How is the idling behaving? With cold or warmed-up car?

From the chart, it appears at 120F, resistance should be 0.9-1.1 K-ohms or 900-1100 ohms. As a test, add a 1000-ohm resistor in series with that temp-sensor to mimic correct response and see if the car idles properly. If so, then the problem is the sensor. If not, it's somewhere else.

 

If the ohms are correct then what causes temperature gauge to not work or ecu, pcu

How measure obdII, ecu or dash temperature gauge for Toyota Camry 2.4le 2004

Toyota Camry 2004le 2.4l temperature gauge on dash works intermittently and how does fuel mixture a) affected by temp sensor b) by fault in connection to c) ecu or obdII d) mil sensors catalytic converter and evap not ready to have emissions test ?

 

Car starts, then dies after a 10-20 seconds seconds.
I put the the metal end of the sensor in 120 degree hot water and did the measurement.
All ignition components are new . Ignitor, coil,wires, Copper plugs, distributor, cap and rotor.
New fuel pump. Pressure is 40psi.Changed all hoses when I was down there. Also new fuel filter.
Checked hoses for vacuum leaks. None.
Ignition timing is dead on. Cam/Crank timing is dead on too. I'm stumped.

 

Hmm, I don't think bad temp-sensor would cause it to die after 10-20s. If anything, it may cause difficulty starting, but will then run OK after warm-up. Maybe test the sensor at 0-F and 200F?

Another approach to inserting resistor in-series with sensor to mimic proper signal is just to bypass the sensor and insert a pot. Rotate the pot to a position with the resistance you want and plug it into the connector.

Can you attach a fuel-pressure gauge to rail? I wonder if fuel-pressure changing after 10-20s.
Also monitor intake-manifold vacuum since the FPR is tied to manifold-vacuum.

 

A coolant temp sensor should last the life of the car, because there's nothing in one to wear out.

 

They do wear out, as the resistance test proves and DannoXYZ has explained. I'm just wondering if it is causing the idle issue, as everything else seems to be within spec.

 

NTC thermistors used in auto applications do wear out over time. Even though they don't have large moving parts that wear mechanically, they do degrade at the microscopic level. The substrate is typically a ceramic or polymer lump that contracts and expands with temperature changes. This changes the resistance of the lump from one side to the other. The repeated expansion and contraction introduces cracks into the material and causes it to slowly turn to a dust. This obviously will change its electrical conductivity and resistance readings.

 

Another less likely possibility is the air-temp sensor. Again, it would mainly affect starting and would run better after some time warmed up. Easy enough to test at the AFM's connector.

Any codes?

Try disconnecting the upstream O2-sensor as well and see if that affects the dying at 10-20s.

 

I believe the air temp sensor is in the AFM, which is also new.
Only 1 02 sensor on the down pipe just after the turbine exit. I'll try that.
Checked for codes 1st thing. No codes

 

If it tests bad....

I have advised many owners on electrical issues and so many, many owners can't accept that if a electrical part tests reveal it doesn't meet spec, IT'S FAULTY!!


There is no if and or butts, you replace the defective part.


No offense intended Jedi. I personally know your a good dude, I just don't see the point of not making the repair.


What am I missing? Why the hesitation?

 

I have advised many owners on electrical issues and so many, many owners can't accept that if a electrical part tests reveal it doesn't meet spec, IT'S FAULTY!!


There is no if and or butts, you replace the defective part.


No offense intended Jedi. I personally know your a good dude, I just don't see the point of not making the repair.


What am I missing? Why the hesitation?

Oh,no hesitation. As soon as I found the part faulty, I ordered it from the dealer on line($58.28 shipped from Toyota Parts Barn). Came today.
I'm just wondering if its the cause of the idle issue.
When something goes wrong, I fix/replace/repair it. I love my 2 too
much.

I'm interested in your opinion on this issue though..
I wonder if the sensor is telling the ECU the engine is over heating and the ECU is shutting it down.( if thats even possible)
Don't know. Thats why I'm here.

 

If there is no improvement after introduction of the new part I'd fall back to the troubleshooting section of the Fuel Injection part of your service manual. Sounds like a fuel starvation issue to me.

Don't rule out that you could have 2 issues at the same time. You've solved one and may have to find another.?

CEL codes are displayed by the ECU when it detects a electronic part is giving defective outputs DURING OPERATION. If after the new sensor replacement it doesn't start there could be more electronic issues that won't be displayed which is why going thru the troubleshooting checklist may be the only way to uncover the problem.

Happy hunting Jed.

 

I have noticed one thing, that 2 of the pick up terminals inside the distributor cap have scrape marks from contact with the rotor, while the other 2 are untouched.

 

Ovalized cap? Strange. Any problems that causes would be full-time, not after 10-20 seconds.

How's the car running with the new coolant temp-sensor?

 

Ovalized cap? Strange. Any problems that causes would be full-time, not after 10-20 seconds.

When I 1st put that cap cap on(and rotor) it ran for a few minutes, then died.I got it from Rock Auto. Don't remember brand name. Japanese, but I don't think OEM.

How's the car running with the new coolant temp-sensor?

I really haven't had the time to mess with the car. I've been short handed with cooks for almost 2 months now. Finally hired one, and he's been out for a week with a torn rotator cuff.
Works been kicking my butt working 6 & 7 days/week.
He's suppose to be back next week. I'll get back with you guys with the results. Gonna buy a new OEM cap and rotor from Toyota Parts Barn.

 

While you have the rotor off grasp the dizzy shaft it sits upon and try to wiggle the shaft. In my Mark1 cars there is a chinzy bearing just under the bottom plate that may/could/might be a problem. Ya never know.

An Ovalized cap is a possible what with the greedy American business owners using cheap $0.50 per hour uncaring Chinese labor.

 

Distributor is new. I did check it for shaft play, as per your advice.. Solid.

 

Could it be something else completely? say a clogged IAC??? crank sensor? I defiantly think you have a wrong cap tho, you should get your old one and reinstall it see if it corrects the problem IMHO

 

Already tested AIC. It checks out.
This engine doesn't use a crank sensor.
Already threw away old cap. It's the correct cap, just defective.
Ordered new OEM cap. Should be here in a couple of days.

 

Testing the IAC is one thing, did you clean it? and I know the feeling of throwing something away and then needing it. So did your cap come in? problem solved?

 

Installed new sensor, new cap and rotor. I have idle now. Set timing.
Idle is fine, but stumbles some with giving gas.
Acts like starving for fuel. Though, I have new HiFlow fuel pump and 40psi fuel pressure.

 

Ah, may be FPR issue?

Test pressure-differential with vacuum-hose at FPR connected and disconnected.

That differential should be the same as intake-manifold vacuum. For example, if manifold-vacuum is 20-inHg, that's 10psi. So fuel-pressure with hose disconnected may be 45psi and connected is 35psi. Although I have seen FPRs that are clogged and not flowing enough fuel regardless of pressure. You can test by collecting injector flows into cups and measuring volume.

 

Had a whole day off this week. yay!
Tested fuel pressure again as per your advice. You were right !
Installed OEM FPR, running much better, but not as well as I'd like.
I can rev it to 35k rpm's , sitting still, but it's not as smooth as it should be. Starting to suspect injectors.
I'm not gonna have much time off until after labor day. I will test injectors then. or I might just replace them with new ones. They are, in fact, 24yrs old.

Thanks Dannoxyz

 

You're welcome! Good job on tracking down these multiple issues.

1. Try narrowing spark-plug gap down to 0.025"

2. Measure impedance of plug-wires and inspect them in the dark for arcing.

3. Measure impedance of injectors. If they're within spec, they just need cleaning. RC-Engineering does a good job. MrInjector.us has good reports, I haven't used them personally, and plan on setting them a batch.

4. Measure voltage at injector connectors. Remove all injectors. With key ON, there should be +12v on one terminal, nothing on the other. With probe still connected, wiggle wires where they enter the connector. Shouldn't be any variation of voltage or dropouts.

Good luck!

 

You're welcome! Good job on tracking down these multiple issues.

1. Try narrowing spark-plug gap down to 0.025"

2. Measure impedance of plug-wires and inspect them in the dark for arcing.

3. Measure impedance of injectors. If they're within spec, they just need cleaning. RC-Engineering does a good job. MrInjector.us has good reports, I haven't used them personally, and plan on setting them a batch.

4. Measure voltage at injector connectors. Remove all injectors. With key ON, there should be +12v on one terminal, nothing on the other. With probe still connected, wiggle wires where they enter the connector. Shouldn't be any variation of voltage or dropouts.

Good luck!

Set gap to .025 as you suggested. idle is smoother, but will not hold higher RPM's for more than 15-20 seconds and then it seems to be running out of gas..
Going to order remanufactured injectors from GB manufacturing.
Are you familiar with this brand?

 

I had already performed tests 3 & 4. And it's within specs. I did find exposed wire on injector terminal #1 and rewired it. The others were visibly OK. I'll do the wiggle though. Wiring is old and I will end up having to rewire the whole engine bay, I'm sure.
Toyota recommends .032 spark plug gap, but since I'm running 18psi of boost, I use .030 as recommended by some guys who run hi boost to compensate for the extra fuel and wetter environment in the chamber. But I will try it.
The plug wires are new, but not OEM, so given everything thats happened, not trusting the brand.
The cap was new(not OEM), but faulty. The FPR was new(not OEM), but also faulty.

So I will check that too.

 

Haven't tried GB myself, but haven't heard anything bad about them. Do they make injectors now? I thought that they sold rebuilt OEM injectors.

Seems like you still have the 10-20s issue. What were your fuel-pressure readings and did they change after 10-20 seconds?

 

They sell remanufactured injectors.

I was using a new FPR from RockAuto. Fuel pressure was in spec at idle. But after a few seconds after turning off engine, pressure fell to 5psi. I put on an OEM FPR, pressure was 40psi @ idle. After shutting off engine, pressure remained at 32psi for 10 minutes , til I disconnected test equipment.

I can rev the engine up to 3k rpm,fuel pressure remains a constant 40psi, but after 7-8 seconds, engine begins to run rough, stumble. It acts like it's running out of gas. I suspect injectors just can't keep up.
Your thoughts?

 

Hmmm, i still feel like there's some data missing...

1. So when the 15-20s stumble occurs, the fuel-pressure maintains steady 40psi?
2. Does it idle OK past 15-20s? Or does it stumble as well?

I've never seen a time-based clogged injectors before. Being digital devices with fully ON/OFF behavior, they always cause a reduction in fuel flow any any duty-cycle. A 1ms pulse-width at idle will have -25% reduction due to clog as well as a 3ms pulse-width in mid-range. I suspect something upstream from the injectors. If fuel-supply is sufficient, that leaves the control-signal from ECU. Is there a way you can read the duty-cycle of the injectors? The older SUN tachs have a dwell feature for old points ignition that can display injector duty-cycle.

What about fuel-pump relay? Can you measure voltage at pump itself and verify that it's switching from low-voltage operation ~9v to full-power? You should be getting full voltage at pump when it switches.

 

Idle is Fine. I did find an exposed wire in the #1 injector terminal.Fixed it and the engine revs to 3Krpm for 40-45s, then seems like it runs out of fuel. I let off the throttle and it goes back to idling fine.
I have an old Craftsman engine analyzer with a dwell tach on it. Will that work ?
It has new OEM fuel pump resistor pack .
Not sure how to measure fuel pump voltage. It's in the tank.

 

Yeah, the Craftsman gauge's dwell function should work. Connect in parallel with the injectors.

To measure pump voltage, trace wiring close to pump. Then pierce the wiring with hook-probe or sewing needles to measure voltage. I think it should increase to full voltage before 3000-rpms.

Also disconnect O2-sensor plug and monitor its voltage directly. Does it change at after 20-40s?

Lastly, monitor AFM voltage. What does it read at idle? And when you rev to 3000-rpms? Does it change when you have the stumble?

I still suspect it's some kind of ignition related issue. There's temporary codes that may not get stored in the ECU. After it does the stumbling, don't turn off the engine. Jumper the diag-port and see if it flashes any codes.

 

checked for codes while engine was running. No codes.
tested voltage for NEW fuel pump. 8.5 @ idle and only 8.65 when revving to 2500-3000rpms. What would keep it from achieving 12+ volts?

Fuel pump resistor checks out. Relay?

 

Coolant sensor shouldn't affect the engine from starting.

 

Thanks, but that has already been ruled out.