what causes a tubby to run rough when cold? Perfect warm.

[misterT]

Hi all,

Anything you can think of is much appreciated!

Here's what I've tried:

New plugs ngk7's
New leads
New rotar arm
Good dizzy cap
New coil
Timing 10btdc bang on at approx 800rpm
New ecu temp sensor (green one)
Afm changed and set up
Fuel pump working
Injectors working
Can't find any boost leaks
Hoses seem ok
Mbc removed- no difference
Compression test ok
Replaced Hks dump valve with standard bov
Air filter cleaned
Turbo ok
Downpipe looks ok
Exhaust looks ok (sounds a bit blowy when cold)
Throttle body cleaned

I've also sprayed wd40 over all the intake components and hoses to check for leaks but all seems ok.

Anybody think of something I've missed? I'm stumpt!

Thanks,
Dean

[Moo]

Hey Dean

I would have said the ECU temp sensor but you've already changed that. Does the car run rough until the temp gauge gets up to halfway then it's like flicking a switch and the car runs fine? If yes then I'd say the new sensor could be duff or there may be a problem in the wiring to the sensor.

[misterT]

Hi Paul, hope all is well with you n the 2!

Yea, symptoms you describe sound familiar.

I've tried 2different sensors so maybe the wiring as you say.

What's the best way to check? Check for power at the plug?

Thanks Paul,
Dean

[platmatt8]

Have you checked for fault codes?

Have you tested the new afm using the BGB?

Have you setup the air bypass screw on the AFM?




Sorry if you checked this already just going through my process of elimination.

[misterT]

yea, no error codes, afm checks ok and I set it up with a digital depth gauge so should be fine.

I'm a bit lost for options now.

The bgb says EGR valve, so i'm going to pull of all the pipes to it and see what happens, maybe change the valve if its simple enough.

Any ideas are much appreciated as i'm suppose to be taking the 2 to get a new ecu fitted monday and want it running perfect before i get there.

thanks, you lovely lot!

Dean.

[Frustrated Pilot]

clean the cold start injector.

Works a treat

[misterT]

Yep, cold start injector is fine too, i've checked or changed so much stuff that i'm forgetting bits.

It started running a bit funny when warm today too!

revs were dropping to around 500 on idle, the up to 750, then back down, etc.

Then one minute it was driving perfect, the next souned louder and wasn't pulling so hard.

It's like its been held back by something but only now and then. When it's running rough, if i boot it, it boost ok but it feels a lot more laggy than normal.

Very strange, i'm conpletely confused.

[Frustrated Pilot]

stab in the dark...

have you checked your injectors? have you checked they are all working fine.

Like my fault if one were to be "on the way out" or blocked then this may be an issue? although mine were all fine.. but i do get a low idle until after 2 mins of running, then it picks up to 1k, then finally dropps to 750 after about 10-15 mins of idle...

although it may be different as mine isnt working at all now

[Baker]

possibilites...

idle control valve
fuel filter
air filter.

[mrdb]

Exhaust manifold leak possibly...

[misterT]

been busy today,

Took off the throttle body, again, gave the icv a good clean up, also swapped fuel rail and injectors.

Air filter has been cleaned recently too and fuel filter is not that old so should be fine.

Adjusted the afm too, after Reading a post I was kindly sent.

Reset the ecu and started her up, ran like a bucket of crap!

Took her for a drive and semmed a lot better, even when cold but sounded really farty n blowy untill warm.

I'm going to have another look at the exhaust, downpipe n manifold tomorow, tighten everything up and see what happens.

Is there any way of checking the manifold for cracks without taking it off?

I'm pretty sure the exhaust and downpipe are ok but really don't fancy taking off the manifold to find it's ok.

Any ideas?

Thanks a lot guys, appreciate your help, we're getting there....

Dean

[Dan88]

It could still be your idle control valve or throttle sensor as cleaning them doesnt always cure them if theres a problem in that department