1HZ idling and blipping intermittently (1 Viewer)

[boozewz]

I've been noticing this for some time on my HZJ79. Whenever idling, its raises rpms a touch, and then goes back to steady for some 10-15 seconds before blipping again and so forth.

What could that be? I've also attached a pic for the FIP set up since its a 2014 model year 1HZ. This not happen on my HZJ80

 

[Jan-78FJ40]

I've been noticing this for some time on my HZJ79. Whenever idling, its raises rpms a touch, and then goes back to steady for some 10-15 seconds before blipping again and so forth.

What could that be? I've also attached a pic for the FIP set up since its a 2014 model year 1HZ. This not happen on my HZJ80



View attachment 1125426

What is happening is that the Air Conditioning idler-up kicks in, which raises the rpm. This is perfectly normal and planned like this.
Look at the injection pump, you will see a little vacuum driven rod push the rpm lever and thereby rising the rpm.
cheers,
jan

 

[IanB]

I was going to say the same thing without even watching your video. You can try shutting off the AC (and center console fridge if equipped), and you should see the symptom disappear. I don't expect you do a lot of driving with the AC off over there, lol.

 

[Tapage]

what a beautiful sound ...

 

[boozewz]

Thanks for that! switched off the AC and sure enough it doesn't happen. Any particular reason why this only happens on the later model 1HZ? My 80 has AC but doesn't have the idler kick up.

 

[Jan-78FJ40]

Your 1HZ in the 80 should have it as well-mine does. Maybe someone took it out, or the vacuum solenoid is not working.
I don't think it is very important. These engines are so strong when idling, the additional load of the A/C compressor makes little difference.

 

[roscoFJ73]

All 1HZ fitted with aircon had it in Australia. They were fitting it to 3F back in the 80s as well.

 

[Tapage]

It might not be well adjusted in your 80 .. or maybe the AC compensator it's leaking vacuum ..?

Gotta run some test and troubleshooting ..

 

[boozewz]

I just had a look under the hood of my 80 and there are no vacuum lines running out of the FIP. Truck idles at 850rpm smoothly, and AC runs very cold. On the 79DC, it idles at 600rpm, and the kick up brings it to 900rpm for a few seconds or so. Funnily enough, the AC is colder in the 80, not that I think its related to the idle-up kick in.

Cheers

 

[Tapage]

pics ..

 

[boozewz]

@Tapage here's the FIP from my HZJ80

 

[Locked79]

Vacuum hose missing off actuator.

 

[boozewz]

Thanks @Locked79 Where is the other end of the vacuum supposed to plug into? It seems a little different than the 79 1HZ

 

[Tapage]

to a vacuum solenoid usually at the fender ..