T Sport Poor Cold Idle

[mark01348]

Hi guys,

As you know recently I changed the cams and rockers recently on my 2003 T Sport. However, the problem I've got has been showing itself before I did the repair. Basically since it has been very very cold, on cold start the revs dip to like 700rpm and I have to blip the throttle and then the revs float at about 1,100rpm and I'm thinking is this also why the secondary air pump isn't coming on or AC when its cold. I haven't had any warning lights on, spark plugs are good and hoses etc are all good and connected properly.

Any ideas? Is idle electronically controlled?

Thank you

[Mick24]

First point of call would to check for any fault codes stored in the ECU as it would narrow the problem down to a specific area.

Are there any other problems with the way the engine runs after the cam and rockers have been replaced ??

Mick

[mark01348]

Hi,

No warning lights on but i'll check after work now to see if they are DTC's or pending problems. Just seems weird for it to dip so much. I checked the I'd set the timing correct etc in the book. Cars spot on, pulling better and sounds great. The only thing I was thinking is has oil from the typhoon induction kit stuck to the MAF sensor maybe causing inaccurate readings?

I'll update later now when I get a chance to connect the computer.

Thanks

[Mick24]

If the MAF is contaminated with oil, it might be the answer if the Intake Air Temp Sensor (built into the MAF) is trying to read outside of its parameters (P0100/P0110).

When you say the timing - cam timing or ignition timing ?

Cam timing as per book with the EX cam dot one tooth above the Inlet cam mark.

Ignition timing checked with TC+CG connected ?

Hopefully a simple fix seeing as you have done the hard bit already

Mick

[mark01348]

The MAF was a lil dirty, cleaned it with some brake solvent cleaner and it didn't make a massive difference on the MAF reading. Probably less than 0.2 gm/sec. Although at the time of starting it after work the idle was fine and the secondary pump kicked in etc.

I did find a DTC, it was an ABS/VSC, can't remember the code, oops, but it was Engine Module Performance which normally comes up when then is an engine ETC current aswell when there wasn't. May have something to do with when I ran it after the cam change.

The timing indicated in the 2ZZ-GE book is exhaust cam dots line up with chain but like 5 degrees back from the centre line and inlet cam dot forward 5 degrees. I'll have to scan it and show you. Seems to be running fine though.

I'll have to see what happens now first thing tomorrow morning when then the temp is low again.

Fingers crossed for tomorrow

[Mick24]

Nothing major found then - sounds like the cam timing is ok from your description then - fingers crossed for a normal cold start idle next time

Mick

[mark01348]

Hi Mick,

The idle was slightly better today, was about 1200-1400 rpm and it didn't drop so the air pump was able to run ok. I'm going to take the Idle Control Valve on Saturday.

I included a picture of where I set the timing chain to match the markings on the cams.

I can't work out how to get the image to display in the message instead of a download link all the time haha

[-T- Sport]

Easiest way is to use photobucket to upload your pics rather than the forums itself. :)

[Mick24]

Hi Mick,

The idle was slightly better today, was about 1200-1400 rpm and it didn't drop so the air pump was able to run ok. I'm going to take the Idle Control Valve on Saturday.

I included a picture of where I set the timing chain to match the markings on the cams.

I can't work out how to get the image to display in the message instead of a download link all the time haha

Sounds like your getting there with the problem - i cleaned my ISC valve last year (uneven hot idle) and the tickover has been rock steady since.

When its unbolted from the TB, you can watch the 4 stage check the valve does when you turn the ignition on

Mick

ps - cam timing was spot on :)