hot. So I'm thinking if it doesn't say if it's supposed to be hot or cold, it's always supposed to be in that range, regardless of engine temperature, right? I didn't check the air gap for the rotor, don't have a feeler gauge on hand. Is that worth checking? I'm thinking that wouldn't be the problem since it only happens when hot.

And one more thing: Could faulty spark plug wires cause this? I noticed that for some reason, a previous shop installed these "7mm hi-suppression radio cable" spark plug wires (to fix another problem). Pretty sure this is some random aftermarket brand or perhaps one of those brands only sold to shops. It's not even a brand, it's just says "7mm hi-suppression radio cable". They're not old at all, probably like 3,000-4,000 miles. But I think I'm going to go to the dealer and get some OEM ones (Sumitomo I believe, the ones on it previously were dated Sumitomo 1998). Even if that's not the problem (Don't really think it is, but you never know I guess), I don't like cheap parts on my car, especially for things like spark plug wires, where the OEM aren't even that expensive.

Darkfire25

Here's another video, but the sound is muffled.

atcfixer

iTrader: (1)

Don't have sound on this pc, but a couple of things I could think of for possible things to check. First the cap, rotor, wires, and plugs can cause a lot of odd ignition problems, not sure if it would be directly related to what you're experiencing, but it's never a bad idea to replace them when you buy a car/truck (I'm assuming it's new to you).

Another thing that comes to mind, since it is temp based would be the temp sensors the ecu uses, the air intake temp (should be a mass air flow meter with intake temp built in for your car I think), and engine coolant temp (pretty sure the gauge and ecu has 2 different sensors, atleast 3.0L's I think are that way). Both should have a resistance test and the results should relate to the actual temp it's at. A lot of the time the engine one is taken at room temp, and boil water and check it for 212F reading.

For the coil tests, I'm almost positive the range is to cover hot and cold.

The pickup coil could be effected by the heat enough that too large of a gap would give a bad signal. It would likely miss when it acts up.

Could check the spark with either a spare spark plug or an actual tester and see if it has a strong spark hot and cold. Normal should be blue/white, weak spark is yellow/orange (lower voltage). Weak spark can be caused from wires, cap, rotor or coil typically.

Not really thinking of anything else off the top of my head. Good luck with the diag work.

Darkfire25

Thanks for the help. I didn't think about the ECU temp sensor. 22R-Es are the same as the 3.0L, separate sensors for ECU and gauge cluster.Those are cheap so I think I'll definitely try out one those, can't hurt anyways. The car isn't new to me, I've had it for over two years actually. But I am ordering some new OEM Toyota wires as well. It has pretty new ones (Less than 5,000 miles), but I think I've figured out the brand and it's some aftermarket brand called Xact (Found a picture of them and it says the exact same thing as the ones on the car right now).

I did once have a check engine code for the air intake temp sensor so maybe that could be it. I reset the codes, but it never came back again. Unfortunately, I don't think there is any test to check the sensor to see if it's good. You're right, by the way, it is located inside the AFM so that would mean a whole new AFM.

atcfixer

iTrader: (1)

The AFM does have a test process, lots of points to check resistance on. I wouldn't think it would act up with heat, but it's possible too (for the air metering section).

Here is a quote I saved for the AFM specs, your 22re might be a different pinout than noted for the 4cyl, since it was truck application.

Darkfire25

Would that tell me if the temp sensor in there is bad? Because I actually did test the AFM previously for this problem and everything was within spec. I guess for some reason I thought it was testing something else in the AFM.

atcfixer

iTrader: (1)

THA is the air intake temp sensor wire, E2 is the "ground" but it's a common signal ground instead of a body/negative ground. The rest would be the air flow metering readings VS and VC and I think FC + E1 is for kicking the fuel pump for engine running (connects whenever the flap is pressed in).

Darkfire25

Despite actually installing the new spark plug wires ECU temp sensor three weeks ago, I finally got around to testing it out. And I'm happy to say I think it's fixed. I just drove for about 50 mins in the city in 90°F weather. My guess is that it was the ECU temp sensor. Makes more sense since it definitely looked to be the original and I only replaced the spark plug wires because they were some aftermarket brand I'd never really heard of (I think they're specifically for auto repair shops to use), not because they were old. I hope it's not just a fluke. It can't be, it for sure would have acted up if it wasn't fixed. Thank you atcfixer for the help, especially since I actually didn't think of the temperature sensor causing the problem.

atcfixer

iTrader: (1)

Not a prob, glad my guess was accurate enough to fix it =).

Rebecca001

I have no idea.

Dicky G

have you tried taking off your tps sensor i had a similar problem on my 22re when the engine was warm it would buck in low gears but once im in 4th or 5th it would smooth out turns out my tps was just junk. Hope this helps