Club G40 Forum

Technical => Engine and Transmission => Topic started by: LeonL on September 14, 2009, 11:00:51 PM

Title: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on September 14, 2009, 11:00:51 PM
Hi,

Got the G40 running fine enough when driving about now.

However i still have two last problems! :(

The car when stationary seems to idle fine. However if i hold the revs at say 2k for example, the revs hunt up and down between 1.5k and 2.5k (not exactly but you get the idea). Also seems to do this when actually driving along sometimes? Although not 100% sure if i just imagine that,lol. This problem occurs when cold and warm.

Second problem, when pulling away or even just touching the throttle when stationary the car seems to hesitate? Kinda like a flat spot maybe? like i touch throttle ever so slightly and the revs fall (hasnt stalled doing this yet) then raise back up. Can also make the car do this if i put the throttle down slightly really fast, car juders about. Its very tempremental and is on and off when it fells like it. This problem also seems to occur when cold and warm.

Could these problems be related?

I've tried to explain the problems the best i can, but sorry if its all a little vauge :(

I've replaced the leads and blue temp sensor so far. Neither made any difference.

The car in general seems to drive very smooth, its just these two problems!

Any ideas? Things to replace which could be causing this problem?

Thanks

Leon
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: PeteG40 on September 14, 2009, 11:02:39 PM
you checked the dizzy timing?
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: boyzey on September 15, 2009, 05:57:34 PM
ye i have something like this but myn gets beta wen warm  bt still ther slightly, my next step is to check the dizzy timing like u say.

i will let ya no if it makes any difference hopefully guna giv it a go at weekend
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: Robin on September 15, 2009, 07:01:53 PM
bloody hate text type!
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: DMWG40 on September 16, 2009, 03:12:41 PM
Quote from: Robin on September 15, 2009, 07:01:53 PM
bloody hate text type!

me too,
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: cheddarcheese on September 16, 2009, 06:29:27 PM
dito
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on September 16, 2009, 06:47:21 PM
I hate spam ;) So lets keep it on topic please, cheers!
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: goosyganger on September 16, 2009, 08:02:02 PM
I had a similar sort of problem, a friend of mine said it sounds like something called pinking. I turned my dizzy further 'anti clockwise' and it is much better, it no longer hunts, or sits at high revs when idling, but does seem slightly delayed reaction on acceleration so I think it needs some final fine adjustments. Have a look, if the dizzy is too far 'clockwise' then just spin it back little bits at a time, it wont damage anything. Process of elimination. It is a pain in the ass though.
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: Dan on September 16, 2009, 08:02:23 PM
So your ignition timing is ok ? Voltage from alternator ?

Have you gone through the diagnostic guide that hayesey put in the FAQ ?
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: PeteG40 on September 17, 2009, 08:13:38 AM
Quote from: goosyganger on September 16, 2009, 08:02:02 PM
I had a similar sort of problem, a friend of mine said it sounds like something called pinking. I turned my dizzy further 'anti clockwise' and it is much better, it no longer hunts, or sits at high revs when idling, but does seem slightly delayed reaction on acceleration so I think it needs some final fine adjustments. Have a look, if the dizzy is too far 'clockwise' then just spin it back little bits at a time, it wont damage anything. Process of elimination. It is a pain in the ass though.

or perhaps you could set it with  a timing light!?!
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: goosyganger on September 17, 2009, 01:59:44 PM
Quote from: PeteG40 on September 17, 2009, 08:13:38 AM
Quote from: goosyganger on September 16, 2009, 08:02:02 PM
I had a similar sort of problem, a friend of mine said it sounds like something called pinking. I turned my dizzy further 'anti clockwise' and it is much better, it no longer hunts, or sits at high revs when idling, but does seem slightly delayed reaction on acceleration so I think it needs some final fine adjustments. Have a look, if the dizzy is too far 'clockwise' then just spin it back little bits at a time, it wont damage anything. Process of elimination. It is a pain in the ass though.

or perhaps you could set it with  a timing light!?!

yeah I have but havent been able to get any of my mates round to help me use it to set it up, and its a bit hopeless when you dont know how. but once it she is finally happy ill get it sorted.
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on September 20, 2009, 07:11:17 PM
Going to get the timing checked and if needed sorted then i'll let you guys know what happens!  :)
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on October 04, 2009, 06:36:13 PM
Update: Timing is fine, problem still occurs?
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: jimbugalee on October 05, 2009, 08:50:43 AM
I had the same problem and eventually took the lambda probe off and it ran a lot better, due to fit a new one this week. 

Also tried about a million others things ... changing alternator, testing and fixing a few problems on the ECU, all new earth leads.  Hope you get it sorted, I know from experience it's soooooooooo annoying
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on October 06, 2009, 05:31:36 PM
Quote from: jimbugalee on October 05, 2009, 08:50:43 AM
I had the same problem and eventually took the lambda probe off and it ran a lot better, due to fit a new one this week. 

Also tried about a million others things ... changing alternator, testing and fixing a few problems on the ECU, all new earth leads.  Hope you get it sorted, I know from experience it's soooooooooo annoying

Let me know how it goes with the new one...
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on October 08, 2009, 07:07:13 PM
Removed standard air intake, air box, filter etc... today and replaced it with a Jabbasport kit. Took it for a wee drive and the car seems to be alot smoother. Didn't hesitate or anything, havn't checked to see if it still hunts revs yet.

Engine was warm/hot though so will wait till later when its stone cold and take for another drive to see if this problem has been eliminated.

Any ideas on why changing the induction for a Jabbasport one could have fixed the problem? Seems very strange!

Will confirm later if problem is solved

Thanks

EDIT: PROBLEM STILL OCCURS
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: PeteG40 on October 08, 2009, 07:49:02 PM
if yr old paper filter was fecked maybe
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on October 08, 2009, 07:59:28 PM
Nah doubt it, looked pretty clean!

Edit: False alarm :( Problem is NOT fixed...Rah
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: jimbugalee on October 09, 2009, 09:02:16 AM
oh no Leon.  I've just spent months trying to sort this problem out.  Mine is now fine with new lamba probe :) Can't believe that's all it was but it may have been a combination of everything I tried.
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on October 09, 2009, 05:34:24 PM
Hm...Unplugged my lamba today and not to sure if it made much difference. But i think it did, didnt seem to hunt revs as much. I'll just buy a new one and see if it sorts it :) Were did you purchase yours from and at what cost?

Cheers
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: jimbugalee on October 10, 2009, 01:48:48 PM
Direct from VW ... think they're about £120 tho booooooooooooooo

Update on mine .... stalled again this morning with new lamba probe so still runs better with it completely off but it is better with a new one.  Think my mechanic is getting a tad annoyed now hehe
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on October 11, 2009, 11:25:19 AM
Hmm...Unplugged mine and drove around for abit and the rev hunting defo improved, didnt seem to be 100% gone but is 99% better! Any ideas on if its safe to run the car without the probe? Does it cause any problems?

Also a faulty probe could be the cause of over fueling correct?

I'll be ordering a Bosch one from Eurocarparts today me thinks :)

Cheers
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: jimbugalee on October 11, 2009, 05:35:12 PM
Anyone got any ideas why it would run 100% better with lamba probe off and with new one on it is improved but still hunts and stalls (mostly when cold)?
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on October 11, 2009, 05:52:48 PM
Quote from: jimbugalee on October 11, 2009, 05:35:12 PM
Anyone got any ideas why it would run 100% better with lamba probe off and with new one on it is improved but still hunts and stalls (mostly when cold)?

Maybe its the actual wire/plug that connects the lamba sensor plug into the ECU (or whatever it goes to)
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: LeonL on October 11, 2009, 07:52:07 PM
PhilJ and tucker checked it ???
Title: Re: Final Problem! Hunting revs, hesitates when throttle is touched
Post by: Shailan on October 20, 2009, 12:29:49 AM
when on idel does it cut out?

check the blue temp sensor, i changed mine recently it was all gunked! runs much better now