Engine Cuts Out and In

[tbryanh]

Engine Cuts Out and In

This is a followup post to https://www.toyota-4runner.org/3rd-gen-t4rs/316455-engine-stutters.html

The engine in my 2000 V6 2WD 4Runner OD 180K cuts out and in when driving on the freeway. Mostly the car cruises good and has good acceleration, but it has its moments. It is a single event (does not repeat itself 2 or 3 times in a row) that goes away quickly. There is no CEL light or pending codes.

Here is the work I did to try and fix it:
New Denso spark plugs, ignition cables, and ignition cable boots. Swapped the ignition coils and the ignitor/ignition control module with my spare car.

Spare car still runs good, but daily driver engine still cuts out and in.

I saw a youtube video about the crankshaft position sensor. It was not specific to any make or model of vehicle. It described some of the symptoms a bad crankshaft position sensor can cause, and it seems mine might be bad.

I am probably going to install a new crankshaft position sensor. I'm researching now how to do this. Any info on how to do this?

Also I am wondering what the camshaft position sensor is for?

I'm guessing that the crankshaft position sensor is for the ignition timing, and the camshaft position sensor is for the injector timing. Is this correct?

 

[phattyduck]

Engine Cuts Out and In

This is a followup post to Engine Stutters

The engine in my 2000 V6 2WD 4Runner OD 180K cuts out and in when driving on the freeway. Mostly the car cruises good and has good acceleration, but it has its moments. It is a single event (does not repeat itself 2 or 3 times in a row) that goes away quickly. There is no CEL light or pending codes.

Here is the work I did to try and fix it:
New Denso spark plugs, ignition cables, and ignition cable boots. Swapped the ignition coils and the ignitor/ignition control module with my spare car.

Spare car still runs good, but daily driver engine still cuts out and in.

I saw a youtube video about the crankshaft position sensor. It was not specific to any make or model of vehicle. It described some of the symptoms a bad crankshaft position sensor can cause, and it seems mine might be bad.

I am probably going to install a new crankshaft position sensor. I'm researching now how to do this. Any info on how to do this?

Also I am wondering what the camshaft position sensor is for?

I'm guessing that the crankshaft position sensor is for the ignition timing, and the camshaft position sensor is for the injector timing. Is this correct?

Both cam and crank sensors are used together for timing of everything on the engine. There are two of them (well, one of each) as a 'backup' in case something goes wrong - but if there is a mismatch, you will get an immediate CEL. I don't expect you have an issue with those sensors.

Something that hasn't been mentioned yet is the throttle position sensor (TPS). If that sensor has 'bad spots' in the range of the sensor (I have seen multiple people report issues at this age with those), it will cause plenty of issues - but not cause a CEL. That is worth checking out.

-Charlie

 

[tbryanh]

I ordered an OEM TPS. The TPS that is in the car now reads 10% Absolute Throttle Position at idle with the car warmed up and the air conditioner off. The idle is 950 RPM.

The idle probably should be 600 RPM, but Absolute Throttle Position is probably correct, at least according to this thread How to Calibrate Throttle Position Sensor (TPS)

With the engine off, the ignition switch on, and the gas peddle pushed to the floor, the Absolute Throttle Position is 70%.

The new TPS might need to be adjusted I suppose.

 

[tbryanh]

Absolute Throttle Position for the spare car is 12-75% with a 700 RPM idle.

 

[phattyduck]

Absolute Throttle Position for the spare car is 12-75% with a 700 RPM idle.

Yeah, min and max numbers are in the normal range. What you would be looking for (on the failing vehicle) is that the TPS has 'dead spots' in the TPS range that you would normally be at during 'cruise' conditions. Obviously, this would have to be tested when hot since this is when it fails.

-Charlie

 

[tbryanh]

Yeah, and the engine needs to be running to vibrate the TPS to test it properly. Part is arriving next week. Thanks.

 

[tbryanh]

While driving today, I monitored the Absolute Throttle Position (ATP) with a scan tool.

Cruising on flatland freeway, ATP was 17%, but it would drop to 0% or 2% when the engine would cut out even though the gas pedal position did not change.

This is a strong indication that the TPS is bad.

 

[tbryanh]

Installed the new OEM TPS, and drove 30 miles. No engine dropouts, and the Absolute Throttle Position reading remained correct (no longer dropped to 0% or 2%).

A nice round of applause goes to Charlie for his help.

 

[T4R2014]

Crank sensor definitely wouldn't be a good guess, and you'd waste a lot of time changing it. Tbh I have yet to see a bad OEM cam or crank sensor. It's more likely for a reluctor wheel on the crank get damaged than a crank sensor go bad. And they usually get damaged by bad mechanic work during timing belt jobs. Always look at input/output data and inspect wiring before throwing sensors at an issue.

 

[tbryanh]

What tool do you use to look at input/output data? I have a pretty simple and cheap scan tool. Maybe I can improve on that.

 

[tbryanh]

Here are pictures of the TPS split in half. Its just a potentiometer (as everyone probably suspected or already knew).

The resistance pad shows wear marks in the area where it is used most (10% - 20% Absolute Throttle Position), and the silver-colored contact fingers have deposits of the resistance pad on them (you might have to zoom into the photo to see the deposits).

Clearly a worn out TPS.