ST215 GTT 3SGTE Rough Idle

[B0000M]

hi, ive had a search around and found nothing, so ill ask;

i've got a 98 GTT Caldina, 70,000kms, ive owned it about 10,000 kms, its all totally standard, and its got an idle issue.

when idling it runs rough, like its missing on 1 cylinder,

hard to explain but if i said it misses on probably every 5th fire of the cylinder would that make sence? so it sortof works lol.

once its up above idle its sweet as, runs fine.


the other thing it does, only when its cold is once its started if you go to accelerate it will occaisonally bog down like a carb'd car would, then you back off, try again and its fine.

2 things may be related- may not.

any ideas to look at would be awesome thanks

[fivebob]

Several things have an effect on the idle. By the sounds of your other problem it may be fuel related.

First thing to check is to see if you have any engine check codes stored in the computer. To do this locate the check connector, which is below the dash on the right side of the steering column, turn the ignition on and then bridge TC & CG pins as shown in the diagram below. Then count the flashes on the Check Engine Light


If there are no codes then it becomes a matter of checking that the individual components are functioning correctly. Even though the symptoms suggest a fueling issue I'd be inclined to try new spark plugs first.

If that doesn't solve the problem then check that the TPS is working correctly and perhaps check that the VSV that is connected to the reference line going to the fuel pressure regulator is functioning as it should. Although I think this may only be used at start up but if it malfunctions it could cause problems with the fuel mixture.

[cedwards]

As Fivebob said check for codes.

Mine bogged when cold, similar to what you describe, new sparkies made a world of difference!
My idle is also alot smoother now, but I wouldn't have called it rough like you describe with yours.

Only having 70000 kilometers makes me think it may not be the sparkplugs though, have you taken them out and checked their condition? Gap should be 0.8mm.

The GTT's also occasionally suffer from cooked coils but this doesn't sound like your problem.

[phraza]

mine does the same thing, mines done 123ks and recently i replaced the rocker cover gasket and new spark plugs but that didnt fix it. i might try those code things as fivebob said next

[matty_j24]

ditto mine also bogs down then you back off the throttle and put foot back down again and away it goes i thought it was to do with the piggy back ecu but must be a common issue.....

[B0000M]

sorry for not checking back sooner.

i forgot to mention ive already replaced the plugs with ngk iridiums, which didnt help at all.

i will try the codes thing and see what comes out of that.

[B0000M]

ok, ive done the diagnostic short thing, i think im doing something wrong...


i turn the key on, short the 2 pins together, and the engine light begins flashing, followed by the abs light. they both flash at least 100 times, i stopped counting after this.

i also tried shorting the pins then turning the key on. same thing

[fivebob]

Constant flashing means there's no codes stored in the ECU.

[B0000M]

If that doesn't solve the problem then check that the TPS is working correctly and perhaps check that the VSV that is connected to the reference line going to the fuel pressure regulator is functioning as it should. Although I think this may only be used at start up but if it malfunctions it could cause problems with the fuel mixture

can anyone help me with some clear instruction on how to go about this?

[Mr.Phreak]

Can't you get the old man to take it to work with him??

[B0000M]

Can't you get the old man to take it to work with him??

that costs money. lots of it.

doing it myself doesnt

[radio8tiv]

Did you have any luck in finding a fix to this problem ?
I would be interested to know as mine is doing something similar