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High Tickover problems


Buzz Billsberry

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Buzz Billsberry

Currently running with VX 2.0lt 16v Xe with delly 45's

and I'm having probs with tick-over or lack of it its currently

between 1500-1600rpm great for fast starts!

Ive checked the linkages balanced the carbs but to know avail

before this started tickover was around 850rpm the problem happened in a blink ie set of from the lights got the nxt lights

T/o 16oo rpm

Management system is a SBD MBE 2D system but wouldn't have thought this was the prob

Any help or if U could point me in the right direction for a local Delli authorised dealer (Yorkshire)

Regards Buzz :cool:

peter.billsberry@btopenworld.com

0113 248 6498

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Frayed throttle cable...pedal not returning to it's proper resting position......Can you get it to tick over "properly" by tugging on the pedal or relieving tension elsewhere on the cable?

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I have had this problem on my car once it got properly hot :devil:  (and it has reoccurred this weekend - idle is now just under 2000rpm   :0  ) engine is an 1800 Zetec with twin 45DCOEs and Alpha3d management.

Last time (4 months and a few track days ago) I took it to EFI Performance in Fareham and they adjusted the TPS and checked the carb balance which seemed to help but as I said now it's back again and I can't see how the TPS could have moved so I guess it's something else.......undoing the throttle cables completely doesn't help so it's not "lack of slack" - maybe there's something in the carbs which is 'sticking'?.

 :durr:

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Buzz Billsberry

Hi Guys

Its not the cable or pedal position. I can get it to drop  2 about 1100rpm if I pull up the throttle bar in the centre of the carbs. Could it be the spindle is bent in one of the carbs??

I don't have a TSP on mine plus the cable is new along with the misabs so I don't think air is leaking in.

Regards Buzz ???

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Hi.  I'm also running vauxhall 2.0l XE with delli 45's, DTA management. Have had a similar problem for several months & so far failed to solve it.  Have checked all cable & linkages, striiped carbs but problem remains.  Idle originally set ~900 but typically runs at 1200.  When idling @1200 If i slow revs by balancing clutch in 1st rev will drop to ~900 & remain @ 900 until next rev the engine.  If you find out the cause let me know. it driving me mad. Well madder than I've always been

pete :devil:

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Paul@Plays-Kool

Buzz,

You don't have a high tickover at the moment, the car won't start!

Pete,

Your problem sounds like the DTA is reading the throttle position sensor & RPM at idle & using load site two which is at 1000 rpm, not load site one at 500 ( it interpolates, or should).  With the car idling at 1100, check on the lap top to see which site on the map is being used.  You may also need to reset the TPS, this is easy enough, just follow the instruction.  :)

Have fun

Paul

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It strikes me for the revs to be higher it has to be one of 3 things or more but I can only fink of 3  ;)

1. Throttle buterfiles are not where they should be (but making sure you unscrew the idle and check the stop is touching it will discount this)

2. throttle is not working cos air is getting in after your throttle thus allowing the engine to breathe additional air. Thi sis normally the old O-rings. These things need to be pressed enough to allow them to do thier job and no to much to allow some vibration to be removed from the carbs. there are other areas that can allow air in. does the engine still idle smootly or is it lumpy as well ?

normally if an o-ring is leaking it will be on one or two intakes only leading to a high but lumpy tickover.

3. Retardation - if the sparks are retarded at tick-over it can lead to a fatser tickover. this could be down to the ecu.

Hope something here helps ?

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Adrian, if the ignition is *advanced* at idle it will make the engine rev faster.. I think Paul has it right, the idle position on the butterfly is on the cusp of change between throttle load position one and load position two , these two sites will have differing advance values and if the engine just slips up into load position two, or for that matter speed position two the extra advance might well pull the engine speed up permanently. Carburettors are notorious for giving fluctuating mixture at idle, especially if they are unbalanced, this can cause the idle to rise and fall by a couple mof hundred RPM and up into the next speed site. Once the engine is forced back down to 900, there it will remain until temperature / carb fluctuations or stiction on the cable or lessening load (the alternator switching states for example) causes it to rise momentarily, then the whole cycle will start again.  The solution is to trim the advance down at the speed site just above idle at closed throttle position, this will cause the engine revs to die back if and when they rise enough to hit that engine speed site.

It is common practice to create this advance 'box' around the idle position. With more sophisticated ECUs the firmware is able to 'target' the required idle and adjust advance on the fly accordingly to retain a rock steady idle regardless of load and temperature.

Dave

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Did I say retarded - Durr I meant advanced.

Mental note - dont post on Techie forums after 10 in the evening !!  ;)

I have found before that you can often quick tweak this (ie without laptop) by rotating the throttle pot a bit.

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