Tickover Trouble

[simonwedge]

Can anyone help with an issue I'm having with the wedge, a 350 with flapper system. I can't get a consistent tickover setup, I can get it ticking over fine but then next time I start it, the tickover is either too low or too high. Probably associaed is that the revs won't die off properly and I'm getting a buzzing from the AFM as if air is gettng dragged past the flap and stopping it from closing. Performance through the rest of the rev range is fine. Things I have tried: 1. Sealed plenum base with silicone, 2. Put jubilee clips on all air pipes, 3. New breathers, 4. Tried different AFM, 5. Set throttle pot and over-run valve to values stated on EFI pages site, 6. New distributor cap, rotor arm and plug leads, 7. Checked and adjusted throttle disc clearance in plenum.

Any ideas?

[2mad]

Could be a faulty module located on the distributor or plug leads.

[1 Finger Bandit]

Hi Simon
I have a spare module for the side of the distributor if you want to try
Cheers Shaun

[adam quantrill]

Sticking throttle cable or linkage - if you tap the throttle does is settle down to the low idle?

Check the throttle cable for fraying at the pedal end.

[simonwedge]

Shaun - that would be great thanks, I'll give you a call and nip over sometime soon.

Adam - new throttle cable as well, smooooth as silk!

[keatsie]

Check the voltage from the throttle position sensor, make sure you get a good progression from idle to about 4.5v wide open.

[blaineuk]

just get a 400. woth hot wire, problem solved.;)

[honestjohntoo]

simonwedge said:

can't get a consistent tickover setup, I can get it ticking over fine but then next time I start it, the tickover is either too low or too high. Probably associaed is that the revs won't die off properly and I'm getting a buzzing from the AFM as if air is gettng dragged past the flap and stopping it from closing

It seem to me you have a combination of two fault conditions.

"Idle speed hang-up", and a "Rogue air leak into the Plenum".

The first can be due to many things, mostly friction related or possibly goo in the throttle disc area, or even maladjustment of the disc/tunnel fit. Click here for a treaty on all the possibilities, but adapt its contents for a single plenum.

The latter cannot always be addressed by simple visual inspection + a can of "EasyStart". One often needs to perform a thorough dynamic test process to check out all the possible air entry points as fully described here Do the tests exactly as described to be sure of missing nothing out.

There is actually a third possibility, thinking about it! A dodgy engine earth connection at the rear of the engine block, behind and below the LH rocker cover, can upset the CTS readings as seen by the ECU, which in turn can play silly bujjers with smooth idling/running The same might be true with any other dodgy connector around the other Efi sensor components, so always worth giving the Efi loom a good wriggling to see if anything shows up. Not too much to take in, I hope?

[simonwedge]

blaineuk said:

just get a 400. woth hot wire, problem solved.;)

There's always a smarta**e isn't there!

[simonwedge]

Right, looks like a full diagnostic session is on the cards! Anyone not too far away from Nuneaton got an external tachometer and CO meter I can borrow?

[honestjohntoo]

simonwedge said:

Right, looks like a full diagnostic session is on the cards!

Way to Go! Indeed, one wonders just how many Rover based Efi system owners are running around with under performing engines and to that end, one can recommend a further fully comprehensive program designed specifically for the basic Flapper arrangement, to maximise the available Power or to simply use the same program (or parts of it) as a routine health check.

Performed just once, it will transform performance of a neglected or maladjusted Efi system, and checked routinely there-after, say annually or biennially, keep things tickety-boo.

It also has the benefit of familiarising an inexperienced owner with the vagaries of the system that for many of us seems distinctly like a black art.

Interested? Go here! Experienced owners? Errors and Omissions welcome!

[350zwelgje]

Once was I was advised to take out the CO-adjuster (located on the AFM) completely and clean it. My problem (not able to adjust idle and CO) was sorted.... Simple, straightforward and perhaps of use to you.

Rob