1HD-T injector pump - high idle speed help

[DaveHDJ80]

Hoping someone can help with my issue.

Motor is 1HD-T in 80 series cruiser. The idle speed has recently increased and sits on 800rpm.

It stays on 800rpm 90% of the time, although it has dropped down to its usual 600ish rpm a couple of times.

I had a look at the A/C idle up actuator today to see if this is the issue. It appears not to be.

Currently, with the engine idling at 800, the A/C idle up actuator does not do anything when it engages - this is because when it is engaged (I have done it manually by sucking on the vac hose) it only moves far enough to just touch the throttle backstop mechanism.

The A/C idle up actuator appears to be working to its proper limit, as I I can see the travel it usually has at the rubber boot has worn on the shaft. Even so, its def not the problem as it doesnt even touch the idle mechanism when its not engaged.

It appears that the main idle is out of adjustment, although this theory is negated by the motor occasionally dropping back to a practical idle on the odd occasion - generally after running at highway speed.

Are there any other idle up mechanisms that could be affecting idle speed?

Or can the whole idle bracket set up move?

It's a bit condusing at the moment, as I can't see how the grub scew could move, and if if it has it doesnt explain why the rpm would drop on occasion.

I am hoping it is something mechanical and not something internal in the injector pump?

I can get photos if required.

Dave

[McLarryBob]

I have maybe a similar issue with my 1HD-T. It idles up a bit sometimes and I have narrowed it down to a slightly sticky throttle cable.
If it's idling high most times I can stick my foot under the accelerator and lift it up (pushing the cable back) and this drops the idle back down.
I can live with this as it is now but one day I'm gonna put in a new cable and return spring on the throttle shaft at the injector pump.

[DaveHDJ80]

It is not the throttle cable. The throttle lever is sitting against the grub screw at rest (as described above).

[80's_delirious]

my 1hd-t idle used to vary from around 550rpm (smooth) to 900rpm (not so smooth), adjusting idle screws etc did nothing to help it. In the end I decided it was likely due to wear and tear on the throttle shaft/pump housing. I had a similar problem once with a carby.
My 1hd-t pump was showing other signs of wear and tear and eventually crapped itself completely

[DaveHDJ80]

Throttle spindle wear in carbies always seems to be much more variable more often. 250odd rpm due to spindle wear would equate to a pretty large butterfly opening.

Injector pump got rebuilt about 130 000 ago.

I'll have to post some photos. The issues seems to be an ajdustment somewhere.

Does anyone have a proper Toyota manual they can scan in the pump page for me?

The Haynes only shows the 1HZ pump.