Idling problem 2.8 V6

[niels]

Hi,

I'm recently experiencing some problems with my s1. When the engine is getting warmed up, the idling speed drops to about 700/750 rpm. (which is too low for me). I can't adjust it aswell. The engine runs fine apart from that.

Any ideas?

Thanks & regards,

niels
S1
netherlands

[james280779]

I had the same prob except mine dropped to 500 then cut out,

All had to do was adjust screw, did not do it myself as I could not find the problem, just what mechanic said then after about 2 hours of head scratching it turned out to be that.
I believe its around the injection system but someone else can prob tell you which one I mean.

sorry for not being alot of help

james

[Le TVR]

The idle adjust is under the throttle body. Needs a large flat screwdriver to turn it.
If that isnt the problem it is worth checking if the flap in the air meter unit is clean and that there are no air leaks to the inlet hoses.

[bigtalljim]

As with the above, I had loads of trouble with my S1 running for ages and can suggest the following list to check in order
1. check the plate in the air/fuel unit, adjust if necessary.
1b. check timing as this can effect idle speed.
2. get engine warmed up and adjust the idle screw under the throttle butterfly, large flat screwdriver
3. if on checking the sparks exhaust etc its too rich or lean. Soot on exhaust a good sign its rich. Adjust mixture very slightly and adjust idle screw to match.

after a bit of fine tune this will sort it out lovely.

good luck, i spent weeks trying to sort high tickover only to find the throttle stop had been adjusted too much and wasnt closing the throttle full

[niels]

thanks for all the help gents

If I turn the idle-adjustment screw under the throttle, not much happens...But I think it has to do with something else.

I checked the 2 connectors (I don't know what they do, but I think one of them is connected to the auxilairy air device, the other is connected close to the throttle mechanism)..

And suddenly...

when I disconnected them and used some contact-spray, the engine idled normally again. Idle adjustment works again.. So I think everything is fine again. But when I drive off, the engine sputters at 3000 rpm, like there's some kind of rev-limiter...

So I get back under the bonnet again.. disconnect and connect the 2 connectors again... and it runs fine again... but the idle speed is gone again...

So I tried both connectors with the engine running... but now nothing happens... It keeps struggling at 700-750 rpm..

I'm back where I started again...

Could this have something to do with the auxilairy air device ?? The problem occurs when the engine is warm (so automatic choke is off)..

Hope you can help! thanks!

Niels
S1
Netherlands

[Le TVR]

There are 2 units powered via the fuel pump relay:

- Aux air device
- Warm up regulator

The Aux air device is to increase the air intake (and rpm) when cold.
The warm up regulator is to control the injection pressure to give a richer mixture when cold.

Both units have electric heaters in them. So if you disconnect/reconnect the effect is not instant, it may take several seconds or longer to stabilise.
Also both units can be heated by the engine heat and disconnecting when the engine is hot may have little effect.

I would guess the problem is related to the Aux air device as this has a big effect on idle rpm.

BUT remember that all these are powered by the fuel pump relay (which is not the most reliable......)

ie problem with fuelpump relay = Aux air device + Warm up regulator + fuel pump = too much load!

As a rough guide these 2 units should read about 20-30 ohms across the terminals if OK.

The warm up regulator could be the source of the 3000 rpm rough running as the injection pressure would be too low if the volts are lost or low.

>> Edited by Le TVR on Monday 9th January 15:29

[niels]

Thanks LeTVR!

I did the engine fault table check in the Bible and it resulted in the same 2 possible causes..

But It will be good to check the relay first.

Cheers

Niels