cpljenkins01

I have a 90 pickup with 3vze and during the summer it was running fine but winter is around the corner and the old yota is showing some issues. When I first start it it has always sputter a for the first couple mins of starting. Here resently it has been acting sluggish till I run it done the road even if I let it warm up first. Today I let it warm up and I went like 3 miles before it started to straighten out but still not the way it normally runs. Its getting worse. I'm thinking its my o2 sensor going bad cuz my air fuel ratio gauge keeps showing lean till it straightens out then it starts moving a little but still leaner than normal. I need some help before I go buying parts I don't need to replace.

rworegon

Burning or using any coolant? How do the spark plugs look?

cpljenkins01

Doesn't use any fluid spark plugs where change about 3,000 miles ago. Its hard to explain. If you start it up and drive it when its still cold it doesn't really do it. But sometimes I can feel the power lose and regain power back and forth till it warms up and it runs fine after.

cpljenkins01

This morning I didn't let it warm up and drove it to work and it ran a lot better but still feel a little power lose.

jennygirl

I would say check your temp sensors at the intake and coolant. IAT and ECT. I've been having issues with mine and the symptoms sound very similar.

The right air/fuel mix is heavily dependent on those sensors

Edit: might as well check the whole AFM while you are at it!

cpljenkins01

How would you test the sensors?

jennygirl

In the FSM, there are instructions describing the resistances one should find at given temperatures. You have to measure that resistance with a multi meter.

Additionally I like to measure the voltage at the ECU pins. Which, for the 22re at least, a lower voltage means higher temp.

In my case, I discovered my intake temp sensor was getting heat soaked- making for lean crappy idle on a warm start. I found this by measuring the voltage at the intake air temp sensor pin after shutting the car off hot. I found that the voltage for this particular sensor dropped, indicating that the sensor was reading a hotter temperature for the intake air until there was enough wind in the engine bay for the AFM to un-heat-soak itself and read the actual intake air temp- which smoothed out the idle and AF mix a few miles down the road.

I hope that helps

cpljenkins01

Is the intake sensor built into the vafm?

cpljenkins01

By fsm you mean a full service manual such as a Haynes manual?

jennygirl

Yes and yes. Also you can find where it hits the ECU at the THA and THW terminals on the ECU (just stick a multimeter lead into where the wire goes into the connector and ground the other end). That is the voltage I am talking about.

I'm not sure how in depth the Haynes is, I like to use the Toyota FSM

cpljenkins01

Ok I will have to check and see if i can find the info I need

cpljenkins01

Ok checked my temp sensor and it is working right. Had another incident with it. I got in and drove 20 miles never gave it time to warm up and it ran normal. Except when I got to my location left it run for 7 mins and shut it off. 2 mins later hoped in and it had no power again till I went 10 or so miles back home then it started to wake up again. It never even had time to drop from operating temp and fuel air ratio did not move off lean till I went around 8 miles

rattlewagon

Is the check engine light on? Some times even if the light isnt on there may be codes stored.

Can you get a video of it running rough?

Did you end up testing the 02 sensor?

A Hayes manual is not a Factory Service Manual (fsm) There are links somewhere around here on where to download them (check the stickies) . The Hayes/chiltons are good, but they wont tell you how to test the 02 sensor, just replace it. Its worth it to get a FSM.

cpljenkins01

No code band not running rough just dont have much power but I will have to check and see on how to check the o2

clok

iTrader: (2)

are the two temp sensors your talking about exh. Temp sensor that screws into the side of the intake plenum , and coolant , the coolant sending unit that screws into the intake manifold towards the back of the motor ? These are the two sensors that are heavily dependent on the right air/fuel mix ?

cpljenkins01

If I set and let it adle for more than 10 mins I won't have power but if I just get in start it and drive its fine.....

the171

I second making sure there is no stored codes. The cel system is pretty good for finding a faulty sensor.

If there is no codes, the EFI system should be in good shape. From there I would replace the fuel pump, and check the related wiring. Check/improve engine grounds. Check batt volts. Check cap/rotor. Check resistance on the distributor pickup coil, and the coil itself.

saurkraut

Fuel filter would be a good thing to replace as well. I've had vehicles run lean because they weren't getting enough fuel due to a restricting and almost plugged filter.

cpljenkins01

Found out my problem I believe finally coolant temp sensor

skypilot

iTrader: (1)

Ahhhhh.... The sensor on the back of the block! Glad you found it! Those are a notorious point of failure.