Sunday, November 13, 2016 - 01:26 am, by: Andrew Brown(Crazyassdrummerboy)
Hi guys,
My idle revs when hot are up at 1000+rpm but only after holding the car on a hill (at the lights for example)
This only happens when I hold the car on a hill with just the clutch, and it takes a long while for the iacv to adjust them back down to the normal 600-700rpm range
- Ecu is recapped professionally - iacv is brand new - TPS is brand new - Air lines are brand new - Maf is brand new also
Car has no other issues with idle or performance
Not sure what the issue is here, any help would be appreciated.
Sunday, November 13, 2016 - 09:29 am, by: Raoul Duke(Hunter)
Might be another case of ECU coolant temp sensor or vacuum probs. With a dying ecu temp sensor (all are pretty dead now, max lifespan of 30 years if incredibly lucky), the car can think it is -40 degrees and will idle high and have low power and so on. People who changed it report to have much more low down grunt, and better fuel economy.
I'm assuming your plugs and wires are good, although you did not change them. If you have not changed them, take engine covers off at night, run a grounded screwdriver over spark plug wires, and if they ark , you need new leads.
You already mentioned ECU was done professionally, along with other things replaced. I read a lot of ECU repairs don't fix the board as the tracks might be damaged, the drivers might be damaged or so on. Capacitors is really only 30% of the job. If you can get your hands on a 2nd ECU to test, do that. Might get lucky. Probably won't. All ECU's from japan in the 90s are said to be dead around now. Another main thing is the capacitors they used were 90c, but in Australia we use 110c capacitors coz it's hot here logically. If you replaced caps with the 90 degree caps, it's likely that on Australia's first hot day out in the sun there when the car was all locked up that day, that the caps failed already. But if idle never changed before or after the ECU was replaced, it's obviously probably not the ECU, but rather some sensor or mechanical problem.
The high idle thing happened to a friend years ago and turned out he had a power steering leak. The vacuum on the power steering idle valve affected idle up to around 2000 revs on some days. It's a $100 part. "idle air up valve" or something. Might be known as pressure switch too. Check it out, it's on the bottom of the pump and has 2 hoses coming from it. If broken, there's your problem. Do you have a power steering leak? Suspect the above if so. He also had a front suspension leak which was replaced at the same time as the power steering switch. So it's either the pressure switch leaking, or the suspension leaking maybe.
I Just read that if your EMV isn't working, or the aircon is having problems it's possible that the idle will be too high too. The fix seems to be either to fix your A/C, or disconnect the wire from the ECU.
AND, a cold start injector on a 1991-1993 can stick causing too high or too low idle I think i read once.
Sunday, November 13, 2016 - 02:09 pm, by: Andrew Brown(Crazyassdrummerboy)
The ecu was done by someone who absolutely knows what they're doing, Tim Schroeter. Board tracks inspected and correct caps used.
Spark plugs, leads, and coil packs are brand new also within the last few months.
I should have mentioned ecu temp sensor is brand new also and the lines running to the idle up power steering have been blocked off completely. o2 sensors are brand new also.
I also have a brand new alternator and freshly rebuilt power steering pump so no issues there either.
No emv as I got a uz31 without the option
Completely stumped as to what might be causing this
Monday, November 14, 2016 - 07:48 pm, by: Raoul Duke(Hunter)
The only thing that controls idle is the idle control valve on top of the engine there. If it's clean it's clean. Does it have a gasket? The other thing that controls idle (up to about 1000rpm) is the throttle sensor on the throttlebody thing there. It goes from 500 to 1000 rpm by turning it.
You say when on a hill the car revs to 1000rpm. So when the car is on an angle, it revs up, but only with the clutch on. This suggests transmisson problem. Fluid, sticky clutch, etc.
This also suggests Air-lock in coolant. Or Maybe engine/trans mounts as when car is on an angle it's leaning on somethin it shouldnt be or some wire is earthing out when leaning... Maybe throttle cable stretching as engine leaning...
Are suspension lines connected to the engine in any way? Can they affect idle?
Did your problem start after installing something new to the car, or did you install parts to try fix the problem?
If the problem started after you installed a part, it's most likely that part. This one time I had a mate who took his back seat out and broke a few wires. The whole car went apeshit apparently because the TV wouldn't talk and read sensors or something. Everythings related on a Soarer.
Tuesday, November 15, 2016 - 06:49 pm, by: Raoul Duke(Hunter)
Just thought of something! I don't think the idle pressure thing actually gets fixed when you buy or reco a new pump. If you are losing fluid, suspect this as it can cause high idles and smoke.
This is the part, it has 2 wangs on it and the two wangs go into two vac hoses.
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