Just wondering,, is it common to have a ISC unit that test OK with a multimeter,,but it still doesn't function correctly?????????
Idle works ok now but still not 100% .
It still drops rpm when put in gear
Thanks.......

That normal my car drops rpm when it put into a gear :)

It's not. It is ment to momentarily drop and then rise back up. Otherwise if you set your base idle at 850 rpm it will drop to about 650rpm,, and when you put on air even lower.
I have my base idle set at 1100rpm to achieve 850 in gear.

Mine sits at 1000rpm then drop to 700 rpm. So it normal lol

Idle should be 700-850
and yes it should drop revs when it is put into gear

Idle should be 700-850
and yes it should drop revs when it is put into gear
Ring a service department at Mitsubishi. When I have asked them and other respectable mechanical places they have told me that it should idle at about 850 in park and when put into gear it should for a split second drop rpm and then rise back up to 850rpm.
My VT commodore sits at about 800rpm this does not shift no matter what I do air con in gear it sits dead on that mark.
I asked Mitsubishi if the TR I have brought should be the same and they have said YES. They also said if it doesn't there is something wrong,,but they said that it's a very, very common thing with TR's ( to drop rpm in gear ),,,,,BUT they are not supposed to.

Anyway I will see if they are correct by about Friday this week as I have asked them to have a look at it. Turns out I know some one there so hope fully they won't try to Jab me too hard.:blah::blah:

Ok so it not normal hmm Lets us know what the fault is :)

Interesting, both my automatic 2nd gens have always done this.
I was always under the impression the idle needs to come UP with A/C as it places more load on the motor and thus needs some more RPM to keep it stable.

;1356781']Interesting, both my automatic 2nd gens have always done this.

Very true. The second gen takes a second or 2 to pick up the rpm when you put it in drive, whereas 3rd gens and most other makes of younger cars don't. I put it down to the "brain power" of the ECU in newer cars versus older cars. When hot, my V6 TS idles correctly but when put in drive it can dip down to 500-600 rpm before the ISC ups the rpm.

Aircon, lights, power steering loads, etc will up the rpm a bit.

If the hot idle is about 750-850 in neutral and it drops to 650-750 in drive the 2nd gen is working ok.

Easiest test of the ISC is to warm the engine up, put in drive, then turn on lights, air and crank the steering wheel from lock to lock. See what that does to the rpm. lol

(But I'm sure someone will tell me I'm wrong again. *sigh*)

Mitsy service department has told me that when you put it in gear the Trans tells the ECU and the ECU tells the ISC to up the idle.
THIS IS JUST WHAT THEY HAVE TOLD ME......MY TR idles ok after I did the bloody engine mounts,,but if I set the base idle at 800-850 It will drop to about 650.
With out the air on this is not too bad,, but with the air on it will drop to about 550-600,,and when the thermo fans come on it will drop even more.
That's why I have the base idle at 1100rpm. It will idle in gear nicely even with the air on,, but because the base idle is so high the cold start is high as well=2000rpm. The cold start in this thing gives me the shits.
This car is my daughters ( 16 ) There has been times when she starts it and straight away slams it into revers this is not much good for the Trans at 2000 rpm. Especially when I have just replaced the trans 2 weeks after we brought it. 2nd gear band went.

So on Friday I will see if Mitsy's are full of it.

. . . the base idle at 1100rpm.

I know all those symptoms too well.

I had to do that with my 4 cylinder when it wouldn't idle under load at traffic lights. Replacing the ISC - kindly supplied by TuffTR - fixed the problem.

A TR with a working original ISC would be a rare animal indeed. lol

Very true. The second gen takes a second or 2 to pick up the rpm when you put it in drive, whereas 3rd gens and most other makes of younger cars don't. I put it down to the "brain power" of the ECU in newer cars versus older cars. When hot, my V6 TS idles correctly but when put in drive it can dip down to 500-600 rpm before the ISC ups the rpm.

Aircon, lights, power steering loads, etc will up the rpm a bit.

If the hot idle is about 750-850 in neutral and it drops to 650-750 in drive the 2nd gen is working ok.

Easiest test of the ISC is to warm the engine up, put in drive, then turn on lights, air and crank the steering wheel from lock to lock. See what that does to the rpm. lol

(But I'm sure someone will tell me I'm wrong again. *sigh*)

Must try this see if it stalls lol


I know all those symptoms too well.

I had to do that with my 4 cylinder when it wouldn't idle under load at traffic lights. Replacing the ISC - kindly supplied by TuffTR - fixed the problem.

A TR with a working original ISC would be a rare animal indeed. lol

Mines still original and seem to be working fine lol But then again my car is weird as it still going strong after 318 thousand kms lol

Must try this see if it stalls lol

Mines still original and seem to be working fine lol But then again my car is weird as it still going strong after 318 thousand kms lol

I bet a previous owner replaced the ISC at roughly 200,000 km. lol

Have no clue as everything still works, rushes off to find a big lump of wood and hangs on tight :D

Careful there Sparky! Remember the "no spam" rule!

Apparently another test you can do for the ISC is to take it out of the throttle body and leave the wire harness connected and turn the ignition on. The barrel should screw all the way out.
When the the ignition is turned off the barrel should screw all the way in .
The guys at Mitsy's have also said some times they have had ISC's that pass all the test but just don't work properly and as soon as they put a new one in problem solved.

They're probably just baiting me so they can slug me as much as they canlol

. . . can slug me as much as they canlol

Goes without saying. lol

Why not test it yourself and replace it yourself? Wreckers, eBay, Madmagna can supply one much cheaper than the dealer.

Goes without saying. lol

Why not test it yourself and replace it yourself? Wreckers, eBay, Madmagna can supply one much cheaper than the dealer.
I have 3 have tried them all ,,but they're all the same. They all test OK with the multimeter,,So thats why I think it might be the ECU. I want Mitsy's to test it and if they say it's no good I'll get one from U-pull it $44.
This Tr SE is a nice car. Something about it I like. Makes me want to spend money on it. :nuts:
I'm just like that I will get a car and spend time fixing it up. I'm not to bad at panel beating and painting ( only with acrylic ) so for about $250 $300 I'll paint the top half where it's a bit sunburn.

OK went to Mitsy's. they made a few adjustments,but said everthing is working ok.
The mechanic said YES it should idle up a bit better when put into gear and when putting on the air etc,,,But given the age of the motor etc, it's about as good as it's going to get.
Car has done 310,000 km.
He also said Yes the car is meant to mantain a stable idle speed. That means what it idles at in Park it should idle in gear. He said that this was one of the better TR's he has driven.

Simplest test for ISC is turn A/c on at idle. If revs rise or maintain, the isc is functioning. If the revs fall to a rough idle, its cactus. Make sure the throttle body is clean, including the passages to the isc. Remove the idle speed adjust screw and clean the pintle, aswell as spraying down the hole into the TB to clean the seat. Remove the isc and clean the plastic tip, aswell as the seat which it closes onto. Have seen a few cars with ISC's replaced, but people neglect to clean the seat - which means the isc will never perform correctly, as it can't seat correctly. Check that the TPS is adjusted correctly, and check that the adjustment of the throttle stop screw hasn't been tampered with. The other common cause of idle dramas on magnas (esp 3rd gens) is blocked PCV valves, which act as vacuum leaks.

Dang cars - all the same :)

What a pity this car from 1994 lol The testing your are on about is for thrid gen not second gen :P