Page 1 of 1

Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 6:22 pm
by Quaser
Hi Guys

Been getting the touring ready for MOT - went to go for a drive after fitting my 6 branch and Remus exhaust but the car is not behaving!

Its idling at around 500k and is very lumpy.

When im driving, im kangarooing down the road! - Only when its over 4k revs, its better and accelerates but when it goes back down it kangarooing again!

I have changed dizzy, rotor arm, plugs, leads, fuel filter, and maf (unichip maf conversion)

What else could it be?

Q

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 6:33 pm
by uzdubmwe30
idle control valve?

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 7:50 pm
by chief
did it play up before fitting the manifold & exhaust :?:

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 8:31 pm
by Quaser
i had a standard manifold and exhaust on it before with no lambda and without changing any of the above - it was lumpy but not as bad as it is now.

Dont think its the ICV as it would not cause the hesitation in acceleration would it?

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 8:53 pm
by abelai
Have you checked that the TPS is working properly? The TPS tells the DME which map to use, idle, normal or WOT.

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 8:54 pm
by abelai
Oh and the obvious one air leaks around the inlet manifold

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 9:26 pm
by Quaser
How can i tell if the tps is working? it was apparently brand new 3000 miles/18 months ago

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 9:42 pm
by abelai
The first check is can you here it click when you open the throttle with your ear by the throttle body and engine off. Also does it make any difference to the idle with the TPS disconnected it should.

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 10:19 pm
by Quaser
OK - just tried it - i can hear clicking with the engine off

started car - lumpy idling, unplugged it - revs instantly rose and it seemed to idle better - still slightly lumpy but that could be cause its cold

Will have to try it out tomorrow and take it for a drive

So is it faulty or doing what it should do?

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 10:55 pm
by Quaser
OK - this thing has me stumped so i took it out for a quick spin with the tps off - hesitation i still there but it is a bit more driveable.

Do you think its a case of it needing a remap or could it be something else?

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sat Nov 03, 2007 11:23 pm
by abelai
Well that at least means your TPS is acually doing something. Does it smell rich on idle whats the cold idle and hot idle speed?

You might want to try reading through all of this:
http://www.e30zone.net/modules.php?name ... ic&t=78455
It has lots of info on testing the TPS, CPS, CTS and ICV.

What difference does disconnecting the vacuum hose to the FPR make(creating an air leak) do the revs increase?

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sun Nov 04, 2007 12:39 am
by siddiqi1
i think it is either ur icv or your crank pos. sensor!

Sabs

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sun Nov 04, 2007 6:59 pm
by Quaser
ok - tried icv and no difference - tried different ecu - no effect!

tried spraying brake cleaner on the rubber elbow - no effect, tried it on cps (dont know why - suppose i just had the can in my hand!!!!) and the revs went up!

Tried the vacuum hose - revs went up slightly

Checked the rubber connectionsunder the inlet manifold as advised by the other thread - and everything seems fine there.

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Sun Nov 04, 2007 8:57 pm
by M5pilot
Crank sensor is the likely culprit here dude.

Are you sure there are no really big airleaks?

Is there something else you could have missed?

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Mon Nov 05, 2007 8:35 am
by Quaser
Just a quick question - whats the order of the leads at the dizzy cap starting from the top?

Just wanna make sure i put them on right

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Mon Nov 05, 2007 3:48 pm
by Quaser
Anyone?

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Mon Nov 05, 2007 3:57 pm
by abelai
The cap is numbered and so are the leads. Firing order is 1,5,3,6,2,4 and number one is at the front of the car

Re: Very lumpy idling and hesitant acceleration when warm

Posted: Mon Nov 05, 2007 7:52 pm
by Quaser
my cap isnt numbered and neither was the previous one - thats why i want to make sure - i take it 1 is at the top of the cap -

1 5, 3, coil, 6, 2, 4

right?