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2.5l Petrol T4 Idling Issue
G'day All, i have just acquired a nice '94 T4 Caravelle, 2.5l Petrol Manual. It's all in pretty good nic, and drives very well. However it suffers from stalling at idle. It was idling at somewhere between 500 and 700 rpm, however after an hour or so of rooting around in the engine bay (and being angered by the fact the post '93 models have no idle adjustment) discovered that there's a microswitch on the throttle (which isn't in the workshop manual) which it appears tells the ECU the throtlle is closed, because after adjusting it's bracket so that it was 'switched' when the throttle was closed, the idle speed went up to the 750 - 800 rpm mark where it should be. It also starts without the use of the throttle now too.
However! I also discovered that the Idle stabilisation valve is not operating, apparently it should be buzzing when at idle all the time. I removed the valve and checked that it wasn't seized, and it buzzed like crazy when hooked up to 12 volts. I then checked the voltage across the plug with the motor idling, and there's nothing coming out... i checked the positive wire to earth on the chassis and there's 0.5 volts. I found someone on "howtomendit.com" appears to have exactly the same problem, but nobody has provided an answer...
It's not so much of a problem now that i've fixed the microswitch thing, but when you turn the A/C on, 90% of the time it stalls, and a short stab at the throttle often has the same result.
Apologies for the newbie essay, any help would be much appreciated.
However! I also discovered that the Idle stabilisation valve is not operating, apparently it should be buzzing when at idle all the time. I removed the valve and checked that it wasn't seized, and it buzzed like crazy when hooked up to 12 volts. I then checked the voltage across the plug with the motor idling, and there's nothing coming out... i checked the positive wire to earth on the chassis and there's 0.5 volts. I found someone on "howtomendit.com" appears to have exactly the same problem, but nobody has provided an answer...
It's not so much of a problem now that i've fixed the microswitch thing, but when you turn the A/C on, 90% of the time it stalls, and a short stab at the throttle often has the same result.
Apologies for the newbie essay, any help would be much appreciated.
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